regenerate-thumbnails.php

<?php /*

**************************************************************************

Plugin Name:  Regenerate Thumbnails
Plugin URI:   http://www.viper007bond.com/wordpress-plugins/regenerate-thumbnails/
Description:  Allows you to regenerate thumbnail images for times when you change thumbnail sizes or switch to a theme with a different featured image size.
Version:      3.0.0 Alpha
Author:       Viper007Bond
Author URI:   http://www.viper007bond.com/

Text Domain:  regenerate-thumbnails
Domain Path:  /localization

**************************************************************************

Copyright (C) 2008-2016 Alex Mills (Viper007Bond)

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 or greater,
as published by the Free Software Foundation.

You may NOT assume that you can use any other version of the GPL.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

The license for this software can likely be found here:
http://www.gnu.org/licenses/gpl-2.0.html

**************************************************************************/

class RegenerateThumbnails {
	/**
	 * This plugin's version number. Used for busting caches.
	 *
	 * @var string
	 */
	public $version = '3.0.0-alpha';

	/**
	 * Stores the menu ID of this plugin, as returned by add_management_page().
	 *
	 * @var string
	 */
	public $menu_id;

	/**
	 * Stores the capability required to use this plugin.
	 * Can be changed using the "regenerate_thumbs_cap" filter.
	 *
	 * @var string
	 */
	public $capability = 'manage_options';

	/**
	 * Stores the single instance of this plugin.
	 *
	 * @access private
	 * @var RegenerateThumbnails
	 */
	private static $instance;

	/**
	 * Constructor. Doesn't actually do anything as instance() creates the class instance.
	 */
	private function __construct() {
	}

	/**
	 * Prevents the class from being cloned.
	 */
	public function __clone() {
		wp_die( "Please don't clone RegenerateThumbnails" );
	}

	/**
	 * Prints the class from being unserialized and woken up.
	 */
	public function __wakeup() {
		wp_die( "Please don't unserialize/wakeup RegenerateThumbnails" );
	}

	/**
	 * Creates a new instance of this class if one hasn't already been made
	 * and then returns the single instance of this class.
	 *
	 * @return RegenerateThumbnails
	 */
	public static function instance() {
		if ( ! isset( self::$instance ) ) {
			self::$instance = new RegenerateThumbnails;
			self::$instance->setup();
		}

		return self::$instance;
	}

	/**
	 * Does the initial setup of the instance of this class including loading the localization
	 * file, registering the various actions and filters, and filtering the plugin's capability.
	 */
	public function setup() {
		if ( ! is_admin() ) {
			return;
		}

		load_plugin_textdomain( 'regenerate-thumbnails', false, dirname( plugin_basename( __FILE__ ) ) . '/localization/' );

		// Add a new item to the Tools menu in the admin menu
		add_action( 'admin_menu', array( $this, 'add_admin_menu' ) );

		// Load the required JavaScript and CSS
		add_action( 'admin_enqueue_scripts', array( $this, 'admin_enqueues' ) );

		// Process the individual image regenerate AJAX requests
		add_action( 'wp_ajax_regeneratethumbnail', array( $this, 'ajax_process_image' ) );

		// For the bulk action dropdowns
		add_action( 'admin_head-upload.php', array( $this, 'add_bulk_actions_via_javascript' ) );
		add_action( 'admin_action_bulk_regenerate_thumbnails', array( $this, 'bulk_action_handler' ) ); // Top drowndown
		add_action( 'admin_action_-1', array( $this, 'bulk_action_handler' ) ); // Bottom dropdown (assumes top dropdown = default value)

		// Add a regenerate button to the non-modal edit media page
		add_action( 'attachment_submitbox_misc_actions', array( $this, 'add_button_to_media_edit_page' ), 99 );

		// Add a regenerate button to the list of fields in the edit media modal
		// Ideally this would with the action links but I'm not good enough with JavaScript to do it
		add_filter( 'attachment_fields_to_edit', array( $this, 'add_button_to_edit_media_modal_fields_area' ), 99, 2 );

		// Add a regenerate link to actions list in the media list view
		add_filter( 'media_row_actions', array( $this, 'add_regenerate_link_to_media_list_view' ), 10, 2 );

		// Allow people to change what capability is required to use this plugin
		$this->capability = apply_filters( 'regenerate_thumbs_cap', $this->capability );
	}

