class-gwiz-batcher.php

<?php
/**
 * Class Gwiz_Batcher
 */
if ( class_exists( 'Gwiz_Batcher' ) ) {
	add_action( 'admin_notices', function() {
		?>
		<div class="notice notice-warning is-dismissible">
			<p>You have two plugins using Gravity Wiz Batcher. Only one should be active at a time.</p>
		</div>
		<?php
	} );
} else {
	class Gwiz_Batcher {

		private $_args;

		public function __construct( $args ) {

			$this->_args = wp_parse_args( $args, array(
				'title' => 'GW Batcher',
				'id'    => 'gw-batcher',
			) );

			add_action( 'wp_ajax_gw_batch_' . $this->_args['id'], array( $this, 'batch' ) );
			add_action( 'wp_ajax_nopriv_gw_batch_' . $this->_args['id'], array( $this, 'batch' ) );
			add_filter( 'gform_addon_navigation', array( $this, 'add_menu_item' ) );

		}

		function add_menu_item( $menu_items ) {
			$menu_items[] = array(
				'name'       => $this->_args['id'],
				'label'      => $this->_args['title'],
				'callback'   => array( $this, 'admin_page' ),
				'permission' => 'gform_full_access',
			);

			return $menu_items;
		}

		public function admin_page() {
			?>
			<style>
				h1 {
					font-family: sans-serif;
					margin-bottom: 20px;
				}

				#gwb-preview {
					border: 1px solid #ccc;
					height: 20px;
					width: 100%;
					margin-bottom: 20px;
					padding: 2px;
					border-radius: 4px;
				}

				#gwb-preview span {
					display: block;
					height: 100%;
					width: 0;
					background-color: #999;
					border-radius: 3px;
					transition: all 0.5s ease;
				}
			</style>

			<div class="wrap">
				<h2><?php echo $this->_args['title']; ?></h2>

				<div class="notice updated" id="gwb-success" style="display: none;">
					<p><strong>Success!</strong></p>
					<p>Please deactivate this plugin.</p>
				</div>

				<div id="gwb-preview"><span></span></div>

				<button id="gwb-start" class="button-primary">Start Batch</button>
			</div>

			<script>

				var ajaxUrl = '<?php echo admin_url( 'admin-ajax.php' ); ?>',
					action = 'gw_batch_<?php echo $this->_args['id']; ?>',
					nonce = '<?php echo wp_create_nonce( "gw_batch_{$this->_args['id']}" ); ?>',
					size = <?php echo $this->_args['size']; ?>;

				(function ($) {

					var $preview = $('#gwb-preview'),
						$start = $('#gwb-start');

					$start.click(function () {
						$start.prop('disabled', true);
						gwBatch(size, 1, 0, null);
					});

					function gwBatch(size, page, count, total) {

						$.post(ajaxUrl, {
							action: action,
							nonce: nonce,
							size: size,
							page: page,
							total: total,
							count: count
						}, function (response) {

							if (response.error) {
								console.log(response.data);
							} else if (response.success) {
								if (typeof response.data == 'string' && response.data == 'done') {
									$preview.find('span').width('100%');

									$('#gwb-success').show(500);
									$preview.hide(500);
									$('#gwb-start').hide(500);
								} else {
									$preview.find('span').width((response.data.count / response.data.total * 100) + '%');
									gwBatch(response.data.size, response.data.page, response.data.count, response.data.total);
								}
							}

						});

					}

				})(jQuery);
			</script>
			<?php
		}

		public function batch() {

			$action = $_POST['action'];
			$nonce  = $_POST['nonce'];

			if ( ! wp_verify_nonce( $nonce, $action ) ) {
				wp_send_json_error( 'Invalid nonce.' );
			}

			$size   = $_POST['size'];
			$page   = $_POST['page'];
			$offset = ( $page * $size ) - $size;
			$count  = max( 0, (int) $_POST['count'] );

			$items = $this->_args['get_items']( $size, $offset );
			$total = $items['total'];
			$items = $items['items'];

			foreach ( $items as $item ) {
				$this->_args['process_item']( $item );
				$count ++;
			}

			if ( $count >= $total ) {
				wp_send_json_success( 'done' );
			} else {
				$page ++;
				wp_send_json_success( compact( 'size', 'page', 'count', 'total' ) );
			}

		}

	}
}