From 143cd2a21b547b0f92f5ebb4816ffdd8d9ba0fa9 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Thu, 21 Jun 2018 17:12:35 -0700
Subject: [PATCH 01/34] WIP

---
 amp.php                                       | 50 ++++++++++++++++---
 includes/class-amp-theme-support.php          | 49 +++++++++++++-----
 .../options/class-amp-options-manager.php     | 20 ++++----
 includes/options/class-amp-options-menu.php   | 36 ++++++++++---
 tests/test-class-amp-theme-support.php        | 14 +++---
 5 files changed, 124 insertions(+), 45 deletions(-)

diff --git a/amp.php b/amp.php
index ef419328c96..43542fb3669 100644
--- a/amp.php
+++ b/amp.php
@@ -272,15 +272,36 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
 }
 
 /**
- * Whether this is in 'canonical mode.'
+ * Whether this is in 'canonical mode'.
  *
- * Themes can register support for this with `add_theme_support( 'amp' )`.
- * Then, this will change the plugin from 'paired mode,' and it won't use its own templates.
- * Nor output frontend markup like the 'rel' link. If the theme registers support for AMP with:
- * `add_theme_support( 'amp', array( 'template_dir' => 'my-amp-templates' ) )`
- * it will retain 'paired mode.
+ * Themes can register support for this with `add_theme_support( 'amp' )`, or via the
+ * following so that only so that single blog posts will be native/canonical, pages are paired,
+ * and everything else has AMP unavailable:
  *
- * @return boolean Whether this is in AMP 'canonical mode'.
+ *      add_theme_support( 'amp', array(
+ *          'template_dir'       => 'amp-templates/', // Optional. In case you need to override the template as a whole.
+ *          'available_callback' => function() {
+ *              // @todo Warning: If a plugin or theme calls is_amp_endpoint() before parse_query() then the conditionals will not work!
+ *              if ( is_single() ) {
+ *                  return 'native';
+ *              } elseif ( is_page() ) {
+ *                  return 'paired'; // Or 'true'.
+ *              } else {
+ *                  return false;
+ *              }
+ *          },
+ *      ) );
+ *
+ * Then, this will change the plugin so that it won't run in 'paired mode' with separate URLs.
+ * Neither will it output the rel=amphtml link on the frontend.
+ *
+ * Paired mode will be retained if the theme registers support for AMP with just a template_dir and no available_callback:
+ *
+ *     add_theme_support( 'amp', array(
+ *         'template_dir' => 'my-amp-templates',
+ *     ) );
+ *
+ * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
 function amp_is_canonical() {
 	$support = get_theme_support( 'amp' );
@@ -289,9 +310,22 @@ function amp_is_canonical() {
 	}
 	if ( is_array( $support ) ) {
 		$args = array_shift( $support );
-		if ( empty( $args['template_dir'] ) ) {
+
+		$is_native = (
+			isset( $args['available_callback'] )
+			&&
+			is_callable( $args['available_callback'] )
+			&&
+			'native' === call_user_func( $args['available_callback'] )
+		);
+		if ( $is_native ) {
 			return true;
 		}
+
+		// If there is no available_callback and yet there is a template_dir, then paired mode is implied.
+		if ( empty( $args['available_callback'] ) && ! empty( $args['template_dir'] ) ) {
+			return false;
+		}
 	}
 	return false;
 }
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 7389490b2bb..a43189097ab 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -24,7 +24,7 @@ class AMP_Theme_Support {
 	 *
 	 * @var string
 	 */
-	const RESPONSE_CACHE_GROUP = 'amp-reponse';
+	const RESPONSE_CACHE_GROUP = 'amp-response';
 
 	/**
 	 * Sanitizer classes.
@@ -148,8 +148,24 @@ public static function apply_options() {
 			$args = array(
 				'__added_via_option' => true,
 			);
-			if ( 'paired' === $theme_support_option ) {
-				$args['template_dir'] = './';
+			if ( 'native' === $theme_support_option ) {
+				$args['available_callback'] = function() {
+					/**
+					 * Queried object.
+					 *
+					 * @var WP_Post $queried_object
+					 */
+					$queried_object = get_queried_object();
+					if ( is_singular() && post_supports_amp( $queried_object ) ) {
+						return 'native';
+					}
+
+					if ( AMP_Options_Manager::get_option( 'non_singular_supported' ) ) {
+						return 'native';
+					}
+
+					return false;
+				};
 			}
 			add_theme_support( 'amp', $args );
 		}
@@ -168,8 +184,9 @@ public static function finish_init() {
 
 		self::ensure_proper_amp_location();
 
-		if ( ! amp_is_canonical() ) {
-			self::register_paired_hooks();
+		$theme_support = get_theme_support( 'amp' );
+		if ( ! empty( $theme_support[0]['template_dir'] ) ) {
+			self::add_amp_template_filters();
 		}
 
 		self::add_hooks();
@@ -285,8 +302,14 @@ public static function is_paired_available() {
 		$args = array_shift( $support );
 
 		if ( isset( $args['available_callback'] ) && is_callable( $args['available_callback'] ) ) {
-			return call_user_func( $args['available_callback'] );
+			/*
+			 * The available_callback here will return a bool or the string 'paired'.
+			 * If it returns 'native' then `amp_is_canonical()` above would have short-circuited.
+			 */
+			return (bool) call_user_func( $args['available_callback'] );
 		}
+
+		// This is the same as if there is a template_dir defined with no available_callback.
 		return true;
 	}
 
@@ -303,13 +326,13 @@ public static function is_customize_preview_iframe() {
 	}
 
 	/**
-	 * Register hooks for paired mode.
+	 * Register filters for loading AMP-specific templates.
 	 */
-	public static function register_paired_hooks() {
+	public static function add_amp_template_filters() {
 		foreach ( self::$template_types as $template_type ) {
-			add_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_paired_template_hierarchy' ) );
+			add_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
 		}
-		add_filter( 'template_include', array( __CLASS__, 'filter_paired_template_include' ), 100 );
+		add_filter( 'template_include', array( __CLASS__, 'filter_amp_template_include' ), 100 );
 	}
 
 	/**
@@ -727,7 +750,7 @@ public static function amend_comment_form() {
 	 * @param array $templates Template hierarchy.
 	 * @return array Templates.
 	 */
-	public static function filter_paired_template_hierarchy( $templates ) {
+	public static function filter_amp_template_hierarchy( $templates ) {
 		$support = get_theme_support( 'amp' );
 		$args    = array_shift( $support );
 		if ( isset( $args['template_dir'] ) ) {
@@ -749,8 +772,8 @@ public static function filter_paired_template_hierarchy( $templates ) {
 	 * @param string $template Template to include.
 	 * @return string Template to include.
 	 */
-	public static function filter_paired_template_include( $template ) {
-		if ( empty( $template ) || ! self::is_paired_available() ) {
+	public static function filter_amp_template_include( $template ) {
+		if ( empty( $template ) ) {
 			wp_safe_redirect( self::get_current_canonical_url(), 302 ); // Temporary redirect because support may come later.
 			exit;
 		}
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 7e0fbf4018e..c41ce3acdc7 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -23,12 +23,13 @@ class AMP_Options_Manager {
 	 * @var array
 	 */
 	protected static $defaults = array(
-		'theme_support'        => 'disabled',
-		'supported_post_types' => array(),
-		'analytics'            => array(),
-		'force_sanitization'   => false,
-		'accept_tree_shaking'  => false,
-		'disable_admin_bar'    => false,
+		'theme_support'          => 'disabled',
+		'supported_post_types'   => array(),
+		'analytics'              => array(),
+		'force_sanitization'     => false,
+		'accept_tree_shaking'    => false,
+		'disable_admin_bar'      => false,
+		'non_singular_supported' => true,
 	);
 
 	/**
@@ -116,9 +117,10 @@ public static function validate_options( $new_options ) {
 			$options['theme_support'] = $new_options['theme_support'];
 		}
 
-		$options['force_sanitization']  = ! empty( $new_options['force_sanitization'] );
-		$options['accept_tree_shaking'] = ! empty( $new_options['accept_tree_shaking'] );
-		$options['disable_admin_bar']   = ! empty( $new_options['disable_admin_bar'] );
+		$options['force_sanitization']     = ! empty( $new_options['force_sanitization'] );
+		$options['accept_tree_shaking']    = ! empty( $new_options['accept_tree_shaking'] );
+		$options['disable_admin_bar']      = ! empty( $new_options['disable_admin_bar'] );
+		$options['non_singular_supported'] = ! empty( $new_options['non_singular_supported'] );
 
 		// Validate post type support.
 		if ( isset( $new_options['supported_post_types'] ) ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index f3e51f34f7b..2c5eb81f3fc 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -99,9 +99,9 @@ public function add_menu_items() {
 		);
 
 		add_settings_field(
-			'supported_post_types',
-			__( 'Post Type Support', 'amp' ),
-			array( $this, 'render_post_types_support' ),
+			'supported_queries',
+			__( 'Supported Queries', 'amp' ),
+			array( $this, 'render_supported_queries' ),
 			AMP_Options_Manager::OPTION_NAME,
 			'general',
 			array(
@@ -276,16 +276,36 @@ public function render_validation_handling() {
 	 *
 	 * @since 0.6
 	 */
-	public function render_post_types_support() {
-		$builtin_support = AMP_Post_Type_Support::get_builtin_supported_post_types();
-		$element_name    = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]';
+	public function render_supported_queries() {
 		?>
 		<script>
 			jQuery( 'input[type=radio][name="amp-options[theme_support]"]' ).change( function() {
-				jQuery( '.amp-post-type-support-field' ).toggleClass( 'hidden', 'paired' !== this.value && 'disabled' !== this.value );
+				jQuery( 'fieldset.non_singular_supported' ).toggleClass( 'hidden', 'disabled' === this.value );
 			} ).filter( ':checked' ).trigger( 'change' );
 		</script>
+
+		<fieldset class="non_singular_supported">
+			<p>
+				<label for="non_singular_supported">
+					<input id="non_singular_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[non_singular_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'non_singular_supported' ) ); ?>>
+					<?php esc_html_e( 'Serve non-singular templates as AMP.', 'amp' ); ?>
+				</label>
+			</p>
+			<p class="description">
+				<?php esc_html_e( 'Non-singular means templates like categories, date archives, author pages, and so on.', 'amp' ); ?>
+			</p>
+		</fieldset>
+
 		<fieldset>
+			<?php
+			$builtin_support = AMP_Post_Type_Support::get_builtin_supported_post_types();
+			$element_name    = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]';
+			?>
+			<legend>
+				<h2 class="title"><?php esc_html_e( 'Post Types', 'amp' ); ?></h2>
+			</legend>
+
+			<!-- TODO Checkbox to allow other queries -->
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
 				<?php
 				$element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}";
@@ -299,7 +319,7 @@ public function render_post_types_support() {
 					id="<?php echo esc_attr( $element_id ); ?>"
 					name="<?php echo esc_attr( $element_name ); ?>"
 					value="<?php echo esc_attr( $post_type->name ); ?>"
-					<?php checked( true, amp_is_canonical() || post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
+					<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
 					<?php disabled( $is_builtin ); ?>
 					>
 				<label for="<?php echo esc_attr( $element_id ); ?>">
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index c95c016311b..07d64cee04a 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -298,7 +298,7 @@ public function test_is_customize_preview_iframe() {
 	/**
 	 * Test register_paired_hooks.
 	 *
-	 * @covers AMP_Theme_Support::register_paired_hooks()
+	 * @covers AMP_Theme_Support::add_amp_template_filters()
 	 */
 	public function test_register_paired_hooks() {
 		$template_types = array(
@@ -309,7 +309,7 @@ public function test_register_paired_hooks() {
 			'author',
 			'category',
 		);
-		AMP_Theme_Support::register_paired_hooks();
+		AMP_Theme_Support::add_amp_template_filters();
 		foreach ( $template_types as $template_type ) {
 			$this->assertEquals( 10, has_filter( "{$template_type}_template_hierarchy", array( self::TESTED_CLASS, 'filter_paired_template_hierarchy' ) ) );
 		}
@@ -761,7 +761,7 @@ public function test_amend_comment_form() {
 	/**
 	 * Test filter_paired_template_hierarchy.
 	 *
-	 * @covers AMP_Theme_Support::filter_paired_template_hierarchy()
+	 * @covers AMP_Theme_Support::filter_amp_template_hierarchy()
 	 */
 	public function test_filter_paired_template_hierarchy() {
 		$template_dir = 'amp-templates';
@@ -773,7 +773,7 @@ public function test_filter_paired_template_hierarchy() {
 			'single-post.php',
 			'single.php',
 		);
-		$filtered_templates = AMP_Theme_Support::filter_paired_template_hierarchy( $templates );
+		$filtered_templates = AMP_Theme_Support::filter_amp_template_hierarchy( $templates );
 		foreach ( $filtered_templates as $key => $filtered_template ) {
 			$this->assertEquals( $template_dir . '/' . $templates[ $key ], $filtered_template );
 		}
@@ -782,7 +782,7 @@ public function test_filter_paired_template_hierarchy() {
 	/**
 	 * Test filter_paired_template_include.
 	 *
-	 * @covers AMP_Theme_Support::filter_paired_template_include()
+	 * @covers AMP_Theme_Support::filter_amp_template_include()
 	 */
 	public function test_filter_paired_template_include() {
 		$template_dir = 'amp-templates';
@@ -790,10 +790,10 @@ public function test_filter_paired_template_include() {
 		add_theme_support( 'amp', array(
 			'template_dir' => $template_dir,
 		) );
-		$this->assertEquals( $template, AMP_Theme_Support::filter_paired_template_include( $template ) );
+		$this->assertEquals( $template, AMP_Theme_Support::filter_amp_template_include( $template ) );
 		remove_theme_support( 'amp' );
 		try {
-			AMP_Theme_Support::filter_paired_template_include( $template );
+			AMP_Theme_Support::filter_amp_template_include( $template );
 		} catch ( Exception $exception ) {
 			$e = $exception;
 		}

From 6149da1c6bbc283cb8f1dc91d66563e6084004ca Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 24 Jun 2018 14:42:05 -0700
Subject: [PATCH 02/34] WIP2

---
 amp.php                              | 53 +++++++++++++------------
 includes/amp-helper-functions.php    | 58 +++++++++++++++++++++-------
 includes/class-amp-theme-support.php |  5 +++
 3 files changed, 76 insertions(+), 40 deletions(-)

diff --git a/amp.php b/amp.php
index 43542fb3669..8090d1e422d 100644
--- a/amp.php
+++ b/amp.php
@@ -279,28 +279,26 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  * and everything else has AMP unavailable:
  *
  *      add_theme_support( 'amp', array(
- *          'template_dir'       => 'amp-templates/', // Optional. In case you need to override the template as a whole.
- *          'available_callback' => function() {
- *              // @todo Warning: If a plugin or theme calls is_amp_endpoint() before parse_query() then the conditionals will not work!
- *              if ( is_single() ) {
- *                  return 'native';
- *              } elseif ( is_page() ) {
- *                  return 'paired'; // Or 'true'.
- *              } else {
- *                  return false;
- *              }
- *          },
+ *          'available_callback' => 'is_single',
  *      ) );
  *
  * Then, this will change the plugin so that it won't run in 'paired mode' with separate URLs.
- * Neither will it output the rel=amphtml link on the frontend.
+ * Neither will it output the rel=amphtml link on the frontend. To serve a site in paired mode, add the paired arg:
  *
- * Paired mode will be retained if the theme registers support for AMP with just a template_dir and no available_callback:
+ *      add_theme_support( 'amp', array(
+ *          'paired' => true,
+ *          'available_callback' => 'is_single',
+ *      ) );
+ *
+ * Paired mode will also be retained if the theme registers support for AMP with just a template_dir and no available_callback:
  *
  *     add_theme_support( 'amp', array(
  *         'template_dir' => 'my-amp-templates',
  *     ) );
  *
+ * @todo Why do we even need this function?
+ * @see \AMP_Theme_Support::is_paired_available()
+ *
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
 function amp_is_canonical() {
@@ -308,27 +306,31 @@ function amp_is_canonical() {
 	if ( true === $support ) {
 		return true;
 	}
+
 	if ( is_array( $support ) ) {
 		$args = array_shift( $support );
 
-		$is_native = (
-			isset( $args['available_callback'] )
-			&&
-			is_callable( $args['available_callback'] )
-			&&
-			'native' === call_user_func( $args['available_callback'] )
-		);
-		if ( $is_native ) {
-			return true;
+		// If paired arg is supplied, then it is never canonical.
+		if ( ! empty( $args['paired'] ) ) {
+			return false;
 		}
 
-		// If there is no available_callback and yet there is a template_dir, then paired mode is implied.
-		if ( empty( $args['available_callback'] ) && ! empty( $args['template_dir'] ) ) {
+		// If there is a template_dir, then paired mode is implied.
+		if ( ! empty( $args['template_dir'] ) ) {
 			return false;
 		}
+//
+//		// Otherwise, the available_callback dictates whether AMP is available.
+//		if ( isset( $args['available_callback'] ) && is_callable( $args['available_callback'] ) ) {
+//			return call_user_func( $args['available_callback'] );
+//		}
 	}
-	return false;
+	return true;
 }
+//
+//function amp_is_available() {
+//
+//}
 
 /**
  * Load classes.
@@ -460,6 +462,7 @@ function _amp_bootstrap_customizer() {
 
 /**
  * Redirects the old AMP URL to the new AMP URL.
+ *
  * If post slug is updated the amp page with old post slug will be redirected to the updated url.
  *
  * @since 0.5
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index a5cc1e25626..254c264f993 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -243,10 +243,6 @@ function amp_add_amphtml_link() {
  * @return bool Whether the post supports AMP.
  */
 function post_supports_amp( $post ) {
-	if ( amp_is_canonical() ) {
-		return true;
-	}
-
 	$errors = AMP_Post_Type_Support::get_support_errors( $post );
 
 	// Return false if an error is found.
@@ -261,9 +257,9 @@ function post_supports_amp( $post ) {
 		case AMP_Post_Meta_Box::DISABLED_STATUS:
 			return false;
 
-		// Disabled by default for custom page templates, page on front and page for posts.
+		// Disabled by default for custom page templates, page on front and page for posts, unless 'amp' theme support is present.
 		default:
-			$enabled = (
+			$enabled = current_theme_supports( 'amp' ) || (
 				! (bool) get_page_template_slug( $post )
 				&&
 				! (
@@ -291,10 +287,12 @@ function post_supports_amp( $post ) {
 }
 
 /**
- * Are we currently on an AMP URL?
+ * Determine whether the current response being served as AMP.
  *
- * @since 1.0 This function can be called before the `parse_query` action because the 'amp' query var is specifically and exclusively used when 'amp' theme support is added.
+ * This function cannot be called before the parse_query action because it needs to be able
+ * to determine the queried object is able to be served as AMP.
  *
+ * @see is_header_video_active()
  * @return bool Whether it is the AMP endpoint.
  */
 function is_amp_endpoint() {
@@ -302,17 +300,47 @@ function is_amp_endpoint() {
 		return false;
 	}
 
-	// When 'amp' theme support is (or will be added) then these are the conditions that are key to be checked.
-	if ( amp_is_canonical() || isset( $_GET[ amp_get_slug() ] ) ) { // WPCS: CSRF OK.
-		return true;
+	$did_parse_query = did_action( 'parse_query' );
+
+	if ( ! $did_parse_query ) {
+		_doing_it_wrong( __FUNCTION__, sprintf( esc_html__( "is_amp_endpoint() was called before the 'parse_query' hook was called. This function will always return 'false' before the 'parse_query' hook is called.", 'amp' ) ), '0.4.2' );
+	}
+
+	$has_amp_query_var = (
+		isset( $_GET[ amp_get_slug() ] ) // WPCS: CSRF OK.
+		||
+		false !== get_query_var( amp_get_slug(), false )
+	);
+
+	// When there is no query var and AMP is not canonical/native, then this is definitely not an AMP endpoint.
+	if ( ! $has_amp_query_var && ! amp_is_canonical() ) {
+		return false;
 	}
 
-	// Condition for non-theme support when /amp/ endpoint is used.
-	if ( false !== get_query_var( amp_get_slug(), false ) ) {
-		return true;
+	/*
+	 * If theme suport is present and there is available_callback, it is what determines whether this is
+	 * an AMP endpoint. The available_callback is is presumed to check post_supports_amp().
+	 * @todo Should available_callback take a WP_Query as its arg? We need to be able to determine whether AMP is supported for another URL.
+	 * @todo Should this not be a filter?
+	 */
+	if ( current_theme_supports( 'amp' ) ) {
+		$args = get_theme_support( 'amp' );
+		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
+			return call_user_func( $args[0]['available_callback'] );
+		}
+	}
+
+	// When there is no theme support, then
+	if ( $did_parse_query ) {
+		$queried_object = get_queried_object();
+		return (
+			is_singular() && $queried_object instanceof WP_Post && post_supports_amp( $queried_object )
+			||
+			! is_singular() && AMP_Options_Manager::get_option( 'non_singular_supported' )
+		);
 	}
 
-	return false;
+	return true;
 }
 
 /**
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index a43189097ab..36cec33def1 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -281,6 +281,7 @@ public static function redirect_ampless_url( $exit = true ) {
 	 * Returns true when there is a template_dir defined in theme support, and if a defined available_callback
 	 * returns true.
 	 *
+	 * @see amp_is_canonical()
 	 * @return bool Whether available.
 	 */
 	public static function is_paired_available() {
@@ -299,6 +300,10 @@ public static function is_paired_available() {
 			return false;
 		}
 
+		if ( ! is_singular() && ! AMP_Options_Manager::get_option( 'non_singular_supported' ) ) {
+			return false;
+		}
+
 		$args = array_shift( $support );
 
 		if ( isset( $args['available_callback'] ) && is_callable( $args['available_callback'] ) ) {

From fab22d437d11066074ba488e3cec65e472d31432 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Tue, 26 Jun 2018 16:13:27 -0700
Subject: [PATCH 03/34] WIP3

---
 includes/amp-helper-functions.php             | 63 ++++++++++++++-----
 includes/class-amp-post-type-support.php      | 17 +++++
 .../options/class-amp-options-manager.php     | 17 ++---
 includes/options/class-amp-options-menu.php   | 56 ++++++++++++-----
 4 files changed, 116 insertions(+), 37 deletions(-)

diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 254c264f993..f4a4491647e 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -317,30 +317,61 @@ function is_amp_endpoint() {
 		return false;
 	}
 
-	/*
-	 * If theme suport is present and there is available_callback, it is what determines whether this is
-	 * an AMP endpoint. The available_callback is is presumed to check post_supports_amp().
-	 * @todo Should available_callback take a WP_Query as its arg? We need to be able to determine whether AMP is supported for another URL.
-	 * @todo Should this not be a filter?
-	 */
+	// Otherwise, it is an AMP endpoint if AMP is available.
+	return amp_get_availability();
+}
+
+/**
+ * Determine availability of AMP for the given query.
+ *
+ * @since 1.0
+ * @global WP_Query $wp_the_query
+ *
+ * @param WP_Query|null $query Query. If null then the global query will be used.
+ * @return bool Whether AMP is available.
+ */
+function amp_get_availability( $query = null ) {
+	global $wp_the_query;
+	if ( ! $query ) {
+		$query = $wp_the_query;
+	}
+
+	if ( ! ( $query instanceof WP_Query ) ) {
+		_doing_it_wrong( __FUNCTION__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
+		return false;
+	}
+
+	$available = null;
 	if ( current_theme_supports( 'amp' ) ) {
 		$args = get_theme_support( 'amp' );
 		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
-			return call_user_func( $args[0]['available_callback'] );
+			$callback = $args[0]['available_callback'];
+
+			// If the available_callback is a method on the query, then call the method on the query itself.
+			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
+				$available = call_user_func( array( $query, $callback ) );
+			} else {
+				$available = call_user_func( $callback );
+			}
 		}
 	}
 
-	// When there is no theme support, then
-	if ( $did_parse_query ) {
-		$queried_object = get_queried_object();
-		return (
-			is_singular() && $queried_object instanceof WP_Post && post_supports_amp( $queried_object )
-			||
-			! is_singular() && AMP_Options_Manager::get_option( 'non_singular_supported' )
-		);
+	// Availability has been is programmatically determined via the available_callback.
+	if ( is_bool( $available ) ) {
+		return $available;
 	}
 
-	return true;
+	if ( $query->is_singular() ) {
+		/**
+		 * Post.
+		 *
+		 * @var WP_Post $queried_object
+		 */
+		$queried_object = $query->get_queried_object();
+		return post_supports_amp( $queried_object ); // @todo FAIL: This is calling get_support_errors(), and get_support_errors() is calling amp_get_availability().
+	} else {
+		return (bool) AMP_Options_Manager::get_option( 'non_singular_supported' ); // @todo Consider other kinds of queries.
+	}
 }
 
 /**
diff --git a/includes/class-amp-post-type-support.php b/includes/class-amp-post-type-support.php
index 22a1bef580b..cc74157d379 100644
--- a/includes/class-amp-post-type-support.php
+++ b/includes/class-amp-post-type-support.php
@@ -94,6 +94,23 @@ public static function get_support_errors( $post ) {
 			$errors[] = 'skip-post';
 		}
 
+		$query = new WP_Query();
+
+		$query->queried_object    = $post;
+		$query->queried_object_id = $post->ID;
+		if ( 'page' === $post->post_type ) {
+			$query->set( 'post_id', $post->ID );
+		} else {
+			$query->set( 'p', $post->ID );
+		}
+		$query->parse_query();
+
+		$availability = amp_get_availability( $query );
+		if ( ! $availability ) {
+			$errors[] = '';
+		}
+
+
 		return $errors;
 	}
 }
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index c41ce3acdc7..099975b8cc0 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -23,13 +23,16 @@ class AMP_Options_Manager {
 	 * @var array
 	 */
 	protected static $defaults = array(
-		'theme_support'          => 'disabled',
-		'supported_post_types'   => array(),
-		'analytics'              => array(),
-		'force_sanitization'     => false,
-		'accept_tree_shaking'    => false,
-		'disable_admin_bar'      => false,
-		'non_singular_supported' => true,
+		'theme_support'           => 'disabled',
+		'supported_post_types'    => array(),
+		'analytics'               => array(),
+		'force_sanitization'      => false,
+		'accept_tree_shaking'     => false,
+		'disable_admin_bar'       => false,
+		'all_templates_supported' => false,
+		'supported_templates'     => array(
+			'single',
+		),
 	);
 
 	/**
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 2c5eb81f3fc..a953786bd78 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -99,13 +99,13 @@ public function add_menu_items() {
 		);
 
 		add_settings_field(
-			'supported_queries',
-			__( 'Supported Queries', 'amp' ),
-			array( $this, 'render_supported_queries' ),
+			'supported_templates',
+			__( 'Supported Templates', 'amp' ),
+			array( $this, 'render_supported_templates' ),
 			AMP_Options_Manager::OPTION_NAME,
 			'general',
 			array(
-				'class' => 'amp-post-type-support-field',
+				'class' => 'amp-template-support-field',
 			)
 		);
 
@@ -272,23 +272,23 @@ public function render_validation_handling() {
 	}
 
 	/**
-	 * Post types support section renderer.
+	 * Supported templates section renderer.
 	 *
-	 * @since 0.6
+	 * @since 1.0
 	 */
-	public function render_supported_queries() {
+	public function render_supported_templates() {
 		?>
 		<script>
 			jQuery( 'input[type=radio][name="amp-options[theme_support]"]' ).change( function() {
-				jQuery( 'fieldset.non_singular_supported' ).toggleClass( 'hidden', 'disabled' === this.value );
+				jQuery( 'fieldset.non_singular_supported, fieldset.all_templates_supported' ).toggleClass( 'hidden', 'disabled' === this.value );
 			} ).filter( ':checked' ).trigger( 'change' );
 		</script>
 
-		<fieldset class="non_singular_supported">
+		<fieldset class="all_templates_supported">
 			<p>
-				<label for="non_singular_supported">
-					<input id="non_singular_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[non_singular_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'non_singular_supported' ) ); ?>>
-					<?php esc_html_e( 'Serve non-singular templates as AMP.', 'amp' ); ?>
+				<label for="all_templates_supported">
+					<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
+					<?php esc_html_e( 'Serve all templates as AMP regardless of what is being queried.', 'amp' ); ?>
 				</label>
 			</p>
 			<p class="description">
@@ -302,10 +302,9 @@ public function render_supported_queries() {
 			$element_name    = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]';
 			?>
 			<legend>
-				<h2 class="title"><?php esc_html_e( 'Post Types', 'amp' ); ?></h2>
+				<h2 class="title"><?php esc_html_e( 'Single Templates', 'amp' ); ?></h2>
 			</legend>
 
-			<!-- TODO Checkbox to allow other queries -->
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
 				<?php
 				$element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}";
@@ -331,6 +330,35 @@ public function render_supported_queries() {
 				<?php esc_html_e( 'Select the content types that you would like to be made available in AMP.', 'amp' ); ?>
 			</p>
 		</fieldset>
+
+		<?php
+		// This is inspired by Jetpack's Widget Conditions.
+		$templates = array(
+			'page' => array(
+				'front' => array(),
+				'posts' => array(),
+				'date'  => array(),
+			),
+			'author' => array(
+				'' => __( 'All author pages', 'amp' ),
+			),
+			'category' => array(
+				'' => __( 'All category pages', 'amp' ),
+			)
+		);
+		?>
+
+		<fieldset class="non_singular_supported">
+			<p>
+				<label for="non_singular_supported">
+					<input id="non_singular_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[non_singular_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'non_singular_supported' ) ); ?>>
+					<?php esc_html_e( 'Serve non-singular templates as AMP.', 'amp' ); ?>
+				</label>
+			</p>
+			<p class="description">
+				<?php esc_html_e( 'Non-singular means templates like categories, date archives, author pages, and so on.', 'amp' ); ?>
+			</p>
+		</fieldset>
 		<?php
 	}
 

From 718e643bd05e9df73d83e7889610e371353bb722 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 12:40:15 -0700
Subject: [PATCH 04/34] WIP4

---
 amp.php                                     |  10 --
 includes/admin/class-amp-post-meta-box.php  |   2 -
 includes/amp-helper-functions.php           |  59 ++-------
 includes/class-amp-post-type-support.php    |  17 ---
 includes/class-amp-theme-support.php        | 128 +++++++++++++++++---
 includes/options/class-amp-options-menu.php |  41 +++++--
 6 files changed, 151 insertions(+), 106 deletions(-)

diff --git a/amp.php b/amp.php
index 8090d1e422d..e4aa3a69529 100644
--- a/amp.php
+++ b/amp.php
@@ -296,7 +296,6 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *         'template_dir' => 'my-amp-templates',
  *     ) );
  *
- * @todo Why do we even need this function?
  * @see \AMP_Theme_Support::is_paired_available()
  *
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
@@ -319,18 +318,9 @@ function amp_is_canonical() {
 		if ( ! empty( $args['template_dir'] ) ) {
 			return false;
 		}
-//
-//		// Otherwise, the available_callback dictates whether AMP is available.
-//		if ( isset( $args['available_callback'] ) && is_callable( $args['available_callback'] ) ) {
-//			return call_user_func( $args['available_callback'] );
-//		}
 	}
 	return true;
 }
-//
-//function amp_is_available() {
-//
-//}
 
 /**
  * Load classes.
diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 55842b335ba..71fe1bc39aa 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -170,8 +170,6 @@ public function render_status( $post ) {
 			is_post_type_viewable( $post->post_type )
 			&&
 			current_user_can( 'edit_post', $post->ID )
-			&&
-			! amp_is_canonical()
 		);
 
 		if ( true !== $verify ) {
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index f4a4491647e..04d250d2a37 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -317,60 +317,23 @@ function is_amp_endpoint() {
 		return false;
 	}
 
-	// Otherwise, it is an AMP endpoint if AMP is available.
-	return amp_get_availability();
-}
-
-/**
- * Determine availability of AMP for the given query.
- *
- * @since 1.0
- * @global WP_Query $wp_the_query
- *
- * @param WP_Query|null $query Query. If null then the global query will be used.
- * @return bool Whether AMP is available.
- */
-function amp_get_availability( $query = null ) {
-	global $wp_the_query;
-	if ( ! $query ) {
-		$query = $wp_the_query;
-	}
-
-	if ( ! ( $query instanceof WP_Query ) ) {
-		_doing_it_wrong( __FUNCTION__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
-		return false;
-	}
-
-	$available = null;
-	if ( current_theme_supports( 'amp' ) ) {
-		$args = get_theme_support( 'amp' );
-		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
-			$callback = $args[0]['available_callback'];
-
-			// If the available_callback is a method on the query, then call the method on the query itself.
-			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
-				$available = call_user_func( array( $query, $callback ) );
-			} else {
-				$available = call_user_func( $callback );
-			}
-		}
-	}
-
-	// Availability has been is programmatically determined via the available_callback.
-	if ( is_bool( $available ) ) {
-		return $available;
-	}
-
-	if ( $query->is_singular() ) {
+	// Check if the queried object supports AMP.
+	if ( is_singular() ) {
 		/**
 		 * Post.
 		 *
 		 * @var WP_Post $queried_object
 		 */
-		$queried_object = $query->get_queried_object();
-		return post_supports_amp( $queried_object ); // @todo FAIL: This is calling get_support_errors(), and get_support_errors() is calling amp_get_availability().
+		$queried_object = get_queried_object();
+		if ( ! post_supports_amp( $queried_object ) ) {
+			return false;
+		}
+	}
+
+	if ( current_theme_supports( 'amp' ) ) {
+		return true === AMP_Theme_Support::get_template_availability();
 	} else {
-		return (bool) AMP_Options_Manager::get_option( 'non_singular_supported' ); // @todo Consider other kinds of queries.
+		return false; // Legacy templates only support posts via AMP_Post_Template.
 	}
 }
 
diff --git a/includes/class-amp-post-type-support.php b/includes/class-amp-post-type-support.php
index cc74157d379..22a1bef580b 100644
--- a/includes/class-amp-post-type-support.php
+++ b/includes/class-amp-post-type-support.php
@@ -94,23 +94,6 @@ public static function get_support_errors( $post ) {
 			$errors[] = 'skip-post';
 		}
 