	/**
	 * Adds a the new item to the admin menu.
	 */
	public function add_admin_menu() {
		$this->menu_id = add_management_page( __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ), __( 'Regen. Thumbnails', 'regenerate-thumbnails' ), $this->capability, 'regenerate-thumbnails', array( $this, 'regenerate_interface' ) );
	}

	/**
	 * Enqueues the requires JavaScript file and stylesheet on the plugin's admin page.
	 *
	 * @param string $hook_suffix The current page's hook suffix as provided by admin-header.php.
	 */
	public function admin_enqueues( $hook_suffix ) {
		if ( $hook_suffix != $this->menu_id ) {
			return;
		}

		wp_enqueue_script( 'regenerate-thumbnails', plugins_url( 'regenerate-thumbnails.js', __FILE__ ), array( 'jquery', 'jquery-ui-progressbar' ), $this->version );

		// This will be removed as soon as https://core.trac.wordpress.org/ticket/18909 is eventually addressed
		wp_enqueue_style( 'jquery-ui-regenthumbs', plugins_url( 'jquery-ui/redmond/jquery-ui-1.7.2.custom.css', __FILE__ ), array(), $this->version );
	}

	/**
	 * Creates a nonce for a given set of image IDs.
	 *
	 * @param array $ids An array of attachment IDs to create the nonce for.
	 *
	 * @return string A nonce name.
	 */
	public function create_nonce_name( $ids ) {
		return 'regenerate-thumbnails|' . implode( ',', $ids );
	}

	/**
	 * Creates a nonced URL to the plugin's admin page for a given set of attachment IDs.
	 *
	 * @param array $ids An array of attachment IDs that should be regenerated.
	 *
	 * @return string The nonced URL to the admin page.
	 */
	public function create_page_url( $ids ) {
		$url_args = array(
			'page'     => 'regenerate-thumbnails',
			'goback'   => 1,
			'ids'      => implode( ',', $ids ),
			'_wpnonce' => wp_create_nonce( $this->create_nonce_name( $ids ) ), // Can't use wp_nonce_url() as it escapes HTML entities
		);

		// https://core.trac.wordpress.org/ticket/17923
		$url_args = array_map( 'rawurlencode', $url_args );

		return add_query_arg( $url_args, admin_url( 'tools.php' ) );
	}

	/**
	 * Adds "Regenerate Thumbnails" below each image in the media library list view.
	 *
	 * @param array  $actions An array of current actions.
	 * @param object $post    The current attachment's post object.
	 *
	 * @return array The new list of actions.
	 */
	public function add_regenerate_link_to_media_list_view( $actions, $post ) {
		if ( 'image/' != substr( $post->post_mime_type, 0, 6 ) || ! current_user_can( $this->capability ) ) {
			return $actions;
		}

		$actions['regenerate_thumbnails'] = '<a href="' . esc_url( $this->create_page_url( array( $post->ID ) ) ) . '" title="' . esc_attr( __( "Regenerate the thumbnails for this single image", 'regenerate-thumbnails' ) ) . '">' . __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ) . '</a>';

		return $actions;
	}

	/**
	 * Add a "Regenerate Thumbnails" button to the submit box on the non-modal "Edit Media" screen for an image attachment.
	 */
	public function add_button_to_media_edit_page() {
		global $post;

		if ( 'image/' != substr( $post->post_mime_type, 0, 6 ) || ! current_user_can( $this->capability ) ) {
			return;
		}

		echo '<div class="misc-pub-section misc-pub-regenerate-thumbnails">';
		echo '<a href="' . esc_url( $this->create_page_url( array( $post->ID ) ) ) . '" class="button-secondary button-large" title="' . esc_attr( __( "Regenerate the thumbnails for this single image", 'regenerate-thumbnails' ) ) . '">' . __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ) . '</a>';
		echo '</div>';
	}

