Add template revision button

lib/experimental/class-gutenberg-rest-template-revision-count.php

@@ -0,0 +1,75 @@
+<?php
+/**
+ * REST API: Gutenberg_REST_Template_Revision_Count class
+ *
+ * @package    gutenberg
+ */
+
+/**
+ * Gutenberg_REST_Template_Revision_Count class
+ *
+ * When merging into core, prepare_revision_links() should be merged with
+ * WP_REST_Templates_Controller::prepare_links().
+ */
+class Gutenberg_REST_Template_Revision_Count extends WP_REST_Templates_Controller {
+	/**
+	 * Add revisions to the response.
+	 *
+	 * @param WP_Block_Template $item    Template instance.
+	 * @param WP_REST_Request   $request Request object.
+	 * @return WP_REST_Response Response object.
+	 */
+	public function prepare_item_for_response( $item, $request ) { // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable
+		$template = $item;
+
+		$fields = $this->get_fields_for_response( $request );
+
+		$response = parent::prepare_item_for_response( $item, $request );
+
+		if ( rest_is_field_included( '_links', $fields ) || rest_is_field_included( '_embedded', $fields ) ) {
+			$links = $this->prepare_revision_links( $template );
+			$response->add_links( $links );
+			if ( ! empty( $links['self']['href'] ) ) {
+				$actions = $this->get_available_actions();
+				$self    = $links['self']['href'];
+				foreach ( $actions as $rel ) {
+					$response->add_link( $rel, $self );
+				}
+			}
+		}
+
+		return $response;
+	}
+
+	/**
+	 * Adds revisions to links.
+	 *
+	 * @since 6.2.0
+	 *
+	 * @param WP_Block_Template $template  Template instance.
+	 * @return array Links for the given post.
+	 */
+	protected function prepare_revision_links( $template ) {
+		$links = array();
+
+		if ( post_type_supports( $this->post_type, 'revisions' ) && (int) $template->wp_id ) {
+			$revisions       = wp_get_latest_revision_id_and_total_count( (int) $template->wp_id );
+			$revisions_count = ! is_wp_error( $revisions ) ? $revisions['count'] : 0;
+			$revisions_base  = sprintf( '/%s/%s/%s/revisions', $this->namespace, $this->rest_base, $template->id );
+
+			$links['version-history'] = array(
+				'href'  => rest_url( $revisions_base ),
+				'count' => $revisions_count,
+			);
+
+			if ( $revisions_count > 0 ) {
+				$links['predecessor-version'] = array(
+					'href' => rest_url( $revisions_base . '/' . $revisions['latest_id'] ),
+					'id'   => $revisions['latest_id'],
+				);
+			}
+		}
+
+		return $links;
+	}
+}

lib/experimental/rest-api.php

@@ -28,6 +28,28 @@ function gutenberg_register_block_editor_settings() {
 }
 add_action( 'rest_api_init', 'gutenberg_register_block_editor_settings' );
 
+
+/**
+ * Hook in to the template and template part post types and decorate
+ * the rest endpoint with the revision count.
+ *
+ * When merging to core, this can be removed once Gutenberg_REST_Template_Revision_Count is
+ * merged with WP_REST_Template_Controller.
+ *
+ * @param array  $args Current registered post type args.
+ * @param string $post_type Name of post type.
+ *
+ * @return array
+ */
+function wp_api_template_revision_args( $args, $post_type ) {
+	if ( 'wp_template' === $post_type || 'wp_template_part' === $post_type ) {
+		$args['rest_controller_class'] = 'Gutenberg_REST_Template_Revision_Count';
+	}
+
+	return $args;
+}
+add_filter( 'register_post_type_args', 'wp_api_template_revision_args', 10, 2 );
+
 /**
  * Shim for get_sample_permalink() to add support for auto-draft status.
  *

lib/load.php

@@ -56,6 +56,8 @@ function gutenberg_is_experiment_enabled( $name ) {
 	if ( ! class_exists( 'WP_Rest_Customizer_Nonces' ) ) {
 		require_once __DIR__ . '/experimental/class-wp-rest-customizer-nonces.php';
 	}
+	require_once __DIR__ . '/experimental/class-gutenberg-rest-template-revision-count.php';
+
 	require_once __DIR__ . '/experimental/rest-api.php';
 }
 