-		$query = new WP_Query();
-
-		$query->queried_object    = $post;
-		$query->queried_object_id = $post->ID;
-		if ( 'page' === $post->post_type ) {
-			$query->set( 'post_id', $post->ID );
-		} else {
-			$query->set( 'p', $post->ID );
-		}
-		$query->parse_query();
-
-		$availability = amp_get_availability( $query );
-		if ( ! $availability ) {
-			$errors[] = '';
-		}
-
-
 		return $errors;
 	}
 }
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 36cec33def1..57644ce47a8 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -337,7 +337,116 @@ public static function add_amp_template_filters() {
 		foreach ( self::$template_types as $template_type ) {
 			add_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
 		}
-		add_filter( 'template_include', array( __CLASS__, 'filter_amp_template_include' ), 100 );
+	}
+
+	/**
+	 * Locate the template for a given query.
+	 *
+	 * @param WP_Query $query Query.
+	 * @return string The template filename if one is located.
+	 */
+	public static function get_query_template( $query ) {
+		foreach ( self::$template_types as $template_type ) {
+			add_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
+		}
+
+		// phpcs:disable -- This is copied from wp-includes/template-loader.php
+		if     ( $query->is_embed()             && $template = get_embed_template()             ) :
+		elseif ( $query->is_404()               && $template = get_404_template()               ) :
+		elseif ( $query->is_search()            && $template = get_search_template()            ) :
+		elseif ( $query->is_front_page()        && $template = get_front_page_template()        ) :
+		elseif ( $query->is_home()              && $template = get_home_template()              ) :
+		elseif ( $query->is_post_type_archive() && $template = get_post_type_archive_template() ) :
+		elseif ( $query->is_tax()               && $template = get_taxonomy_template()          ) :
+		elseif ( $query->is_attachment()        && $template = get_attachment_template()        ) :
+		elseif ( $query->is_single()            && $template = get_single_template()            ) :
+		elseif ( $query->is_page()              && $template = get_page_template()              ) :
+		elseif ( $query->is_singular()          && $template = get_singular_template()          ) :
+		elseif ( $query->is_category()          && $template = get_category_template()          ) :
+		elseif ( $query->is_tag()               && $template = get_tag_template()               ) :
+		elseif ( $query->is_author()            && $template = get_author_template()            ) :
+		elseif ( $query->is_date()              && $template = get_date_template()              ) :
+		elseif ( $query->is_archive()           && $template = get_archive_template()           ) :
+		else :
+			$template = get_index_template();
+		endif;
+		// phpcs:enable
+
+		/** This filter is documented in wp-includes/template-loader.php */
+		$template = apply_filters( 'template_include', $template );
+
+		foreach ( self::$template_types as $template_type ) {
+			remove_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
+		}
+
+		return $template;
+	}
+
+	/**
+	 * Determine template availability of AMP for the given query.
+	 *
+	 * This is not intended to return whether AMP is available for a _specific_ post. For that, use `post_supports_amp()`.
+	 *
+	 * @since 1.0
+	 * @global WP_Query $wp_query
+	 * @see post_supports_amp()
+	 *
+	 * @param WP_Query|WP_Post|null $query Query or queried post. If null then the global query will be used.
+	 * @return true|WP_Error True if template is available, WP_Error if otherwise.
+	 */
+	public static function get_template_availability( $query = null ) {
+		global $wp_query;
+
+		if ( $query instanceof WP_Post ) {
+			$post  = $query;
+			$query = new WP_Query();
+
+			$query->queried_object    = $post;
+			$query->queried_object_id = $post->ID;
+			if ( 'page' === $post->post_type ) {
+				$query->set( 'post_id', $post->ID );
+			} else {
+				$query->set( 'p', $post->ID );
+			}
+			$query->parse_query();
+		} elseif ( ! $query ) {
+			$query = $wp_query;
+		}
+
+		if ( ! ( $query instanceof WP_Query ) ) {
+			_doing_it_wrong( __FUNCTION__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
+			return new WP_Error( 'no_query_available' );
+		}
+
+		if ( ! current_theme_supports( 'amp' ) ) {
+			return new WP_Error( 'no_theme_support' );
+		}
+
+		$args = get_theme_support( 'amp' );
+		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
+			$callback = $args[0]['available_callback'];
+
+			// If the available_callback is a method on the query, then call the method on the query itself.
+			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
+				$available = call_user_func( array( $query, $callback ) );
+			} else {
+				$available = call_user_func( $callback );
+			}
+			if ( false === $available ) {
+				return new WP_Error( 'unavailable_by_callback' );
+			}
+		}
+
+		// Make sure there is a template available for the query in the template_dir if it is defined..
+		if ( ! empty( $args[0]['template_dir'] ) ) {
+			$template = self::get_query_template( $query );
+			if ( empty( $template ) || ! file_exists( $template ) ) {
+				return new WP_Error( 'no_existing_template' );
+			}
+		}
+
+		// If all checks have passed, then the template is available.
+		return true;
 	}
 
 	/**
@@ -768,23 +877,6 @@ public static function filter_amp_template_hierarchy( $templates ) {
 		return $templates;
 	}
 
-	/**
-	 * Redirect to the non-canonical URL when the template to include is empty.
-	 *
-	 * This is a failsafe in case an index.php is not located in the AMP template_dir,
-	 * and the available_callback fails to omit a given request from being available in AMP.
-	 *
-	 * @param string $template Template to include.
-	 * @return string Template to include.
-	 */
-	public static function filter_amp_template_include( $template ) {
-		if ( empty( $template ) ) {
-			wp_safe_redirect( self::get_current_canonical_url(), 302 ); // Temporary redirect because support may come later.
-			exit;
-		}
-		return $template;
-	}
-
 	/**
 	 * Get canonical URL for current request.
 	 *
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index a953786bd78..a0c5e20a1cb 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -292,7 +292,7 @@ public function render_supported_templates() {
 				</label>
 			</p>
 			<p class="description">
-				<?php esc_html_e( 'Non-singular means templates like categories, date archives, author pages, and so on.', 'amp' ); ?>
+				<?php esc_html_e( 'This will allow all of the URLs on your site to be served as AMP by default.', 'amp' ); ?>
 			</p>
 		</fieldset>
 
@@ -302,7 +302,7 @@ public function render_supported_templates() {
 			$element_name    = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]';
 			?>
 			<legend>
-				<h2 class="title"><?php esc_html_e( 'Single Templates', 'amp' ); ?></h2>
+				<h4 class="title"><?php esc_html_e( 'Singular', 'amp' ); ?></h4>
 			</legend>
 
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
@@ -333,19 +333,38 @@ public function render_supported_templates() {
 
 		<?php
 		// This is inspired by Jetpack's Widget Conditions.
+		// @todo We need to construct a WP_Query for each? There will neeed to
 		$templates = array(
-			'page' => array(
-				'front' => array(),
-				'posts' => array(),
-				'date'  => array(),
-			),
-			'author' => array(
+			'author'   => array(
 				'' => __( 'All author pages', 'amp' ),
 			),
-			'category' => array(
-				'' => __( 'All category pages', 'amp' ),
-			)
+			'category' => array_merge(
+				array(
+					'' => __( 'All category pages', 'amp' ),
+				)
+			),
+			'tag'      => array_merge(
+				array(
+					'' => __( 'All tag pages', 'amp' ),
+				)
+			),
+			'date'     => array(
+				''      => __( 'All date archives', 'amp' ),
+				'day'   => __( 'Daily archives', 'amp' ),
+				'month' => __( 'Monthly archives', 'amp' ),
+				'year'  => __( 'Yearly archives', 'amp' ),
+			),
+			'page'     => array(
+				'front'   => __( 'Front page', 'amp' ),
+				'posts'   => __( 'Posts page', 'amp' ),
+				'archive' => __( 'Archive page', 'amp' ),
+				'404'     => __( '404 error page', 'amp' ),
+				'search'  => __( 'Search results', 'amp' ),
+			),
+			// @todo Post type archives.
+			// @todo Custom taxonomies.
 		);
+
 		?>
 
 		<fieldset class="non_singular_supported">

From 1d2053c85aff75b8f7814f63fbdbe7cf16a2bb98 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 16:42:27 -0700
Subject: [PATCH 05/34] WIP5

---
 includes/class-amp-post-type-support.php      |   2 +-
 includes/class-amp-theme-support.php          |  85 +++++++++++
 .../options/class-amp-options-manager.php     |   8 +-
 includes/options/class-amp-options-menu.php   | 133 ++++++++----------
 4 files changed, 152 insertions(+), 76 deletions(-)

diff --git a/includes/class-amp-post-type-support.php b/includes/class-amp-post-type-support.php
index 22a1bef580b..24ca1b074b0 100644
--- a/includes/class-amp-post-type-support.php
+++ b/includes/class-amp-post-type-support.php
@@ -29,7 +29,7 @@ public static function get_builtin_supported_post_types() {
 	public static function get_eligible_post_types() {
 		return array_merge(
 			self::get_builtin_supported_post_types(),
-			array( 'page' ),
+			array( 'page', 'attachment' ),
 			array_values( get_post_types(
 				array(
 					'public'   => true,
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 57644ce47a8..4a4752799e6 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -449,6 +449,91 @@ public static function get_template_availability( $query = null ) {
 		return true;
 	}
 
+	/**
+	 * Get conditionals which are used for determining availability.
+	 *
+	 * @return array Selections.
+	 */
+	public static function get_template_conditional_options() {
+		$templates = array(
+			'home'     => array(
+				'label'    => __( 'Homepage', 'amp' ),
+				'callback' => 'is_front_page',
+			),
+			'blog'     => array(
+				'label'    => __( 'Blog', 'amp' ),
+				'callback' => 'is_home',
+			),
+			'archives' => array(
+				'label'       => __( 'Archives', 'amp' ),
+				'description' => __( 'Including index pages for categories, tags, authors, and dates.', 'amp' ),
+				'callback'    => 'is_archive',
+				'children'    => array(
+					'author' => array(
+						'label'    => __( 'Author', 'amp' ),
+						'callback' => 'is_author',
+					),
+					'date'   => array(
+						'label'    => __( 'Date', 'amp' ),
+						'callback' => 'is_date',
+					),
+				),
+			),
+			'search'   => array(
+				'label'    => __( 'Search', 'amp' ),
+				'callback' => 'is_search',
+			),
+			'404'      => array(
+				'label'    => __( 'Not Found (404)', 'amp' ),
+				'callback' => 'is_404',
+			),
+			'other'    => array(
+				'label'    => __( 'Other', 'amp' ),
+				'callback' => '__return_true',
+			),
+		);
+
+		if ( taxonomy_exists( 'category' ) ) {
+			$templates['archives']['children']['category'] = array(
+				'label'    => get_taxonomy( 'category' )->labels->name,
+				'callback' => 'is_category',
+			);
+		}
+		if ( taxonomy_exists( 'post_tag' ) ) {
+			$templates['archives']['children']['tag'] = array(
+				'label'    => get_taxonomy( 'post_tag' )->labels->name,
+				'callback' => 'is_tag',
+			);
+		}
+		$taxonomy_args = array(
+			'_builtin'           => false,
+			'publicly_queryable' => true,
+		);
+		foreach ( get_taxonomies( $taxonomy_args, 'objects' ) as $taxonomy ) {
+			$templates['archives']['children'][ 'tax_' . $taxonomy->name ] = array(
+				'label'    => $taxonomy->labels->name,
+				'callback' => function ( WP_Query $query ) use ( $taxonomy ) {
+					return $query->is_tax( $taxonomy->name );
+				},
+			);
+		}
+
+		$post_type_args = array(
+			'has_archive'        => true,
+			'publicly_queryable' => true,
+		);
+		foreach ( get_post_types( $post_type_args, 'objects' ) as $post_type ) {
+			$templates['archives']['children'][ 'post_type_archive_' . $post_type->name ] = array(
+				'label'    => $post_type->labels->archives,
+				'callback' => function ( WP_Query $query ) use ( $post_type ) {
+					return $query->is_post_type_archive( $post_type->name );
+				},
+			);
+		}
+
+		return $templates;
+	}
+
 	/**
 	 * Register hooks.
 	 */
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 099975b8cc0..d24ba94f226 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -120,10 +120,10 @@ public static function validate_options( $new_options ) {
 			$options['theme_support'] = $new_options['theme_support'];
 		}
 
-		$options['force_sanitization']     = ! empty( $new_options['force_sanitization'] );
-		$options['accept_tree_shaking']    = ! empty( $new_options['accept_tree_shaking'] );
-		$options['disable_admin_bar']      = ! empty( $new_options['disable_admin_bar'] );
-		$options['non_singular_supported'] = ! empty( $new_options['non_singular_supported'] );
+		$options['force_sanitization']      = ! empty( $new_options['force_sanitization'] );
+		$options['accept_tree_shaking']     = ! empty( $new_options['accept_tree_shaking'] );
+		$options['disable_admin_bar']       = ! empty( $new_options['disable_admin_bar'] );
+		$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
 
 		// Validate post type support.
 		if ( isset( $new_options['supported_post_types'] ) ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index a0c5e20a1cb..048b2b2c23b 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -278,13 +278,7 @@ public function render_validation_handling() {
 	 */
 	public function render_supported_templates() {
 		?>
-		<script>
-			jQuery( 'input[type=radio][name="amp-options[theme_support]"]' ).change( function() {
-				jQuery( 'fieldset.non_singular_supported, fieldset.all_templates_supported' ).toggleClass( 'hidden', 'disabled' === this.value );
-			} ).filter( ':checked' ).trigger( 'change' );
-		</script>
-
-		<fieldset class="all_templates_supported">
+		<fieldset id="all_templates_supported_fieldset">
 			<p>
 				<label for="all_templates_supported">
 					<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
@@ -296,88 +290,85 @@ public function render_supported_templates() {
 			</p>
 		</fieldset>
 
-		<fieldset>
-			<?php
-			$builtin_support = AMP_Post_Type_Support::get_builtin_supported_post_types();
-			$element_name    = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]';
-			?>
-			<legend>
-				<h4 class="title"><?php esc_html_e( 'Singular', 'amp' ); ?></h4>
-			</legend>
-
+		<fieldset id="singular_templates_fieldset">
+			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
+			<h4 class="title"><?php esc_html_e( 'Singular Templates', 'amp' ); ?></h4>
+			<ul>
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
-				<?php
-				$element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}";
-				$is_builtin = in_array( $post_type->name, $builtin_support, true );
-				?>
-				<?php if ( $is_builtin ) : ?>
-					<input type="hidden" name="<?php echo esc_attr( $element_name ); ?>" value="<?php echo esc_attr( $post_type->name ); ?>">
-				<?php endif; ?>
+				<li>
+				<?php $element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}"; ?>
 				<input
 					type="checkbox"
 					id="<?php echo esc_attr( $element_id ); ?>"
 					name="<?php echo esc_attr( $element_name ); ?>"
 					value="<?php echo esc_attr( $post_type->name ); ?>"
 					<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
-					<?php disabled( $is_builtin ); ?>
 					>
+				<!-- @todo Hidden to capture actual state? -->
 				<label for="<?php echo esc_attr( $element_id ); ?>">
 					<?php echo esc_html( $post_type->label ); ?>
 				</label>
-				<br>
+				</li>
 			<?php endforeach; ?>
-			<p class="description">
-				<?php esc_html_e( 'Select the content types that you would like to be made available in AMP.', 'amp' ); ?>
-			</p>
+			</ul>
+		</fieldset>
+
+		<fieldset id="non_singular_templates_fieldset">
+			<style>
+				#non_singular_templates_fieldset ul ul {
+					margin-left: 40px;
+				}
+			</style>
+			<h4 class="title"><?php esc_html_e( 'Non-Singular Templates', 'amp' ); ?></h4>
+			<?php self::list_template_conditional_options( AMP_Theme_Support::get_template_conditional_options() ); ?>
 		</fieldset>
 
+		<script>
+			(function ( $ ) {
+				var templateModeInputs, themeSupportDisabledInput, allTemplatesSupportedInput;
+				templateModeInputs = $( 'input[type=radio][name="amp-options[theme_support]"]' );
+				themeSupportDisabledInput = $( '#theme_support_disabled' );
+				allTemplatesSupportedInput = $( '#all_templates_supported' );
+
+				function updateFieldsetVisibility() {
+					$( '#all_templates_supported_fieldset' ).toggleClass( 'hidden', themeSupportDisabledInput.prop( 'checked' ) );
+					$( '#singular_templates_fieldset' ).toggleClass( 'hidden', allTemplatesSupportedInput.prop( 'checked' ) && ! themeSupportDisabledInput.prop( 'checked' ) );
+					$( '#non_singular_templates_fieldset' ).toggleClass( 'hidden', allTemplatesSupportedInput.prop( 'checked' ) || themeSupportDisabledInput.prop( 'checked' ) );
+				}
+
+				templateModeInputs.on( 'change', updateFieldsetVisibility );
+				allTemplatesSupportedInput.on( 'click', updateFieldsetVisibility );
+				updateFieldsetVisibility();
+			})( jQuery );
+		</script>
 		<?php
-		// This is inspired by Jetpack's Widget Conditions.
-		// @todo We need to construct a WP_Query for each? There will neeed to
-		$templates = array(
-			'author'   => array(
-				'' => __( 'All author pages', 'amp' ),
-			),
-			'category' => array_merge(
-				array(
-					'' => __( 'All category pages', 'amp' ),
-				)
-			),
-			'tag'      => array_merge(
-				array(
-					'' => __( 'All tag pages', 'amp' ),
-				)
-			),
-			'date'     => array(
-				''      => __( 'All date archives', 'amp' ),
-				'day'   => __( 'Daily archives', 'amp' ),
-				'month' => __( 'Monthly archives', 'amp' ),
-				'year'  => __( 'Yearly archives', 'amp' ),
-			),
-			'page'     => array(
-				'front'   => __( 'Front page', 'amp' ),
-				'posts'   => __( 'Posts page', 'amp' ),
-				'archive' => __( 'Archive page', 'amp' ),
-				'404'     => __( '404 error page', 'amp' ),
-				'search'  => __( 'Search results', 'amp' ),
-			),
-			// @todo Post type archives.
-			// @todo Custom taxonomies.
-		);
+	}
 
+	/**
+	 * @param array $options Options.
+	 * @param bool $parent_checked
+	 */
+	private function list_template_conditional_options( $options, $parent_checked = false ) {
+		$element_name = AMP_Options_Manager::OPTION_NAME . '[supported_templates][]';
 		?>
+		<ul>
+			<?php foreach ( $options as $id => $option ) : ?>
+				<?php
+				$has_children = ! empty( $option['children'] );
+				$element_id   = AMP_Options_Manager::OPTION_NAME . '-supported-templates-' . $id;
+				?>
+				<li>
+					<input type="checkbox" id="<?php echo esc_attr( $element_id ); ?>" name="<?php echo esc_attr( $element_name ); ?>" value="<?php echo esc_attr( $id ); ?>">
+					<label for="<?php echo esc_attr( $element_id ); ?>">
+						<?php echo esc_html( $option['label'] ); ?>
+					</label>
 
-		<fieldset class="non_singular_supported">
-			<p>
-				<label for="non_singular_supported">
-					<input id="non_singular_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[non_singular_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'non_singular_supported' ) ); ?>>
-					<?php esc_html_e( 'Serve non-singular templates as AMP.', 'amp' ); ?>
-				</label>
-			</p>
-			<p class="description">
-				<?php esc_html_e( 'Non-singular means templates like categories, date archives, author pages, and so on.', 'amp' ); ?>
-			</p>
-		</fieldset>
+					<?php if ( $has_children ) : ?>
+						<?php self::list_template_conditional_options( $option['children'] ); ?>
+					<?php endif; ?>
+				</li>
+			<?php endforeach; ?>
+		</ul>
 		<?php
 	}
 

From 2eda94babe442b70c8bfeff0932f4a56ad2563af Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 21:46:34 -0700
Subject: [PATCH 06/34] WIP6

---
 includes/class-amp-post-type-support.php      | 31 +++++++++----------
 .../options/class-amp-options-manager.php     |  7 ++---
 includes/options/class-amp-options-menu.php   | 28 ++++++++++++++---
 tests/test-class-amp-post-type-support.php    | 12 ++-----
 4 files changed, 43 insertions(+), 35 deletions(-)

diff --git a/includes/class-amp-post-type-support.php b/includes/class-amp-post-type-support.php
index 24ca1b074b0..31270d540bf 100644
--- a/includes/class-amp-post-type-support.php
+++ b/includes/class-amp-post-type-support.php
@@ -14,9 +14,11 @@ class AMP_Post_Type_Support {
 	/**
 	 * Get post types that plugin supports out of the box (which cannot be disabled).
 	 *
+	 * @deprecated
 	 * @return string[] Post types.
 	 */
 	public static function get_builtin_supported_post_types() {
+		_deprecated_function( __METHOD__, '1.0' );
 		return array_filter( array( 'post' ), 'post_type_exists' );
 	}
 
@@ -27,17 +29,12 @@ public static function get_builtin_supported_post_types() {
 	 * @return string[] Post types eligible for AMP.
 	 */
 	public static function get_eligible_post_types() {
-		return array_merge(
-			self::get_builtin_supported_post_types(),
-			array( 'page', 'attachment' ),
-			array_values( get_post_types(
-				array(
-					'public'   => true,
-					'_builtin' => false,
-				),
-				'names'
-			) )
-		);
+		return array_values( get_post_types(
+			array(
+				'public' => true,
+			),
+			'names'
+		) );
 	}
 
 	/**
@@ -49,10 +46,11 @@ public static function get_eligible_post_types() {
 	 * @since 0.6
 	 */
 	public static function add_post_type_support() {
-		$post_types = array_merge(
-			self::get_builtin_supported_post_types(),
-			AMP_Options_Manager::get_option( 'supported_post_types', array() )
-		);
+		if ( current_theme_supports( 'amp' ) && AMP_Options_Manager::get_option( 'all_templates_supported' ) ) {
+			$post_types = self::get_eligible_post_types();
+		} else {
+			$post_types = AMP_Options_Manager::get_option( 'supported_post_types', array() );
+		}
 		foreach ( $post_types as $post_type ) {
 			add_post_type_support( $post_type, amp_get_slug() );
 		}
@@ -72,8 +70,7 @@ public static function get_support_errors( $post ) {
 		}
 		$errors = array();
 
-		// Because `add_rewrite_endpoint` doesn't let us target specific post_types.
-		if ( isset( $post->post_type ) && ! post_type_supports( $post->post_type, amp_get_slug() ) ) {
+		if ( ! post_type_supports( $post->post_type, amp_get_slug() ) ) {
 			$errors[] = 'post-type-support';
 		}
 
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index d24ba94f226..f87f89b6a54 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -24,7 +24,7 @@ class AMP_Options_Manager {
 	 */
 	protected static $defaults = array(
 		'theme_support'           => 'disabled',
-		'supported_post_types'    => array(),
+		'supported_post_types'    => array( 'post' ),
 		'analytics'               => array(),
 		'force_sanitization'      => false,
 		'accept_tree_shaking'     => false,
@@ -126,8 +126,8 @@ public static function validate_options( $new_options ) {
 		$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
 
 		// Validate post type support.
+		$options['supported_post_types'] = array();
 		if ( isset( $new_options['supported_post_types'] ) ) {
-			$options['supported_post_types'] = array();
 			foreach ( $new_options['supported_post_types'] as $post_type ) {
 				if ( ! post_type_exists( $post_type ) ) {
 					add_settings_error( self::OPTION_NAME, 'unknown_post_type', __( 'Unrecognized post type.', 'amp' ) );
@@ -192,11 +192,10 @@ public static function validate_options( $new_options ) {
 	 * @see add_settings_error()
 	 */
 	public static function check_supported_post_type_update_errors() {
-		$builtin_support = AMP_Post_Type_Support::get_builtin_supported_post_types();
 		$supported_types = self::get_option( 'supported_post_types', array() );
 		foreach ( AMP_Post_Type_Support::get_eligible_post_types() as $name ) {
 			$post_type = get_post_type_object( $name );
-			if ( empty( $post_type ) || in_array( $post_type->name, $builtin_support, true ) ) {
+			if ( empty( $post_type ) ) {
 				continue;
 			}
 
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 048b2b2c23b..5664a06f01a 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -293,6 +293,9 @@ public function render_supported_templates() {
 		<fieldset id="singular_templates_fieldset">
 			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
 			<h4 class="title"><?php esc_html_e( 'Singular Templates', 'amp' ); ?></h4>
+			<p>
+				<?php esc_html_e( 'The following content types will be available as AMP by default, but you can override this on an item-by-item basis:', 'amp' ); ?>
+			</p>
 			<ul>
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
 				<li>
@@ -304,7 +307,6 @@ public function render_supported_templates() {
 					value="<?php echo esc_attr( $post_type->name ); ?>"
 					<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
 					>
-				<!-- @todo Hidden to capture actual state? -->
 				<label for="<?php echo esc_attr( $element_id ); ?>">
 					<?php echo esc_html( $post_type->label ); ?>
 				</label>
@@ -321,9 +323,18 @@ public function render_supported_templates() {
 			</style>
 			<h4 class="title"><?php esc_html_e( 'Non-Singular Templates', 'amp' ); ?></h4>
 			<?php self::list_template_conditional_options( AMP_Theme_Support::get_template_conditional_options() ); ?>
+			<script>
+				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
+				(function ( $ ) {
+					$( '#non_singular_templates_fieldset input[type=checkbox]' ).on( 'click', function() {
+						$( this ).siblings( 'ul' ).find( 'input[type=checkbox]' ).prop( 'checked', this.checked );
+					} );
+				})( jQuery );
+			</script>
 		</fieldset>
 
 		<script>
+			// Update the visibility of the fieldsets based on the selected template mode and then whether all templates are indicated to be supported.
 			(function ( $ ) {
 				var templateModeInputs, themeSupportDisabledInput, allTemplatesSupportedInput;
 				templateModeInputs = $( 'input[type=radio][name="amp-options[theme_support]"]' );
@@ -331,9 +342,18 @@ public function render_supported_templates() {
 				allTemplatesSupportedInput = $( '#all_templates_supported' );
 
 				function updateFieldsetVisibility() {
-					$( '#all_templates_supported_fieldset' ).toggleClass( 'hidden', themeSupportDisabledInput.prop( 'checked' ) );
-					$( '#singular_templates_fieldset' ).toggleClass( 'hidden', allTemplatesSupportedInput.prop( 'checked' ) && ! themeSupportDisabledInput.prop( 'checked' ) );
-					$( '#non_singular_templates_fieldset' ).toggleClass( 'hidden', allTemplatesSupportedInput.prop( 'checked' ) || themeSupportDisabledInput.prop( 'checked' ) );
+					$( '#all_templates_supported_fieldset, #singular_templates_fieldset > .title' ).toggleClass(
+						'hidden',
+						themeSupportDisabledInput.prop( 'checked' )
+					);
+					$( '#singular_templates_fieldset' ).toggleClass(
+						'hidden',
+						allTemplatesSupportedInput.prop( 'checked' ) && ! themeSupportDisabledInput.prop( 'checked' )
+					);
+					$( '#non_singular_templates_fieldset' ).toggleClass(
+						'hidden',
+						allTemplatesSupportedInput.prop( 'checked' ) || themeSupportDisabledInput.prop( 'checked' )
+					);
 				}
 
 				templateModeInputs.on( 'change', updateFieldsetVisibility );
diff --git a/tests/test-class-amp-post-type-support.php b/tests/test-class-amp-post-type-support.php
index b32674715d4..7197654366a 100644
--- a/tests/test-class-amp-post-type-support.php
+++ b/tests/test-class-amp-post-type-support.php
@@ -22,15 +22,6 @@ public function tearDown() {
 		unregister_post_type( 'secret' );
 	}
 
-	/**
-	 * Test get_builtin_supported_post_types.
-	 *
-	 * @covers AMP_Post_Type_Support::get_builtin_supported_post_types()
-	 */
-	public function test_get_builtin_supported_post_types() {
-		$this->assertEquals( array( 'post' ), AMP_Post_Type_Support::get_builtin_supported_post_types() );
-	}
-
 	/**
 	 * Test get_eligible_post_types.
 	 *
@@ -46,10 +37,11 @@ public function test_get_eligible_post_types() {
 			'public' => false,
 		) );
 
-		$this->assertEquals(
+		$this->assertEqualSets(
 			array(
 				'post',
 				'page',
+				'attachment',
 				'book',
 			),
 			AMP_Post_Type_Support::get_eligible_post_types()

From 3377ecfd3ac02471ee50c5e0dc311a5e3c935533 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 22:22:01 -0700
Subject: [PATCH 07/34] WIP7

---
 includes/class-amp-theme-support.php          | 37 ++++++++++++-------
 .../options/class-amp-options-manager.php     | 15 ++++++--
 includes/options/class-amp-options-menu.php   | 30 ++++++++++-----
 3 files changed, 54 insertions(+), 28 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 4a4752799e6..48f59590eee 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -468,16 +468,16 @@ public static function get_template_conditional_options() {
 				'label'       => __( 'Archives', 'amp' ),
 				'description' => __( 'Including index pages for categories, tags, authors, and dates.', 'amp' ),
 				'callback'    => 'is_archive',
-				'children'    => array(
-					'author' => array(
-						'label'    => __( 'Author', 'amp' ),
-						'callback' => 'is_author',
-					),
-					'date'   => array(
-						'label'    => __( 'Date', 'amp' ),
-						'callback' => 'is_date',
-					),
-				),
+			),
+			'author' => array(
+				'label'    => __( 'Author', 'amp' ),
+				'callback' => 'is_author',
+				'parent'   => 'archives',
+			),
+			'date'   => array(
+				'label'    => __( 'Date', 'amp' ),
+				'callback' => 'is_date',
+				'parent'   => 'archives',
 			),
 			'search'   => array(
 				'label'    => __( 'Search', 'amp' ),
@@ -494,24 +494,28 @@ public static function get_template_conditional_options() {
 		);
 
 		if ( taxonomy_exists( 'category' ) ) {
-			$templates['archives']['children']['category'] = array(
+			$templates['tax[category]'] = array(
 				'label'    => get_taxonomy( 'category' )->labels->name,
 				'callback' => 'is_category',
+				'parent'   => 'archives',
 			);
 		}
 		if ( taxonomy_exists( 'post_tag' ) ) {
-			$templates['archives']['children']['tag'] = array(
+			$templates['tax[post_tag]'] = array(
 				'label'    => get_taxonomy( 'post_tag' )->labels->name,
 				'callback' => 'is_tag',
+				'parent'   => 'archives',
 			);
 		}
+
 		$taxonomy_args = array(
 			'_builtin'           => false,
 			'publicly_queryable' => true,
 		);
 		foreach ( get_taxonomies( $taxonomy_args, 'objects' ) as $taxonomy ) {
-			$templates['archives']['children'][ 'tax_' . $taxonomy->name ] = array(
+			$templates[ sprintf( 'tax[%s]', $taxonomy->name ) ] = array(
 				'label'    => $taxonomy->labels->name,
+				'parent'   => 'archives',
 				'callback' => function ( WP_Query $query ) use ( $taxonomy ) {
 					return $query->is_tax( $taxonomy->name );
 				},
@@ -523,7 +527,7 @@ public static function get_template_conditional_options() {
 			'publicly_queryable' => true,
 		);
 		foreach ( get_post_types( $post_type_args, 'objects' ) as $post_type ) {
-			$templates['archives']['children'][ 'post_type_archive_' . $post_type->name ] = array(
+			$templates[ sprintf( 'post_type_archive[%s]', $post_type->name ) ] = array(
 				'label'    => $post_type->labels->archives,
 				'callback' => function ( WP_Query $query ) use ( $post_type ) {
 					return $query->is_post_type_archive( $post_type->name );
@@ -531,6 +535,11 @@ public static function get_template_conditional_options() {
 			);
 		}
 
+		$supported_templates = AMP_Options_Manager::get_option( 'supported_templates' );
+		foreach ( $templates as $id => &$template ) {
+			$template['supported'] = in_array( $id, $supported_templates, true );
+		}
+
 		return $templates;
 	}
 
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index f87f89b6a54..a089832a633 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -29,10 +29,8 @@ class AMP_Options_Manager {
 		'force_sanitization'      => false,
 		'accept_tree_shaking'     => false,
 		'disable_admin_bar'       => false,
-		'all_templates_supported' => false,
-		'supported_templates'     => array(
-			'single',
-		),
+		'all_templates_supported' => true,
+		'supported_templates'     => array(),
 	);
 
 	/**
@@ -137,6 +135,15 @@ public static function validate_options( $new_options ) {
 			}
 		}
 
+		// Validate supported templates.
+		$options['supported_templates'] = array();
+		if ( isset( $new_options['supported_templates'] ) ) {
+			$options['supported_templates'] = array_intersect(
+				$new_options['supported_templates'],
+				array_keys( AMP_Theme_Support::get_template_conditional_options() )
+			);
+		}
+
 		// Validate analytics.
 		if ( isset( $new_options['analytics'] ) ) {
 			foreach ( $new_options['analytics'] as $id => $data ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 5664a06f01a..4865c76a316 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -322,7 +322,9 @@ public function render_supported_templates() {
 				}
 			</style>
 			<h4 class="title"><?php esc_html_e( 'Non-Singular Templates', 'amp' ); ?></h4>
-			<?php self::list_template_conditional_options( AMP_Theme_Support::get_template_conditional_options() ); ?>
+			<?php
+			self::list_template_conditional_options( AMP_Theme_Support::get_template_conditional_options() );
+			?>
 			<script>
 				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
 				(function ( $ ) {
@@ -365,27 +367,35 @@ function updateFieldsetVisibility() {
 	}
 
 	/**
-	 * @param array $options Options.
-	 * @param bool $parent_checked
+	 * List template conditional options.
+	 *
+	 * @param array       $options Options.
+	 * @param string|null $parent  ID of the parent option.
 	 */
-	private function list_template_conditional_options( $options, $parent_checked = false ) {
+	private function list_template_conditional_options( $options, $parent = null ) {
 		$element_name = AMP_Options_Manager::OPTION_NAME . '[supported_templates][]';
 		?>
 		<ul>
 			<?php foreach ( $options as $id => $option ) : ?>
 				<?php
-				$has_children = ! empty( $option['children'] );
-				$element_id   = AMP_Options_Manager::OPTION_NAME . '-supported-templates-' . $id;
+				$element_id = AMP_Options_Manager::OPTION_NAME . '-supported-templates-' . $id;
+				if ( $parent ? empty( $option['parent'] ) || $parent !== $option['parent'] : ! empty( $option['parent'] ) ) {
+					continue;
+				}
 				?>
 				<li>
-					<input type="checkbox" id="<?php echo esc_attr( $element_id ); ?>" name="<?php echo esc_attr( $element_name ); ?>" value="<?php echo esc_attr( $id ); ?>">
+					<input
+						type="checkbox"
+						id="<?php echo esc_attr( $element_id ); ?>"
+						name="<?php echo esc_attr( $element_name ); ?>"
+						value="<?php echo esc_attr( $id ); ?>"
+						<?php checked( ! empty( $option['supported'] ) ); ?>
+					>
 					<label for="<?php echo esc_attr( $element_id ); ?>">
 						<?php echo esc_html( $option['label'] ); ?>
 					</label>
 
-					<?php if ( $has_children ) : ?>
-						<?php self::list_template_conditional_options( $option['children'] ); ?>
-					<?php endif; ?>
+					<?php self::list_template_conditional_options( $options, $id ); ?>
 				</li>
 			<?php endforeach; ?>
 		</ul>

From e5f4b77013694ee6c4f45eb8a68ca26a6316691d Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 23:09:05 -0700
Subject: [PATCH 08/34] Remove needless get_query_template

---
 includes/class-amp-theme-support.php | 60 ++--------------------------
 1 file changed, 4 insertions(+), 56 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 48f59590eee..9439806bd33 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -339,49 +339,6 @@ public static function add_amp_template_filters() {
 		}
 	}
 
-	/**
-	 * Locate the template for a given query.
-	 *
-	 * @param WP_Query $query Query.
-	 * @return string The template filename if one is located.
-	 */
-	public static function get_query_template( $query ) {
-		foreach ( self::$template_types as $template_type ) {
-			add_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
-		}
-
-		// phpcs:disable -- This is copied from wp-includes/template-loader.php
-		if     ( $query->is_embed()             && $template = get_embed_template()             ) :
-		elseif ( $query->is_404()               && $template = get_404_template()               ) :
-		elseif ( $query->is_search()            && $template = get_search_template()            ) :
-		elseif ( $query->is_front_page()        && $template = get_front_page_template()        ) :
-		elseif ( $query->is_home()              && $template = get_home_template()              ) :
-		elseif ( $query->is_post_type_archive() && $template = get_post_type_archive_template() ) :
-		elseif ( $query->is_tax()               && $template = get_taxonomy_template()          ) :
-		elseif ( $query->is_attachment()        && $template = get_attachment_template()        ) :
-		elseif ( $query->is_single()            && $template = get_single_template()            ) :
-		elseif ( $query->is_page()              && $template = get_page_template()              ) :
-		elseif ( $query->is_singular()          && $template = get_singular_template()          ) :
-		elseif ( $query->is_category()          && $template = get_category_template()          ) :
-		elseif ( $query->is_tag()               && $template = get_tag_template()               ) :
-		elseif ( $query->is_author()            && $template = get_author_template()            ) :
-		elseif ( $query->is_date()              && $template = get_date_template()              ) :
-		elseif ( $query->is_archive()           && $template = get_archive_template()           ) :
-		else :
-			$template = get_index_template();
-		endif;
-		// phpcs:enable
-
-		/** This filter is documented in wp-includes/template-loader.php */
-		$template = apply_filters( 'template_include', $template );
-
-		foreach ( self::$template_types as $template_type ) {
-			remove_filter( "{$template_type}_template_hierarchy", array( __CLASS__, 'filter_amp_template_hierarchy' ) );
-		}
-
-		return $template;
-	}
-
 	/**
 	 * Determine template availability of AMP for the given query.
 	 *
@@ -437,14 +394,6 @@ public static function get_template_availability( $query = null ) {
 			}
 		}
 