	/**
	 * Adds a "Regenerate Thumbnails" button to the edit media modal view.
	 *
	 * Ideally it would be down with the actions but I'm not good enough at JavaScript
	 * in order to be able to do it, so instead I'm adding it to the bottom of the list
	 * of media fields. Pull requests to improve this are welcome!
	 *
	 * @param array  $form_fields An array of existing form fields.
	 * @param object $post        The current media item, as a post object.
	 *
	 * @return array The new array of form fields.
	 */
	public function add_button_to_edit_media_modal_fields_area( $form_fields, $post ) {
		$form_fields['regenerate_thumbnails'] = array(
			'label'         => '',
			'input'         => 'html',
			'html'          => '<a href="' . esc_url( $this->create_page_url( array( $post->ID ) ) ) . '" class="button-secondary button-large" title="' . esc_attr( __( "Regenerate the thumbnails for this single image", 'regenerate-thumbnails' ) ) . '">' . __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ) . '</a>',
			'show_in_modal' => true,
			'show_in_edit'  => false,
		);

		return $form_fields;
	}

	/**
	 * Add "Regenerate Thumbnails" to the bulk actions dropdown on the media list using Javascript.
	 */
	public function add_bulk_actions_via_javascript() {
		if ( ! current_user_can( $this->capability ) ) {
			return;
		}
		?>
		<script type="text/javascript">
			jQuery(document).ready(function ($) {
				$('select[name^="action"] option:last-child').before('<option value="bulk_regenerate_thumbnails"><?php echo esc_attr( __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ) ); ?></option>');
			});
		</script>
	<?php
	}

	/**
	 * Handles the submission of the new bulk actions entry and redirects to the admin page with the selected attachment IDs.
	 */
	public function bulk_action_handler() {
		if ( empty( $_REQUEST['action'] ) || empty( $_REQUEST['action2'] ) || ( 'bulk_regenerate_thumbnails' != $_REQUEST['action'] && 'bulk_regenerate_thumbnails' != $_REQUEST['action2'] ) ) {
			return;
		}

		if ( empty( $_REQUEST['media'] ) || ! is_array( $_REQUEST['media'] ) ) {
			return;
		}

		check_admin_referer( 'bulk-media' );

		wp_safe_redirect( $this->create_page_url( array_map( 'intval', $_REQUEST['media'] ) ) );
		exit();
	}

	/**
	 * The main Regenerate Thumbnails interface, as displayed at Tools → Regen. Thumbnails.
	 */
	public function regenerate_interface() {
		if ( ! current_user_can( $this->capability ) ) {
			wp_die( __( 'Cheatin&#8217; uh?' ) );
		}

		// This is a container for the results message that gets shown using JavaScript
		echo '<div id="message" class="updated" style="display:none"></div>' . "\n";

		// Just an overall wrapper, used to help style
		echo '<div class="wrap regenthumbs">' . "\n";

		echo '<h1>' . __( 'Regenerate Thumbnails', 'regenerate-thumbnails' ) . "</h1>\n";

		// Make sure image editing is supported
		if ( ! wp_image_editor_supports() ) {
			echo '<p>' . __( "Sorry but your server doesn't support image editing which means that WordPress can't create thumbnails. Please ask your host to install the Imagick or GD PHP extensions.", 'regenerate-thumbnails' ) . '</p>';
		}
		// Display the introduction page
		elseif ( empty( $_POST['regenerate-thumbnails'] ) && empty( $_REQUEST['ids'] ) ) {
			$this->regenerate_interface_introduction();
		}
		// Regenerate button was pushed, so start the operation
		else {
			$this->regenerate_interface_process();
		}

		echo '</div>'; // end "wrap regenthumbs"


		return;
		## Old page is below for reference while rewriting it above



		global $wpdb;

		?>

		<div id="message" class="updated fade" style="display:none"></div>

		<div class="wrap regenthumbs">
			<h2><?php _e( 'Regenerate Thumbnails', 'regenerate-thumbnails' ); ?></h2>

			<?php

			// If the button was clicked
			if ( ! empty( $_POST['regenerate-thumbnails'] ) || ! empty( $_REQUEST['ids'] ) ) {
				// Capability check
				if ( ! current_user_can( $this->capability ) ) {
					wp_die( __( 'Cheatin&#8217; uh?' ) );
				}

				// Create the list of image IDs
				if ( ! empty( $_REQUEST['ids'] ) ) {
					$images = array_map( 'intval', explode( ',', trim( $_REQUEST['ids'], ',' ) ) );
					$ids    = implode( ',', $images );

					// Form nonce check
					check_admin_referer( $this->create_nonce_name( $images ) );
				} else {
					check_admin_referer( 'regenerate-thumbnails' );