packages/edit-site/src/components/sidebar-edit-mode/template-card/index.js

@@ -1,8 +1,9 @@
 /**
  * WordPress dependencies
  */
+import { __ } from '@wordpress/i18n';
 import { useSelect } from '@wordpress/data';
-import { Icon } from '@wordpress/components';
+import { PanelRow, Icon } from '@wordpress/components';
 import { store as editorStore } from '@wordpress/editor';
 import { store as coreStore } from '@wordpress/core-data';
 import { decodeEntities } from '@wordpress/html-entities';
@@ -13,6 +14,7 @@ import { decodeEntities } from '@wordpress/html-entities';
 import { store as editSiteStore } from '../../../store';
 import TemplateActions from './template-actions';
 import TemplateAreas from './template-areas';
+import LastRevision from './last-revision';
 
 export default function TemplateCard() {
 	const {
@@ -38,20 +40,28 @@ export default function TemplateCard() {
 	}
 
 	return (
-		<div className="edit-site-template-card">
-			<Icon className="edit-site-template-card__icon" icon={ icon } />
-			<div className="edit-site-template-card__content">
-				<div className="edit-site-template-card__header">
-					<h2 className="edit-site-template-card__title">
-						{ decodeEntities( title ) }
-					</h2>
-					<TemplateActions template={ template } />
+		<>
+			<div className="edit-site-template-card">
+				<Icon className="edit-site-template-card__icon" icon={ icon } />
+				<div className="edit-site-template-card__content">
+					<div className="edit-site-template-card__header">
+						<h2 className="edit-site-template-card__title">
+							{ decodeEntities( title ) }
+						</h2>
+						<TemplateActions template={ template } />
+					</div>
+					<div className="edit-site-template-card__description">
+						{ decodeEntities( description ) }
+					</div>
+					<TemplateAreas />
 				</div>
-				<div className="edit-site-template-card__description">
-					{ decodeEntities( description ) }
-				</div>
-				<TemplateAreas />
 			</div>
-		</div>
+			<PanelRow
+				header={ __( 'Editing history' ) }
+				className="edit-site-template-revisions"
+			>
+				<LastRevision />
+			</PanelRow>
+		</>
 	);
 }

packages/edit-site/src/components/sidebar-edit-mode/template-card/last-revision.js

@@ -0,0 +1,75 @@
+/**
+ * WordPress dependencies
+ */
+import { Button } from '@wordpress/components';
+import { sprintf, _n } from '@wordpress/i18n';
+import { backup } from '@wordpress/icons';
+import { addQueryArgs } from '@wordpress/url';
+import { PostTypeSupportCheck } from '@wordpress/editor';
+
+/**
+ * Internal dependencies
+ */
+import useEditedEntityRecord from '../../use-edited-entity-record';
+
+const useRevisionData = () => {
+	const { record: currentTemplate } = useEditedEntityRecord();
+
+	const lastRevisionId =
+		currentTemplate?._links?.[ 'predecessor-version' ]?.[ 0 ]?.id ?? null;
+
+	const revisionsCount =
+		( currentTemplate?._links?.[ 'version-history' ]?.[ 0 ]?.count ?? 0 ) +
+		1;
+
+	return {
+		currentTemplate,
+		lastRevisionId,
+		revisionsCount,
+	};
+};
+
+function PostLastRevisionCheck( { children } ) {
+	const { lastRevisionId, revisionsCount } = useRevisionData();
+
+	if ( ! lastRevisionId || revisionsCount < 2 ) {
+		return null;
+	}
+
+	return (
+		<PostTypeSupportCheck supportKeys="revisions">
+			{ children }
+		</PostTypeSupportCheck>
+	);
+}
+
+const PostLastRevision = () => {
+	const { lastRevisionId, revisionsCount } = useRevisionData();
+
+	return (
+		<PostLastRevisionCheck>
+			<Button
+				href={ addQueryArgs( 'revision.php', {
+					revision: lastRevisionId,
+					gutenberg: true,
+				} ) }
+				className="edit-site-template-last-revision__title"
+				icon={ backup }
+			>
+				{ sprintf(
+					/* translators: %d: number of revisions */
+					_n( '%d Revision', '%d Revisions', revisionsCount ),
+					revisionsCount
+				) }
+			</Button>
+		</PostLastRevisionCheck>
+	);
+};
+
+export default function LastRevision() {
+	return (
+		<PostLastRevisionCheck>
+			<PostLastRevision />
+		</PostLastRevisionCheck>
+	);
+}

packages/edit-site/src/components/sidebar-edit-mode/template-card/style.scss

@@ -59,6 +59,10 @@
 	}
 }
 
+.edit-site-template-revisions {
+	margin-left: math.div(-$grid-unit-10, 2);
+}
+
 h3.edit-site-template-card__template-areas-title {
 	font-weight: 500;
 	margin: 0 0 $grid-unit-10;