-		// Make sure there is a template available for the query in the template_dir if it is defined..
-		if ( ! empty( $args[0]['template_dir'] ) ) {
-			$template = self::get_query_template( $query );
-			if ( empty( $template ) || ! file_exists( $template ) ) {
-				return new WP_Error( 'no_existing_template' );
-			}
-		}
-
 		// If all checks have passed, then the template is available.
 		return true;
 	}
@@ -469,12 +418,12 @@ public static function get_template_conditional_options() {
 				'description' => __( 'Including index pages for categories, tags, authors, and dates.', 'amp' ),
 				'callback'    => 'is_archive',
 			),
-			'author' => array(
+			'author'   => array(
 				'label'    => __( 'Author', 'amp' ),
 				'callback' => 'is_author',
 				'parent'   => 'archives',
 			),
-			'date'   => array(
+			'date'     => array(
 				'label'    => __( 'Date', 'amp' ),
 				'callback' => 'is_date',
 				'parent'   => 'archives',
@@ -953,8 +902,6 @@ public static function amend_comment_form() {
 	/**
 	 * Prepends template hierarchy with template_dir for AMP paired mode templates.
 	 *
-	 * @see get_query_template()
-	 *
 	 * @param array $templates Template hierarchy.
 	 * @return array Templates.
 	 */
@@ -964,7 +911,8 @@ public static function filter_amp_template_hierarchy( $templates ) {
 		if ( isset( $args['template_dir'] ) ) {
 			$amp_templates = array();
 			foreach ( $templates as $template ) {
-				$amp_templates[] = $args['template_dir'] . '/' . $template;
+				$amp_templates[] = $args['template_dir'] . '/' . $template; // Let template_dir have precedence.
+				$amp_templates[] = $template;
 			}
 			$templates = $amp_templates;
 		}

From a7bf31e605168c07a7d0a8c63f6463e021f27798 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 27 Jun 2018 23:41:34 -0700
Subject: [PATCH 09/34] WIP8

---
 includes/class-amp-theme-support.php          | 31 ++++++++++++++++---
 .../options/class-amp-options-manager.php     |  2 +-
 includes/options/class-amp-options-menu.php   |  3 +-
 3 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 9439806bd33..72e65a8c836 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -380,6 +380,13 @@ public static function get_template_availability( $query = null ) {
 		}
 
 		$args = get_theme_support( 'amp' );
+
+		// @todo All of this needs to be refactored.
+		$supported_templates = AMP_Theme_Support::get_supportable_templates();
+
+		// @todo For each $supported_templates, call the callback. Then for each callback that returns true, check if also 'supported'. If supported is false but there is a decendant that is true, then consider true.
+		// @todo A theme can prevent a template from being offered by filtering the. ELIMINATE available_callback.
+
 		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
 			$callback = $args[0]['available_callback'];
 
@@ -399,11 +406,11 @@ public static function get_template_availability( $query = null ) {
 	}
 
 	/**
-	 * Get conditionals which are used for determining availability.
+	 * Get the templates which can be supported.
 	 *
-	 * @return array Selections.
+	 * @return array Supportable templates.
 	 */
-	public static function get_template_conditional_options() {
+	public static function get_supportable_templates() {
 		$templates = array(
 			'home'     => array(
 				'label'    => __( 'Homepage', 'amp' ),
@@ -484,9 +491,25 @@ public static function get_template_conditional_options() {
 			);
 		}
 
+		/**
+		 * Filters list of supportable templates.
+		 *
+		 * A theme or plugin can force a given template to be supported or not by preemptively
+		 * setting the 'supported' flag for a given template. Otherwise, if the flag is undefined
+		 * then the user will be able to toggle it themselves in the admin.
+		 *
+		 * @since 1.0
+		 *
+		 * @param array $templates Supportable templates.
+		 */
+		$templates = apply_filters( 'amp_supportable_templates', $templates );
+
 		$supported_templates = AMP_Options_Manager::get_option( 'supported_templates' );
 		foreach ( $templates as $id => &$template ) {
-			$template['supported'] = in_array( $id, $supported_templates, true );
+			$template['immutable'] = isset( $template['supported'] );
+			if ( ! $template['immutable'] ) {
+				$template['supported'] = in_array( $id, $supported_templates, true );
+			}
 		}
 
 		return $templates;
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index a089832a633..ebfd274388a 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -140,7 +140,7 @@ public static function validate_options( $new_options ) {
 		if ( isset( $new_options['supported_templates'] ) ) {
 			$options['supported_templates'] = array_intersect(
 				$new_options['supported_templates'],
-				array_keys( AMP_Theme_Support::get_template_conditional_options() )
+				array_keys( AMP_Theme_Support::get_supportable_templates() )
 			);
 		}
 
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 4865c76a316..66e55a0d61b 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -323,7 +323,7 @@ public function render_supported_templates() {
 			</style>
 			<h4 class="title"><?php esc_html_e( 'Non-Singular Templates', 'amp' ); ?></h4>
 			<?php
-			self::list_template_conditional_options( AMP_Theme_Support::get_template_conditional_options() );
+			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
 			?>
 			<script>
 				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
@@ -390,6 +390,7 @@ private function list_template_conditional_options( $options, $parent = null ) {
 						name="<?php echo esc_attr( $element_name ); ?>"
 						value="<?php echo esc_attr( $id ); ?>"
 						<?php checked( ! empty( $option['supported'] ) ); ?>
+						<?php disabled( ! empty( $option['immutable'] ) ); ?>
 					>
 					<label for="<?php echo esc_attr( $element_id ); ?>">
 						<?php echo esc_html( $option['label'] ); ?>

From f4405926f938f82019493bd0ad31b76eca091da9 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Thu, 28 Jun 2018 17:00:58 -0700
Subject: [PATCH 10/34] WIP9 [ci skip]

---
 includes/admin/class-amp-post-meta-box.php    |  28 ++-
 includes/amp-helper-functions.php             |   5 +-
 includes/class-amp-theme-support.php          | 178 +++++++++++-------
 includes/options/class-amp-options-menu.php   |  33 ++--
 .../class-amp-validation-manager.php          |   2 +-
 templates/admin/amp-status.php                |  25 +--
 6 files changed, 176 insertions(+), 95 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 71fe1bc39aa..1d5e5bc309c 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -176,8 +176,34 @@ public function render_status( $post ) {
 			return;
 		}
 
-		$errors = AMP_Post_Type_Support::get_support_errors( $post );
 		$status = post_supports_amp( $post ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
+		$errors = AMP_Post_Type_Support::get_support_errors( $post );
+
+		// @todo This logic is duplicated with get_template_availability().
+		// @todo It would really be ideal if we could get_template_availability() here to support custom special cases.
+		// Handle special case of the static front page or page for posts.
+		if ( current_theme_supports( 'amp' ) && 'page' === get_option( 'show_on_front' ) ) {
+			$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+			$is_template_supported = false;
+			if ( (int) get_option( 'page_on_front' ) === (int) $post->ID ) {
+				$is_template_supported = (
+					! empty( $supportable_templates['is_front_page']['supported'] )
+					||
+					( empty( $supportable_templates['is_front_page']['immutable'] ) && AMP_Options_Manager::get_option( 'all_templates_supported' ) )
+				);
+			} elseif ( (int) get_option( 'page_for_posts' ) === (int) $post->ID ) {
+				$is_template_supported = (
+					! empty( $supportable_templates['is_home']['supported'] )
+					||
+					( empty( $supportable_templates['is_home']['immutable'] ) && AMP_Options_Manager::get_option( 'all_templates_supported' ) )
+				);
+			}
+			if ( ! $is_template_supported ) {
+				$errors[] = 'template-unavailable';
+				$status   = self::DISABLED_STATUS;
+			}
+		}
+
 		$labels = array(
 			'enabled'  => __( 'Enabled', 'amp' ),
 			'disabled' => __( 'Disabled', 'amp' ),
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 04d250d2a37..fbf46811ae5 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -257,7 +257,10 @@ function post_supports_amp( $post ) {
 		case AMP_Post_Meta_Box::DISABLED_STATUS:
 			return false;
 
-		// Disabled by default for custom page templates, page on front and page for posts, unless 'amp' theme support is present.
+		/*
+		 * Disabled by default for custom page templates, page on front and page for posts, unless 'amp' theme
+		 * support is present (in which case AMP_Theme_Support::get_template_availability() determines availability).
+		 */
 		default:
 			$enabled = current_theme_supports( 'amp' ) || (
 				! (bool) get_page_template_slug( $post )
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 72e65a8c836..c2bb18fa3f0 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -348,25 +348,12 @@ public static function add_amp_template_filters() {
 	 * @global WP_Query $wp_query
 	 * @see post_supports_amp()
 	 *
-	 * @param WP_Query|WP_Post|null $query Query or queried post. If null then the global query will be used.
+	 * @param WP_Query|null $query Query or queried post. If null then the global query will be used.
 	 * @return true|WP_Error True if template is available, WP_Error if otherwise.
 	 */
 	public static function get_template_availability( $query = null ) {
 		global $wp_query;
-
-		if ( $query instanceof WP_Post ) {
-			$post  = $query;
-			$query = new WP_Query();
-
-			$query->queried_object    = $post;
-			$query->queried_object_id = $post->ID;
-			if ( 'page' === $post->post_type ) {
-				$query->set( 'post_id', $post->ID );
-			} else {
-				$query->set( 'p', $post->ID );
-			}
-			$query->parse_query();
-		} elseif ( ! $query ) {
+		if ( ! $query ) {
 			$query = $wp_query;
 		}
 
@@ -379,28 +366,81 @@ public static function get_template_availability( $query = null ) {
 			return new WP_Error( 'no_theme_support' );
 		}
 
-		$args = get_theme_support( 'amp' );
+		// @todo Add theme support flag
 
-		// @todo All of this needs to be refactored.
-		$supported_templates = AMP_Theme_Support::get_supportable_templates();
+		if ( $query->is_singular() ) {
+//				return true;
+		}
 
-		// @todo For each $supported_templates, call the callback. Then for each callback that returns true, check if also 'supported'. If supported is false but there is a decendant that is true, then consider true.
-		// @todo A theme can prevent a template from being offered by filtering the. ELIMINATE available_callback.
+		// Singular queries
+//			if ( $query->is_singular() ) {
+//				/**
+//				 * Queried object.
+//				 *
+//				 * @var WP_Post $queried_object
+//				 */
+//				$queried_object = $query->get_queried_object();
+//				return post_supports_amp( $queried_object )
+//			}
 
-		if ( isset( $args[0]['available_callback'] ) && is_callable( $args[0]['available_callback'] ) ) {
-			$callback = $args[0]['available_callback'];
+		$matching_templates    = array();
+		$supportable_templates = self::get_supportable_templates();
+		foreach ( $supportable_templates as $id => $supportable_template ) {
+			if ( empty( $supportable_template['callback'] ) ) {
+				$callback = $id;
+			} else {
+				$callback = $supportable_template['callback'];
+			}
 
+			// @todo Consider using the $id as the conditional callback.
 			// If the available_callback is a method on the query, then call the method on the query itself.
 			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
-				$available = call_user_func( array( $query, $callback ) );
+				$is_match = call_user_func( array( $query, $callback ) );
 			} else {
-				$available = call_user_func( $callback );
+				$is_match = call_user_func( $callback );
+			}
+
+			if ( $is_match ) {
+				$matching_templates[ $id ] = (
+					! empty( $supportable_template['supported'] )
+					||
+					( AMP_Options_Manager::get_option( 'all_templates_supported' ) && empty( $supportable_template['immutable'] ) )
+				);
 			}
-			if ( false === $available ) {
-				return new WP_Error( 'unavailable_by_callback' );
+		}
+
+		// Make sure children override their parents.
+		$matching_template_ids = array_keys( $matching_templates );
+		foreach ( $matching_template_ids as $id ) {
+			$has_children = false;
+			foreach ( $supportable_templates as $other_id => $supportable_template ) {
+				if ( $other_id === $id ) {
+					continue;
+				}
+				if ( isset( $supportable_template['parent'] ) && $id === $supportable_template['parent'] ) {
+					$has_children = true;
+					break;
+				}
+			}
+
+			// Delete all matching parent templates since the child will override them.
+			if ( ! $has_children ) {
+				$supportable_template = $supportable_templates[ $id ];
+				while ( ! empty( $supportable_template['parent'] ) ) {
+					$parent               = $supportable_template['parent'];
+					$supportable_template = $supportable_templates[ $parent ];
+
+					// Let the child supported status override the parent's supported status.
+					unset( $matching_templates[ $parent ] );
+				}
 			}
 		}
 
+		// If there aren't any matching templates left that are supported, then we consider it to not be available.
+		if ( ! in_array( true, $matching_templates, true ) ) {
+			return new WP_Error( 'no_supported_template' );
+		}
+
 		// If all checks have passed, then the template is available.
 		return true;
 	}
@@ -412,55 +452,53 @@ public static function get_template_availability( $query = null ) {
 	 */
 	public static function get_supportable_templates() {
 		$templates = array(
-			'home'     => array(
-				'label'    => __( 'Homepage', 'amp' ),
-				'callback' => 'is_front_page',
-			),
-			'blog'     => array(
-				'label'    => __( 'Blog', 'amp' ),
-				'callback' => 'is_home',
-			),
-			'archives' => array(
-				'label'       => __( 'Archives', 'amp' ),
-				'description' => __( 'Including index pages for categories, tags, authors, and dates.', 'amp' ),
-				'callback'    => 'is_archive',
-			),
-			'author'   => array(
-				'label'    => __( 'Author', 'amp' ),
-				'callback' => 'is_author',
-				'parent'   => 'archives',
-			),
-			'date'     => array(
-				'label'    => __( 'Date', 'amp' ),
-				'callback' => 'is_date',
-				'parent'   => 'archives',
-			),
-			'search'   => array(
-				'label'    => __( 'Search', 'amp' ),
-				'callback' => 'is_search',
-			),
-			'404'      => array(
-				'label'    => __( 'Not Found (404)', 'amp' ),
-				'callback' => 'is_404',
-			),
-			'other'    => array(
-				'label'    => __( 'Other', 'amp' ),
-				'callback' => '__return_true',
+			'is_front_page' => array(
+				'label' => __( 'Homepage', 'amp' ),
 			),
 		);
+		if ( 'page' === get_option( 'show_on_front' ) ) {
+			// In other words, same as is_posts_page.
+			$templates['is_home'] = array(
+				'label' => __( 'Blog', 'amp' ),
+			);
+		}
+		$templates = array_merge(
+			$templates,
+			array(
+				'is_archive' => array(
+					'label'       => __( 'Archives', 'amp' ),
+				),
+				'is_author'  => array(
+					'label'    => __( 'Author', 'amp' ),
+					'parent' => 'is_archive',
+				),
+				'is_date'    => array(
+					'label'  => __( 'Date', 'amp' ),
+					'parent' => 'is_archive',
+				),
+				'is_search'  => array(
+					'label' => __( 'Search', 'amp' ),
+				),
+				'is_404'     => array(
+					'label' => __( 'Not Found (404)', 'amp' ),
+				),
+//				'other'    => array(
+//					'label'    => __( 'Other', 'amp' ),
+//					'callback' => '__return_true', // @todo This can be treated as the parent of all, as the default.
+//				),
+			)
+		);
 
 		if ( taxonomy_exists( 'category' ) ) {
-			$templates['tax[category]'] = array(
+			$templates['is_category'] = array(
 				'label'    => get_taxonomy( 'category' )->labels->name,
-				'callback' => 'is_category',
-				'parent'   => 'archives',
+				'parent'   => 'is_archive',
 			);
 		}
 		if ( taxonomy_exists( 'post_tag' ) ) {
-			$templates['tax[post_tag]'] = array(
-				'label'    => get_taxonomy( 'post_tag' )->labels->name,
-				'callback' => 'is_tag',
-				'parent'   => 'archives',
+			$templates['is_tag'] = array(
+				'label'  => get_taxonomy( 'post_tag' )->labels->name,
+				'parent' => 'is_archive',
 			);
 		}
 
@@ -469,9 +507,9 @@ public static function get_supportable_templates() {
 			'publicly_queryable' => true,
 		);
 		foreach ( get_taxonomies( $taxonomy_args, 'objects' ) as $taxonomy ) {
-			$templates[ sprintf( 'tax[%s]', $taxonomy->name ) ] = array(
+			$templates[ sprintf( 'is_tax[%s]', $taxonomy->name ) ] = array(
 				'label'    => $taxonomy->labels->name,
-				'parent'   => 'archives',
+				'parent'   => 'is_archive',
 				'callback' => function ( WP_Query $query ) use ( $taxonomy ) {
 					return $query->is_tax( $taxonomy->name );
 				},
@@ -483,7 +521,7 @@ public static function get_supportable_templates() {
 			'publicly_queryable' => true,
 		);
 		foreach ( get_post_types( $post_type_args, 'objects' ) as $post_type ) {
-			$templates[ sprintf( 'post_type_archive[%s]', $post_type->name ) ] = array(
+			$templates[ sprintf( 'is_post_type_archive[%s]', $post_type->name ) ] = array(
 				'label'    => $post_type->labels->archives,
 				'callback' => function ( WP_Query $query ) use ( $post_type ) {
 					return $query->is_post_type_archive( $post_type->name );
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 66e55a0d61b..443fbcbd803 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -134,6 +134,9 @@ public function render_theme_support() {
 			||
 			! empty( $support_args[0]['__added_via_option'] )
 		);
+
+		// @todo Consider $theme_support['paired'] and if set, and true, only show Paired option; otherwise, show Native option.
+		// @todo Change $theme_support_mutable to be if ! empty( $theme_support['optional'] ) or ! $theme_support['required']?
 		if ( ! $theme_support_mutable ) {
 			if ( amp_is_canonical() ) {
 				$theme_support = 'native';
@@ -277,6 +280,8 @@ public function render_validation_handling() {
 	 * @since 1.0
 	 */
 	public function render_supported_templates() {
+
+		// @todo If AMP theme support is native and required, let all_templates_supported be true? Maybe template support could have an all_templates_supported flag?
 		?>
 		<fieldset id="all_templates_supported_fieldset">
 			<p>
@@ -299,17 +304,17 @@ public function render_supported_templates() {
 			<ul>
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
 				<li>
-				<?php $element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}"; ?>
-				<input
-					type="checkbox"
-					id="<?php echo esc_attr( $element_id ); ?>"
-					name="<?php echo esc_attr( $element_name ); ?>"
-					value="<?php echo esc_attr( $post_type->name ); ?>"
-					<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
-					>
-				<label for="<?php echo esc_attr( $element_id ); ?>">
-					<?php echo esc_html( $post_type->label ); ?>
-				</label>
+					<?php $element_id = AMP_Options_Manager::OPTION_NAME . "-supported_post_types-{$post_type->name}"; ?>
+					<input
+						type="checkbox"
+						id="<?php echo esc_attr( $element_id ); ?>"
+						name="<?php echo esc_attr( $element_name ); ?>"
+						value="<?php echo esc_attr( $post_type->name ); ?>"
+						<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
+						>
+					<label for="<?php echo esc_attr( $element_id ); ?>">
+						<?php echo esc_html( $post_type->label ); ?>
+					</label>
 				</li>
 			<?php endforeach; ?>
 			</ul>
@@ -396,6 +401,12 @@ private function list_template_conditional_options( $options, $parent = null ) {
 						<?php echo esc_html( $option['label'] ); ?>
 					</label>
 
+					<?php if ( ! empty( $option['description'] ) ) : ?>
+						<span class="description">
+							&mdash; <?php echo esc_html( $option['description'] ); ?>
+						</span>
+					<?php endif; ?>
+
 					<?php self::list_template_conditional_options( $options, $id ); ?>
 				</li>
 			<?php endforeach; ?>
diff --git a/includes/validation/class-amp-validation-manager.php b/includes/validation/class-amp-validation-manager.php
index 428d5f59f44..1e9a0bca866 100644
--- a/includes/validation/class-amp-validation-manager.php
+++ b/includes/validation/class-amp-validation-manager.php
@@ -218,7 +218,7 @@ public static function is_sanitization_forcibly_accepted() {
 	 * @param WP_Admin_Bar $wp_admin_bar Admin bar.
 	 */
 	public static function add_admin_bar_menu_items( $wp_admin_bar ) {
-		if ( is_admin() || ! self::has_cap() || ! ( amp_is_canonical() || AMP_Theme_Support::is_paired_available() ) ) {
+		if ( is_admin() || ! self::has_cap() || is_wp_error( AMP_Theme_Support::get_template_availability() ) ) {
 			self::$amp_admin_bar_item_added = false;
 			return;
 		}
diff --git a/templates/admin/amp-status.php b/templates/admin/amp-status.php
index 51454ae8635..9473f9906d0 100644
--- a/templates/admin/amp-status.php
+++ b/templates/admin/amp-status.php
@@ -41,22 +41,25 @@
 			<div class="inline notice notice-warning notice-alt">
 				<p>
 					<?php
-					$support_errors_codes = AMP_Post_Type_Support::get_support_errors( $post );
-					$support_errors       = array();
-					if ( in_array( 'password-protected', $support_errors_codes, true ) ) {
-						$support_errors[] = __( 'AMP cannot be enabled on password protected posts.', 'amp' );
+					$error_messages = array();
+					if ( in_array( 'template-unavailable', $errors, true ) ) {
+						/* translators: %s is URL to AMP settings screen */
+						$error_messages[] = wp_kses_post( sprintf( __( 'There are no <a href="%s">supported templates</a> to display this in AMP.', 'amp' ), esc_url( admin_url( 'admin.php?page=' . AMP_Options_Manager::OPTION_NAME ) ) ) );
+					}
+					if ( in_array( 'password-protected', $errors, true ) ) {
+						$error_messages[] = __( 'AMP cannot be enabled on password protected posts.', 'amp' );
 					}
-					if ( in_array( 'post-type-support', $support_errors_codes, true ) ) {
+					if ( in_array( 'post-type-support', $errors, true ) ) {
 						/* translators: %s is URL to AMP settings screen */
-						$support_errors[] = wp_kses_post( sprintf( __( 'AMP cannot be enabled because this <a href="%s">post type does not support it</a>.', 'amp' ), admin_url( 'admin.php?page=' . AMP_Options_Manager::OPTION_NAME ) ) );
+						$error_messages[] = wp_kses_post( sprintf( __( 'AMP cannot be enabled because this <a href="%s">post type does not support it</a>.', 'amp' ), esc_url( admin_url( 'admin.php?page=' . AMP_Options_Manager::OPTION_NAME ) ) ) );
 					}
-					if ( in_array( 'skip-post', $support_errors_codes, true ) ) {
-						$support_errors[] = __( 'A plugin or theme has disabled AMP support.', 'amp' );
+					if ( in_array( 'skip-post', $errors, true ) ) {
+						$error_messages[] = __( 'A plugin or theme has disabled AMP support.', 'amp' );
 					}
-					if ( count( array_diff( $support_errors_codes, array( 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post' ) ) ) > 0 ) {
-						$support_errors[] = __( 'Unavailable for an unknown reason.', 'amp' );
+					if ( count( array_diff( $errors, array( 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post' ) ) ) > 0 ) {
+						$error_messages[] = __( 'Unavailable for an unknown reason.', 'amp' );
 					}
-					echo implode( ' ', $support_errors ); // WPCS: xss ok.
+					echo implode( ' ', $error_messages ); // WPCS: xss ok.
 					?>
 				</p>
 			</div>

From 8f46ee7482bcdedfbba35c09b06da674769b23dd Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Thu, 28 Jun 2018 18:09:52 -0700
Subject: [PATCH 11/34] WIP10 [ci skip]

---
 includes/admin/class-amp-post-meta-box.php  |  1 +
 includes/amp-helper-functions.php           | 25 +++++-----
 includes/class-amp-theme-support.php        | 52 +++++++++++++--------
 includes/options/class-amp-options-menu.php |  4 +-
 4 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 1d5e5bc309c..b32bd563e76 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -170,6 +170,7 @@ public function render_status( $post ) {
 			is_post_type_viewable( $post->post_type )
 			&&
 			current_user_can( 'edit_post', $post->ID )
+			// @todo What if a site does not have non-AMP pages? Formerly this was indicated via amp_is_canonical(). Now we need a flag for whether AMP is exclusive to a theme, in which case all templates and post types must render AMP. In other words, all_templates_supported.
 		);
 
 		if ( true !== $verify ) {
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index fbf46811ae5..61a198c148c 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -320,22 +320,21 @@ function is_amp_endpoint() {
 		return false;
 	}
 
-	// Check if the queried object supports AMP.
-	if ( is_singular() ) {
-		/**
-		 * Post.
-		 *
-		 * @var WP_Post $queried_object
-		 */
-		$queried_object = get_queried_object();
-		if ( ! post_supports_amp( $queried_object ) ) {
-			return false;
-		}
-	}
-
 	if ( current_theme_supports( 'amp' ) ) {
 		return true === AMP_Theme_Support::get_template_availability();
 	} else {
+
+		// Check if the queried object supports AMP.
+		if ( is_singular() ) {
+			/**
+			 * Post.
+			 *
+			 * @var WP_Post $queried_object
+			 */
+			$queried_object = get_queried_object();
+			return post_supports_amp( $queried_object );
+		}
+
 		return false; // Legacy templates only support posts via AMP_Post_Template.
 	}
 }
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index c2bb18fa3f0..6917eef0121 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -366,25 +366,21 @@ public static function get_template_availability( $query = null ) {
 			return new WP_Error( 'no_theme_support' );
 		}
 
-		// @todo Add theme support flag
+		$matching_templates    = array();
+		$supportable_templates = self::get_supportable_templates();
 
-		if ( $query->is_singular() ) {
-//				return true;
+		/*
+		 * Singular template support is included here though it is not explicitly listed among the templates by default.
+		 * It is the post type support that is used to indicate whether a given singular post template should be served
+		 * via post_supports_amp() including the metabox toggle to enable/disable AMP, and the amp_skip_post filter.
+		 */
+		if ( ! isset( $supportable_templates['is_singular'] ) ) {
+			$supportable_templates['is_singular'] = array(
+				'callback'  => 'is_singular',
+				'supported' => true,
+			);
 		}
 
-		// Singular queries
-//			if ( $query->is_singular() ) {
-//				/**
-//				 * Queried object.
-//				 *
-//				 * @var WP_Post $queried_object
-//				 */
-//				$queried_object = $query->get_queried_object();
-//				return post_supports_amp( $queried_object )
-//			}
-
-		$matching_templates    = array();
-		$supportable_templates = self::get_supportable_templates();
 		foreach ( $supportable_templates as $id => $supportable_template ) {
 			if ( empty( $supportable_template['callback'] ) ) {
 				$callback = $id;
@@ -436,11 +432,26 @@ public static function get_template_availability( $query = null ) {
 			}
 		}
 
+		error_log( json_encode( $matching_templates ) );
+
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! in_array( true, $matching_templates, true ) ) {
 			return new WP_Error( 'no_supported_template' );
 		}
 
+		// For singular queries, post_supports_amp() is given the final say.
+		if ( $query->is_singular() ) {
+			/**
+			 * Queried object.
+			 *
+			 * @var WP_Post $queried_object
+			 */
+			$queried_object = $query->get_queried_object();
+			if ( ! post_supports_amp( $queried_object ) ) {
+				return new WP_Error( 'post_lacks_amp_support' );
+			}
+		}
+
 		// If all checks have passed, then the template is available.
 		return true;
 	}
@@ -448,6 +459,7 @@ public static function get_template_availability( $query = null ) {
 	/**
 	 * Get the templates which can be supported.
 	 *
+	 * @todo The callback could have support for running in an admin context.
 	 * @return array Supportable templates.
 	 */
 	public static function get_supportable_templates() {
@@ -466,10 +478,10 @@ public static function get_supportable_templates() {
 			$templates,
 			array(
 				'is_archive' => array(
-					'label'       => __( 'Archives', 'amp' ),
+					'label' => __( 'Archives', 'amp' ),
 				),
 				'is_author'  => array(
-					'label'    => __( 'Author', 'amp' ),
+					'label'  => __( 'Author', 'amp' ),
 					'parent' => 'is_archive',
 				),
 				'is_date'    => array(
@@ -491,8 +503,8 @@ public static function get_supportable_templates() {
 
 		if ( taxonomy_exists( 'category' ) ) {
 			$templates['is_category'] = array(
-				'label'    => get_taxonomy( 'category' )->labels->name,
-				'parent'   => 'is_archive',
+				'label'  => get_taxonomy( 'category' )->labels->name,
+				'parent' => 'is_archive',
 			);
 		}
 		if ( taxonomy_exists( 'post_tag' ) ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 443fbcbd803..e4e2272ed1e 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -297,7 +297,7 @@ public function render_supported_templates() {
 
 		<fieldset id="singular_templates_fieldset">
 			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
-			<h4 class="title"><?php esc_html_e( 'Singular Templates', 'amp' ); ?></h4>
+			<h4 class="title"><?php esc_html_e( 'Content Types', 'amp' ); ?></h4>
 			<p>
 				<?php esc_html_e( 'The following content types will be available as AMP by default, but you can override this on an item-by-item basis:', 'amp' ); ?>
 			</p>
@@ -326,7 +326,7 @@ public function render_supported_templates() {
 					margin-left: 40px;
 				}
 			</style>
-			<h4 class="title"><?php esc_html_e( 'Non-Singular Templates', 'amp' ); ?></h4>
+			<h4 class="title"><?php esc_html_e( 'Templates', 'amp' ); ?></h4>
 			<?php
 			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
 			?>

From 0131c52b03f1a190e0963c9fab54bd33dd0706b9 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Thu, 28 Jun 2018 20:44:23 -0700
Subject: [PATCH 12/34] WIP11 [ci skip]

---
 amp.php                              |  8 +++--
 includes/amp-helper-functions.php    |  3 +-
 includes/class-amp-theme-support.php | 54 +++++-----------------------
 3 files changed, 17 insertions(+), 48 deletions(-)

diff --git a/amp.php b/amp.php
index e4aa3a69529..413fa62248d 100644
--- a/amp.php
+++ b/amp.php
@@ -301,6 +301,10 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
 function amp_is_canonical() {
+	if ( ! current_theme_supports( 'amp' ) ) {
+		return false;
+	}
+
 	$support = get_theme_support( 'amp' );
 	if ( true === $support ) {
 		return true;
@@ -310,8 +314,8 @@ function amp_is_canonical() {
 		$args = array_shift( $support );
 
 		// If paired arg is supplied, then it is never canonical.
-		if ( ! empty( $args['paired'] ) ) {
-			return false;
+		if ( isset( $args['paired'] ) ) {
+			return ! $args['paired'];
 		}
 
 		// If there is a template_dir, then paired mode is implied.
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 61a198c148c..623c3a7e40a 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -321,7 +321,8 @@ function is_amp_endpoint() {
 	}
 
 	if ( current_theme_supports( 'amp' ) ) {
-		return true === AMP_Theme_Support::get_template_availability();
+		$template_available = true === AMP_Theme_Support::get_template_availability();
+		return amp_is_canonical() ? $template_available : $has_amp_query_var;
 	} else {
 
 		// Check if the queried object supports AMP.
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 6917eef0121..0c15885cebb 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -118,7 +118,7 @@ public static function init() {
 			$args = array_shift( $support );
 			if ( ! is_array( $args ) ) {
 				trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-			} elseif ( count( array_diff( array_keys( $args ), array( 'template_dir', 'available_callback', 'comments_live_list', '__added_via_option' ) ) ) !== 0 ) {
+			} elseif ( count( array_diff( array_keys( $args ), array( 'template_dir', 'available_callback', 'comments_live_list', 'paired', '__added_via_option' ) ) ) !== 0 ) {
 				trigger_error( esc_html__( 'Expected AMP theme support to only have template_dir and/or available_callback.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
 			}
 		}
@@ -147,26 +147,8 @@ public static function apply_options() {
 
 			$args = array(
 				'__added_via_option' => true,
+				'paired'             => ( 'paired' === $theme_support_option ),
 			);
-			if ( 'native' === $theme_support_option ) {
-				$args['available_callback'] = function() {
-					/**
-					 * Queried object.
-					 *
-					 * @var WP_Post $queried_object
-					 */
-					$queried_object = get_queried_object();
-					if ( is_singular() && post_supports_amp( $queried_object ) ) {
-						return 'native';
-					}
-
-					if ( AMP_Options_Manager::get_option( 'non_singular_supported' ) ) {
-						return 'native';
-					}
-
-					return false;
-				};
-			}
 			add_theme_support( 'amp', $args );
 		}
 	}
@@ -278,43 +260,27 @@ public static function redirect_ampless_url( $exit = true ) {
 	 * Determines whether paired mode is available.
 	 *
 	 * When 'amp' theme support has not been added or canonical mode is enabled, then this returns false.
-	 * Returns true when there is a template_dir defined in theme support, and if a defined available_callback
-	 * returns true.
+	 *
+	 * @since 0.7
+	 * @since 1.0 This no longer looks at the available_callback bit instead calls get_template_availability.
 	 *
 	 * @see amp_is_canonical()
 	 * @return bool Whether available.
 	 */
 	public static function is_paired_available() {
-		$support = get_theme_support( 'amp' );
-		if ( empty( $support ) || amp_is_canonical() ) {
+		if ( ! current_theme_supports( 'amp' ) ) {
 			return false;
 		}
 
-		/**
-		 * Queried object.
-		 *
-		 * @var WP_Post $queried_object
-		 */
-		$queried_object = get_queried_object();
-		if ( is_singular() && ! post_supports_amp( $queried_object ) ) {
+		if ( amp_is_canonical() ) {
 			return false;
 		}
 
-		if ( ! is_singular() && ! AMP_Options_Manager::get_option( 'non_singular_supported' ) ) {
+		$availability = self::get_template_availability();
+		if ( is_wp_error( $availability ) ) {
 			return false;
 		}
 
-		$args = array_shift( $support );
-
-		if ( isset( $args['available_callback'] ) && is_callable( $args['available_callback'] ) ) {
-			/*
-			 * The available_callback here will return a bool or the string 'paired'.
-			 * If it returns 'native' then `amp_is_canonical()` above would have short-circuited.
-			 */
-			return (bool) call_user_func( $args['available_callback'] );
-		}
-
-		// This is the same as if there is a template_dir defined with no available_callback.
 		return true;
 	}
 
@@ -432,8 +398,6 @@ public static function get_template_availability( $query = null ) {
 			}
 		}
 
-		error_log( json_encode( $matching_templates ) );
-
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! in_array( true, $matching_templates, true ) ) {
 			return new WP_Error( 'no_supported_template' );

From 5288ccbd1c9066002487986f395c10b6012f1daa Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Fri, 29 Jun 2018 11:10:46 -0700
Subject: [PATCH 13/34] WIP12 [ci skip]

---
 amp.php                                     | 55 ++++++-------
 includes/admin/class-amp-post-meta-box.php  | 35 ++++----
 includes/amp-helper-functions.php           | 49 +-----------
 includes/class-amp-post-type-support.php    | 42 ++++++++++
 includes/class-amp-theme-support.php        | 88 ++++++++++++++++++---
 includes/options/class-amp-options-menu.php | 10 ++-
 templates/admin/amp-status.php              |  2 +-
 7 files changed, 172 insertions(+), 109 deletions(-)

diff --git a/amp.php b/amp.php
index 413fa62248d..69d5e8cda37 100644
--- a/amp.php
+++ b/amp.php
@@ -274,29 +274,34 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
 /**
  * Whether this is in 'canonical mode'.
  *
- * Themes can register support for this with `add_theme_support( 'amp' )`, or via the
- * following so that only so that single blog posts will be native/canonical, pages are paired,
- * and everything else has AMP unavailable:
+ * Themes can register support for this with `add_theme_support( 'amp' )`:
  *
- *      add_theme_support( 'amp', array(
- *          'available_callback' => 'is_single',
- *      ) );
+ *      add_theme_support( 'amp' );
  *
- * Then, this will change the plugin so that it won't run in 'paired mode' with separate URLs.
- * Neither will it output the rel=amphtml link on the frontend. To serve a site in paired mode, add the paired arg:
+ * This will serve templates in native AMP by default but the user would be able to change the template mode
+ * from native to paired in the admin. To force only native to be available, such as when you are using AMP components
+ * in your theme templates, do:
  *
  *      add_theme_support( 'amp', array(
- *          'paired' => true,
- *          'available_callback' => 'is_single',
+ *          'mode' => 'native',
  *      ) );
  *
- * Paired mode will also be retained if the theme registers support for AMP with just a template_dir and no available_callback:
+ * If you want to force AMP to always be served on a given template, use the amp_supportable_templates filter,
+ * for example to always serve the Category template in AMP:
+ *
+ *      add_filter( 'amp_supportable_templates', function( $templates ) {
+ *          $templates['is_category']['supported'] = true;
+ *          return $template;
+ *      } );
  *
- *     add_theme_support( 'amp', array(
- *         'template_dir' => 'my-amp-templates',
- *     ) );
+ * Or if you want to prevent AMP from ever being served on the homepage:
  *
- * @see \AMP_Theme_Support::is_paired_available()
+ *      add_filter( 'amp_supportable_templates', function( $templates ) {
+ *          $templates['is_front_page']['supported'] = false;
+ *          return $template;
+ *      } );
+ *
+ * @todo There needs to be a required flag which is the same as forcing all to be supported. This would be the same in the UI as the all_templates_supported flag. Might as well rename all_templates_supported to just required. If required is set to be false, or if any of the supported templates are immutable, then this option should not be available.
  *
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
@@ -305,25 +310,17 @@ function amp_is_canonical() {
 		return false;
 	}
 
+	$mode    = 'native';
 	$support = get_theme_support( 'amp' );
-	if ( true === $support ) {
-		return true;
-	}
-
 	if ( is_array( $support ) ) {
 		$args = array_shift( $support );
-
-		// If paired arg is supplied, then it is never canonical.
-		if ( isset( $args['paired'] ) ) {
-			return ! $args['paired'];
-		}
-
-		// If there is a template_dir, then paired mode is implied.
-		if ( ! empty( $args['template_dir'] ) ) {
-			return false;
+		if ( isset( $args['mode'] ) ) {
+			$mode = $args['mode'];
+		} elseif ( ! empty( $args['template_dir'] ) ) {
+			$mode = 'paired'; // If there is a template_dir, then paired mode is implied.
 		}
 	}
-	return true;
+	return 'native' === $mode;
 }
 
 /**
diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index b32bd563e76..f8f0d6fa9f6 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -177,29 +177,26 @@ public function render_status( $post ) {
 			return;
 		}
 
-		$status = post_supports_amp( $post ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
 		$errors = AMP_Post_Type_Support::get_support_errors( $post );
+		$status = empty( $errors ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
+		$errors = array_diff( $errors, array( 'post-status-disabled' ) ); // Subtract the status which the metabox will allow to be toggled.
 