					// Directly querying the database is normally frowned upon, but all
					// of the API functions will return the full post objects which will
					// suck up lots of memory. This is best, just not as future proof.
					if ( ! $images = $wpdb->get_results( "SELECT ID FROM $wpdb->posts WHERE post_type = 'attachment' AND post_mime_type LIKE 'image/%' ORDER BY ID DESC" ) ) {
						echo '	<p>' . sprintf( __( "Unable to find any images. Are you sure <a href='%s'>some exist</a>?", 'regenerate-thumbnails' ), esc_url( admin_url( 'upload.php?post_mime_type=image' ) ) ) . "</p></div>";

						return;
					}

					// Generate the list of IDs
					$ids = array();
					foreach ( $images as $image ) {
						$ids[] = $image->ID;
					}
					$ids = implode( ',', $ids );
				}


				echo '	<p>' . __( "Please be patient while the thumbnails are regenerated. This can take a while if your server is slow (inexpensive hosting) or if you have many images. Do not navigate away from this page until this script is done or the thumbnails will not be resized. You will be notified via this page when the regenerating is completed.", 'regenerate-thumbnails' ) . '</p>';

				$count = count( $images );

				$text_goback     = ( ! empty( $_GET['goback'] ) ) ? sprintf( __( 'To go back to the previous page, <a href="%s">click here</a>.', 'regenerate-thumbnails' ), 'javascript:history.go(-1)' ) : '';
				$text_failures   = sprintf( __( 'All done! %1$s image(s) were successfully resized in %2$s seconds and there were %3$s failure(s). To try regenerating the failed images again, <a href="%4$s">click here</a>. %5$s', 'regenerate-thumbnails' ), "' + rt_successes + '", "' + rt_totaltime + '", "' + rt_errors + '", esc_url( wp_nonce_url( admin_url( 'tools.php?page=regenerate-thumbnails&goback=1' ), 'regenerate-thumbnails' ) . '&ids=' ) . "' + rt_failedlist + '", $text_goback );
				$text_nofailures = sprintf( __( 'All done! %1$s image(s) were successfully resized in %2$s seconds and there were 0 failures. %3$s', 'regenerate-thumbnails' ), "' + rt_successes + '", "' + rt_totaltime + '", $text_goback );
				?>


				<noscript><p><em><?php _e( 'You must enable Javascript in order to proceed!', 'regenerate-thumbnails' ) ?></em></p></noscript>

				<div id="regenthumbs-bar" style="position:relative;height:25px;">
					<div id="regenthumbs-bar-percent" style="position:absolute;left:50%;top:50%;width:300px;margin-left:-150px;height:25px;margin-top:-9px;font-weight:bold;text-align:center;"></div>
				</div>

				<p><input type="button" class="button hide-if-no-js" name="regenthumbs-stop" id="regenthumbs-stop" value="<?php _e( 'Abort Resizing Images', 'regenerate-thumbnails' ) ?>" /></p>

				<h3 class="title"><?php _e( 'Debugging Information', 'regenerate-thumbnails' ) ?></h3>

				<p>
					<?php printf( __( 'Total Images: %s', 'regenerate-thumbnails' ), $count ); ?><br />
					<?php printf( __( 'Images Resized: %s', 'regenerate-thumbnails' ), '<span id="regenthumbs-debug-successcount">0</span>' ); ?><br />
					<?php printf( __( 'Resize Failures: %s', 'regenerate-thumbnails' ), '<span id="regenthumbs-debug-failurecount">0</span>' ); ?>
				</p>

				<ol id="regenthumbs-debuglist">
					<li style="display:none"></li>
				</ol>

				<script type="text/javascript">
					jQuery(document).ready(function ($) {
						var i;
						var rt_images = [<?php echo $ids; ?>];
						var rt_total = rt_images.length;
						var rt_count = 1;
						var rt_percent = 0;
						var rt_successes = 0;
						var rt_errors = 0;
						var rt_failedlist = '';
						var rt_resulttext = '';
						var rt_timestart = new Date().getTime();
						var rt_timeend = 0;
						var rt_totaltime = 0;
						var rt_continue = true;

						// Create the progress bar
						$("#regenthumbs-bar").progressbar();
						$("#regenthumbs-bar-percent").html("0%");