-		// @todo This logic is duplicated with get_template_availability().
-		// @todo It would really be ideal if we could get_template_availability() here to support custom special cases.
+		// @todo If ! supported and immutable, don't show the toggle at all?
 		// Handle special case of the static front page or page for posts.
-		if ( current_theme_supports( 'amp' ) && 'page' === get_option( 'show_on_front' ) ) {
-			$supportable_templates = AMP_Theme_Support::get_supportable_templates();
-			$is_template_supported = false;
-			if ( (int) get_option( 'page_on_front' ) === (int) $post->ID ) {
-				$is_template_supported = (
-					! empty( $supportable_templates['is_front_page']['supported'] )
-					||
-					( empty( $supportable_templates['is_front_page']['immutable'] ) && AMP_Options_Manager::get_option( 'all_templates_supported' ) )
-				);
-			} elseif ( (int) get_option( 'page_for_posts' ) === (int) $post->ID ) {
-				$is_template_supported = (
-					! empty( $supportable_templates['is_home']['supported'] )
-					||
-					( empty( $supportable_templates['is_home']['immutable'] ) && AMP_Options_Manager::get_option( 'all_templates_supported' ) )
-				);
+		if ( current_theme_supports( 'amp' ) ) {
+
+			$query = new WP_Query();
+			if ( 'page' === $post->post_type ) {
+				$query->set( 'page_id', $post->ID );
+			} else {
+				$query->set( 'p', $post->ID );
 			}
-			if ( ! $is_template_supported ) {
+			$query->queried_object    = $post;
+			$query->queried_object_id = $post->ID;
+			$query->parse_query_vars();
+
+			$availability = AMP_Theme_Support::get_template_availability( $query );
+			if ( $availability instanceof WP_Error && 0 !== count( array_diff( $availability->get_error_codes(), $errors, array( 'post-status-disabled' ) ) ) ) {
 				$errors[] = 'template-unavailable';
 				$status   = self::DISABLED_STATUS;
 			}
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 623c3a7e40a..e11f6b830c4 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -239,54 +239,10 @@ function amp_add_amphtml_link() {
  * @see   AMP_Post_Type_Support::get_support_errors()
  *
  * @param WP_Post $post Post.
- *
  * @return bool Whether the post supports AMP.
  */
 function post_supports_amp( $post ) {
-	$errors = AMP_Post_Type_Support::get_support_errors( $post );
-
-	// Return false if an error is found.
-	if ( ! empty( $errors ) ) {
-		return false;
-	}
-
-	switch ( get_post_meta( $post->ID, AMP_Post_Meta_Box::STATUS_POST_META_KEY, true ) ) {
-		case AMP_Post_Meta_Box::ENABLED_STATUS:
-			return true;
-
-		case AMP_Post_Meta_Box::DISABLED_STATUS:
-			return false;
-
-		/*
-		 * Disabled by default for custom page templates, page on front and page for posts, unless 'amp' theme
-		 * support is present (in which case AMP_Theme_Support::get_template_availability() determines availability).
-		 */
-		default:
-			$enabled = current_theme_supports( 'amp' ) || (
-				! (bool) get_page_template_slug( $post )
-				&&
-				! (
-					'page' === $post->post_type
-					&&
-					'page' === get_option( 'show_on_front' )
-					&&
-					in_array( (int) $post->ID, array(
-						(int) get_option( 'page_on_front' ),
-						(int) get_option( 'page_for_posts' ),
-					), true )
-				)
-			);
-
-			/**
-			 * Filters whether default AMP status should be enabled or not.
-			 *
-			 * @since 0.6
-			 *
-			 * @param string  $status Status.
-			 * @param WP_Post $post   Post.
-			 */
-			return apply_filters( 'amp_post_status_default_enabled', $enabled, $post );
-	}
+	return 0 === count( AMP_Post_Type_Support::get_support_errors( $post ) );
 }
 
 /**
@@ -299,6 +255,7 @@ function post_supports_amp( $post ) {
  * @return bool Whether it is the AMP endpoint.
  */
 function is_amp_endpoint() {
+	global $wp_query;
 	if ( is_admin() || is_feed() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) ) {
 		return false;
 	}
@@ -326,7 +283,7 @@ function is_amp_endpoint() {
 	} else {
 
 		// Check if the queried object supports AMP.
-		if ( is_singular() ) {
+		if ( is_singular() || ( $wp_query instanceof WP_Query && $wp_query->is_posts_page ) ) {
 			/**
 			 * Post.
 			 *
diff --git a/includes/class-amp-post-type-support.php b/includes/class-amp-post-type-support.php
index 31270d540bf..48a8d6d4d5a 100644
--- a/includes/class-amp-post-type-support.php
+++ b/includes/class-amp-post-type-support.php
@@ -91,6 +91,48 @@ public static function get_support_errors( $post ) {
 			$errors[] = 'skip-post';
 		}
 
+		$status = get_post_meta( $post->ID, AMP_Post_Meta_Box::STATUS_POST_META_KEY, true );
+		if ( $status ) {
+			if ( AMP_Post_Meta_Box::DISABLED_STATUS === $status ) {
+				$errors[] = 'post-status-disabled';
+			}
+		} else {
+			/*
+			 * Disabled by default for custom page templates, page on front and page for posts, unless 'amp' theme
+			 * support is present (in which case AMP_Theme_Support::get_template_availability() determines availability).
+			 */
+			$enabled = (
+				current_theme_supports( 'amp' )
+				||
+				(
+					! (bool) get_page_template_slug( $post )
+					&&
+					! (
+						'page' === $post->post_type
+						&&
+						'page' === get_option( 'show_on_front' )
+						&&
+						in_array( (int) $post->ID, array(
+							(int) get_option( 'page_on_front' ),
+							(int) get_option( 'page_for_posts' ),
+						), true )
+					)
+				)
+			);
+
+			/**
+			 * Filters whether default AMP status should be enabled or not.
+			 *
+			 * @since 0.6
+			 *
+			 * @param string  $status Status.
+			 * @param WP_Post $post   Post.
+			 */
+			$enabled = apply_filters( 'amp_post_status_default_enabled', $enabled, $post );
+			if ( ! $enabled ) {
+				$errors[] = 'post-status-disabled';
+			}
+		}
 		return $errors;
 	}
 }
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 0c15885cebb..65e88ce2eec 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -90,6 +90,14 @@ class AMP_Theme_Support {
 	 */
 	protected static $is_output_buffering = false;
 
+	/**
+	 * Theme support options that were added via option.
+	 *
+	 * @since 1.0
+	 * @var false|array
+	 */
+	protected static $support_added_via_option = false;
+
 	/**
 	 * Initialize.
 	 *
@@ -118,7 +126,7 @@ public static function init() {
 			$args = array_shift( $support );
 			if ( ! is_array( $args ) ) {
 				trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-			} elseif ( count( array_diff( array_keys( $args ), array( 'template_dir', 'available_callback', 'comments_live_list', 'paired', '__added_via_option' ) ) ) !== 0 ) {
+			} elseif ( count( array_diff( array_keys( $args ), array( 'template_dir', 'available_callback', 'comments_live_list', 'mode', 'optional' ) ) ) !== 0 ) {
 				trigger_error( esc_html__( 'Expected AMP theme support to only have template_dir and/or available_callback.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
 			}
 		}
@@ -133,24 +141,56 @@ public static function init() {
 		add_action( 'wp', array( __CLASS__, 'finish_init' ), PHP_INT_MAX );
 	}
 
+	/**
+	 * Determine whether theme support as added via option.
+	 *
+	 * @since 1.0
+	 * @return bool Optional support added.
+	 */
+	public static function is_support_added_via_option() {
+		return false !== self::$support_added_via_option;
+	}
+
 	/**
 	 * Apply options for whether theme support is enabled via admin and what sanitization is performed by default.
 	 *
 	 * @see AMP_Post_Type_Support::add_post_type_support() For where post type support is added, since it is irrespective of theme support.
 	 */
 	public static function apply_options() {
+		self::$support_added_via_option = false;
+
+		$theme_support_option = AMP_Options_Manager::get_option( 'theme_support' );
+		$theme_support_args   = false;
+
+		// @todo Do we really need this optional flag? Yes. As it allows us to define the mode. Maybe it should be 'required' instead. Key for theme marketplaces? But if a theme is using the AMP features anyway, then it should have AMP as built-in and not be optional.
+
+		// If theme support is present in the theme, but it is marked as optional, then go ahead and remove it if theme support is not enabled in the admin.
+		if ( current_theme_supports( 'amp' ) ) {
+			$support            = get_theme_support( 'amp' );
+			$theme_support_args = array();
+			if ( is_array( $support ) ) {
+				$theme_support_args = array_shift( $support );
+				if ( ! empty( $theme_support_args['optional'] ) && 'disabled' === $theme_support_option ) {
+					remove_theme_support( 'amp' );
+					return;
+				}
+			}
+		}
+
+		// If theme support is not present, then allow it to be added via the admin.
 		if ( ! current_theme_supports( 'amp' ) ) {
-			$theme_support_option = AMP_Options_Manager::get_option( 'theme_support' );
 			if ( 'disabled' === $theme_support_option ) {
 				return;
 			}
 
-			$args = array(
-				'__added_via_option' => true,
-				'paired'             => ( 'paired' === $theme_support_option ),
+			$option_args = array(
+				'mode' => $theme_support_option,
 			);
-			add_theme_support( 'amp', $args );
+			add_theme_support( 'amp', array_merge( $option_args, $theme_support_args ) );
+			self::$support_added_via_option = $option_args;
 		}
+
+		// @todo Allow paired mode to be switched via option if optional flag is true?
 	}
 
 	/**
@@ -404,15 +444,20 @@ public static function get_template_availability( $query = null ) {
 		}
 
 		// For singular queries, post_supports_amp() is given the final say.
-		if ( $query->is_singular() ) {
+		if ( $query->is_singular() || $query->is_posts_page ) {
 			/**
 			 * Queried object.
 			 *
 			 * @var WP_Post $queried_object
 			 */
 			$queried_object = $query->get_queried_object();
-			if ( ! post_supports_amp( $queried_object ) ) {
-				return new WP_Error( 'post_lacks_amp_support' );
+			$support_errors = AMP_Post_Type_Support::get_support_errors( $queried_object );
+			if ( ! empty( $support_errors ) ) {
+				$error = new WP_Error();
+				foreach ( $support_errors as $support_error ) {
+					$error->add( $support_error, '' );
+				}
+				return $error;
 			}
 		}
 
@@ -428,16 +473,35 @@ public static function get_template_availability( $query = null ) {
 	 */
 	public static function get_supportable_templates() {
 		$templates = array(
-			'is_front_page' => array(
-				'label' => __( 'Homepage', 'amp' ),
+			'is_singular' => array(
+				'label' => __( 'Singular', 'amp' ),
+				// This needs to default to true.
 			),
 		);
 		if ( 'page' === get_option( 'show_on_front' ) ) {
-			// In other words, same as is_posts_page.
+			$templates['is_front_page'] = array(
+				'label'  => __( 'Homepage', 'amp' ),
+				'parent' => 'is_singular',
+			);
+			if ( AMP_Post_Meta_Box::DISABLED_STATUS === get_post_meta( get_option( 'page_on_front' ), AMP_Post_Meta_Box::STATUS_POST_META_KEY, true ) ) {
+				/* translators: %s is the URL to the edit post screen */
+				$templates['is_front_page']['description'] = sprintf( __( 'Currently disabled at the <a href="%s" target="_blank">page level</a>.', 'amp' ), esc_url( get_edit_post_link( get_option( 'page_on_front' ) ) ) );
+			}
+
+			// In other words, same as is_posts_page, *but* it not is_singular.
 			$templates['is_home'] = array(
 				'label' => __( 'Blog', 'amp' ),
 			);
+			if ( AMP_Post_Meta_Box::DISABLED_STATUS === get_post_meta( get_option( 'page_for_posts' ), AMP_Post_Meta_Box::STATUS_POST_META_KEY, true ) ) {
+				/* translators: %s is the URL to the edit post screen */
+				$templates['is_home']['description'] = sprintf( __( 'Currently disabled at the <a href="%s" target="_blank">page level</a>.', 'amp' ), esc_url( get_edit_post_link( get_option( 'page_for_posts' ) ) ) );
+			}
+		} else {
+			$templates['is_home'] = array(
+				'label' => __( 'Homepage', 'amp' ),
+			);
 		}
+
 		$templates = array_merge(
 			$templates,
 			array(
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index e4e2272ed1e..30d7f342487 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -132,7 +132,7 @@ public function render_theme_support() {
 		$theme_support_mutable = (
 			empty( $support_args )
 			||
-			! empty( $support_args[0]['__added_via_option'] )
+			AMP_Theme_Support::is_support_added_via_option()
 		);
 
 		// @todo Consider $theme_support['paired'] and if set, and true, only show Paired option; otherwise, show Native option.
@@ -387,6 +387,12 @@ private function list_template_conditional_options( $options, $parent = null ) {
 				if ( $parent ? empty( $option['parent'] ) || $parent !== $option['parent'] : ! empty( $option['parent'] ) ) {
 					continue;
 				}
+
+				// Skip showing an option if it doesn't have a label.
+				if ( empty( $option['label'] ) ) {
+					continue;
+				}
+
 				?>
 				<li>
 					<input
@@ -403,7 +409,7 @@ private function list_template_conditional_options( $options, $parent = null ) {
 
 					<?php if ( ! empty( $option['description'] ) ) : ?>
 						<span class="description">
-							&mdash; <?php echo esc_html( $option['description'] ); ?>
+							&mdash; <?php echo wp_kses_post( $option['description'] ); ?>
 						</span>
 					<?php endif; ?>
 
diff --git a/templates/admin/amp-status.php b/templates/admin/amp-status.php
index 9473f9906d0..8bf6696f958 100644
--- a/templates/admin/amp-status.php
+++ b/templates/admin/amp-status.php
@@ -56,7 +56,7 @@
 					if ( in_array( 'skip-post', $errors, true ) ) {
 						$error_messages[] = __( 'A plugin or theme has disabled AMP support.', 'amp' );
 					}
-					if ( count( array_diff( $errors, array( 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post' ) ) ) > 0 ) {
+					if ( count( array_diff( $errors, array( 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post', 'template-unavailable' ) ) ) > 0 ) {
 						$error_messages[] = __( 'Unavailable for an unknown reason.', 'amp' );
 					}
 					echo implode( ' ', $error_messages ); // WPCS: xss ok.

From 3f4ef4c5599e0ec5cf1927e20dbf9801f9e37bc1 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Fri, 29 Jun 2018 11:18:10 -0700
Subject: [PATCH 14/34] WIP13 [ci skip]

---
 includes/class-amp-theme-support.php           | 18 ++----------------
 includes/options/class-amp-options-manager.php |  4 +++-
 2 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 65e88ce2eec..75d823a1071 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -374,19 +374,6 @@ public static function get_template_availability( $query = null ) {
 
 		$matching_templates    = array();
 		$supportable_templates = self::get_supportable_templates();
-
-		/*
-		 * Singular template support is included here though it is not explicitly listed among the templates by default.
-		 * It is the post type support that is used to indicate whether a given singular post template should be served
-		 * via post_supports_amp() including the metabox toggle to enable/disable AMP, and the amp_skip_post filter.
-		 */
-		if ( ! isset( $supportable_templates['is_singular'] ) ) {
-			$supportable_templates['is_singular'] = array(
-				'callback'  => 'is_singular',
-				'supported' => true,
-			);
-		}
-
 		foreach ( $supportable_templates as $id => $supportable_template ) {
 			if ( empty( $supportable_template['callback'] ) ) {
 				$callback = $id;
@@ -468,14 +455,13 @@ public static function get_template_availability( $query = null ) {
 	/**
 	 * Get the templates which can be supported.
 	 *
-	 * @todo The callback could have support for running in an admin context.
 	 * @return array Supportable templates.
 	 */
 	public static function get_supportable_templates() {
 		$templates = array(
 			'is_singular' => array(
-				'label' => __( 'Singular', 'amp' ),
-				// This needs to default to true.
+				'label'       => __( 'Singular', 'amp' ),
+				'description' => __( 'Required for the above content types.', 'amp' ),
 			),
 		);
 		if ( 'page' === get_option( 'show_on_front' ) ) {
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index ebfd274388a..0ec87537169 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -30,7 +30,9 @@ class AMP_Options_Manager {
 		'accept_tree_shaking'     => false,
 		'disable_admin_bar'       => false,
 		'all_templates_supported' => true,
-		'supported_templates'     => array(),
+		'supported_templates'     => array(
+			'is_singular',
+		),
 	);
 
 	/**

From a616e84cd03eb218378c3582779a9d500e27db2e Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 00:07:05 -0700
Subject: [PATCH 15/34] Don't show post enable/disable if template is not
 available

Fix up some tests
Address CR feedback

[ci skip]
---
 includes/admin/class-amp-post-meta-box.php    |  34 +++--
 includes/amp-helper-functions.php             |  31 ++---
 includes/class-amp-theme-support.php          | 116 ++++++++++++++----
 includes/options/class-amp-options-menu.php   |   4 +-
 .../class-amp-validation-manager.php          |   8 +-
 templates/admin/amp-status.php                |  11 +-
 tests/test-class-amp-meta-box.php             |  12 +-
 tests/test-class-amp-options-manager.php      |  18 +--
 tests/test-class-amp-theme-support.php        |  31 ++---
 tests/test-class-amp-widget-archives.php      |  10 ++
 tests/test-class-amp-widget-categories.php    |  14 ++-
 tests/test-class-amp-widget-media-video.php   |  14 ++-
 tests/test-class-amp-widget-text.php          |  13 +-
 13 files changed, 204 insertions(+), 112 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index f8f0d6fa9f6..8747467878f 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -143,12 +143,20 @@ public function enqueue_admin_assets() {
 			array( 'jquery' ),
 			AMP__VERSION
 		);
+
+		if ( current_theme_supports( 'amp' ) ) {
+			$availability   = AMP_Theme_Support::get_template_availability( $post );
+			$support_errors = $availability['errors'];
+		} else {
+			$support_errors = AMP_Post_Type_Support::get_support_errors( $post );
+		}
+
 		wp_add_inline_script( self::ASSETS_HANDLE, sprintf( 'ampPostMetaBox.boot( %s );',
 			wp_json_encode( array(
 				'previewLink'     => esc_url_raw( add_query_arg( amp_get_slug(), '', get_preview_post_link( $post ) ) ),
 				'canonical'       => amp_is_canonical(),
-				'enabled'         => post_supports_amp( $post ),
-				'canSupport'      => count( AMP_Post_Type_Support::get_support_errors( $post ) ) === 0,
+				'enabled'         => empty( $support_errors ),
+				'canSupport'      => 0 === count( array_diff( $support_errors, array( 'post-status-disabled' ) ) ),
 				'statusInputName' => self::STATUS_INPUT_NAME,
 				'l10n'            => array(
 					'ampPreviewBtnLabel' => __( 'Preview changes in AMP (opens in new window)', 'amp' ),
@@ -170,7 +178,6 @@ public function render_status( $post ) {
 			is_post_type_viewable( $post->post_type )
 			&&
 			current_user_can( 'edit_post', $post->ID )
-			// @todo What if a site does not have non-AMP pages? Formerly this was indicated via amp_is_canonical(). Now we need a flag for whether AMP is exclusive to a theme, in which case all templates and post types must render AMP. In other words, all_templates_supported.
 		);
 
 		if ( true !== $verify ) {
@@ -181,23 +188,14 @@ public function render_status( $post ) {
 		$status = empty( $errors ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
 		$errors = array_diff( $errors, array( 'post-status-disabled' ) ); // Subtract the status which the metabox will allow to be toggled.
 
-		// @todo If ! supported and immutable, don't show the toggle at all?
 		// Handle special case of the static front page or page for posts.
 		if ( current_theme_supports( 'amp' ) ) {
-
-			$query = new WP_Query();
-			if ( 'page' === $post->post_type ) {
-				$query->set( 'page_id', $post->ID );
-			} else {
-				$query->set( 'p', $post->ID );
-			}
-			$query->queried_object    = $post;
-			$query->queried_object_id = $post->ID;
-			$query->parse_query_vars();
-
-			$availability = AMP_Theme_Support::get_template_availability( $query );
-			if ( $availability instanceof WP_Error && 0 !== count( array_diff( $availability->get_error_codes(), $errors, array( 'post-status-disabled' ) ) ) ) {
-				$errors[] = 'template-unavailable';
+			$availability = AMP_Theme_Support::get_template_availability( $post );
+			if ( true === $availability['immutable'] ) {
+				$errors[] = 'status_immutable';
+				$status   = $availability['supported'] ? self::ENABLED_STATUS : self::DISABLED_STATUS;
+			} elseif ( ! $availability['supported'] && in_array( 'template_unsupported', $availability['errors'], true ) ) {
+				$errors[] = 'template_unsupported';
 				$status   = self::DISABLED_STATUS;
 			}
 		}
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index e11f6b830c4..964a563ce94 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -249,13 +249,14 @@ function post_supports_amp( $post ) {
  * Determine whether the current response being served as AMP.
  *
  * This function cannot be called before the parse_query action because it needs to be able
- * to determine the queried object is able to be served as AMP.
+ * to determine the queried object is able to be served as AMP. If 'amp' theme support is not
+ * present, this function returns true just if the query var is present. If theme support is
+ * present, then it returns true in paired mode if an AMP template is available and the query
+ * var is present, or else in native mode if just the template is available.
  *
- * @see is_header_video_active()
  * @return bool Whether it is the AMP endpoint.
  */
 function is_amp_endpoint() {
-	global $wp_query;
 	if ( is_admin() || is_feed() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) ) {
 		return false;
 	}
@@ -272,29 +273,17 @@ function is_amp_endpoint() {
 		false !== get_query_var( amp_get_slug(), false )
 	);
 
+	if ( ! current_theme_supports( 'amp' ) ) {
+		return $has_amp_query_var;
+	}
+
 	// When there is no query var and AMP is not canonical/native, then this is definitely not an AMP endpoint.
 	if ( ! $has_amp_query_var && ! amp_is_canonical() ) {
 		return false;
 	}
 
-	if ( current_theme_supports( 'amp' ) ) {
-		$template_available = true === AMP_Theme_Support::get_template_availability();
-		return amp_is_canonical() ? $template_available : $has_amp_query_var;
-	} else {
-
-		// Check if the queried object supports AMP.
-		if ( is_singular() || ( $wp_query instanceof WP_Query && $wp_query->is_posts_page ) ) {
-			/**
-			 * Post.
-			 *
-			 * @var WP_Post $queried_object
-			 */
-			$queried_object = get_queried_object();
-			return post_supports_amp( $queried_object );
-		}
-
-		return false; // Legacy templates only support posts via AMP_Post_Template.
-	}
+	$availability = AMP_Theme_Support::get_template_availability();
+	return amp_is_canonical() ? $availability['supported'] : ( $has_amp_query_var && $availability['supported'] );
 }
 
 /**
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 75d823a1071..207da9c5572 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -142,7 +142,7 @@ public static function init() {
 	}
 
 	/**
-	 * Determine whether theme support as added via option.
+	 * Determine whether theme support was added via option.
 	 *
 	 * @since 1.0
 	 * @return bool Optional support added.
@@ -177,6 +177,10 @@ public static function apply_options() {
 			}
 		}
 
+		if ( ! $theme_support_args ) {
+			$theme_support_args = array();
+		}
+
 		// If theme support is not present, then allow it to be added via the admin.
 		if ( ! current_theme_supports( 'amp' ) ) {
 			if ( 'disabled' === $theme_support_option ) {
@@ -317,11 +321,7 @@ public static function is_paired_available() {
 		}
 
 		$availability = self::get_template_availability();
-		if ( is_wp_error( $availability ) ) {
-			return false;
-		}
-
-		return true;
+		return $availability['supported'];
 	}
 
 	/**
@@ -354,24 +354,59 @@ public static function add_amp_template_filters() {
 	 * @global WP_Query $wp_query
 	 * @see post_supports_amp()
 	 *
-	 * @param WP_Query|null $query Query or queried post. If null then the global query will be used.
-	 * @return true|WP_Error True if template is available, WP_Error if otherwise.
+	 * @param WP_Query|WP_Post|null $query Query or queried post. If null then the global query will be used.
+	 * @return array {
+	 *     Template availability.
+	 *
+	 *     @type bool        $supported Whether the template is supported in AMP.
+	 *     @type bool|null   $immutable Whether the supported status is known to be unchangeable.
+	 *     @type string|null $template  The ID of the matched template (conditional), such as 'is_singular', or null if nothing was matched.
+	 *     @type string[]    $errors    List of the errors or reasons for why the template is not available.
+	 * }
 	 */
 	public static function get_template_availability( $query = null ) {
 		global $wp_query;
 		if ( ! $query ) {
 			$query = $wp_query;
+		} elseif ( $query instanceof WP_Post ) {
+			$post  = $query;
+			$query = new WP_Query();
+			if ( 'page' === $post->post_type ) {
+				$query->set( 'page_id', $post->ID );
+			} else {
+				$query->set( 'p', $post->ID );
+			}
+			$query->queried_object    = $post;
+			$query->queried_object_id = $post->ID;
+			$query->parse_query_vars();
 		}
 
+		$default_response = array(
+			'errors'    => array(),
+			'supported' => false,
+			'immutable' => null,
+			'template'  => null,
+		);
+
 		if ( ! ( $query instanceof WP_Query ) ) {
 			_doing_it_wrong( __FUNCTION__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
-			return new WP_Error( 'no_query_available' );
+			return array_merge(
+				$default_response,
+				array( 'errors' => array( 'no_query_available' ) )
+			);
 		}
 
 		if ( ! current_theme_supports( 'amp' ) ) {
-			return new WP_Error( 'no_theme_support' );
+			return array_merge(
+				$default_response,
+				array( 'errors' => array( 'no_theme_support' ) )
+			);
 		}
 
+		// Make sure global $wp_query is set in case of conditionals that unfortunately look at global scope.
+		$prev_query = $wp_query;
+		$wp_query   = $query; // WPCS: override ok.
+
 		$matching_templates    = array();
 		$supportable_templates = self::get_supportable_templates();
 		foreach ( $supportable_templates as $id => $supportable_template ) {
@@ -381,23 +416,33 @@ public static function get_template_availability( $query = null ) {
 				$callback = $supportable_template['callback'];
 			}
 
-			// @todo Consider using the $id as the conditional callback.
 			// If the available_callback is a method on the query, then call the method on the query itself.
 			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
 				$is_match = call_user_func( array( $query, $callback ) );
-			} else {
+			} elseif ( is_callable( $callback ) ) {
 				$is_match = call_user_func( $callback );
+			} else {
+				/* translators: %s is the supportable template ID. */
+				_doing_it_wrong( __FUNCTION__, esc_html__( 'Supportable template "%s" does not have a callable callback.', 'amp' ), '1.0' );
+				$is_match = false;
 			}
 
 			if ( $is_match ) {
-				$matching_templates[ $id ] = (
-					! empty( $supportable_template['supported'] )
-					||
-					( AMP_Options_Manager::get_option( 'all_templates_supported' ) && empty( $supportable_template['immutable'] ) )
+				$matching_templates[ $id ] = array(
+					'template'  => $id,
+					'supported' => (
+						! empty( $supportable_template['supported'] )
+						||
+						( AMP_Options_Manager::get_option( 'all_templates_supported' ) && empty( $supportable_template['immutable'] ) )
+					),
+					'immutable' => ! empty( $supportable_template['immutable'] ),
 				);
 			}
 		}
 
+		// Restore previous $wp_query (if any).
+		$wp_query = $prev_query; // WPCS: override ok.
+
 		// Make sure children override their parents.
 		$matching_template_ids = array_keys( $matching_templates );
 		foreach ( $matching_template_ids as $id ) {
@@ -425,9 +470,24 @@ public static function get_template_availability( $query = null ) {
 			}
 		}
 
+		if ( count( $matching_templates ) > 1 ) {
+			_doing_it_wrong( __FUNCTION__, esc_html__( 'Did not expect there to be more than one matching template. Did you filter amp_supportable_templates to not honor the template hierarchy?', 'amp' ), '1.0' );
+		}
+
+		$matching_template = array_shift( $matching_templates );
+
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
-		if ( ! in_array( true, $matching_templates, true ) ) {
-			return new WP_Error( 'no_supported_template' );
+		if ( ! $matching_template ) {
+			return array_merge(
+				$default_response,
+				array( 'errors' => array( 'no_matching_template' ) )
+			);
+		}
+		$matching_template = array_merge( $default_response, $matching_template );
+
+		// If there aren't any matching templates left that are supported, then we consider it to not be available.
+		if ( empty( $matching_template['supported'] ) ) {
+			$matching_template['errors'][] = 'template_unsupported';
 		}
 
 		// For singular queries, post_supports_amp() is given the final say.
@@ -440,16 +500,12 @@ public static function get_template_availability( $query = null ) {
 			$queried_object = $query->get_queried_object();
 			$support_errors = AMP_Post_Type_Support::get_support_errors( $queried_object );
 			if ( ! empty( $support_errors ) ) {
-				$error = new WP_Error();
-				foreach ( $support_errors as $support_error ) {
-					$error->add( $support_error, '' );
-				}
-				return $error;
+				$matching_template['errors']    = array_merge( $matching_template['errors'], $support_errors );
+				$matching_template['supported'] = false;
 			}
 		}
 
-		// If all checks have passed, then the template is available.
-		return true;
+		return $matching_template;
 	}
 
 	/**
@@ -560,7 +616,13 @@ public static function get_supportable_templates() {
 		 *
 		 * A theme or plugin can force a given template to be supported or not by preemptively
 		 * setting the 'supported' flag for a given template. Otherwise, if the flag is undefined
-		 * then the user will be able to toggle it themselves in the admin.
+		 * then the user will be able to toggle it themselves in the admin. Each array item should
+		 * have a key that corresponds to a template conditional function. If the key is such a
+		 * function, then the key is used to evaluate whether the given template entry is a match.
+		 * Otherwise, a supportable template item can include a callback value which is used instead.
+		 * Each item needs a 'label' value. Additionally, if the supportable template is a subset of
+		 * another condition (e.g. is_singular > is_single) then this relationship needs to be
+		 * indicated via the 'parent' value.
 		 *
 		 * @since 1.0
 		 *
@@ -572,7 +634,7 @@ public static function get_supportable_templates() {
 		foreach ( $templates as $id => &$template ) {
 			$template['immutable'] = isset( $template['supported'] );
 			if ( ! $template['immutable'] ) {
-				$template['supported'] = in_array( $id, $supported_templates, true );
+				$template['supported'] = AMP_Options_Manager::get_option( 'all_templates_supported' ) || in_array( $id, $supported_templates, true );
 			}
 		}
 