						// Stop button
						$("#regenthumbs-stop").click(function () {
							rt_continue = false;
							$('#regenthumbs-stop').val("<?php echo $this->esc_quotes( __( 'Stopping...', 'regenerate-thumbnails' ) ); ?>");
						});

						// Clear out the empty list element that's there for HTML validation purposes
						$("#regenthumbs-debuglist li").remove();

						// Called after each resize. Updates debug information and the progress bar.
						function RegenThumbsUpdateStatus(id, success, response) {
							$("#regenthumbs-bar").progressbar("value", ( rt_count / rt_total ) * 100);
							$("#regenthumbs-bar-percent").html(Math.round(( rt_count / rt_total ) * 1000) / 10 + "%");
							rt_count = rt_count + 1;

							if (success) {
								rt_successes = rt_successes + 1;
								$("#regenthumbs-debug-successcount").html(rt_successes);
								$("#regenthumbs-debuglist").append("<li>" + response.success + "</li>");
							}
							else {
								rt_errors = rt_errors + 1;
								rt_failedlist = rt_failedlist + ',' + id;
								$("#regenthumbs-debug-failurecount").html(rt_errors);
								$("#regenthumbs-debuglist").append("<li>" + response.error + "</li>");
							}
						}

						// Called when all images have been processed. Shows the results and cleans up.
						function RegenThumbsFinishUp() {
							rt_timeend = new Date().getTime();
							rt_totaltime = Math.round(( rt_timeend - rt_timestart ) / 1000);

							$('#regenthumbs-stop').hide();

							if (rt_errors > 0) {
								rt_resulttext = '<?php echo $text_failures; ?>';
							} else {
								rt_resulttext = '<?php echo $text_nofailures; ?>';
							}

							$("#message").html("<p><strong>" + rt_resulttext + "</strong></p>");
							$("#message").show();
						}

						// Regenerate a specified image via AJAX
						function RegenThumbs(id) {
							$.ajax({
								type   : 'POST',
								url    : ajaxurl,
								data   : {action: "regeneratethumbnail", id: id},
								success: function (response) {
									if (response === null) {
										response = new Object;
										response.success = false;
										response.error = "The resize request was abnormally terminated (ID " + id + "). This is likely due to the image exceeding available memory.";
									}

									if (response.success) {
										RegenThumbsUpdateStatus(id, true, response);
									}
									else {
										RegenThumbsUpdateStatus(id, false, response);
									}

									if (rt_images.length && rt_continue) {
										RegenThumbs(rt_images.shift());
									}
									else {
										RegenThumbsFinishUp();
									}
								},
								error  : function (response) {
									RegenThumbsUpdateStatus(id, false, response);

									if (rt_images.length && rt_continue) {
										RegenThumbs(rt_images.shift());
									}
									else {
										RegenThumbsFinishUp();
									}
								}
							});
						}

						RegenThumbs(rt_images.shift());
					});
				</script>
			<?php
			}

			// No button click? Display the form.
			else {
			?>
				<form method="post" action="">
					<?php wp_nonce_field( 'regenerate-thumbnails' ) ?>

					<p><?php printf( __( "Use this tool to regenerate thumbnails for all images that you have uploaded to your site. This is useful if you've changed any of the thumbnail dimensions on the <a href='%s'>media settings page</a> or switched themes. Old thumbnails will be kept to avoid any broken images due to hard-coded URLs.", 'regenerate-thumbnails' ), esc_url( admin_url( 'options-media.php' ) ) ); ?></p>

					<p><?php printf( __( "You can regenerate specific images (rather than all images) from the <a href='%s'>Media</a> page. Hover over an image's row and click the link to resize just that one image or use the checkboxes and the &quot;Bulk Actions&quot; dropdown to resize multiple images (WordPress 3.1+ only).", 'regenerate-thumbnails' ), esc_url( admin_url( 'upload.php' ) ) ); ?></p>

					<p><?php _e( "Thumbnail regeneration is not reversible, but you can just change your thumbnail dimensions back to the old values and click the button again if you don't like the results.", 'regenerate-thumbnails' ); ?></p>

					<p><?php _e( 'To begin, just press the button below.', 'regenerate-thumbnails' ); ?></p>

					<p><input type="submit" class="button hide-if-no-js" name="regenerate-thumbnails" id="regenerate-thumbnails" value="<?php _e( 'Regenerate All Thumbnails', 'regenerate-thumbnails' ) ?>" /></p>