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 30d7f342487..1bc96fc2a3f 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -299,7 +299,7 @@ public function render_supported_templates() {
 			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
 			<h4 class="title"><?php esc_html_e( 'Content Types', 'amp' ); ?></h4>
 			<p>
-				<?php esc_html_e( 'The following content types will be available as AMP by default, but you can override this on an item-by-item basis:', 'amp' ); ?>
+				<?php esc_html_e( 'The following content types will be available as AMP:', 'amp' ); ?>
 			</p>
 			<ul>
 			<?php foreach ( array_map( 'get_post_type_object', AMP_Post_Type_Support::get_eligible_post_types() ) as $post_type ) : ?>
@@ -310,7 +310,7 @@ public function render_supported_templates() {
 						id="<?php echo esc_attr( $element_id ); ?>"
 						name="<?php echo esc_attr( $element_name ); ?>"
 						value="<?php echo esc_attr( $post_type->name ); ?>"
-						<?php checked( true, post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
+						<?php checked( post_type_supports( $post_type->name, amp_get_slug() ) ); ?>
 						>
 					<label for="<?php echo esc_attr( $element_id ); ?>">
 						<?php echo esc_html( $post_type->label ); ?>
diff --git a/includes/validation/class-amp-validation-manager.php b/includes/validation/class-amp-validation-manager.php
index 1e9a0bca866..9c7a34484cd 100644
--- a/includes/validation/class-amp-validation-manager.php
+++ b/includes/validation/class-amp-validation-manager.php
@@ -218,7 +218,13 @@ public static function is_sanitization_forcibly_accepted() {
 	 * @param WP_Admin_Bar $wp_admin_bar Admin bar.
 	 */
 	public static function add_admin_bar_menu_items( $wp_admin_bar ) {
-		if ( is_admin() || ! self::has_cap() || is_wp_error( AMP_Theme_Support::get_template_availability() ) ) {
+		if ( is_admin() || ! self::has_cap() ) {
+			self::$amp_admin_bar_item_added = false;
+			return;
+		}
+
+		$availability = AMP_Theme_Support::get_template_availability();
+		if ( ! $availability['supported'] ) {
 			self::$amp_admin_bar_item_added = false;
 			return;
 		}
diff --git a/templates/admin/amp-status.php b/templates/admin/amp-status.php
index 8bf6696f958..61d542ea6df 100644
--- a/templates/admin/amp-status.php
+++ b/templates/admin/amp-status.php
@@ -42,7 +42,14 @@
 				<p>
 					<?php
 					$error_messages = array();
-					if ( in_array( 'template-unavailable', $errors, true ) ) {
+					if ( in_array( 'status_immutable', $errors, true ) ) {
+						if ( self::ENABLED_STATUS === $status ) {
+							$error_messages[] = __( 'Your site does not allow AMP to be disabled.', 'amp' );
+						} else {
+							$error_messages[] = __( 'Your site does not allow AMP to be enabled.', 'amp' );
+						}
+					}
+					if ( in_array( 'template_unsupported', $errors, true ) ) {
 						/* translators: %s is URL to AMP settings screen */
 						$error_messages[] = wp_kses_post( sprintf( __( 'There are no <a href="%s">supported templates</a> to display this in AMP.', 'amp' ), esc_url( admin_url( 'admin.php?page=' . AMP_Options_Manager::OPTION_NAME ) ) ) );
 					}
@@ -56,7 +63,7 @@
 					if ( in_array( 'skip-post', $errors, true ) ) {
 						$error_messages[] = __( 'A plugin or theme has disabled AMP support.', 'amp' );
 					}
-					if ( count( array_diff( $errors, array( 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post', 'template-unavailable' ) ) ) > 0 ) {
+					if ( count( array_diff( $errors, array( 'status_immutable', 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post', 'template_unsupported' ) ) ) > 0 ) {
 						$error_messages[] = __( 'Unavailable for an unknown reason.', 'amp' );
 					}
 					echo implode( ' ', $error_messages ); // WPCS: xss ok.
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index aefba4db352..65ab75016c6 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -76,19 +76,19 @@ public function test_enqueue_admin_assets() {
 	 * @see AMP_Settings::render_status()
 	 */
 	public function test_render_status() {
-		$post = $this->factory->post->create_and_get();
-		wp_set_current_user( $this->factory->user->create( array(
+		$post = $this->factory()->post->create_and_get();
+		wp_set_current_user( $this->factory()->user->create( array(
 			'role' => 'administrator',
 		) ) );
 		$amp_status_markup = '<div class="misc-pub-section misc-amp-status"';
 
-		// This is in AMP 'canonical mode,' so it shouldn't have the AMP status.
+		// This is in AMP 'native mode' so it shouldn't have the AMP status.
 		add_theme_support( 'amp' );
 		ob_start();
 		$this->instance->render_status( $post );
-		$this->assertNotContains( $amp_status_markup, ob_get_clean() );
+		$this->assertContains( $amp_status_markup, ob_get_clean() );
 
-		// This is not in AMP 'canonical mode'.
+		// This is not in AMP 'canonical mode', but rather classic mode.
 		remove_theme_support( 'amp' );
 		ob_start();
 		$this->instance->render_status( $post );
@@ -101,7 +101,7 @@ public function test_render_status() {
 		$this->assertEmpty( ob_get_clean() );
 
 		add_post_type_support( 'post', amp_get_slug() );
-		wp_set_current_user( $this->factory->user->create( array(
+		wp_set_current_user( $this->factory()->user->create( array(
 			'role' => 'subscriber',
 		) ) );
 
diff --git a/tests/test-class-amp-options-manager.php b/tests/test-class-amp-options-manager.php
index 39b00c4138b..94ddce6f983 100644
--- a/tests/test-class-amp-options-manager.php
+++ b/tests/test-class-amp-options-manager.php
@@ -90,14 +90,18 @@ public function test_get_and_set_options() {
 
 		AMP_Options_Manager::register_settings(); // Adds validate_options as filter.
 		delete_option( AMP_Options_Manager::OPTION_NAME );
-		$this->assertSame(
+		$this->assertEquals(
 			array(
-				'theme_support'        => 'disabled',
-				'supported_post_types' => array(),
-				'analytics'            => array(),
-				'force_sanitization'   => false,
-				'accept_tree_shaking'  => false,
-				'disable_admin_bar'    => false,
+				'theme_support'           => 'disabled',
+				'supported_post_types'    => array(),
+				'analytics'               => array(),
+				'force_sanitization'      => false,
+				'accept_tree_shaking'     => false,
+				'disable_admin_bar'       => false,
+				'all_templates_supported' => true,
+				'supported_templates'     => array(
+					'is_singular',
+				),
 			),
 			AMP_Options_Manager::get_options()
 		);
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 07d64cee04a..dd7bbcc5653 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -311,9 +311,8 @@ public function test_register_paired_hooks() {
 		);
 		AMP_Theme_Support::add_amp_template_filters();
 		foreach ( $template_types as $template_type ) {
-			$this->assertEquals( 10, has_filter( "{$template_type}_template_hierarchy", array( self::TESTED_CLASS, 'filter_paired_template_hierarchy' ) ) );
+			$this->assertEquals( 10, has_filter( "{$template_type}_template_hierarchy", array( self::TESTED_CLASS, 'filter_amp_template_hierarchy' ) ) );
 		}
-		$this->assertEquals( 100, has_filter( 'template_include', array( self::TESTED_CLASS, 'filter_paired_template_include' ) ) );
 	}
 
 	/**
@@ -774,30 +773,14 @@ public function test_filter_paired_template_hierarchy() {
 			'single.php',
 		);
 		$filtered_templates = AMP_Theme_Support::filter_amp_template_hierarchy( $templates );
-		foreach ( $filtered_templates as $key => $filtered_template ) {
-			$this->assertEquals( $template_dir . '/' . $templates[ $key ], $filtered_template );
-		}
-	}
 
-	/**
-	 * Test filter_paired_template_include.
-	 *
-	 * @covers AMP_Theme_Support::filter_amp_template_include()
-	 */
-	public function test_filter_paired_template_include() {
-		$template_dir = 'amp-templates';
-		$template     = 'single.php';
-		add_theme_support( 'amp', array(
-			'template_dir' => $template_dir,
-		) );
-		$this->assertEquals( $template, AMP_Theme_Support::filter_amp_template_include( $template ) );
-		remove_theme_support( 'amp' );
-		try {
-			AMP_Theme_Support::filter_amp_template_include( $template );
-		} catch ( Exception $exception ) {
-			$e = $exception;
+		$expected_templates = array();
+		foreach ( $templates as $template ) {
+			$expected_templates[] = $template_dir . '/' . $template;
+			$expected_templates[] = $template;
 		}
-		$this->assertTrue( isset( $e ) );
+
+		$this->assertEquals( $expected_templates, $filtered_templates );
 	}
 
 	/**
diff --git a/tests/test-class-amp-widget-archives.php b/tests/test-class-amp-widget-archives.php
index bef6d8639ee..8a63adc69bd 100644
--- a/tests/test-class-amp-widget-archives.php
+++ b/tests/test-class-amp-widget-archives.php
@@ -32,6 +32,16 @@ public function setUp() {
 		$this->widget = new AMP_Widget_Archives();
 	}
 
+	/**
+	 * Tear down.
+	 *
+	 * @inheritdoc
+	 */
+	public function tearDown() {
+		parent::tearDown();
+		remove_theme_support( 'amp' );
+	}
+
 	/**
 	 * Test construct().
 	 *
diff --git a/tests/test-class-amp-widget-categories.php b/tests/test-class-amp-widget-categories.php
index b79bc42dea2..d8c7b918300 100644
--- a/tests/test-class-amp-widget-categories.php
+++ b/tests/test-class-amp-widget-categories.php
@@ -15,7 +15,7 @@ class Test_AMP_Widget_Categories extends WP_UnitTestCase {
 	/**
 	 * Instance of the widget.
 	 *
-	 * @var object.
+	 * @var AMP_Widget_Categories
 	 */
 	public $widget;
 
@@ -26,12 +26,22 @@ class Test_AMP_Widget_Categories extends WP_UnitTestCase {
 	 */
 	public function setUp() {
 		parent::setUp();
-		add_theme_support( 'amp ' );
+		add_theme_support( 'amp' );
 		wp_maybe_load_widgets();
 		AMP_Theme_Support::init();
 		$this->widget = new AMP_Widget_Categories();
 	}
 
+	/**
+	 * Tear down.
+	 *
+	 * @inheritdoc
+	 */
+	public function tearDown() {
+		parent::tearDown();
+		remove_theme_support( 'amp' );
+	}
+
 	/**
 	 * Test construct().
 	 *
diff --git a/tests/test-class-amp-widget-media-video.php b/tests/test-class-amp-widget-media-video.php
index d93556d85ab..b1efc616337 100644
--- a/tests/test-class-amp-widget-media-video.php
+++ b/tests/test-class-amp-widget-media-video.php
@@ -17,7 +17,7 @@ class Test_AMP_Widget_Media_Video extends WP_UnitTestCase {
 	/**
 	 * Instance of the widget.
 	 *
-	 * @var object.
+	 * @var AMP_Widget_Media_Video.
 	 */
 	public $widget;
 
@@ -34,6 +34,17 @@ public function setUp() {
 		parent::setUp();
 		wp_maybe_load_widgets();
 		$this->widget = new $class();
+		add_theme_support( 'amp' );
+	}
+
+	/**
+	 * Tear down.
+	 *
+	 * @inheritdoc
+	 */
+	public function tearDown() {
+		parent::tearDown();
+		remove_theme_support( 'amp' );
 	}
 
 	/**
@@ -42,6 +53,7 @@ public function setUp() {
 	 * @covers AMP_Widget_Media_Video::inject_video_max_width_style()
 	 */
 	public function test_inject_video_max_width_style() {
+		$this->assertTrue( is_amp_endpoint() );
 		$video           = '<video src="http://example.com" height="100" width="200"></video>';
 		$video_no_height = '<video src="http://example.com" width="200"></video>';
 		$this->assertEquals( $video, $this->widget->inject_video_max_width_style( $video ) );
diff --git a/tests/test-class-amp-widget-text.php b/tests/test-class-amp-widget-text.php
index 26d371d666f..f0f0e8b6694 100644
--- a/tests/test-class-amp-widget-text.php
+++ b/tests/test-class-amp-widget-text.php
@@ -34,6 +34,17 @@ public function setUp() {
 		parent::setUp();
 		wp_maybe_load_widgets();
 		$this->widget = new $class();
+		add_theme_support( 'amp' );
+	}
+
+	/**
+	 * Tear down.
+	 *
+	 * @inheritdoc
+	 */
+	public function tearDown() {
+		parent::tearDown();
+		remove_theme_support( 'amp' );
 	}
 
 	/**
@@ -42,7 +53,7 @@ public function setUp() {
 	 * @covers AMP_Widget_Text::inject_video_max_width_style()
 	 */
 	public function test_inject_video_max_width_style() {
-		add_theme_support( 'amp' );
+		$this->assertTrue( is_amp_endpoint() );
 		$video            = '<video src="http://example.com" height="100" width="200"></video>';
 		$video_only_width = '<video src="http://example.com/this-video" width="500">';
 		$this->assertEquals( $video, $this->widget->inject_video_max_width_style( array( $video ) ) );

From a7371d17fc376cccb59294a7ab44a29d61d951f0 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 09:57:21 -0700
Subject: [PATCH 16/34] Simplify logic in AMP_Post_Meta_Box::render_status

[ci skip]
---
 includes/admin/class-amp-post-meta-box.php | 15 ++++++---------
 tests/test-amp-helper-functions.php        |  1 +
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 8747467878f..3981c44529d 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -184,20 +184,17 @@ public function render_status( $post ) {
 			return;
 		}
 
-		$errors = AMP_Post_Type_Support::get_support_errors( $post );
-		$status = empty( $errors ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
-		$errors = array_diff( $errors, array( 'post-status-disabled' ) ); // Subtract the status which the metabox will allow to be toggled.
-
-		// Handle special case of the static front page or page for posts.
 		if ( current_theme_supports( 'amp' ) ) {
 			$availability = AMP_Theme_Support::get_template_availability( $post );
+			$status       = $availability['supported'] ? self::ENABLED_STATUS : self::DISABLED_STATUS;
+			$errors       = array_diff( $availability['errors'], array( 'post-status-disabled' ) ); // Subtract the status which the metabox will allow to be toggled.
 			if ( true === $availability['immutable'] ) {
 				$errors[] = 'status_immutable';
-				$status   = $availability['supported'] ? self::ENABLED_STATUS : self::DISABLED_STATUS;
-			} elseif ( ! $availability['supported'] && in_array( 'template_unsupported', $availability['errors'], true ) ) {
-				$errors[] = 'template_unsupported';
-				$status   = self::DISABLED_STATUS;
 			}
+		} else {
+			$errors = AMP_Post_Type_Support::get_support_errors( $post );
+			$status = empty( $errors ) ? self::ENABLED_STATUS : self::DISABLED_STATUS;
+			$errors = array_diff( $errors, array( 'post-status-disabled' ) ); // Subtract the status which the metabox will allow to be toggled.
 		}
 
 		$labels = array(
diff --git a/tests/test-amp-helper-functions.php b/tests/test-amp-helper-functions.php
index d7391910cfd..290660ba1ce 100644
--- a/tests/test-amp-helper-functions.php
+++ b/tests/test-amp-helper-functions.php
@@ -316,6 +316,7 @@ public function test_amp_add_amphtml_link( $canonical_url, $amphtml_url ) {
 	 * @covers \is_amp_endpoint()
 	 */
 	public function test_is_amp_endpoint() {
+		$this->go_to( get_permalink( $this->factory()->post->create() ) );
 		$this->assertFalse( is_amp_endpoint() );
 
 		// Legacy query var.

From 1adad3e224d82c1bdd9367e7b6512e8b00729ef2 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 15:59:17 -0700
Subject: [PATCH 17/34] Fix tests regarding amp status metabox

[ci skip]
---
 includes/admin/class-amp-post-meta-box.php |  2 +-
 templates/admin/amp-status.php             |  4 +--
 tests/test-amp-render-post.php             |  5 ++--
 tests/test-class-amp-meta-box.php          | 32 +++++++++++++++++-----
 4 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 3981c44529d..58c14246363 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -203,7 +203,7 @@ public function render_status( $post ) {
 		);
 
 		// The preceding variables are used inside the following amp-status.php template.
-		include_once AMP__DIR__ . '/templates/admin/amp-status.php';
+		include AMP__DIR__ . '/templates/admin/amp-status.php';
 	}
 
 	/**
diff --git a/templates/admin/amp-status.php b/templates/admin/amp-status.php
index 61d542ea6df..8dc6fc6f9f9 100644
--- a/templates/admin/amp-status.php
+++ b/templates/admin/amp-status.php
@@ -49,7 +49,7 @@
 							$error_messages[] = __( 'Your site does not allow AMP to be enabled.', 'amp' );
 						}
 					}
-					if ( in_array( 'template_unsupported', $errors, true ) ) {
+					if ( in_array( 'template_unsupported', $errors, true ) || in_array( 'no_matching_template', $errors, true ) ) {
 						/* translators: %s is URL to AMP settings screen */
 						$error_messages[] = wp_kses_post( sprintf( __( 'There are no <a href="%s">supported templates</a> to display this in AMP.', 'amp' ), esc_url( admin_url( 'admin.php?page=' . AMP_Options_Manager::OPTION_NAME ) ) ) );
 					}
@@ -63,7 +63,7 @@
 					if ( in_array( 'skip-post', $errors, true ) ) {
 						$error_messages[] = __( 'A plugin or theme has disabled AMP support.', 'amp' );
 					}
-					if ( count( array_diff( $errors, array( 'status_immutable', 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post', 'template_unsupported' ) ) ) > 0 ) {
+					if ( count( array_diff( $errors, array( 'status_immutable', 'page-on-front', 'page-for-posts', 'password-protected', 'post-type-support', 'skip-post', 'template_unsupported', 'no_matching_template' ) ) ) > 0 ) {
 						$error_messages[] = __( 'Unavailable for an unknown reason.', 'amp' );
 					}
 					echo implode( ' ', $error_messages ); // WPCS: xss ok.
diff --git a/tests/test-amp-render-post.php b/tests/test-amp-render-post.php
index 13fa8b7ec59..4c839562c66 100644
--- a/tests/test-amp-render-post.php
+++ b/tests/test-amp-render-post.php
@@ -35,8 +35,8 @@ public function test__valid_post() {
 	 * @covers \is_amp_endpoint()
 	 */
 	public function test__is_amp_endpoint() {
-		$user_id = $this->factory->user->create();
-		$post_id = $this->factory->post->create( array(
+		$user_id = $this->factory()->user->create();
+		$post_id = $this->factory()->post->create( array(
 			'post_author' => $user_id,
 		) );
 
@@ -58,6 +58,7 @@ public function test__is_amp_endpoint() {
 		$this->assertFalse( $after_is_amp_endpoint, 'is_amp_endpoint was not reset after amp_render_post' );
 
 		add_theme_support( 'amp' );
+		$this->go_to( get_permalink( $post_id ) );
 		$this->assertTrue( is_amp_endpoint() );
 
 		// Make is_admin() true, as requests for an admin page aren't for AMP endpoints.
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index 65ab75016c6..94661312891 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -80,26 +80,44 @@ public function test_render_status() {
 		wp_set_current_user( $this->factory()->user->create( array(
 			'role' => 'administrator',
 		) ) );
+		add_post_type_support( 'post', amp_get_slug() );
 		$amp_status_markup = '<div class="misc-pub-section misc-amp-status"';
+		$checkbox_enabled  = '<input id="amp-status-enabled" type="radio" name="amp_status" value="enabled"  checked=\'checked\'>';
 
-		// This is in AMP 'native mode' so it shouldn't have the AMP status.
-		add_theme_support( 'amp' );
+		// This is not in AMP 'canonical mode' but rather classic paired mode.
+		remove_theme_support( 'amp' );
 		ob_start();
 		$this->instance->render_status( $post );
-		$this->assertContains( $amp_status_markup, ob_get_clean() );
+		$output = ob_get_clean();
+		$this->assertContains( $amp_status_markup, $output );
+		$this->assertContains( $checkbox_enabled, $output );
 
-		// This is not in AMP 'canonical mode', but rather classic mode.
-		remove_theme_support( 'amp' );
+		// This is in AMP native mode with a template that can be rendered.
+		add_theme_support( 'amp' );
 		ob_start();
 		$this->instance->render_status( $post );
-		$this->assertContains( $amp_status_markup, ob_get_clean() );
+		$output = ob_get_clean();
+		$this->assertContains( $amp_status_markup, $output );
+		$this->assertContains( $checkbox_enabled, $output );
 
+		// Post type no longer supports AMP, so no status input.
 		remove_post_type_support( 'post', amp_get_slug() );
+		ob_start();
+		$this->instance->render_status( $post );
+		$output = ob_get_clean();
+		$this->assertContains( 'post type does not support it', $output );
+		$this->assertNotContains( $checkbox_enabled, $output );
+		add_post_type_support( 'post', amp_get_slug() );
 
+		// No template is available to render the post.
+		add_filter( 'amp_supportable_templates', '__return_empty_array' );
 		ob_start();
 		$this->instance->render_status( $post );
-		$this->assertEmpty( ob_get_clean() );
+		$output = ob_get_clean();
+		$this->assertContains( 'no supported templates to display this in AMP.', strip_tags( $output ) );
+		$this->assertNotContains( $checkbox_enabled, $output );
 
+		// User doesn't have the capability to display the metabox.
 		add_post_type_support( 'post', amp_get_slug() );
 		wp_set_current_user( $this->factory()->user->create( array(
 			'role' => 'subscriber',

From fafb94e193bfffa87a0f521adfb0a621069974ee Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 16:07:29 -0700
Subject: [PATCH 18/34] Mock the gfycat requests during unit tests

[ci skip]
---
 tests/test-class-amp-gfycat-embed-handler.php | 14 ++++++++++++++
 tests/test-class-amp-meta-box.php             |  2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/tests/test-class-amp-gfycat-embed-handler.php b/tests/test-class-amp-gfycat-embed-handler.php
index b22409aae25..d5da538f13b 100644
--- a/tests/test-class-amp-gfycat-embed-handler.php
+++ b/tests/test-class-amp-gfycat-embed-handler.php
@@ -19,6 +19,20 @@ public function setUp() {
 		global $post;
 		parent::setUp();
 
+		// Mock the HTTP request.
+		add_filter( 'pre_http_request', function( $pre, $r, $url ) {
+			if ( false === strpos( $url, 'tautwhoppingcougar' ) ) {
+				return $pre;
+			}
+			return array(
+				'body'     => '{"version":"1.0","type":"video","provider_name":"https://gfycat.com","width":500,"height":281,"title":"Melanie Raccoon riding bike-side angle (reddit)","html":"<iframe src=\'https://gfycat.com/ifr/tautwhoppingcougar\' frameborder=\'0\' scrolling=\'no\' width=\'500\' height=\'281.25\'  allowfullscreen></iframe>"}',
+				'response' => array(
+					'code'    => 200,
+					'message' => 'OK',
+				),
+			);
+		}, 10, 3 );
+
 		/*
 		 * As #34115 in 4.9 a post is not needed for context to run oEmbeds. Prior ot 4.9, the WP_Embed::shortcode()
 		 * method would short-circuit when this is the case:
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index 94661312891..919b4bd69c3 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -114,7 +114,7 @@ public function test_render_status() {
 		ob_start();
 		$this->instance->render_status( $post );
 		$output = ob_get_clean();
-		$this->assertContains( 'no supported templates to display this in AMP.', strip_tags( $output ) );
+		$this->assertContains( 'no supported templates to display this in AMP.', wp_strip_all_tags( $output ) );
 		$this->assertNotContains( $checkbox_enabled, $output );
 
 		// User doesn't have the capability to display the metabox.

From 95fd958f1986c47e7475901e3457d4c9f1e1a63c Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 20:52:08 -0700
Subject: [PATCH 19/34] Let template_availability return supported when no
 templates match but all supported

* Fix remaining unit tests
* Mock external HTTP requests

[ci skip]
---
 includes/class-amp-theme-support.php         | 17 +++++++++++++----
 tests/test-class-amp-hulu-embed-handler.php  | 15 +++++++++++++++
 tests/test-class-amp-imgur-embed-handler.php | 15 +++++++++++++++
 tests/test-class-amp-meta-box.php            |  1 +
 tests/test-class-amp-options-manager.php     |  9 ++++++++-
 tests/test-class-amp-options-menu.php        |  2 +-
 tests/test-class-amp-post-type-support.php   |  4 +++-
 tests/test-class-amp-theme-support.php       | 12 +++++++++---
 tests/test-class-amp-widget-archives.php     |  1 +
 tests/test-class-amp-widget-categories.php   |  1 +
 10 files changed, 67 insertions(+), 10 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 207da9c5572..da72c07a10c 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -478,10 +478,19 @@ public static function get_template_availability( $query = null ) {
 
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! $matching_template ) {
-			return array_merge(
-				$default_response,
-				array( 'errors' => array( 'no_matching_template' ) )
-			);
+			if ( AMP_Options_Manager::get_option( 'all_templates_supported' ) ) {
+				return array_merge(
+					$default_response,
+					array(
+						'supported' => true,
+					)
+				);
+			} else {
+				return array_merge(
+					$default_response,
+					array( 'errors' => array( 'no_matching_template' ) )
+				);
+			}
 		}
 		$matching_template = array_merge( $default_response, $matching_template );
 
diff --git a/tests/test-class-amp-hulu-embed-handler.php b/tests/test-class-amp-hulu-embed-handler.php
index e002fa3443b..dbf178ab0ee 100644
--- a/tests/test-class-amp-hulu-embed-handler.php
+++ b/tests/test-class-amp-hulu-embed-handler.php
@@ -19,6 +19,21 @@ public function setUp() {
 		global $post;
 		parent::setUp();
 
+		// Mock the HTTP request.
+		add_filter( 'pre_http_request', function( $pre, $r, $url ) {
+			unset( $r );
+			if ( false === strpos( $url, '771496' ) ) {
+				return $pre;
+			}
+			return array(
+				'body'     => '{"title":"Out of the Box / Run Down Race Car (Doc McStuffins)","author_name":"Disney Junior","type":"video","provider_name":"Hulu","air_date":"Fri Mar 23 00:00:00 UTC 2012","embed_url":"//www.hulu.com/embed.html?eid=_hHzwnAcj3RrXMJFDDvkuw","thumbnail_url":"http://ib.huluim.com/video/60528019?size=240x180&caller=h1o&img=i","width":500,"thumbnail_width":500,"provider_url":"//www.hulu.com/","thumbnail_height":375,"cache_age":3600,"version":"1.0","large_thumbnail_url":"http://ib.huluim.com/video/60528019?size=512x288&caller=h1o&img=i","height":289,"large_thumbnail_width":512,"html":"<iframe width=\\"500\\" height=\\"289\\" src=\\"//www.hulu.com/embed.html?eid=_hHzwnAcj3RrXMJFDDvkuw\\" frameborder=\\"0\\" scrolling=\\"no\\" webkitAllowFullScreen mozallowfullscreen allowfullscreen> </iframe>","duration":1446.25,"large_thumbnail_height":288}',
+				'response' => array(
+					'code'    => 200,
+					'message' => 'OK',
+				),
+			);
+		}, 10, 3 );
+
 		/*
 		 * As #34115 in 4.9 a post is not needed for context to run oEmbeds. Prior ot 4.9, the WP_Embed::shortcode()
 		 * method would short-circuit when this is the case:
diff --git a/tests/test-class-amp-imgur-embed-handler.php b/tests/test-class-amp-imgur-embed-handler.php
index 38f749e5d8a..8def972a598 100644
--- a/tests/test-class-amp-imgur-embed-handler.php
+++ b/tests/test-class-amp-imgur-embed-handler.php
@@ -19,6 +19,21 @@ public function setUp() {
 		global $post;
 		parent::setUp();
 
+		// Mock the HTTP request.
+		add_filter( 'pre_http_request', function( $pre, $r, $url ) {
+			unset( $r );
+			if ( false === strpos( $url, 'f462IUj' ) ) {
+				return $pre;
+			}
+			return array(
+				'body'     => '{"version":"1.0","type":"rich","provider_name":"Imgur","provider_url":"https:\\/\\/imgur.com","width":500,"height":750,"html":"<blockquote class=\\"imgur-embed-pub\\" lang=\\"en\\" data-id=\\"f462IUj\\"><a href=\\"https:\\/\\/imgur.com\\/f462IUj\\">Getting that beach body ready<\\/a><\\/blockquote><script async src=\\"\\/\\/s.imgur.com\\/min\\/embed.js\\" charset=\\"utf-8\\"><\\/script>"}', // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedScript, WordPress.Arrays.ArrayDeclarationSpacing.ArrayItemNoNewLine
+				'response' => array(
+					'code'    => 200,
+					'message' => 'OK',
+				),
+			);
+		}, 10, 3 );
+
 		/*
 		 * As #34115 in 4.9 a post is not needed for context to run oEmbeds. Prior ot 4.9, the WP_Embed::shortcode()
 		 * method would short-circuit when this is the case:
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index 919b4bd69c3..62a0faa9519 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -111,6 +111,7 @@ public function test_render_status() {
 
 		// No template is available to render the post.
 		add_filter( 'amp_supportable_templates', '__return_empty_array' );
+		AMP_Options_Manager::update_option( 'all_templates_supported', false );
 		ob_start();
 		$this->instance->render_status( $post );
 		$output = ob_get_clean();
diff --git a/tests/test-class-amp-options-manager.php b/tests/test-class-amp-options-manager.php
index 94ddce6f983..c8f8441283a 100644
--- a/tests/test-class-amp-options-manager.php
+++ b/tests/test-class-amp-options-manager.php
@@ -93,7 +93,9 @@ public function test_get_and_set_options() {
 		$this->assertEquals(
 			array(
 				'theme_support'           => 'disabled',
-				'supported_post_types'    => array(),
+				'supported_post_types'    => array(
+					'post',
+				),
 				'analytics'               => array(),
 				'force_sanitization'      => false,
 				'accept_tree_shaking'     => false,
@@ -210,6 +212,11 @@ public function test_get_and_set_options() {
 	 */
 	public function test_check_supported_post_type_update_errors() {
 		global $wp_settings_errors;
+		add_theme_support( 'amp' );
+		AMP_Options_Manager::update_option( 'all_templates_supported', false );
+		foreach ( get_post_types() as $post_type ) {
+			remove_post_type_support( $post_type, 'amp' );
+		}
 
 		register_post_type( 'foo', array(
 			'public' => true,
diff --git a/tests/test-class-amp-options-menu.php b/tests/test-class-amp-options-menu.php
index aff7e0294bf..9276b250bed 100644
--- a/tests/test-class-amp-options-menu.php
+++ b/tests/test-class-amp-options-menu.php
@@ -77,7 +77,7 @@ public function test_add_menu_items() {
 		// Test add_setting_field().
 		$this->assertArrayHasKey( 'amp-options', $wp_settings_fields );
 		$this->assertArrayHasKey( 'general', $wp_settings_fields['amp-options'] );
-		$this->assertArrayHasKey( 'supported_post_types', $wp_settings_fields['amp-options']['general'] );
+		$this->assertArrayHasKey( 'supported_templates', $wp_settings_fields['amp-options']['general'] );
 	}
 
 	/**
diff --git a/tests/test-class-amp-post-type-support.php b/tests/test-class-amp-post-type-support.php
index 7197654366a..d362b8148dd 100644
--- a/tests/test-class-amp-post-type-support.php
+++ b/tests/test-class-amp-post-type-support.php
@@ -54,6 +54,7 @@ public function test_get_eligible_post_types() {
 	 * @covers AMP_Post_Type_Support::add_post_type_support()
 	 */
 	public function test_add_post_type_support() {
+		remove_theme_support( 'amp' );
 		register_post_type( 'book', array(
 			'label'  => 'Book',
 			'public' => true,
@@ -62,7 +63,7 @@ public function test_add_post_type_support() {
 			'label'  => 'Poem',
 			'public' => true,
 		) );
-		AMP_Options_Manager::update_option( 'supported_post_types', array( 'poem' ) );
+		AMP_Options_Manager::update_option( 'supported_post_types', array( 'post', 'poem' ) );
 
 		AMP_Post_Type_Support::add_post_type_support();
 		$this->assertTrue( post_type_supports( 'post', amp_get_slug() ) );
@@ -76,6 +77,7 @@ public function test_add_post_type_support() {
 	 * @covers AMP_Post_Type_Support::get_support_errors()
 	 */
 	public function test_get_support_error() {
+		remove_theme_support( 'amp' );
 		register_post_type( 'book', array(
 			'label'  => 'Book',
 			'public' => true,
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index dd7bbcc5653..3191b581040 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -264,11 +264,15 @@ public function test_is_paired_available() {
 		$this->assertTrue( AMP_Theme_Support::is_paired_available() );
 		remove_filter( 'amp_skip_post', '__return_true' );
 
-		// Check that available_callback works.
+		// Check that mode=paired works.
 		add_theme_support( 'amp', array(
-			'template_dir'       => 'amp-templates',
-			'available_callback' => 'is_singular',
+			'mode' => 'paired',
 		) );
+		add_filter( 'amp_supportable_templates', function( $supportable_templates ) {
+			$supportable_templates['is_singular']['supported'] = true;
+			$supportable_templates['is_search']['supported']   = false;
+			return $supportable_templates;
+		} );
 		query_posts( array( 'p' => $post_id ) ); // phpcs:ignore
 		$this->assertTrue( is_singular() );
 		$this->assertTrue( AMP_Theme_Support::is_paired_available() );
@@ -1068,6 +1072,8 @@ public function test_prepare_response() {
 		$wp_widget_factory = new WP_Widget_Factory();
 		wp_widgets_init();
 
+		$this->assertTrue( is_amp_endpoint() );
+
 		add_action( 'wp_enqueue_scripts', function() {
 			wp_enqueue_script( 'amp-list' );
 		} );
diff --git a/tests/test-class-amp-widget-archives.php b/tests/test-class-amp-widget-archives.php
index 8a63adc69bd..4c88a277824 100644
--- a/tests/test-class-amp-widget-archives.php
+++ b/tests/test-class-amp-widget-archives.php
@@ -62,6 +62,7 @@ public function test_construct() {
 	 * @see AMP_Widget_Archives::widget().
 	 */
 	public function test_widget() {
+		$this->assertTrue( is_amp_endpoint() );
 		$arguments = array(
 			'before_widget' => '<div>',
 			'after_widget'  => '</div>',
diff --git a/tests/test-class-amp-widget-categories.php b/tests/test-class-amp-widget-categories.php
index d8c7b918300..0eea973f18a 100644
--- a/tests/test-class-amp-widget-categories.php
+++ b/tests/test-class-amp-widget-categories.php
@@ -62,6 +62,7 @@ public function test_construct() {
 	 * @covers AMP_Widget_Categories::widget()
 	 */
 	public function test_widget() {
+		$this->assertTrue( is_amp_endpoint() );
 		$arguments = array(
 			'before_widget' => '<div>',
 			'after_widget'  => '</div>',

From 7e56c8b15ca2afdfbad655565a0c4f2547649fb6 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 21:04:35 -0700
Subject: [PATCH 20/34] Add unrecognized_templates_supported for Other
 templates

[ci skip]
---
 includes/class-amp-theme-support.php          |  7 +----
 .../options/class-amp-options-manager.php     | 26 ++++++++++---------
 includes/options/class-amp-options-menu.php   |  6 +++++
 tests/test-class-amp-meta-box.php             |  1 +
 tests/test-class-amp-options-manager.php      | 21 +++++++--------
 5 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index da72c07a10c..bbf31e210a9 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -163,7 +163,6 @@ public static function apply_options() {
 		$theme_support_args   = false;
 
 		// @todo Do we really need this optional flag? Yes. As it allows us to define the mode. Maybe it should be 'required' instead. Key for theme marketplaces? But if a theme is using the AMP features anyway, then it should have AMP as built-in and not be optional.
-
 		// If theme support is present in the theme, but it is marked as optional, then go ahead and remove it if theme support is not enabled in the admin.
 		if ( current_theme_supports( 'amp' ) ) {
 			$support            = get_theme_support( 'amp' );
@@ -478,7 +477,7 @@ public static function get_template_availability( $query = null ) {
 
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! $matching_template ) {
-			if ( AMP_Options_Manager::get_option( 'all_templates_supported' ) ) {
+			if ( AMP_Options_Manager::get_option( 'all_templates_supported' ) || AMP_Options_Manager::get_option( 'unrecognized_templates_supported' ) ) {
 				return array_merge(
 					$default_response,
 					array(
@@ -573,10 +572,6 @@ public static function get_supportable_templates() {
 				'is_404'     => array(
 					'label' => __( 'Not Found (404)', 'amp' ),
 				),
-//				'other'    => array(
-//					'label'    => __( 'Other', 'amp' ),
-//					'callback' => '__return_true', // @todo This can be treated as the parent of all, as the default.
-//				),
 			)
 		);
 
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 0ec87537169..29b13e63f5f 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -23,14 +23,15 @@ class AMP_Options_Manager {
 	 * @var array
 	 */
 	protected static $defaults = array(
-		'theme_support'           => 'disabled',
-		'supported_post_types'    => array( 'post' ),
-		'analytics'               => array(),
-		'force_sanitization'      => false,
-		'accept_tree_shaking'     => false,
-		'disable_admin_bar'       => false,
-		'all_templates_supported' => true,
-		'supported_templates'     => array(
+		'theme_support'                    => 'disabled',
+		'supported_post_types'             => array( 'post' ),
+		'analytics'                        => array(),
+		'force_sanitization'               => false,
+		'accept_tree_shaking'              => false,
+		'disable_admin_bar'                => false,
+		'all_templates_supported'          => true,
+		'unrecognized_templates_supported' => true,
+		'supported_templates'              => array(
 			'is_singular',
 		),
 	);
@@ -120,10 +121,11 @@ public static function validate_options( $new_options ) {
 			$options['theme_support'] = $new_options['theme_support'];
 		}
 
-		$options['force_sanitization']      = ! empty( $new_options['force_sanitization'] );
-		$options['accept_tree_shaking']     = ! empty( $new_options['accept_tree_shaking'] );
-		$options['disable_admin_bar']       = ! empty( $new_options['disable_admin_bar'] );
-		$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
+		$options['force_sanitization']               = ! empty( $new_options['force_sanitization'] );
+		$options['accept_tree_shaking']              = ! empty( $new_options['accept_tree_shaking'] );
+		$options['disable_admin_bar']                = ! empty( $new_options['disable_admin_bar'] );
+		$options['all_templates_supported']          = ! empty( $new_options['all_templates_supported'] );
+		$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
 
 		// Validate post type support.
 		$options['supported_post_types'] = array();
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 1bc96fc2a3f..314684ae285 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -330,6 +330,12 @@ public function render_supported_templates() {
 			<?php
 			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
 			?>
+			<p>
+				<label for="unrecognized_templates_supported">
+					<input id="unrecognized_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[unrecognized_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'unrecognized_templates_supported' ) ); ?>>
+					<?php esc_html_e( 'Other', 'amp' ); ?>
+				</label>
+			</p>
 			<script>
 				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
 				(function ( $ ) {
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index 62a0faa9519..a22796c7bf3 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -112,6 +112,7 @@ public function test_render_status() {
 		// No template is available to render the post.
 		add_filter( 'amp_supportable_templates', '__return_empty_array' );
 		AMP_Options_Manager::update_option( 'all_templates_supported', false );
+		AMP_Options_Manager::update_option( 'unrecognized_templates_supported', false );
 		ob_start();
 		$this->instance->render_status( $post );
 		$output = ob_get_clean();
diff --git a/tests/test-class-amp-options-manager.php b/tests/test-class-amp-options-manager.php
index c8f8441283a..8e8ed0c69dd 100644
--- a/tests/test-class-amp-options-manager.php
+++ b/tests/test-class-amp-options-manager.php
@@ -92,18 +92,15 @@ public function test_get_and_set_options() {
 		delete_option( AMP_Options_Manager::OPTION_NAME );
 		$this->assertEquals(
 			array(
-				'theme_support'           => 'disabled',
-				'supported_post_types'    => array(
-					'post',
-				),
-				'analytics'               => array(),
-				'force_sanitization'      => false,
-				'accept_tree_shaking'     => false,
-				'disable_admin_bar'       => false,
-				'all_templates_supported' => true,
-				'supported_templates'     => array(
-					'is_singular',
-				),
+				'theme_support'                    => 'disabled',
+				'supported_post_types'             => array( 'post' ),
+				'analytics'                        => array(),
+				'force_sanitization'               => false,
+				'accept_tree_shaking'              => false,
+				'disable_admin_bar'                => false,
+				'all_templates_supported'          => true,
+				'unrecognized_templates_supported' => true,
+				'supported_templates'              => array( 'is_singular' ),
 			),
 			AMP_Options_Manager::get_options()
 		);

From bfb202ae673d273e77e0b7f388de61032205c242 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sat, 30 Jun 2018 23:10:36 -0700
Subject: [PATCH 21/34] Let theme support args define templates_supported

* Make sure admin screen shows proper options when optional amp theme support has been disabled.
* Add get_theme_support_args method.
---
 amp.php                                       |  29 ++--
 includes/class-amp-theme-support.php          | 156 ++++++++++++++----
 .../options/class-amp-options-manager.php     |  50 +++---
 includes/options/class-amp-options-menu.php   | 106 +++++++-----
 tests/test-class-amp-theme-support.php        |   2 +-
 5 files changed, 230 insertions(+), 113 deletions(-)

diff --git a/amp.php b/amp.php
index 69d5e8cda37..acac3f5b7ed 100644
--- a/amp.php
+++ b/amp.php
@@ -286,22 +286,29 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *          'mode' => 'native',
  *      ) );
  *
- * If you want to force AMP to always be served on a given template, use the amp_supportable_templates filter,
+ * If you want to force AMP to always be served on a given template, you can use the templates_supported arg,
  * for example to always serve the Category template in AMP:
  *
- *      add_filter( 'amp_supportable_templates', function( $templates ) {
- *          $templates['is_category']['supported'] = true;
- *          return $template;
- *      } );
+ *      add_theme_support( 'amp', array(
+ *          'templates_supported' => array(
+ *              'is_category' => true,
+ *          ),
+ *      ) );
  *
- * Or if you want to prevent AMP from ever being served on the homepage:
+ * Or if you want to prevent AMP from being used on the front page and on any Other template that is unrecognized:
  *
- *      add_filter( 'amp_supportable_templates', function( $templates ) {
- *          $templates['is_front_page']['supported'] = false;
- *          return $template;
- *      } );
+ *      add_theme_support( 'amp', array(
+ *          'templates_supported' => array(
+ *              'is_front_page' => false,
+ *              'unrecognized' => false,
+ *          ),
+ *      ) );
  *
- * @todo There needs to be a required flag which is the same as forcing all to be supported. This would be the same in the UI as the all_templates_supported flag. Might as well rename all_templates_supported to just required. If required is set to be false, or if any of the supported templates are immutable, then this option should not be available.
+ * Or if you want to force AMP to be used on all templates:
+ *
+ *      add_theme_support( 'amp', array(
+ *          'templates_supported' => 'all',
+ *      ) );
  *
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index bbf31e210a9..eed6ec0cd31 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -90,6 +90,19 @@ class AMP_Theme_Support {
 	 */
 	protected static $is_output_buffering = false;
 
+	/**
+	 * Original theme support args prior to being read.
+	 *
+	 * This is needed to be able to properly populate the admin screen with AMP options defined by theme support
+	 * when the theme support is optional and disabled in the admin. For example, it allows for the original
+	 * template `mode` from the theme support to be displayed in the admin screen even though read_theme_support
+	 * may have removed the `optional` the theme support.
+	 *
+	 * @see AMP_Theme_Support::read_theme_support()
+	 * @var array
+	 */
+	protected static $initial_theme_support_args = array();
+
 	/**
 	 * Theme support options that were added via option.
 	 *
@@ -104,7 +117,7 @@ class AMP_Theme_Support {
 	 * @since 0.7
 	 */
 	public static function init() {
-		self::apply_options();
+		self::read_theme_support();
 		if ( ! current_theme_supports( 'amp' ) ) {
 			return;
 		}
@@ -120,17 +133,6 @@ public static function init() {
 
 		require_once AMP__DIR__ . '/includes/amp-post-template-actions.php';
 
-		// Validate theme support usage.
-		$support = get_theme_support( 'amp' );
-		if ( WP_DEBUG && is_array( $support ) ) {
-			$args = array_shift( $support );
-			if ( ! is_array( $args ) ) {
-				trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-			} elseif ( count( array_diff( array_keys( $args ), array( 'template_dir', 'available_callback', 'comments_live_list', 'mode', 'optional' ) ) ) !== 0 ) {
-				trigger_error( esc_html__( 'Expected AMP theme support to only have template_dir and/or available_callback.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-			}
-		}
-
 		add_action( 'widgets_init', array( __CLASS__, 'register_widgets' ) );
 
 		/*
@@ -152,30 +154,47 @@ public static function is_support_added_via_option() {
 	}
 
 	/**
-	 * Apply options for whether theme support is enabled via admin and what sanitization is performed by default.
+	 * Read theme support and apply options from admin for whether theme support is enabled and via what template is enabled.
 	 *
 	 * @see AMP_Post_Type_Support::add_post_type_support() For where post type support is added, since it is irrespective of theme support.
 	 */
-	public static function apply_options() {
+	public static function read_theme_support() {
 		self::$support_added_via_option = false;
 
-		$theme_support_option = AMP_Options_Manager::get_option( 'theme_support' );
-		$theme_support_args   = false;
-
-		// @todo Do we really need this optional flag? Yes. As it allows us to define the mode. Maybe it should be 'required' instead. Key for theme marketplaces? But if a theme is using the AMP features anyway, then it should have AMP as built-in and not be optional.
-		// If theme support is present in the theme, but it is marked as optional, then go ahead and remove it if theme support is not enabled in the admin.
+		self::$initial_theme_support_args = false;
 		if ( current_theme_supports( 'amp' ) ) {
-			$support            = get_theme_support( 'amp' );
-			$theme_support_args = array();
+			self::$initial_theme_support_args = array();
+
+			$support = get_theme_support( 'amp' );
 			if ( is_array( $support ) ) {
-				$theme_support_args = array_shift( $support );
-				if ( ! empty( $theme_support_args['optional'] ) && 'disabled' === $theme_support_option ) {
-					remove_theme_support( 'amp' );
-					return;
+				self::$initial_theme_support_args = array_shift( $support );
+
+				// Validate theme support usage.
+				if ( WP_DEBUG ) {
+					$keys = array( 'template_dir', 'comments_live_list', 'mode', 'optional', 'templates_supported' );
+					if ( ! is_array( self::$initial_theme_support_args ) ) {
+						trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
+					} elseif ( count( array_diff( array_keys( self::$initial_theme_support_args ), $keys ) ) !== 0 ) {
+						trigger_error( esc_html( sprintf(  // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
+							/* translators: %1$s is expected keys and %2$s is actual keys */
+							__( 'Expected AMP theme support to keys (%1$s) but saw (%2$s)', 'amp' ),
+							join( ', ', $keys ),
+							join( ', ', array_keys( self::$initial_theme_support_args ) )
+						) ) );
+					}
 				}
 			}
 		}
 
+		$theme_support_option = AMP_Options_Manager::get_option( 'theme_support' );
+		$theme_support_args   = self::$initial_theme_support_args;
+
+		// If theme support is present in the theme, but it is marked as optional, then go ahead and remove it if theme support is not enabled in the admin.
+		if ( current_theme_supports( 'amp' ) && ! empty( $theme_support_args['optional'] ) && 'disabled' === $theme_support_option ) {
+			remove_theme_support( 'amp' );
+			return;
+		}
+
 		if ( ! $theme_support_args ) {
 			$theme_support_args = array();
 		}
@@ -192,8 +211,37 @@ public static function apply_options() {
 			add_theme_support( 'amp', array_merge( $option_args, $theme_support_args ) );
 			self::$support_added_via_option = $option_args;
 		}
+	}
 
-		// @todo Allow paired mode to be switched via option if optional flag is true?
+	/**
+	 * Get the theme support args.
+	 *
+	 * @since 1.0
+	 *
+	 * @param array $options Options.
+	 * @return array|false Theme support args.
+	 */
+	public static function get_theme_support_args( $options = array() ) {
+		$options = array_merge(
+			array( 'initial' => false ),
+			$options
+		);
+
+		if ( $options['initial'] ) {
+			return self::$initial_theme_support_args;
+		}
+
+		if ( ! current_theme_supports( 'amp' ) ) {
+			return false;
+		}
+
+		$theme_support_args = get_theme_support( 'amp' );
+		if ( is_array( $theme_support_args ) ) {
+			$theme_support_args = array_shift( $theme_support_args );
+		} else {
+			$theme_support_args = array();
+		}
+		return $theme_support_args;
 	}
 
 	/**
@@ -209,8 +257,8 @@ public static function finish_init() {
 
 		self::ensure_proper_amp_location();
 
-		$theme_support = get_theme_support( 'amp' );
-		if ( ! empty( $theme_support[0]['template_dir'] ) ) {
+		$theme_support = self::get_theme_support_args();
+		if ( ! empty( $theme_support['template_dir'] ) ) {
 			self::add_amp_template_filters();
 		}
 
@@ -344,6 +392,17 @@ public static function add_amp_template_filters() {
 		}
 	}
 
+	/**
+	 * Return whether support for all templates is required by the theme.
+	 *
+	 * @since 1.0
+	 * @return bool Whether theme requires all templates to support AMP.
+	 */
+	public static function is_template_support_required() {
+		$theme_support_args = self::get_theme_support_args( array( 'initial' => true ) );
+		return ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] );
+	}
+
 	/**
 	 * Determine template availability of AMP for the given query.
 	 *
@@ -395,13 +454,29 @@ public static function get_template_availability( $query = null ) {
 			);
 		}
 
-		if ( ! current_theme_supports( 'amp' ) ) {
+		$theme_support_args = self::get_theme_support_args();
+		if ( false === $theme_support_args ) {
 			return array_merge(
 				$default_response,
 				array( 'errors' => array( 'no_theme_support' ) )
 			);
 		}
 
+		$all_templates_supported_by_theme_support = false;
+		$theme_templates_supported                = array();
+		if ( isset( $theme_support_args['templates_supported'] ) ) {
+			$all_templates_supported_by_theme_support = 'all' === $theme_support_args['templates_supported'];
+			if ( is_array( $theme_support_args['templates_supported'] ) ) {
+				$theme_templates_supported = $theme_support_args['templates_supported'];
+			}
+		}
+		$all_templates_supported          = (
+			$all_templates_supported_by_theme_support || AMP_Options_Manager::get_option( 'all_templates_supported' )
+		);
+		$unrecognized_templates_supported = (
+			isset( $theme_templates_supported['unrecognized'] ) ? true === $theme_templates_supported['unrecognized'] : AMP_Options_Manager::get_option( 'unrecognized_templates_supported' )
+		);
+
 		// Make sure global $wp_query is set in case of conditionals that unfortunately look at global scope.
 		$prev_query = $wp_query;
 		$wp_query   = $query; // WPCS: override ok.
@@ -415,7 +490,7 @@ public static function get_template_availability( $query = null ) {
 				$callback = $supportable_template['callback'];
 			}
 
-			// If the available_callback is a method on the query, then call the method on the query itself.
+			// If the callback is a method on the query, then call the method on the query itself.
 			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
 				$is_match = call_user_func( array( $query, $callback ) );
 			} elseif ( is_callable( $callback ) ) {
@@ -433,6 +508,8 @@ public static function get_template_availability( $query = null ) {
 						! empty( $supportable_template['supported'] )
 						||
 						( AMP_Options_Manager::get_option( 'all_templates_supported' ) && empty( $supportable_template['immutable'] ) )
+						||
+						$all_templates_supported_by_theme_support // Make sure theme support flag is given final say.
 					),
 					'immutable' => ! empty( $supportable_template['immutable'] ),
 				);
@@ -477,7 +554,7 @@ public static function get_template_availability( $query = null ) {
 
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! $matching_template ) {
-			if ( AMP_Options_Manager::get_option( 'all_templates_supported' ) || AMP_Options_Manager::get_option( 'unrecognized_templates_supported' ) ) {
+			if ( $all_templates_supported || $unrecognized_templates_supported ) {
 				return array_merge(
 					$default_response,
 					array(
@@ -615,6 +692,16 @@ public static function get_supportable_templates() {
 			);
 		}
 
+		// Pre-populate template supported state by theme support flag.
+		$theme_support_args = self::get_theme_support_args( array( 'initial' => true ) );
+		if ( isset( $theme_support_args['templates_supported'] ) && is_array( $theme_support_args['templates_supported'] ) ) {
+			foreach ( $templates as $id => &$template ) {
+				if ( isset( $theme_support_args['templates_supported'][ $id ] ) ) {
+					$templates[ $id ]['supported'] = $theme_support_args['templates_supported'][ $id ];
+				}
+			}
+		}
+
 		/**
 		 * Filters list of supportable templates.
 		 *
@@ -837,10 +924,10 @@ protected static function wp_kses_amp_mustache( $text ) {
 	 * @return string|null URL if redirect to be done; otherwise function will exist.
 	 */
 	public static function filter_comment_post_redirect( $url, $comment ) {
-		$theme_support = get_theme_support( 'amp' );
+		$theme_support = self::get_theme_support_args();
 
 		// Cause a page refresh if amp-live-list is not implemented for comments via add_theme_support( 'amp', array( 'comments_live_list' => true ) ).
-		if ( empty( $theme_support[0]['comments_live_list'] ) ) {
+		if ( empty( $theme_support['comments_live_list'] ) ) {
 			/*
 			 * Add the comment ID to the URL to force AMP to refresh the page.
 			 * This is ideally a temporary workaround to deal with https://github.com/ampproject/amphtml/issues/14170
@@ -1059,8 +1146,7 @@ public static function amend_comment_form() {
 	 * @return array Templates.
 	 */
 	public static function filter_amp_template_hierarchy( $templates ) {
-		$support = get_theme_support( 'amp' );
-		$args    = array_shift( $support );
+		$args = self::get_theme_support_args();
 		if ( isset( $args['template_dir'] ) ) {
 			$amp_templates = array();
 			foreach ( $templates as $template ) {
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 29b13e63f5f..6dee88a3046 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -121,31 +121,37 @@ public static function validate_options( $new_options ) {
 			$options['theme_support'] = $new_options['theme_support'];
 		}
 
-		$options['force_sanitization']               = ! empty( $new_options['force_sanitization'] );
-		$options['accept_tree_shaking']              = ! empty( $new_options['accept_tree_shaking'] );
-		$options['disable_admin_bar']                = ! empty( $new_options['disable_admin_bar'] );
-		$options['all_templates_supported']          = ! empty( $new_options['all_templates_supported'] );
-		$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
-
-		// Validate post type support.
-		$options['supported_post_types'] = array();
-		if ( isset( $new_options['supported_post_types'] ) ) {
-			foreach ( $new_options['supported_post_types'] as $post_type ) {
-				if ( ! post_type_exists( $post_type ) ) {
-					add_settings_error( self::OPTION_NAME, 'unknown_post_type', __( 'Unrecognized post type.', 'amp' ) );
-				} else {
-					$options['supported_post_types'][] = $post_type;
+		$options['force_sanitization']  = ! empty( $new_options['force_sanitization'] );
+		$options['accept_tree_shaking'] = ! empty( $new_options['accept_tree_shaking'] );
+		$options['disable_admin_bar']   = ! empty( $new_options['disable_admin_bar'] );
+
+		$theme_support_args = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) );
+		if ( ! AMP_Theme_Support::is_template_support_required() ) {
+			$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
+			if ( ! isset( $theme_support_args['templates_supported']['unrecognized'] ) ) {
+				$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
+			}
+
+			// Validate post type support.
+			$options['supported_post_types'] = array();
+			if ( isset( $new_options['supported_post_types'] ) ) {
+				foreach ( $new_options['supported_post_types'] as $post_type ) {
+					if ( ! post_type_exists( $post_type ) ) {
+						add_settings_error( self::OPTION_NAME, 'unknown_post_type', __( 'Unrecognized post type.', 'amp' ) );
+					} else {
+						$options['supported_post_types'][] = $post_type;
+					}
 				}
 			}
-		}
 
-		// Validate supported templates.
-		$options['supported_templates'] = array();
-		if ( isset( $new_options['supported_templates'] ) ) {
-			$options['supported_templates'] = array_intersect(
-				$new_options['supported_templates'],
-				array_keys( AMP_Theme_Support::get_supportable_templates() )
-			);
+			// Validate supported templates.
+			$options['supported_templates'] = array();
+			if ( isset( $new_options['supported_templates'] ) ) {
+				$options['supported_templates'] = array_intersect(
+					$new_options['supported_templates'],
+					array_keys( AMP_Theme_Support::get_supportable_templates() )
+				);
+			}
 		}
 
 		// Validate analytics.
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 314684ae285..da1ad1a895f 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -126,18 +126,19 @@ public function add_menu_items() {
 	 */
 	public function render_theme_support() {
 		$theme_support = AMP_Options_Manager::get_option( 'theme_support' );
-
-		$support_args = get_theme_support( 'amp' );
+		$support_args  = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) );
 
 		$theme_support_mutable = (
 			empty( $support_args )
 			||
+			! empty( $support_args['optional'] )
+			||
 			AMP_Theme_Support::is_support_added_via_option()
 		);
 
-		// @todo Consider $theme_support['paired'] and if set, and true, only show Paired option; otherwise, show Native option.
-		// @todo Change $theme_support_mutable to be if ! empty( $theme_support['optional'] ) or ! $theme_support['required']?
-		if ( ! $theme_support_mutable ) {
+		$mode_mutable = ! ( is_array( $support_args ) && isset( $support_args['mode'] ) );
+
+		if ( ! $theme_support_mutable || ( ! $mode_mutable && 'disabled' !== $theme_support ) ) {
 			if ( amp_is_canonical() ) {
 				$theme_support = 'native';
 			} else {
@@ -167,24 +168,28 @@ public function render_theme_support() {
 				<dd>
 					<?php esc_html_e( 'Display AMP responses in classic (legacy) post templates in a basic design that does not match your theme\'s templates.', 'amp' ); ?>
 				</dd>
-				<dt>
-					<input type="radio" id="theme_support_paired" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="paired" <?php checked( $theme_support, 'paired' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
-					<label for="theme_support_paired">
-						<strong><?php esc_html_e( 'Paired', 'amp' ); ?></strong>
-					</label>
-				</dt>
-				<dd>
-					<?php esc_html_e( 'Reuse active theme\'s templates to display AMP responses, but use separate URLs for AMP. The canonical URLs for your site will not have AMP. If there are AMP validation errors encountered in the AMP response and the validation errors are not accepted for sanitization, then the AMP version will redirect to the non-AMP version.', 'amp' ); ?>
-				</dd>
-				<dt>
-					<input type="radio" id="theme_support_native" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="native" <?php checked( $theme_support, 'native' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
-					<label for="theme_support_native">
-						<strong><?php esc_html_e( 'Native', 'amp' ); ?></strong>
-					</label>
-				</dt>
-				<dd>
-					<?php esc_html_e( 'Reuse active theme\'s templates to display AMP responses but do not use separate URLs for AMP. Your canonical URLs are AMP. Select this if you want to use AMP-specific blocks in your content. Any AMP validation errors will be automatically sanitized.', 'amp' ); ?>
-				</dd>
+				<?php if ( $mode_mutable || ! amp_is_canonical() ) : ?>
+					<dt>
+						<input type="radio" id="theme_support_paired" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="paired" <?php checked( $theme_support, 'paired' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
+						<label for="theme_support_paired">
+							<strong><?php esc_html_e( 'Paired', 'amp' ); ?></strong>
+						</label>
+					</dt>
+					<dd>
+						<?php esc_html_e( 'Reuse active theme\'s templates to display AMP responses, but use separate URLs for AMP. The canonical URLs for your site will not have AMP. If there are AMP validation errors encountered in the AMP response and the validation errors are not accepted for sanitization, then the AMP version will redirect to the non-AMP version.', 'amp' ); ?>
+					</dd>
+				<?php endif; ?>
+				<?php if ( $mode_mutable || amp_is_canonical() ) : ?>
+					<dt>
+						<input type="radio" id="theme_support_native" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="native" <?php checked( $theme_support, 'native' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
+						<label for="theme_support_native">
+							<strong><?php esc_html_e( 'Native', 'amp' ); ?></strong>
+						</label>
+					</dt>
+					<dd>
+						<?php esc_html_e( 'Reuse active theme\'s templates to display AMP responses but do not use separate URLs for AMP. Your canonical URLs are AMP. Select this if you want to use AMP-specific blocks in your content. Any AMP validation errors will be automatically sanitized.', 'amp' ); ?>
+					</dd>
+				<?php endif; ?>
 			</dl>
 		</fieldset>
 		<?php
@@ -193,7 +198,7 @@ public function render_theme_support() {
 	/**
 	 * Post types support section renderer.
 	 *
-	 * @todo If dirty AMP is ever allowed, then automatically forcing sanitization in native should be able to be turned off.
+	 * @todo If dirty AMP is ever allowed (that is, post-processed documents which can be served with non-sanitized valdation errors), then automatically forcing sanitization in native should be able to be turned off.
 	 *
 	 * @since 1.0
 	 */
@@ -280,22 +285,30 @@ public function render_validation_handling() {
 	 * @since 1.0
 	 */
 	public function render_supported_templates() {
+		$theme_support_args = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ); // Initial so we can get before removed if optional.
 
-		// @todo If AMP theme support is native and required, let all_templates_supported be true? Maybe template support could have an all_templates_supported flag?
 		?>
 		<fieldset id="all_templates_supported_fieldset">
-			<p>
-				<label for="all_templates_supported">
-					<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
-					<?php esc_html_e( 'Serve all templates as AMP regardless of what is being queried.', 'amp' ); ?>
-				</label>
-			</p>
-			<p class="description">
-				<?php esc_html_e( 'This will allow all of the URLs on your site to be served as AMP by default.', 'amp' ); ?>
-			</p>
+			<?php if ( AMP_Theme_Support::is_template_support_required() ) : ?>
+				<div class="notice notice-info notice-alt inline">
+					<p>
+						<?php esc_html_e( 'The current theme requires all templates to support AMP.', 'amp' ); ?>
+					</p>
+				</div>
+			<?php else : ?>
+				<p>
+					<label for="all_templates_supported">
+						<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
+						<?php esc_html_e( 'Serve all templates as AMP regardless of what is being queried.', 'amp' ); ?>
+					</label>
+				</p>
+				<p class="description">
+					<?php esc_html_e( 'This will allow all of the URLs on your site to be served as AMP by default.', 'amp' ); ?>
+				</p>
+			<?php endif; ?>
 		</fieldset>
 
-		<fieldset id="singular_templates_fieldset">
+		<fieldset id="supported_post_types_fieldset">
 			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
 			<h4 class="title"><?php esc_html_e( 'Content Types', 'amp' ); ?></h4>
 			<p>
@@ -320,9 +333,9 @@ public function render_supported_templates() {
 			</ul>
 		</fieldset>
 
-		<fieldset id="non_singular_templates_fieldset">
+		<fieldset id="supported_templates_fieldset">
 			<style>
-				#non_singular_templates_fieldset ul ul {
+				#supported_templates_fieldset ul ul {
 					margin-left: 40px;
 				}
 			</style>
@@ -331,15 +344,19 @@ public function render_supported_templates() {
 			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
 			?>
 			<p>
+				<?php
+				$disabled = isset( $theme_support_args['templates_supported']['unrecognized'] );
+				$checked  = $disabled ? $theme_support_args['templates_supported']['unrecognized'] : AMP_Options_Manager::get_option( 'unrecognized_templates_supported' );
+				?>
 				<label for="unrecognized_templates_supported">
-					<input id="unrecognized_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[unrecognized_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'unrecognized_templates_supported' ) ); ?>>
+					<input id="unrecognized_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[unrecognized_templates_supported]' ); ?>" <?php checked( $checked ); ?> <?php disabled( $disabled ); ?>>
 					<?php esc_html_e( 'Other', 'amp' ); ?>
 				</label>
 			</p>
 			<script>
 				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
 				(function ( $ ) {
-					$( '#non_singular_templates_fieldset input[type=checkbox]' ).on( 'click', function() {
+					$( '#supported_templates_fieldset input[type=checkbox]' ).on( 'click', function() {
 						$( this ).siblings( 'ul' ).find( 'input[type=checkbox]' ).prop( 'checked', this.checked );
 					} );
 				})( jQuery );
@@ -355,17 +372,18 @@ public function render_supported_templates() {
 				allTemplatesSupportedInput = $( '#all_templates_supported' );
 
 				function updateFieldsetVisibility() {
-					$( '#all_templates_supported_fieldset, #singular_templates_fieldset > .title' ).toggleClass(
+					var allTemplatesSupported = 0 === allTemplatesSupportedInput.length || allTemplatesSupportedInput.prop( 'checked' );
+					$( '#all_templates_supported_fieldset, #supported_post_types_fieldset > .title' ).toggleClass(
 						'hidden',
 						themeSupportDisabledInput.prop( 'checked' )
 					);
-					$( '#singular_templates_fieldset' ).toggleClass(
+					$( '#supported_post_types_fieldset' ).toggleClass(
 						'hidden',
-						allTemplatesSupportedInput.prop( 'checked' ) && ! themeSupportDisabledInput.prop( 'checked' )
+						allTemplatesSupported && ! themeSupportDisabledInput.prop( 'checked' )
 					);
-					$( '#non_singular_templates_fieldset' ).toggleClass(
+					$( '#supported_templates_fieldset' ).toggleClass(
 						'hidden',
-						allTemplatesSupportedInput.prop( 'checked' ) || themeSupportDisabledInput.prop( 'checked' )
+						allTemplatesSupported || themeSupportDisabledInput.prop( 'checked' )
 					);
 				}
 
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 3191b581040..33e68c5a5e7 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -92,7 +92,7 @@ public function test_init() {
 		} catch ( Exception $exception ) {
 			$e = $exception;
 		}
-		$this->assertEquals( 'Expected AMP theme support to only have template_dir and/or available_callback.', $e->getMessage() );
+		$this->assertStringStartsWith( 'Expected AMP theme support to keys', $e->getMessage() );
 	}
 
 	/**

From 2062816e4cfcc686bf6e4840c000700c6cab68e3 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 09:21:46 -0700
Subject: [PATCH 22/34] Persist user selection even when checkbox disabled

* De-duplicate logic
---
 includes/class-amp-theme-support.php          | 43 +++++++++++--------
 .../options/class-amp-options-manager.php     |  6 ++-
 includes/options/class-amp-options-menu.php   | 27 ++++++++----
 3 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index eed6ec0cd31..09c62518338 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -504,13 +504,7 @@ public static function get_template_availability( $query = null ) {
 			if ( $is_match ) {
 				$matching_templates[ $id ] = array(
 					'template'  => $id,
-					'supported' => (
-						! empty( $supportable_template['supported'] )
-						||
-						( AMP_Options_Manager::get_option( 'all_templates_supported' ) && empty( $supportable_template['immutable'] ) )
-						||
-						$all_templates_supported_by_theme_support // Make sure theme support flag is given final say.
-					),
+					'supported' => ! empty( $supportable_template['supported'] ),
 					'immutable' => ! empty( $supportable_template['immutable'] ),
 				);
 			}
@@ -692,16 +686,6 @@ public static function get_supportable_templates() {
 			);
 		}
 
-		// Pre-populate template supported state by theme support flag.
-		$theme_support_args = self::get_theme_support_args( array( 'initial' => true ) );
-		if ( isset( $theme_support_args['templates_supported'] ) && is_array( $theme_support_args['templates_supported'] ) ) {
-			foreach ( $templates as $id => &$template ) {
-				if ( isset( $theme_support_args['templates_supported'][ $id ] ) ) {
-					$templates[ $id ]['supported'] = $theme_support_args['templates_supported'][ $id ];
-				}
-			}
-		}
-
 		/**
 		 * Filters list of supportable templates.
 		 *
@@ -721,11 +705,34 @@ public static function get_supportable_templates() {
 		 */
 		$templates = apply_filters( 'amp_supportable_templates', $templates );
 
+		// Obtain the initial template supported state by theme support flag.
+		$theme_support_args        = self::get_theme_support_args( array( 'initial' => true ) );
+		$theme_supported_templates = array();
+		if ( isset( $theme_support_args['templates_supported'] ) ) {
+			$theme_supported_templates = $theme_support_args['templates_supported'];
+		}
+
 		$supported_templates = AMP_Options_Manager::get_option( 'supported_templates' );
 		foreach ( $templates as $id => &$template ) {
+
+			// Capture user-elected support from options. This allows us to preserve the original user selection through programmatic overrides.
+			$template['user_supported'] = in_array( $id, $supported_templates, true );
+
+			// Consider supported templates from theme support args.
+			if ( ! isset( $template['supported'] ) ) {
+				if ( 'all' === $theme_supported_templates ) {
+					$template['supported'] = true;
+				} elseif ( is_array( $theme_supported_templates ) && isset( $theme_supported_templates[ $id ] ) ) {
+					$template['supported'] = $theme_supported_templates[ $id ];
+				}
+			}
+
+			// Make supported state immutable if it was programmatically set.
 			$template['immutable'] = isset( $template['supported'] );
+
+			// Set supported state from user preference.
 			if ( ! $template['immutable'] ) {
-				$template['supported'] = AMP_Options_Manager::get_option( 'all_templates_supported' ) || in_array( $id, $supported_templates, true );
+				$template['supported'] = AMP_Options_Manager::get_option( 'all_templates_supported' ) || $template['user_supported'];
 			}
 		}
 
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 6dee88a3046..fd052b5f93d 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -24,7 +24,7 @@ class AMP_Options_Manager {
 	 */
 	protected static $defaults = array(
 		'theme_support'                    => 'disabled',
-		'supported_post_types'             => array( 'post' ),
+		'supported_post_types'             => array( 'post' ), // @todo Try updating from 0.7 to 1.0.
 		'analytics'                        => array(),
 		'force_sanitization'               => false,
 		'accept_tree_shaking'              => false,
@@ -32,7 +32,7 @@ class AMP_Options_Manager {
 		'all_templates_supported'          => true,
 		'unrecognized_templates_supported' => true,
 		'supported_templates'              => array(
-			'is_singular',
+			'is_singular', // @todo Why?
 		),
 	);
 
@@ -132,6 +132,7 @@ public static function validate_options( $new_options ) {
 				$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
 			}
 
+			// @todo Store associative array instead?
 			// Validate post type support.
 			$options['supported_post_types'] = array();
 			if ( isset( $new_options['supported_post_types'] ) ) {
@@ -144,6 +145,7 @@ public static function validate_options( $new_options ) {
 				}
 			}
 
+			// @todo Store associative array instead.
 			// Validate supported templates.
 			$options['supported_templates'] = array();
 			if ( isset( $new_options['supported_templates'] ) ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index da1ad1a895f..5c5b70557f5 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -419,14 +419,25 @@ private function list_template_conditional_options( $options, $parent = null ) {
 
 				?>
 				<li>
-					<input
-						type="checkbox"
-						id="<?php echo esc_attr( $element_id ); ?>"
-						name="<?php echo esc_attr( $element_name ); ?>"
-						value="<?php echo esc_attr( $id ); ?>"
-						<?php checked( ! empty( $option['supported'] ) ); ?>
-						<?php disabled( ! empty( $option['immutable'] ) ); ?>
-					>
+					<?php if ( empty( $option['immutable'] ) ) : ?>
+						<input
+							type="checkbox"
+							id="<?php echo esc_attr( $element_id ); ?>"
+							name="<?php echo esc_attr( $element_name ); ?>"
+							value="<?php echo esc_attr( $id ); ?>"
+							<?php checked( ! empty( $option['user_supported'] ) ); ?>
+						>
+					<?php else : // Persist user selection even when checkbox disabled, when selection forced by theme/filter. ?>
+						<input
+							type="checkbox"
+							id="<?php echo esc_attr( $element_id ); ?>"
+							<?php checked( ! empty( $option['supported'] ) ); ?>
+							<?php disabled( true ); ?>
+						>
+						<?php if ( ! empty( $option['user_supported'] ) ) : ?>
+							<input type="hidden" name="<?php echo esc_attr( $element_name ); ?>" value="<?php echo esc_attr( $id ); ?>">
+						<?php endif; ?>
+					<?php endif; ?>
 					<label for="<?php echo esc_attr( $element_id ); ?>">
 						<?php echo esc_html( $option['label'] ); ?>
 					</label>

From 1c759e5c7fab98f6ec8a6faa8567382d489e4d78 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 15:46:12 -0700
Subject: [PATCH 23/34] Add tests for read_theme_support,
 is_support_added_via_option, get_theme_support_args

Store version with options to keep track of format
---
 includes/class-amp-theme-support.php          | 10 ++--
 .../options/class-amp-options-manager.php     | 13 ++--
 includes/options/class-amp-options-menu.php   |  1 +
 tests/test-class-amp-options-manager.php      |  2 +-
 tests/test-class-amp-theme-support.php        | 60 +++++++++++++++++--
 5 files changed, 69 insertions(+), 17 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 09c62518338..35cd52d4a95 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -157,8 +157,10 @@ public static function is_support_added_via_option() {
 	 * Read theme support and apply options from admin for whether theme support is enabled and via what template is enabled.
 	 *
 	 * @see AMP_Post_Type_Support::add_post_type_support() For where post type support is added, since it is irrespective of theme support.
+	 *
+	 * @param bool $check_args Whether the theme support args should be checked.
 	 */
-	public static function read_theme_support() {
+	public static function read_theme_support( $check_args = WP_DEBUG ) {
 		self::$support_added_via_option = false;
 
 		self::$initial_theme_support_args = false;
@@ -170,7 +172,7 @@ public static function read_theme_support() {
 				self::$initial_theme_support_args = array_shift( $support );
 
 				// Validate theme support usage.
-				if ( WP_DEBUG ) {
+				if ( $check_args ) {
 					$keys = array( 'template_dir', 'comments_live_list', 'mode', 'optional', 'templates_supported' );
 					if ( ! is_array( self::$initial_theme_support_args ) ) {
 						trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
@@ -199,8 +201,8 @@ public static function read_theme_support() {
 			$theme_support_args = array();
 		}
 
-		// If theme support is not present, then allow it to be added via the admin.
-		if ( ! current_theme_supports( 'amp' ) ) {
+		// If theme support is not present (or it is optional), then allow it to be added via the admin.
+		if ( ! current_theme_supports( 'amp' ) || ! empty( $theme_support_args['optional'] ) ) {
 			if ( 'disabled' === $theme_support_option ) {
 				return;
 			}
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index fd052b5f93d..71f3a0f7caa 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -24,16 +24,14 @@ class AMP_Options_Manager {
 	 */
 	protected static $defaults = array(
 		'theme_support'                    => 'disabled',
-		'supported_post_types'             => array( 'post' ), // @todo Try updating from 0.7 to 1.0.
+		'supported_post_types'             => array( 'post' ),
 		'analytics'                        => array(),
 		'force_sanitization'               => false,
 		'accept_tree_shaking'              => false,
 		'disable_admin_bar'                => false,
 		'all_templates_supported'          => true,
-		'unrecognized_templates_supported' => true,
-		'supported_templates'              => array(
-			'is_singular', // @todo Why?
-		),
+		'unrecognized_templates_supported' => false,
+		'supported_templates'              => array( 'is_singular' ),
 	);
 
 	/**
@@ -132,7 +130,6 @@ public static function validate_options( $new_options ) {
 				$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
 			}
 
-			// @todo Store associative array instead?
 			// Validate post type support.
 			$options['supported_post_types'] = array();
 			if ( isset( $new_options['supported_post_types'] ) ) {
@@ -145,7 +142,6 @@ public static function validate_options( $new_options ) {
 				}
 			}
 
-			// @todo Store associative array instead.
 			// Validate supported templates.
 			$options['supported_templates'] = array();
 			if ( isset( $new_options['supported_templates'] ) ) {
@@ -201,6 +197,9 @@ public static function validate_options( $new_options ) {
 			}
 		}
 
+		// Store the current version with the options so we know the format.
+		$options['version'] = AMP__VERSION;
+
 		return $options;
 	}
 
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 5c5b70557f5..f2b516aee1b 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -258,6 +258,7 @@ public function render_validation_handling() {
 			<script>
 				jQuery( 'input[type=radio][name="amp-options[theme_support]"]' ).change( function() {
 					jQuery( '.amp-force-sanitize' ).toggleClass( 'hidden', 'native' === this.value );
+					jQuery( '.amp-validation-field' ).toggleClass( 'hidden', 'disabled' === this.value );
 					jQuery( '.amp-force-sanitize-canonical' ).toggleClass( 'hidden', 'native' !== this.value );
 					jQuery( '#force_sanitization' ).trigger( 'change' );
 				} ).filter( ':checked' ).trigger( 'change' );
diff --git a/tests/test-class-amp-options-manager.php b/tests/test-class-amp-options-manager.php
index 8e8ed0c69dd..da45e161304 100644
--- a/tests/test-class-amp-options-manager.php
+++ b/tests/test-class-amp-options-manager.php
@@ -99,7 +99,7 @@ public function test_get_and_set_options() {
 				'accept_tree_shaking'              => false,
 				'disable_admin_bar'                => false,
 				'all_templates_supported'          => true,
-				'unrecognized_templates_supported' => true,
+				'unrecognized_templates_supported' => false,
 				'supported_templates'              => array( 'is_singular' ),
 			),
 			AMP_Options_Manager::get_options()
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 33e68c5a5e7..cfad79577dc 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -73,26 +73,76 @@ public function test_init() {
 		$this->assertEquals( 10, has_action( 'widgets_init', array( self::TESTED_CLASS, 'register_widgets' ) ) );
 		$this->assertEquals( PHP_INT_MAX, has_action( 'wp', array( self::TESTED_CLASS, 'finish_init' ) ) );
 		$this->assertFalse( isset( $_REQUEST['__amp_source_origin'] ) ); // WPCS: CSRF ok.
+	}
 
-		add_theme_support( 'amp', 'invalid_argumnet_type' );
+	/**
+	 * Test read_theme_support, get_theme_support_args, and is_support_added_via_option.
+	 *
+	 * @covers \AMP_Theme_Support::read_theme_support()
+	 * @covers \AMP_Theme_Support::is_support_added_via_option()
+	 * @covers \AMP_Theme_Support::get_theme_support_args()
+	 */
+	public function test_read_theme_support_and_support_args() {
+
+		// Test invalid arg for theme support.
+		add_theme_support( 'amp', 'invalid_argument_type' );
 		$e = null;
 		try {
-			AMP_Theme_Support::init();
+			AMP_Theme_Support::read_theme_support( true );
 		} catch ( Exception $exception ) {
 			$e = $exception;
 		}
 		$this->assertInstanceOf( 'PHPUnit_Framework_Error_Notice', $e );
 		$this->assertEquals( 'Expected AMP theme support arg to be array.', $e->getMessage() );
+		$this->assertTrue( current_theme_supports( 'amp' ) );
 
-		add_theme_support( 'amp', array(
+		// Test invalid args for theme support.
+		$args = array(
+			'mode'              => 'native',
 			'invalid_param_key' => array(),
-		) );
+		);
+		add_theme_support( 'amp', $args );
 		try {
-			AMP_Theme_Support::init();
+			AMP_Theme_Support::read_theme_support( true );
 		} catch ( Exception $exception ) {
 			$e = $exception;
 		}
 		$this->assertStringStartsWith( 'Expected AMP theme support to keys', $e->getMessage() );
+		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args() );
+		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ) );
+		$this->assertTrue( current_theme_supports( 'amp' ) );
+
+		// Test behavior of optional flag, that AMP is not enabled if the DB option is not set.
+		$args = array(
+			'optional' => true,
+			'mode'     => 'native',
+		);
+		AMP_Options_Manager::update_option( 'theme_support', 'disabled' );
+		add_theme_support( 'amp', $args );
+		AMP_Theme_Support::read_theme_support();
+		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ) );
+		$this->assertFalse( AMP_Theme_Support::get_theme_support_args() );
+		$this->assertFalse( AMP_Theme_Support::is_support_added_via_option() );
+		$this->assertFalse( current_theme_supports( 'amp' ) );
+
+		// Test again with option set, but some configs supplied via theme support.
+		AMP_Options_Manager::update_option( 'theme_support', 'native' );
+		$args = array(
+			'optional'            => true,
+			'templates_supported' => 'native',
+		);
+		add_theme_support( 'amp', $args );
+		AMP_Theme_Support::read_theme_support();
+		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ) );
+		$this->assertEquals(
+			array_merge(
+				$args,
+				array( 'mode' => 'native' )
+			),
+			AMP_Theme_Support::get_theme_support_args( array( 'initial' => false ) )
+		);
+		$this->assertTrue( AMP_Theme_Support::is_support_added_via_option() );
+		$this->assertTrue( current_theme_supports( 'amp' ) );
 	}
 
 	/**

From 221c3f098b0d55ea3d7026fa47c76666b40a00fd Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 20:22:08 -0700
Subject: [PATCH 24/34] Improve testing of finish_init; add test stubs

* Clean up covers tags
* Remove unnecessary is_template_support_required
---
 includes/class-amp-theme-support.php          | 17 ++---
 .../options/class-amp-options-manager.php     |  4 +-
 includes/options/class-amp-options-menu.php   |  2 +-
 tests/test-class-amp-base-sanitizer.php       |  4 +-
 tests/test-class-amp-theme-support.php        | 73 +++++++++++++++----
 5 files changed, 68 insertions(+), 32 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 35cd52d4a95..65665ade482 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -309,10 +309,12 @@ public static function ensure_proper_amp_location( $exit = true ) {
 				$new_url = add_query_arg( amp_get_slug(), '', amp_remove_endpoint( $old_url ) );
 				if ( $old_url !== $new_url ) {
 					wp_safe_redirect( $new_url, 302 );
+					// @codeCoverageIgnoreStart
 					if ( $exit ) {
 						exit;
 					}
 					return true;
+					// @codeCoverageIgnoreEnd
 				}
 			}
 		}
@@ -343,10 +345,12 @@ public static function redirect_ampless_url( $exit = true ) {
 		 * occur or when a non-canonical AMP theme is used.
 		 */
 		wp_safe_redirect( $ampless_url, 302 );
+		// @codeCoverageIgnoreStart
 		if ( $exit ) {
 			exit;
 		}
 		return true;
+		// @codeCoverageIgnoreEnd
 	}
 
 	/**
@@ -394,17 +398,6 @@ public static function add_amp_template_filters() {
 		}
 	}
 
-	/**
-	 * Return whether support for all templates is required by the theme.
-	 *
-	 * @since 1.0
-	 * @return bool Whether theme requires all templates to support AMP.
-	 */
-	public static function is_template_support_required() {
-		$theme_support_args = self::get_theme_support_args( array( 'initial' => true ) );
-		return ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] );
-	}
-
 	/**
 	 * Determine template availability of AMP for the given query.
 	 *
@@ -475,7 +468,7 @@ public static function get_template_availability( $query = null ) {
 		$all_templates_supported          = (
 			$all_templates_supported_by_theme_support || AMP_Options_Manager::get_option( 'all_templates_supported' )
 		);
-		$unrecognized_templates_supported = (
+		$unrecognized_templates_supported = ( // @todo Get this from $supportable_templates.
 			isset( $theme_templates_supported['unrecognized'] ) ? true === $theme_templates_supported['unrecognized'] : AMP_Options_Manager::get_option( 'unrecognized_templates_supported' )
 		);
 
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 71f3a0f7caa..a4f82af1620 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -124,7 +124,9 @@ public static function validate_options( $new_options ) {
 		$options['disable_admin_bar']   = ! empty( $new_options['disable_admin_bar'] );
 
 		$theme_support_args = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) );
-		if ( ! AMP_Theme_Support::is_template_support_required() ) {
+
+		$is_template_support_required = ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] );
+		if ( ! $is_template_support_required ) {
 			$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
 			if ( ! isset( $theme_support_args['templates_supported']['unrecognized'] ) ) {
 				$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index f2b516aee1b..f30b611637e 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -290,7 +290,7 @@ public function render_supported_templates() {
 
 		?>
 		<fieldset id="all_templates_supported_fieldset">
-			<?php if ( AMP_Theme_Support::is_template_support_required() ) : ?>
+			<?php if ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] ) : ?>
 				<div class="notice notice-info notice-alt inline">
 					<p>
 						<?php esc_html_e( 'The current theme requires all templates to support AMP.', 'amp' ); ?>
diff --git a/tests/test-class-amp-base-sanitizer.php b/tests/test-class-amp-base-sanitizer.php
index c51236f749b..fd6a3541874 100644
--- a/tests/test-class-amp-base-sanitizer.php
+++ b/tests/test-class-amp-base-sanitizer.php
@@ -108,7 +108,7 @@ public function get_data() {
 	 * @param array $source_attributes   Source Attrs.
 	 * @param array $expected_attributes Expected Attrs.
 	 * @param array $args                Args.
-	 * @covers AMP_Base_Sanitizer::enforce_fixed_height()
+	 * @covers AMP_Base_Sanitizer::set_layout()
 	 */
 	public function test_set_layout( $source_attributes, $expected_attributes, $args = array() ) {
 		$sanitizer           = new AMP_Test_Stub_Sanitizer( new DOMDocument(), $args );
@@ -316,7 +316,7 @@ public function test_filter_data_amp_attributes() {
 	/**
 	 * Tests set_attachment_layout_attributes.
 	 *
-	 * @covers AMP_Base_Sanitizer::set_attachment_layout_attributes()
+	 * @covers AMP_Base_Sanitizer::filter_attachment_layout_attributes()
 	 */
 	public function test_filter_attachment_layout_attributes() {
 		$sanitizer    = new AMP_Test_Stub_Sanitizer( new DOMDocument(), array() );
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index cfad79577dc..11f111ac012 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -57,7 +57,6 @@ public function tearDown() {
 	 * Test init.
 	 *
 	 * @covers AMP_Theme_Support::init()
-	 * @covers AMP_Theme_Support::finish_init()
 	 */
 	public function test_init() {
 		$_REQUEST['__amp_source_origin'] = 'foo';
@@ -146,38 +145,43 @@ public function test_read_theme_support_and_support_args() {
 	}
 
 	/**
-	 * Test that amphtml link is added at the right time.
+	 * Test that init finalization, including amphtml link is added at the right time.
 	 *
 	 * @covers AMP_Theme_Support::finish_init()
 	 */
-	public function test_amphtml_link() {
+	public function test_finish_init() {
 		$post_id = $this->factory()->post->create( array( 'post_title' => 'Test' ) );
 		add_theme_support( 'amp', array(
-			'template_dir'       => '...',
-			'available_callback' => function() {
-				return is_singular();
-			},
+			'mode'         => 'paired',
+			'template_dir' => 'amp',
 		) );
 
-		// Test paired mode singular.
+		// Test paired mode singular, where not on endpoint that it causes amphtml link to be added.
 		remove_action( 'wp_head', 'amp_add_amphtml_link' );
 		$this->go_to( get_permalink( $post_id ) );
+		$this->assertFalse( is_amp_endpoint() );
 		AMP_Theme_Support::finish_init();
 		$this->assertEquals( 10, has_action( 'wp_head', 'amp_add_amphtml_link' ) );
 
-		// Test paired mode homepage.
+		// Test paired mode homepage, where still not on endpoint that it causes amphtml link to be added.
 		remove_action( 'wp_head', 'amp_add_amphtml_link' );
 		$this->go_to( home_url() );
+		$this->assertFalse( is_amp_endpoint() );
 		AMP_Theme_Support::finish_init();
 		$this->assertEquals( 10, has_action( 'wp_head', 'amp_add_amphtml_link' ) );
 
-		// Test canonical.
+		// Test canonical, so amphtml link is not added and init finalizes.
 		remove_action( 'wp_head', 'amp_add_amphtml_link' );
-		remove_theme_support( 'amp' );
-		add_theme_support( 'amp' );
+		add_theme_support( 'amp', array(
+			'mode'         => 'native',
+			'template_dir' => 'amp',
+		) );
 		$this->go_to( get_permalink( $post_id ) );
+		$this->assertTrue( is_amp_endpoint() );
 		AMP_Theme_Support::finish_init();
 		$this->assertFalse( has_action( 'wp_head', 'amp_add_amphtml_link' ) );
+		$this->assertEquals( 10, has_filter( 'index_template_hierarchy', array( 'AMP_Theme_Support', 'filter_amp_template_hierarchy' ) ), 'Expected add_amp_template_filters to have been called since template_dir is not empty' );
+		$this->assertEquals( 20, has_action( 'wp_head', 'amp_add_generator_metadata' ), 'Expected add_hooks to have been called' );
 	}
 
 	/**
@@ -350,11 +354,11 @@ public function test_is_customize_preview_iframe() {
 	}
 
 	/**
-	 * Test register_paired_hooks.
+	 * Test add_amp_template_filters.
 	 *
 	 * @covers AMP_Theme_Support::add_amp_template_filters()
 	 */
-	public function test_register_paired_hooks() {
+	public function test_add_amp_template_filters() {
 		$template_types = array(
 			'paged',
 			'index',
@@ -409,6 +413,34 @@ public function test_validate_non_amp_theme() {
 		$this->assertContains( '<script type="text/javascript" src="https://cdn.ampproject.org/v0/amp-mathml-latest.js" async custom-element="amp-mathml"></script>', $sanitized_html ); // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedScript
 	}
 
+	/**
+	 * Test get_template_availability.
+	 *
+	 * @covers AMP_Theme_Support::get_template_availability()
+	 */
+	public function test_get_template_availability() {
+		$this->markTestIncomplete();
+		// @todo Test nested.
+		// @todo Test callback vs ID.
+		// @todo Test with query, post, or page.
+		// @todo Test without availability of WP_Query (no_query_available).
+		// @todo Test without theme support (no_theme_support).
+		// @todo Test unrecognized by theme support arg.
+		// @todo Test unrecognized.
+	}
+
+	/**
+	 * Test get_supportable_templates.
+	 *
+	 * @covers AMP_Theme_Support::get_supportable_templates()
+	 */
+	public function test_get_supportable_templates() {
+		$this->markTestIncomplete();
+		// @todo Register custom taxonomy.
+		// @todo Set static front page
+		// @todo Add custom post types.
+	}
+
 	/**
 	 * Test add_hooks.
 	 *
@@ -812,11 +844,11 @@ public function test_amend_comment_form() {
 	}
 
 	/**
-	 * Test filter_paired_template_hierarchy.
+	 * Test filter_amp_template_hierarchy.
 	 *
 	 * @covers AMP_Theme_Support::filter_amp_template_hierarchy()
 	 */
-	public function test_filter_paired_template_hierarchy() {
+	public function test_filter_amp_template_hierarchy() {
 		$template_dir = 'amp-templates';
 		add_theme_support( 'amp', array(
 			'template_dir' => $template_dir,
@@ -950,6 +982,15 @@ public function test_filter_cancel_comment_reply_link() {
 		$this->assertContains( 'Click here to cancel reply.', $filtered_link_no_text_passed );
 	}
 
+	/**
+	 * Test init_admin_bar.
+	 *
+	 * @covers \AMP_Theme_Support::init_admin_bar()
+	 */
+	public function test_init_admin_bar() {
+		$this->markTestIncomplete();
+	}
+
 	/**
 	 * Test print_amp_styles.
 	 *

From 3d07eac72467132c99c20b0db85115080e0293fc Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 20:49:53 -0700
Subject: [PATCH 25/34] Discard matching is_home when there are other matching
 templates

---
 includes/class-amp-theme-support.php | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 65665ade482..18a8f0e593c 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -489,7 +489,7 @@ public static function get_template_availability( $query = null ) {
 			if ( is_string( $callback ) && 'is_' === substr( $callback, 0, 3 ) && method_exists( $query, $callback ) ) {
 				$is_match = call_user_func( array( $query, $callback ) );
 			} elseif ( is_callable( $callback ) ) {
-				$is_match = call_user_func( $callback );
+				$is_match = call_user_func( $callback, $query );
 			} else {
 				/* translators: %s is the supportable template ID. */
 				_doing_it_wrong( __FUNCTION__, esc_html__( 'Supportable template "%s" does not have a callable callback.', 'amp' ), '1.0' );
@@ -535,6 +535,15 @@ public static function get_template_availability( $query = null ) {
 			}
 		}
 
+		// The is_home() condition is the default so discard it if there are other matching templates.
+		if ( count( $matching_templates ) > 1 && isset( $matching_templates['is_home'] ) ) {
+			unset( $matching_templates['is_home'] );
+		}
+
+		/*
+		 * If there are more than one matching templates, then something is probably not right.
+		 * Template conditions need to be set up properly to prevent this from happening.
+		 */
 		if ( count( $matching_templates ) > 1 ) {
 			_doing_it_wrong( __FUNCTION__, esc_html__( 'Did not expect there to be more than one matching template. Did you filter amp_supportable_templates to not honor the template hierarchy?', 'amp' ), '1.0' );
 		}

From c32d76b62e3322974fffb7936f75b69faaaca106 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 21:03:53 -0700
Subject: [PATCH 26/34] Elimiante Other/unrecognized template option since
 indistinguishable from is_home

* Devs should use filter to add support for custom templates
* When a custom template is added via amp_supportable_templates filter then is_home will be discarded if there is another match
---
 includes/class-amp-theme-support.php          |  5 +----
 .../options/class-amp-options-manager.php     | 20 ++++++++-----------
 includes/options/class-amp-options-menu.php   | 10 ----------
 tests/test-class-amp-meta-box.php             |  1 -
 tests/test-class-amp-options-manager.php      | 17 ++++++++--------
 tests/test-class-amp-theme-support.php        |  2 --
 6 files changed, 17 insertions(+), 38 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 18a8f0e593c..3f06cc24455 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -468,9 +468,6 @@ public static function get_template_availability( $query = null ) {
 		$all_templates_supported          = (
 			$all_templates_supported_by_theme_support || AMP_Options_Manager::get_option( 'all_templates_supported' )
 		);
-		$unrecognized_templates_supported = ( // @todo Get this from $supportable_templates.
-			isset( $theme_templates_supported['unrecognized'] ) ? true === $theme_templates_supported['unrecognized'] : AMP_Options_Manager::get_option( 'unrecognized_templates_supported' )
-		);
 
 		// Make sure global $wp_query is set in case of conditionals that unfortunately look at global scope.
 		$prev_query = $wp_query;
@@ -552,7 +549,7 @@ public static function get_template_availability( $query = null ) {
 
 		// If there aren't any matching templates left that are supported, then we consider it to not be available.
 		if ( ! $matching_template ) {
-			if ( $all_templates_supported || $unrecognized_templates_supported ) {
+			if ( $all_templates_supported ) {
 				return array_merge(
 					$default_response,
 					array(
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index a4f82af1620..40eb41f85ee 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -23,15 +23,14 @@ class AMP_Options_Manager {
 	 * @var array
 	 */
 	protected static $defaults = array(
-		'theme_support'                    => 'disabled',
-		'supported_post_types'             => array( 'post' ),
-		'analytics'                        => array(),
-		'force_sanitization'               => false,
-		'accept_tree_shaking'              => false,
-		'disable_admin_bar'                => false,
-		'all_templates_supported'          => true,
-		'unrecognized_templates_supported' => false,
-		'supported_templates'              => array( 'is_singular' ),
+		'theme_support'           => 'disabled',
+		'supported_post_types'    => array( 'post' ),
+		'analytics'               => array(),
+		'force_sanitization'      => false,
+		'accept_tree_shaking'     => false,
+		'disable_admin_bar'       => false,
+		'all_templates_supported' => true,
+		'supported_templates'     => array( 'is_singular' ),
 	);
 
 	/**
@@ -128,9 +127,6 @@ public static function validate_options( $new_options ) {
 		$is_template_support_required = ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] );
 		if ( ! $is_template_support_required ) {
 			$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
-			if ( ! isset( $theme_support_args['templates_supported']['unrecognized'] ) ) {
-				$options['unrecognized_templates_supported'] = ! empty( $new_options['unrecognized_templates_supported'] );
-			}
 
 			// Validate post type support.
 			$options['supported_post_types'] = array();
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index f30b611637e..207cdfd2733 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -344,16 +344,6 @@ public function render_supported_templates() {
 			<?php
 			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
 			?>
-			<p>
-				<?php
-				$disabled = isset( $theme_support_args['templates_supported']['unrecognized'] );
-				$checked  = $disabled ? $theme_support_args['templates_supported']['unrecognized'] : AMP_Options_Manager::get_option( 'unrecognized_templates_supported' );
-				?>
-				<label for="unrecognized_templates_supported">
-					<input id="unrecognized_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[unrecognized_templates_supported]' ); ?>" <?php checked( $checked ); ?> <?php disabled( $disabled ); ?>>
-					<?php esc_html_e( 'Other', 'amp' ); ?>
-				</label>
-			</p>
 			<script>
 				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
 				(function ( $ ) {
diff --git a/tests/test-class-amp-meta-box.php b/tests/test-class-amp-meta-box.php
index a22796c7bf3..62a0faa9519 100644
--- a/tests/test-class-amp-meta-box.php
+++ b/tests/test-class-amp-meta-box.php
@@ -112,7 +112,6 @@ public function test_render_status() {
 		// No template is available to render the post.
 		add_filter( 'amp_supportable_templates', '__return_empty_array' );
 		AMP_Options_Manager::update_option( 'all_templates_supported', false );
-		AMP_Options_Manager::update_option( 'unrecognized_templates_supported', false );
 		ob_start();
 		$this->instance->render_status( $post );
 		$output = ob_get_clean();
diff --git a/tests/test-class-amp-options-manager.php b/tests/test-class-amp-options-manager.php
index da45e161304..d1fa7507d22 100644
--- a/tests/test-class-amp-options-manager.php
+++ b/tests/test-class-amp-options-manager.php
@@ -92,15 +92,14 @@ public function test_get_and_set_options() {
 		delete_option( AMP_Options_Manager::OPTION_NAME );
 		$this->assertEquals(
 			array(
-				'theme_support'                    => 'disabled',
-				'supported_post_types'             => array( 'post' ),
-				'analytics'                        => array(),
-				'force_sanitization'               => false,
-				'accept_tree_shaking'              => false,
-				'disable_admin_bar'                => false,
-				'all_templates_supported'          => true,
-				'unrecognized_templates_supported' => false,
-				'supported_templates'              => array( 'is_singular' ),
+				'theme_support'           => 'disabled',
+				'supported_post_types'    => array( 'post' ),
+				'analytics'               => array(),
+				'force_sanitization'      => false,
+				'accept_tree_shaking'     => false,
+				'disable_admin_bar'       => false,
+				'all_templates_supported' => true,
+				'supported_templates'     => array( 'is_singular' ),
 			),
 			AMP_Options_Manager::get_options()
 		);
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 11f111ac012..d6e3d8eb2ac 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -425,8 +425,6 @@ public function test_get_template_availability() {
 		// @todo Test with query, post, or page.
 		// @todo Test without availability of WP_Query (no_query_available).
 		// @todo Test without theme support (no_theme_support).
-		// @todo Test unrecognized by theme support arg.
-		// @todo Test unrecognized.
 	}
 
 	/**

From 1bc42517e78ae45c099b53fb3be6e2ce956d6330 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 21:42:32 -0700
Subject: [PATCH 27/34] Restore the availability of AMP components in non-AMP
 documents in native sites

Revert "Remove dirty AMP support; rename Disabled to Classic"

This reverts most of commit 5bae33e55bf41e709bd46541c011d3ca36b42fc8.
---
 includes/admin/class-amp-editor-blocks.php | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/includes/admin/class-amp-editor-blocks.php b/includes/admin/class-amp-editor-blocks.php
index 7e880cea840..d2820e5e14c 100644
--- a/includes/admin/class-amp-editor-blocks.php
+++ b/includes/admin/class-amp-editor-blocks.php
@@ -43,6 +43,22 @@ public function init() {
 		if ( function_exists( 'gutenberg_init' ) ) {
 			add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_block_editor_assets' ) );
 			add_filter( 'wp_kses_allowed_html', array( $this, 'whitelist_block_atts_in_wp_kses_allowed_html' ), 10, 2 );
+
+			/*
+			 * Dirty AMP is required when a site is in native mode but not all templates are being served
+			 * as AMP. In particular, if a single post is using AMP-specific Gutenberg Blocks which make
+			 * use of AMP components, and the singular template is served as AMP but the blog page is not,
+			 * then the non-AMP blog page need to load the AMP runtime scripts so that the AMP components
+			 * in the posts displayed there will be rendered properly. This is only relevant on native AMP
+			 * sites because the AMP Gutenberg blocks are only made available in that mode; they are not
+			 * presented in the Gutenberg inserter in paired mode. In general, using AMP components in
+			 * non-AMP documents is still not officially supported, so it's occurrence is being minimized
+			 * as much as possible. For more, see <https://github.com/Automattic/amp-wp/issues/1192>.
+			 */
+			if ( amp_is_canonical() ) {
+				add_filter( 'the_content', array( $this, 'tally_content_requiring_amp_scripts' ) );
+				add_action( 'wp_print_footer_scripts', array( $this, 'print_dirty_amp_scripts' ) );
+			}
 		}
 	}
 
@@ -145,4 +161,32 @@ public function enqueue_block_editor_assets() {
 			) ) )
 		);
 	}
+
+	/**
+	 * Tally the AMP component scripts that are needed in a dirty AMP document.
+	 *
+	 * @param string $content Content.
+	 * @return string Content (unmodified).
+	 */
+	public function tally_content_requiring_amp_scripts( $content ) {
+		if ( ! is_amp_endpoint() ) {
+			$pattern = sprintf( '/<(%s)\b.*?>/s', join( '|', $this->amp_blocks ) );
+			if ( preg_match_all( $pattern, $content, $matches ) ) {
+				$this->content_required_amp_scripts = array_merge(
+					$this->content_required_amp_scripts,
+					$matches[1]
+				);
+			}
+		}
+		return $content;
+	}
+
+	/**
+	 * Print AMP scripts required for AMP components used in a non-AMP document (dirty AMP).
+	 */
+	public function print_dirty_amp_scripts() {
+		if ( ! is_amp_endpoint() && ! empty( $this->content_required_amp_scripts ) ) {
+			wp_scripts()->do_items( $this->content_required_amp_scripts );
+		}
+	}
 }

From 11ea3d1378e50b507fe74316dfeaff1179071a4f Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 21:48:34 -0700
Subject: [PATCH 28/34] Remove unused variable and fix phpcs issue

---
 amp.php                              | 9 ---------
 includes/class-amp-theme-support.php | 6 +-----
 2 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/amp.php b/amp.php
index acac3f5b7ed..09fa1402bd7 100644
--- a/amp.php
+++ b/amp.php
@@ -295,15 +295,6 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *          ),
  *      ) );
  *
- * Or if you want to prevent AMP from being used on the front page and on any Other template that is unrecognized:
- *
- *      add_theme_support( 'amp', array(
- *          'templates_supported' => array(
- *              'is_front_page' => false,
- *              'unrecognized' => false,
- *          ),
- *      ) );
- *
  * Or if you want to force AMP to be used on all templates:
  *
  *      add_theme_support( 'amp', array(
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 3f06cc24455..f9fdf7ee146 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -458,14 +458,10 @@ public static function get_template_availability( $query = null ) {
 		}
 
 		$all_templates_supported_by_theme_support = false;
-		$theme_templates_supported                = array();
 		if ( isset( $theme_support_args['templates_supported'] ) ) {
 			$all_templates_supported_by_theme_support = 'all' === $theme_support_args['templates_supported'];
-			if ( is_array( $theme_support_args['templates_supported'] ) ) {
-				$theme_templates_supported = $theme_support_args['templates_supported'];
-			}
 		}
-		$all_templates_supported          = (
+		$all_templates_supported = (
 			$all_templates_supported_by_theme_support || AMP_Options_Manager::get_option( 'all_templates_supported' )
 		);
 

From 4bde27d9c057f01566164324ac9c36fcd713698d Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Sun, 1 Jul 2018 22:44:10 -0700
Subject: [PATCH 29/34] Add tests for
 AMP_Theme_Support::get_supportable_templates()

---
 includes/class-amp-theme-support.php   |   1 +
 tests/test-class-amp-theme-support.php | 114 ++++++++++++++++++++++++-
 2 files changed, 111 insertions(+), 4 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index f9fdf7ee146..138230e9b3a 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -677,6 +677,7 @@ public static function get_supportable_templates() {
 		foreach ( get_post_types( $post_type_args, 'objects' ) as $post_type ) {
 			$templates[ sprintf( 'is_post_type_archive[%s]', $post_type->name ) ] = array(
 				'label'    => $post_type->labels->archives,
+				'parent'   => 'is_archive',
 				'callback' => function ( WP_Query $query ) use ( $post_type ) {
 					return $query->is_post_type_archive( $post_type->name );
 				},
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index d6e3d8eb2ac..6c3a79d9f75 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -433,10 +433,116 @@ public function test_get_template_availability() {
 	 * @covers AMP_Theme_Support::get_supportable_templates()
 	 */
 	public function test_get_supportable_templates() {
-		$this->markTestIncomplete();
-		// @todo Register custom taxonomy.
-		// @todo Set static front page
-		// @todo Add custom post types.
+
+		register_taxonomy( 'accolade', 'post', array(
+			'public' => true,
+		) );
+		register_taxonomy( 'complaint', 'post', array(
+			'public' => false,
+		) );
+		register_post_type( 'announcement', array(
+			'public'      => true,
+			'has_archive' => true,
+		) );
+
+		// Test default case with non-static front page.
+		update_option( 'show_on_front', 'posts' );
+		AMP_Options_Manager::update_option( 'all_templates_supported', true );
+		$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+		foreach ( $supportable_templates as $id => $supportable_template ) {
+			$this->assertFalse( is_numeric( $id ) );
+			$this->assertArrayHasKey( 'label', $supportable_template, "$id has label" );
+			$this->assertTrue( $supportable_template['supported'] );
+			$this->assertFalse( $supportable_template['immutable'] );
+		}
+		$this->assertArrayHasKey( 'is_singular', $supportable_templates );
+		$this->assertArrayNotHasKey( 'is_front_page', $supportable_templates );
+		$this->assertArrayHasKey( 'is_home', $supportable_templates );
+		$this->assertArrayNotHasKey( 'parent', $supportable_templates['is_home'] );
+
+		// Test common templates.
+		$this->assertArrayHasKey( 'is_singular', $supportable_templates );
+		$this->assertArrayHasKey( 'is_archive', $supportable_templates );
+		$this->assertArrayHasKey( 'is_author', $supportable_templates );
+		$this->assertArrayHasKey( 'is_date', $supportable_templates );
+		$this->assertArrayHasKey( 'is_search', $supportable_templates );
+		$this->assertArrayHasKey( 'is_404', $supportable_templates );
+		$this->assertArrayHasKey( 'is_category', $supportable_templates );
+		$this->assertArrayHasKey( 'is_tag', $supportable_templates );
+		$this->assertArrayHasKey( 'is_tax[accolade]', $supportable_templates );
+		$this->assertEquals( 'is_archive', $supportable_templates['is_tax[accolade]']['parent'] );
+		$this->assertArrayNotHasKey( 'is_tax[complaint]', $supportable_templates );
+		$this->assertArrayHasKey( 'is_post_type_archive[announcement]', $supportable_templates );
+		$this->assertEquals( 'is_archive', $supportable_templates['is_post_type_archive[announcement]']['parent'] );
+
+		// Test static homepage and page for posts.
+		$page_on_front  = $this->factory()->post->create( array( 'post_type' => 'page' ) );
+		$page_for_posts = $this->factory()->post->create( array( 'post_type' => 'page' ) );
+		update_option( 'show_on_front', 'page' );
+		update_option( 'page_for_posts', $page_for_posts );
+		update_option( 'page_on_front', $page_on_front );
+		$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+		foreach ( $supportable_templates as $id => $supportable_template ) {
+			$this->assertFalse( is_numeric( $id ) );
+			$this->assertArrayHasKey( 'label', $supportable_template, "$id has label" );
+		}
+		$this->assertArrayHasKey( 'is_front_page', $supportable_templates );
+		$this->assertArrayHasKey( 'parent', $supportable_templates['is_front_page'] );
+		$this->assertEquals( 'is_singular', $supportable_templates['is_front_page']['parent'] );
+
+		// Test inclusion of custom template, forcing category to be not-supported, and singular to be supported.
+		add_filter( 'amp_supportable_templates', function( $templates ) {
+			$templates['is_category']['supported'] = false;
+			$templates['is_singular']['supported'] = true;
+
+			$templates['is_custom'] = array(
+				'label'    => 'Custom',
+				'callback' => function( WP_Query $query ) {
+					return false !== $query->get( 'custom', false );
+				},
+			);
+			return $templates;
+		} );
+		$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+		$this->assertTrue( $supportable_templates['is_category']['immutable'] );
+		$this->assertFalse( $supportable_templates['is_category']['supported'] );
+		$this->assertFalse( $supportable_templates['is_category']['user_supported'] );
+		$this->assertTrue( $supportable_templates['is_singular']['immutable'] );
+		$this->assertTrue( $supportable_templates['is_singular']['supported'] );
+		$this->assertTrue( $supportable_templates['is_singular']['user_supported'] );
+		$this->assertArrayHasKey( 'is_custom', $supportable_templates );
+		remove_all_filters( 'amp_supportable_templates' );
+
+		// Test supporting templates by theme support args: all.
+		AMP_Options_Manager::update_option( 'all_templates_supported', false );
+		add_theme_support( 'amp', array(
+			'templates_supported' => 'all',
+		) );
+		AMP_Theme_Support::init();
+		$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+		foreach ( $supportable_templates as $supportable_template ) {
+			$this->assertTrue( $supportable_template['supported'] );
+			$this->assertTrue( $supportable_template['immutable'] );
+		}
+
+		// Test supporting templates by theme support args: selective templates.
+		AMP_Options_Manager::update_option( 'all_templates_supported', false );
+		add_theme_support( 'amp', array(
+			'templates_supported' => array(
+				'is_date'   => true,
+				'is_author' => false,
+			),
+		) );
+		AMP_Theme_Support::init();
+		$supportable_templates = AMP_Theme_Support::get_supportable_templates();
+		$this->assertTrue( $supportable_templates['is_date']['supported'] );
+		$this->assertTrue( $supportable_templates['is_date']['immutable'] );
+		$this->assertFalse( $supportable_templates['is_author']['supported'] );
+		$this->assertTrue( $supportable_templates['is_author']['immutable'] );
+		$this->assertTrue( $supportable_templates['is_singular']['supported'] );
+		$this->assertFalse( $supportable_templates['is_singular']['immutable'] );
+		$this->assertFalse( $supportable_templates['is_category']['supported'] );
+		$this->assertFalse( $supportable_templates['is_category']['immutable'] );
 	}
 
 	/**

From c172763022a8264683ff8994b6edc4bb0a06243d Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Mon, 2 Jul 2018 00:16:57 -0700
Subject: [PATCH 30/34] Add test for
 AMP_Theme_Support::get_template_availability()

---
 includes/class-amp-theme-support.php   |   7 +-
 tests/test-class-amp-theme-support.php | 103 +++++++++++++++++++++++--
 2 files changed, 102 insertions(+), 8 deletions(-)

diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index 138230e9b3a..f373a004724 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -442,7 +442,7 @@ public static function get_template_availability( $query = null ) {
 		);
 
 		if ( ! ( $query instanceof WP_Query ) ) {
-			_doing_it_wrong( __FUNCTION__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
+			_doing_it_wrong( __METHOD__, esc_html__( 'No WP_Query available.', 'amp' ), '1.0' );
 			return array_merge(
 				$default_response,
 				array( 'errors' => array( 'no_query_available' ) )
@@ -503,6 +503,9 @@ public static function get_template_availability( $query = null ) {
 
 		// Make sure children override their parents.
 		$matching_template_ids = array_keys( $matching_templates );
+		foreach ( array_diff( array_keys( $supportable_templates ), $matching_template_ids ) as $template_id ) {
+			unset( $supportable_templates[ $template_id ] );
+		}
 		foreach ( $matching_template_ids as $id ) {
 			$has_children = false;
 			foreach ( $supportable_templates as $other_id => $supportable_template ) {
@@ -538,7 +541,7 @@ public static function get_template_availability( $query = null ) {
 		 * Template conditions need to be set up properly to prevent this from happening.
 		 */
 		if ( count( $matching_templates ) > 1 ) {
-			_doing_it_wrong( __FUNCTION__, esc_html__( 'Did not expect there to be more than one matching template. Did you filter amp_supportable_templates to not honor the template hierarchy?', 'amp' ), '1.0' );
+			_doing_it_wrong( __METHOD__, esc_html__( 'Did not expect there to be more than one matching template. Did you filter amp_supportable_templates to not honor the template hierarchy?', 'amp' ), '1.0' );
 		}
 
 		$matching_template = array_shift( $matching_templates );
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 6c3a79d9f75..99084230af3 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -413,18 +413,109 @@ public function test_validate_non_amp_theme() {
 		$this->assertContains( '<script type="text/javascript" src="https://cdn.ampproject.org/v0/amp-mathml-latest.js" async custom-element="amp-mathml"></script>', $sanitized_html ); // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedScript
 	}
 
+	/**
+	 * Test incorrect usage for get_template_availability.
+	 *
+	 * @expectedIncorrectUsage AMP_Theme_Support::get_template_availability
+	 * @covers AMP_Theme_Support::get_template_availability()
+	 */
+	public function test_incorrect_usage_get_template_availability() {
+		global $wp_query;
+
+		// Test no query available.
+		$wp_query     = null; // WPCS: override ok.
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertInternalType( 'array', $availability );
+		$this->assertEquals( array( 'no_query_available' ), $availability['errors'] );
+		$this->assertFalse( $availability['supported'] );
+		$this->assertNull( $availability['immutable'] );
+		$this->assertNull( $availability['template'] );
+
+		// Test no theme support.
+		remove_theme_support( 'amp' );
+		$this->go_to( get_permalink( $this->factory()->post->create() ) );
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertEquals( array( 'no_theme_support' ), $availability['errors'] );
+		$this->assertFalse( $availability['supported'] );
+		$this->assertNull( $availability['immutable'] );
+		$this->assertNull( $availability['template'] );
+	}
+
 	/**
 	 * Test get_template_availability.
 	 *
 	 * @covers AMP_Theme_Support::get_template_availability()
 	 */
 	public function test_get_template_availability() {
-		$this->markTestIncomplete();
-		// @todo Test nested.
-		// @todo Test callback vs ID.
-		// @todo Test with query, post, or page.
-		// @todo Test without availability of WP_Query (no_query_available).
-		// @todo Test without theme support (no_theme_support).
+		global $wp_query;
+		$post_id = $this->factory()->post->create();
+		query_posts( array( 'p' => $post_id ) ); // phpcs:ignore
+
+		// Test successful match of singular template.
+		$this->assertTrue( is_singular() );
+		AMP_Options_Manager::update_option( 'all_templates_supported', false );
+		add_theme_support( 'amp' );
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertEmpty( $availability['errors'] );
+		$this->assertTrue( $availability['supported'] );
+		$this->assertFalse( $availability['immutable'] );
+		$this->assertEquals( 'is_singular', $availability['template'] );
+
+		// Test successful match when passing WP_Query and WP_Post into method.
+		$query        = $wp_query;
+		$wp_query     = null; // WPCS: override ok.
+		$availability = AMP_Theme_Support::get_template_availability( $query );
+		$this->assertTrue( $availability['supported'] );
+		$this->assertEquals( 'is_singular', $availability['template'] );
+		$availability = AMP_Theme_Support::get_template_availability( get_post( $post_id ) );
+		$this->assertTrue( $availability['supported'] );
+		$this->assertEquals( 'is_singular', $availability['template'] );
+		$this->assertNull( $wp_query ); // Make sure it is reset.
+
+		// Test nested hierarchy.
+		AMP_Options_Manager::update_option( 'supported_templates', array( 'is_special' ) );
+		add_filter( 'amp_supportable_templates', function( $templates ) {
+			$templates['is_single']  = array(
+				'label'     => 'Single post',
+				'supported' => false,
+				'parent'    => 'is_singular',
+			);
+			$templates['is_special'] = array(
+				'label'    => 'Special post',
+				'parent'   => 'is_single',
+				'callback' => function( WP_Query $query ) {
+					return $query->is_singular() && 'special' === get_post( $query->get_queried_object_id() )->post_name;
+				},
+			);
+			$templates['is_page']    = array(
+				'label'     => 'Page',
+				'supported' => true,
+				'parent'    => 'is_singular',
+			);
+			return $templates;
+		} );
+
+		$availability = AMP_Theme_Support::get_template_availability( get_post( $post_id ) );
+		$this->assertFalse( $availability['supported'] );
+		$this->assertTrue( $availability['immutable'] );
+		$this->assertEquals( 'is_single', $availability['template'] );
+
+		$special_id   = $this->factory()->post->create( array(
+			'post_type' => 'post',
+			'post_name' => 'special',
+		) );
+		$availability = AMP_Theme_Support::get_template_availability( get_post( $special_id ) );
+		$this->assertTrue( $availability['supported'] );
+		$this->assertEquals( 'is_special', $availability['template'] );
+		$this->assertFalse( $availability['immutable'] );
+
+		$availability = AMP_Theme_Support::get_template_availability( $this->factory()->post->create_and_get( array( 'post_type' => 'page' ) ) );
+		$this->assertFalse( $availability['supported'] );
+		$this->assertEquals( array( 'post-type-support' ), $availability['errors'] );
+		$this->assertEquals( 'is_page', $availability['template'] );
+		add_post_type_support( 'page', 'amp' );
+		$availability = AMP_Theme_Support::get_template_availability( $this->factory()->post->create_and_get( array( 'post_type' => 'page' ) ) );
+		$this->assertTrue( $availability['supported'] );
 	}
 
 	/**

From 38b5546fc1a34c387f9b698ead370845ab775d58 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Mon, 2 Jul 2018 00:47:50 -0700
Subject: [PATCH 31/34] Add test for custom template

---
 tests/test-class-amp-theme-support.php | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 99084230af3..13ce040fa90 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -473,7 +473,7 @@ public function test_get_template_availability() {
 		$this->assertNull( $wp_query ); // Make sure it is reset.
 
 		// Test nested hierarchy.
-		AMP_Options_Manager::update_option( 'supported_templates', array( 'is_special' ) );
+		AMP_Options_Manager::update_option( 'supported_templates', array( 'is_special', 'is_custom' ) );
 		add_filter( 'amp_supportable_templates', function( $templates ) {
 			$templates['is_single']  = array(
 				'label'     => 'Single post',
@@ -492,8 +492,18 @@ public function test_get_template_availability() {
 				'supported' => true,
 				'parent'    => 'is_singular',
 			);
+			$templates['is_custom']  = array(
+				'label'    => 'Custom',
+				'callback' => function( WP_Query $query ) {
+					return false !== $query->get( 'custom', false );
+				},
+			);
 			return $templates;
 		} );
+		add_filter( 'query_vars', function( $vars ) {
+			$vars[] = 'custom';
+			return $vars;
+		} );
 
 		$availability = AMP_Theme_Support::get_template_availability( get_post( $post_id ) );
 		$this->assertFalse( $availability['supported'] );
@@ -516,6 +526,12 @@ public function test_get_template_availability() {
 		add_post_type_support( 'page', 'amp' );
 		$availability = AMP_Theme_Support::get_template_availability( $this->factory()->post->create_and_get( array( 'post_type' => 'page' ) ) );
 		$this->assertTrue( $availability['supported'] );
+
+		// Test custom.
+		$this->go_to( '/?custom=1' );
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertTrue( $availability['supported'] );
+		$this->assertEquals( 'is_custom', $availability['template'] );
 	}
 
 	/**

From acf9849ef0b3094dfb18b4c15a0980f22d8b9b15 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Mon, 2 Jul 2018 11:31:22 -0700
Subject: [PATCH 32/34] Restore available_callback but mark as deprecated

Use _doing_it_wrong() instead of trigger_error()
---
 includes/admin/class-amp-post-meta-box.php    |   5 +
 includes/class-amp-theme-support.php          |  63 ++++++---
 .../options/class-amp-options-manager.php     |  26 ++--
 includes/options/class-amp-options-menu.php   | 132 ++++++++++--------
 tests/test-class-amp-theme-support.php        | 100 ++++++++++---
 5 files changed, 216 insertions(+), 110 deletions(-)

diff --git a/includes/admin/class-amp-post-meta-box.php b/includes/admin/class-amp-post-meta-box.php
index 58c14246363..325e81e7b9d 100644
--- a/includes/admin/class-amp-post-meta-box.php
+++ b/includes/admin/class-amp-post-meta-box.php
@@ -184,6 +184,11 @@ public function render_status( $post ) {
 			return;
 		}
 
+		/*
+		 * When theme support is present then theme templates can be served in AMP and we check first if the template is available.
+		 * Checking for template availability will include a check for get_support_errors. Otherwise, if theme support is not present
+		 * then we just check get_support_errors.
+		 */
 		if ( current_theme_supports( 'amp' ) ) {
 			$availability = AMP_Theme_Support::get_template_availability( $post );
 			$status       = $availability['supported'] ? self::ENABLED_STATUS : self::DISABLED_STATUS;
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index f373a004724..fbc25ba3050 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -157,10 +157,8 @@ public static function is_support_added_via_option() {
 	 * Read theme support and apply options from admin for whether theme support is enabled and via what template is enabled.
 	 *
 	 * @see AMP_Post_Type_Support::add_post_type_support() For where post type support is added, since it is irrespective of theme support.
-	 *
-	 * @param bool $check_args Whether the theme support args should be checked.
 	 */
-	public static function read_theme_support( $check_args = WP_DEBUG ) {
+	public static function read_theme_support() {
 		self::$support_added_via_option = false;
 
 		self::$initial_theme_support_args = false;
@@ -172,18 +170,20 @@ public static function read_theme_support( $check_args = WP_DEBUG ) {
 				self::$initial_theme_support_args = array_shift( $support );
 
 				// Validate theme support usage.
-				if ( $check_args ) {
-					$keys = array( 'template_dir', 'comments_live_list', 'mode', 'optional', 'templates_supported' );
-					if ( ! is_array( self::$initial_theme_support_args ) ) {
-						trigger_error( esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-					} elseif ( count( array_diff( array_keys( self::$initial_theme_support_args ), $keys ) ) !== 0 ) {
-						trigger_error( esc_html( sprintf(  // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
-							/* translators: %1$s is expected keys and %2$s is actual keys */
-							__( 'Expected AMP theme support to keys (%1$s) but saw (%2$s)', 'amp' ),
-							join( ', ', $keys ),
-							join( ', ', array_keys( self::$initial_theme_support_args ) )
-						) ) );
-					}
+				$keys = array( 'template_dir', 'comments_live_list', 'mode', 'optional', 'templates_supported', 'available_callback' );
+				if ( ! is_array( self::$initial_theme_support_args ) ) {
+					_doing_it_wrong( 'add_theme_support', esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ), '1.0' ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
+				} elseif ( count( array_diff( array_keys( self::$initial_theme_support_args ), $keys ) ) !== 0 ) {
+					_doing_it_wrong( 'add_theme_support', esc_html( sprintf(  // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
+						/* translators: %1$s is expected keys and %2$s is actual keys */
+						__( 'Expected AMP theme support to keys (%1$s) but saw (%2$s)', 'amp' ),
+						join( ', ', $keys ),
+						join( ', ', array_keys( self::$initial_theme_support_args ) )
+					) ), '1.0' );
+				}
+
+				if ( isset( self::$initial_theme_support_args['available_callback'] ) ) {
+					_doing_it_wrong( 'add_theme_support', esc_html__( 'The available_callback is deprecated when adding amp theme support in favor of declaratively setting the supported_templates.', 'amp' ), '1.0' );
 				}
 			}
 		}
@@ -359,7 +359,6 @@ public static function redirect_ampless_url( $exit = true ) {
 	 * When 'amp' theme support has not been added or canonical mode is enabled, then this returns false.
 	 *
 	 * @since 0.7
-	 * @since 1.0 This no longer looks at the available_callback bit instead calls get_template_availability.
 	 *
 	 * @see amp_is_canonical()
 	 * @return bool Whether available.
@@ -457,6 +456,38 @@ public static function get_template_availability( $query = null ) {
 			);
 		}
 
+		// Support available_callback from 0.7, though it is deprecated.
+		if ( isset( $theme_support_args['available_callback'] ) && is_callable( $theme_support_args['available_callback'] ) ) {
+			/**
+			 * Queried object.
+			 *
+			 * @var WP_Post $queried_object
+			 */
+			$queried_object = $query->get_queried_object();
+			if ( ( is_singular() || $query->is_posts_page ) && ! post_supports_amp( $queried_object ) ) {
+				return array_merge(
+					$default_response,
+					array(
+						'errors'    => array( 'no-post-support' ),
+						'supported' => false,
+						'immutable' => true,
+					)
+				);
+			}
+
+			$response = array_merge(
+				$default_response,
+				array(
+					'supported' => call_user_func( $theme_support_args['available_callback'] ),
+					'immutable' => true,
+				)
+			);
+			if ( ! $response['supported'] ) {
+				$response['errors'][] = 'available_callback';
+			}
+			return $response;
+		}
+
 		$all_templates_supported_by_theme_support = false;
 		if ( isset( $theme_support_args['templates_supported'] ) ) {
 			$all_templates_supported_by_theme_support = 'all' === $theme_support_args['templates_supported'];
diff --git a/includes/options/class-amp-options-manager.php b/includes/options/class-amp-options-manager.php
index 40eb41f85ee..e18bdbc1bad 100644
--- a/includes/options/class-amp-options-manager.php
+++ b/includes/options/class-amp-options-manager.php
@@ -122,24 +122,24 @@ public static function validate_options( $new_options ) {
 		$options['accept_tree_shaking'] = ! empty( $new_options['accept_tree_shaking'] );
 		$options['disable_admin_bar']   = ! empty( $new_options['disable_admin_bar'] );
 
+		// Validate post type support.
+		$options['supported_post_types'] = array();
+		if ( isset( $new_options['supported_post_types'] ) ) {
+			foreach ( $new_options['supported_post_types'] as $post_type ) {
+				if ( ! post_type_exists( $post_type ) ) {
+					add_settings_error( self::OPTION_NAME, 'unknown_post_type', __( 'Unrecognized post type.', 'amp' ) );
+				} else {
+					$options['supported_post_types'][] = $post_type;
+				}
+			}
+		}
+
 		$theme_support_args = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) );
 
 		$is_template_support_required = ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] );
-		if ( ! $is_template_support_required ) {
+		if ( ! $is_template_support_required && ! isset( $theme_support_args['available_callback'] ) ) {
 			$options['all_templates_supported'] = ! empty( $new_options['all_templates_supported'] );
 
-			// Validate post type support.
-			$options['supported_post_types'] = array();
-			if ( isset( $new_options['supported_post_types'] ) ) {
-				foreach ( $new_options['supported_post_types'] as $post_type ) {
-					if ( ! post_type_exists( $post_type ) ) {
-						add_settings_error( self::OPTION_NAME, 'unknown_post_type', __( 'Unrecognized post type.', 'amp' ) );
-					} else {
-						$options['supported_post_types'][] = $post_type;
-					}
-				}
-			}
-
 			// Validate supported templates.
 			$options['supported_templates'] = array();
 			if ( isset( $new_options['supported_templates'] ) ) {
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 207cdfd2733..82672bc1df6 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -287,27 +287,35 @@ public function render_validation_handling() {
 	 */
 	public function render_supported_templates() {
 		$theme_support_args = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ); // Initial so we can get before removed if optional.
-
 		?>
-		<fieldset id="all_templates_supported_fieldset">
-			<?php if ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] ) : ?>
-				<div class="notice notice-info notice-alt inline">
+
+		<?php if ( ! isset( $theme_support_args['available_callback'] ) ) : ?>
+			<fieldset id="all_templates_supported_fieldset">
+				<?php if ( isset( $theme_support_args['templates_supported'] ) && 'all' === $theme_support_args['templates_supported'] ) : ?>
+					<div class="notice notice-info notice-alt inline">
+						<p>
+							<?php esc_html_e( 'The current theme requires all templates to support AMP.', 'amp' ); ?>
+						</p>
+					</div>
+				<?php else : ?>
 					<p>
-						<?php esc_html_e( 'The current theme requires all templates to support AMP.', 'amp' ); ?>
+						<label for="all_templates_supported">
+							<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
+							<?php esc_html_e( 'Serve all templates as AMP regardless of what is being queried.', 'amp' ); ?>
+						</label>
 					</p>
-				</div>
-			<?php else : ?>
+					<p class="description">
+						<?php esc_html_e( 'This will allow all of the URLs on your site to be served as AMP by default.', 'amp' ); ?>
+					</p>
+				<?php endif; ?>
+			</fieldset>
+		<?php else : ?>
+			<div class="notice notice-warning notice-alt inline">
 				<p>
-					<label for="all_templates_supported">
-						<input id="all_templates_supported" type="checkbox" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[all_templates_supported]' ); ?>" <?php checked( AMP_Options_Manager::get_option( 'all_templates_supported' ) ); ?>>
-						<?php esc_html_e( 'Serve all templates as AMP regardless of what is being queried.', 'amp' ); ?>
-					</label>
-				</p>
-				<p class="description">
-					<?php esc_html_e( 'This will allow all of the URLs on your site to be served as AMP by default.', 'amp' ); ?>
+					<?php esc_html_e( 'Your theme is using the deprecated available_callback argument for AMP theme support.', 'amp' ); ?>
 				</p>
-			<?php endif; ?>
-		</fieldset>
+			</div>
+		<?php endif; ?>
 
 		<fieldset id="supported_post_types_fieldset">
 			<?php $element_name = AMP_Options_Manager::OPTION_NAME . '[supported_post_types][]'; ?>
@@ -334,55 +342,57 @@ public function render_supported_templates() {
 			</ul>
 		</fieldset>
 
-		<fieldset id="supported_templates_fieldset">
-			<style>
-				#supported_templates_fieldset ul ul {
-					margin-left: 40px;
-				}
-			</style>
-			<h4 class="title"><?php esc_html_e( 'Templates', 'amp' ); ?></h4>
-			<?php
-			self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
-			?>
+		<?php if ( ! isset( $theme_support_args['available_callback'] ) ) : ?>
+			<fieldset id="supported_templates_fieldset">
+				<style>
+					#supported_templates_fieldset ul ul {
+						margin-left: 40px;
+					}
+				</style>
+				<h4 class="title"><?php esc_html_e( 'Templates', 'amp' ); ?></h4>
+				<?php
+				self::list_template_conditional_options( AMP_Theme_Support::get_supportable_templates() );
+				?>
+				<script>
+					// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
+					(function ( $ ) {
+						$( '#supported_templates_fieldset input[type=checkbox]' ).on( 'click', function() {
+							$( this ).siblings( 'ul' ).find( 'input[type=checkbox]' ).prop( 'checked', this.checked );
+						} );
+					})( jQuery );
+				</script>
+			</fieldset>
+
 			<script>
-				// Let clicks on parent items automatically cause the children checkboxes to have same checked state applied.
+				// Update the visibility of the fieldsets based on the selected template mode and then whether all templates are indicated to be supported.
 				(function ( $ ) {
-					$( '#supported_templates_fieldset input[type=checkbox]' ).on( 'click', function() {
-						$( this ).siblings( 'ul' ).find( 'input[type=checkbox]' ).prop( 'checked', this.checked );
-					} );
+					var templateModeInputs, themeSupportDisabledInput, allTemplatesSupportedInput;
+					templateModeInputs = $( 'input[type=radio][name="amp-options[theme_support]"]' );
+					themeSupportDisabledInput = $( '#theme_support_disabled' );
+					allTemplatesSupportedInput = $( '#all_templates_supported' );
+
+					function updateFieldsetVisibility() {
+						var allTemplatesSupported = 0 === allTemplatesSupportedInput.length || allTemplatesSupportedInput.prop( 'checked' );
+						$( '#all_templates_supported_fieldset, #supported_post_types_fieldset > .title' ).toggleClass(
+							'hidden',
+							themeSupportDisabledInput.prop( 'checked' )
+						);
+						$( '#supported_post_types_fieldset' ).toggleClass(
+							'hidden',
+							allTemplatesSupported && ! themeSupportDisabledInput.prop( 'checked' )
+						);
+						$( '#supported_templates_fieldset' ).toggleClass(
+							'hidden',
+							allTemplatesSupported || themeSupportDisabledInput.prop( 'checked' )
+						);
+					}
+
+					templateModeInputs.on( 'change', updateFieldsetVisibility );
+					allTemplatesSupportedInput.on( 'click', updateFieldsetVisibility );
+					updateFieldsetVisibility();
 				})( jQuery );
 			</script>
-		</fieldset>
-
-		<script>
-			// Update the visibility of the fieldsets based on the selected template mode and then whether all templates are indicated to be supported.
-			(function ( $ ) {
-				var templateModeInputs, themeSupportDisabledInput, allTemplatesSupportedInput;
-				templateModeInputs = $( 'input[type=radio][name="amp-options[theme_support]"]' );
-				themeSupportDisabledInput = $( '#theme_support_disabled' );
-				allTemplatesSupportedInput = $( '#all_templates_supported' );
-
-				function updateFieldsetVisibility() {
-					var allTemplatesSupported = 0 === allTemplatesSupportedInput.length || allTemplatesSupportedInput.prop( 'checked' );
-					$( '#all_templates_supported_fieldset, #supported_post_types_fieldset > .title' ).toggleClass(
-						'hidden',
-						themeSupportDisabledInput.prop( 'checked' )
-					);
-					$( '#supported_post_types_fieldset' ).toggleClass(
-						'hidden',
-						allTemplatesSupported && ! themeSupportDisabledInput.prop( 'checked' )
-					);
-					$( '#supported_templates_fieldset' ).toggleClass(
-						'hidden',
-						allTemplatesSupported || themeSupportDisabledInput.prop( 'checked' )
-					);
-				}
-
-				templateModeInputs.on( 'change', updateFieldsetVisibility );
-				allTemplatesSupportedInput.on( 'click', updateFieldsetVisibility );
-				updateFieldsetVisibility();
-			})( jQuery );
-		</script>
+		<?php endif; ?>
 		<?php
 	}
 
diff --git a/tests/test-class-amp-theme-support.php b/tests/test-class-amp-theme-support.php
index 13ce040fa90..ad0bbdb75c2 100644
--- a/tests/test-class-amp-theme-support.php
+++ b/tests/test-class-amp-theme-support.php
@@ -75,41 +75,62 @@ public function test_init() {
 	}
 
 	/**
-	 * Test read_theme_support, get_theme_support_args, and is_support_added_via_option.
+	 * Test add_theme_support(amp) with invalid arg.
 	 *
+	 * @expectedIncorrectUsage add_theme_support
 	 * @covers \AMP_Theme_Support::read_theme_support()
-	 * @covers \AMP_Theme_Support::is_support_added_via_option()
 	 * @covers \AMP_Theme_Support::get_theme_support_args()
 	 */
-	public function test_read_theme_support_and_support_args() {
-
-		// Test invalid arg for theme support.
+	public function test_read_theme_support_bad_arg_type() {
 		add_theme_support( 'amp', 'invalid_argument_type' );
-		$e = null;
-		try {
-			AMP_Theme_Support::read_theme_support( true );
-		} catch ( Exception $exception ) {
-			$e = $exception;
-		}
-		$this->assertInstanceOf( 'PHPUnit_Framework_Error_Notice', $e );
-		$this->assertEquals( 'Expected AMP theme support arg to be array.', $e->getMessage() );
+		AMP_Theme_Support::read_theme_support();
 		$this->assertTrue( current_theme_supports( 'amp' ) );
+	}
 
-		// Test invalid args for theme support.
+	/**
+	 * Test add_theme_support(amp) with invalid args.
+	 *
+	 * @expectedIncorrectUsage add_theme_support
+	 * @covers \AMP_Theme_Support::read_theme_support()
+	 * @covers \AMP_Theme_Support::get_theme_support_args()
+	 */
+	public function test_read_theme_support_bad_args_array() {
 		$args = array(
 			'mode'              => 'native',
 			'invalid_param_key' => array(),
 		);
 		add_theme_support( 'amp', $args );
-		try {
-			AMP_Theme_Support::read_theme_support( true );
-		} catch ( Exception $exception ) {
-			$e = $exception;
-		}
-		$this->assertStringStartsWith( 'Expected AMP theme support to keys', $e->getMessage() );
+		AMP_Theme_Support::read_theme_support();
+		$this->assertTrue( current_theme_supports( 'amp' ) );
 		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args() );
 		$this->assertEquals( $args, AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) ) );
 		$this->assertTrue( current_theme_supports( 'amp' ) );
+	}
+
+	/**
+	 * Test add_theme_support(amp) with invalid args.
+	 *
+	 * @expectedIncorrectUsage add_theme_support
+	 * @covers \AMP_Theme_Support::read_theme_support()
+	 */
+	public function test_read_theme_support_bad_available_callback() {
+		add_theme_support( 'amp', array(
+			'available_callback' => function() {
+				return (bool) wp_rand( 0, 1 );
+			},
+		) );
+		AMP_Theme_Support::read_theme_support();
+		$this->assertTrue( current_theme_supports( 'amp' ) );
+	}
+
+	/**
+	 * Test read_theme_support, get_theme_support_args, and is_support_added_via_option.
+	 *
+	 * @covers \AMP_Theme_Support::read_theme_support()
+	 * @covers \AMP_Theme_Support::is_support_added_via_option()
+	 * @covers \AMP_Theme_Support::get_theme_support_args()
+	 */
+	public function test_read_theme_support_and_support_args() {
 
 		// Test behavior of optional flag, that AMP is not enabled if the DB option is not set.
 		$args = array(
@@ -441,6 +462,45 @@ public function test_incorrect_usage_get_template_availability() {
 		$this->assertNull( $availability['template'] );
 	}
 
+	/**
+	 * Test get_template_availability with available_callback.
+	 *
+	 * @expectedIncorrectUsage add_theme_support
+	 * @covers AMP_Theme_Support::get_template_availability()
+	 */
+	public function test_get_template_availability_with_available_callback() {
+		$this->go_to( get_permalink( $this->factory()->post->create() ) );
+		add_theme_support( 'amp', array(
+			'available_callback' => '__return_true',
+		) );
+		AMP_Theme_Support::init();
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertEquals(
+			$availability,
+			array(
+				'supported' => true,
+				'immutable' => true,
+				'template'  => null,
+				'errors'    => array(),
+			)
+		);
+
+		add_theme_support( 'amp', array(
+			'available_callback' => '__return_false',
+		) );
+		AMP_Theme_Support::init();
+		$availability = AMP_Theme_Support::get_template_availability();
+		$this->assertEquals(
+			$availability,
+			array(
+				'supported' => false,
+				'immutable' => true,
+				'template'  => null,
+				'errors'    => array( 'available_callback' ),
+			)
+		);
+	}
+
 	/**
 	 * Test get_template_availability.
 	 *

From 7091b35ec7f316680cf5d1c6cf77a66dd6aa47b8 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Mon, 2 Jul 2018 11:44:37 -0700
Subject: [PATCH 33/34] Fix generation of AMP permalink for attachments

---
 includes/amp-helper-functions.php    | 3 +++
 includes/class-amp-theme-support.php | 1 +
 2 files changed, 4 insertions(+)

diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 964a563ce94..aa2d825554d 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -123,6 +123,9 @@ function amp_get_permalink( $post_id ) {
 			||
 			// If the post type is hierarchical then the /amp/ endpoint isn't available.
 			is_post_type_hierarchical( get_post_type( $post_id ) )
+			||
+			// Attachment pages don't accept the /amp/ endpoint.
+			'attachment' === get_post_type( $post_id )
 		);
 		if ( $use_query_var ) {
 			$amp_url = add_query_arg( amp_get_slug(), '', $permalink );
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index fbc25ba3050..709d1082208 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -172,6 +172,7 @@ public static function read_theme_support() {
 				// Validate theme support usage.
 				$keys = array( 'template_dir', 'comments_live_list', 'mode', 'optional', 'templates_supported', 'available_callback' );
 				if ( ! is_array( self::$initial_theme_support_args ) ) {
+					self::$initial_theme_support_args = array();
 					_doing_it_wrong( 'add_theme_support', esc_html__( 'Expected AMP theme support arg to be array.', 'amp' ), '1.0' ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
 				} elseif ( count( array_diff( array_keys( self::$initial_theme_support_args ), $keys ) ) !== 0 ) {
 					_doing_it_wrong( 'add_theme_support', esc_html( sprintf(  // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error

From b54fcc0e9278eecebf91bb104e4ee23881cc1019 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Mon, 2 Jul 2018 12:32:53 -0700
Subject: [PATCH 34/34] Fix initialization of paried mode and Customizer, and
 fix support options on admin screen

---
 amp.php                                     | 16 +++++++++++++++-
 includes/options/class-amp-options-menu.php | 14 ++++----------
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/amp.php b/amp.php
index 09fa1402bd7..18baaf95225 100644
--- a/amp.php
+++ b/amp.php
@@ -301,6 +301,7 @@ function amp_correct_query_when_is_front_page( WP_Query $query ) {
  *          'templates_supported' => 'all',
  *      ) );
  *
+ * @see AMP_Theme_Support::read_theme_support()
  * @return boolean Whether this is in AMP 'canonical' mode, that is whether it is native and there is not separate AMP URL current URL.
  */
 function amp_is_canonical() {
@@ -311,9 +312,22 @@ function amp_is_canonical() {
 	$mode    = 'native';
 	$support = get_theme_support( 'amp' );
 	if ( is_array( $support ) ) {
-		$args = array_shift( $support );
+		$args    = array_shift( $support );
+		$support = AMP_Options_Manager::get_option( 'theme_support' );
+
+		// If support is optional, look at DB option if mode is not explicitly set in theme support.
+		if ( ! empty( $args['optional'] ) ) {
+			if ( 'disabled' === $support ) {
+				return false;
+			} elseif ( ! isset( $args['mode'] ) ) {
+				return 'native' === $support;
+			}
+		}
+
 		if ( isset( $args['mode'] ) ) {
 			$mode = $args['mode'];
+		} elseif ( 'disabled' !== $support ) {
+			$mode = $support; // Supplied via admin screen.
 		} elseif ( ! empty( $args['template_dir'] ) ) {
 			$mode = 'paired'; // If there is a template_dir, then paired mode is implied.
 		}
diff --git a/includes/options/class-amp-options-menu.php b/includes/options/class-amp-options-menu.php
index 82672bc1df6..4ce89cf0958 100644
--- a/includes/options/class-amp-options-menu.php
+++ b/includes/options/class-amp-options-menu.php
@@ -129,21 +129,15 @@ public function render_theme_support() {
 		$support_args  = AMP_Theme_Support::get_theme_support_args( array( 'initial' => true ) );
 
 		$theme_support_mutable = (
-			empty( $support_args )
-			||
 			! empty( $support_args['optional'] )
 			||
 			AMP_Theme_Support::is_support_added_via_option()
 		);
 
-		$mode_mutable = ! ( is_array( $support_args ) && isset( $support_args['mode'] ) );
+		$mode_mutable = ! isset( $support_args['mode'] );
 
 		if ( ! $theme_support_mutable || ( ! $mode_mutable && 'disabled' !== $theme_support ) ) {
-			if ( amp_is_canonical() ) {
-				$theme_support = 'native';
-			} else {
-				$theme_support = 'paired';
-			}
+			$theme_support = isset( $support_args['mode'] ) ? $support_args['mode'] : 'native';
 		}
 
 		$should_have_theme_support = in_array( get_template(), array( 'twentyfifteen', 'twentysixteen', 'twentyseventeen' ), true );
@@ -168,7 +162,7 @@ public function render_theme_support() {
 				<dd>
 					<?php esc_html_e( 'Display AMP responses in classic (legacy) post templates in a basic design that does not match your theme\'s templates.', 'amp' ); ?>
 				</dd>
-				<?php if ( $mode_mutable || ! amp_is_canonical() ) : ?>
+				<?php if ( $mode_mutable || 'paired' === $support_args['mode'] ) : ?>
 					<dt>
 						<input type="radio" id="theme_support_paired" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="paired" <?php checked( $theme_support, 'paired' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
 						<label for="theme_support_paired">
@@ -179,7 +173,7 @@ public function render_theme_support() {
 						<?php esc_html_e( 'Reuse active theme\'s templates to display AMP responses, but use separate URLs for AMP. The canonical URLs for your site will not have AMP. If there are AMP validation errors encountered in the AMP response and the validation errors are not accepted for sanitization, then the AMP version will redirect to the non-AMP version.', 'amp' ); ?>
 					</dd>
 				<?php endif; ?>
-				<?php if ( $mode_mutable || amp_is_canonical() ) : ?>
+				<?php if ( $mode_mutable || 'native' === $support_args['mode'] ) : ?>
 					<dt>
 						<input type="radio" id="theme_support_native" name="<?php echo esc_attr( AMP_Options_Manager::OPTION_NAME . '[theme_support]' ); ?>" value="native" <?php checked( $theme_support, 'native' ); ?> <?php disabled( ! $theme_support_mutable ); ?>>
 						<label for="theme_support_native">