					<noscript><p><em><?php _e( 'You must enable Javascript in order to proceed!', 'regenerate-thumbnails' ) ?></em></p></noscript>

				</form>
			<?php
			} // End if button
			?>
		</div>

	<?php
	}

	/**
	 * Outputs the introduction on the plugin's page.
	 *
	 * The start button is a part of this.
	 */
	public function regenerate_interface_introduction() {
		?>
		<form method="post">
			<?php wp_nonce_field( 'regenerate-thumbnails' ) ?>

			<p><?php printf( __( "Use this tool to regenerate thumbnails for all images that you have uploaded to your site. This is useful if you've changed any of the thumbnail dimensions on the <a href='%s'>media settings page</a> or switched themes. Old thumbnails will be kept to avoid any broken images due to hard-coded URLs.", 'regenerate-thumbnails' ), esc_url( admin_url( 'options-media.php' ) ) ); ?></p>

			<p><?php printf( __( "You can regenerate specific images (rather than all images) from the <a href='%s'>Media</a> page. Hover over an image's row and click the link to resize just that one image or use the checkboxes and the &quot;Bulk Actions&quot; dropdown to resize multiple images.", 'regenerate-thumbnails' ), esc_url( admin_url( 'upload.php?mode=list' ) ) ); ?></p>

			<p><?php _e( "Thumbnail regeneration is not reversible, but you can just change your thumbnail dimensions back to the old values and click the button again if you don't like the results.", 'regenerate-thumbnails' ); ?></p>

			<p><?php _e( 'To begin, just press the button below.', 'regenerate-thumbnails' ); ?></p>

			<p><?php submit_button( __( 'Regenerate All Thumbnails', 'regenerate-thumbnails' ), 'primary hide-if-no-js', 'regenerate-thumbnails' ); ?></p>

			<noscript><p><em><?php _e( 'You must enable Javascript in order to proceed!', 'regenerate-thumbnails' ) ?></em></p></noscript>

		</form>
		<?php


		echo '<h2 style="margin-top:50px">' . __( 'Thumbnail Sizes', 'regenerate-thumbnails' ) . "</h2>\n";

		echo '<p>' . __( 'The following thumbnail sizes will be generated, overwriting any existing thumbnails of the same size:', 'regenerate-thumbnails' ) . "</p>\n";

		echo "<ul>\n";
		foreach ( $this->get_thumbnail_sizes() as $thumbnail_size => $thumbnail_details ) {
			echo '<li>';
			printf(
			/* translators: This is a thumbnail size description, such as "<strong>post-thumbnail:</strong> 825&#215;510 (Cropped)", &#215; being the fancy "x" */
				__( '<strong>%1$s:</strong> %2$d&#215;%3$d pixels (%4$s)', 'regenerate-thumbnails' ),
				esc_html( $thumbnail_size ),
				(int) $thumbnail_details['width'],
				(int) $thumbnail_details['height'],
				( $thumbnail_details['crop'] ) ? __( 'cropped to fit', 'regenerate-thumbnails' ) : __( 'proportionally resized', 'regenerate-thumbnails' )
			);
			echo "</li>\n";
		}
		echo "</ul>\n";


		echo '<h2 style="margin-top:50px">' . __( 'Command Line Interface', 'regenerate-thumbnails' ) . "</h2>\n";

		echo '<p>';
		printf(
			__( 'If you have command line access to your server via SSH, consider using <a href="%1$s">WP-CLI</a> instead of this plugin to regenerate thumbmails. It has <a href="%2$s">a built-in command</a> for generating thumbnails that is significantly faster than this plugin since a separate HTTP request per image is not required.', 'regenerate-thumbnails' ),
			'http://wp-cli.org/',
			'http://wp-cli.org/commands/media/regenerate/'
		);
		echo "</p>\n";
	}


	public function regenerate_interface_process() {
		var_dump( $_POST );
	}

	/**
	 * Returns an array of all thumbnail sizes, including their label, size, and crop setting.
	 *
	 * @return array An array, with the thumbnail label as the key and an array of thumbnail properties (width, height, crop).
	 */
	public function get_thumbnail_sizes() {
		global $_wp_additional_image_sizes;

		$thumbnail_sizes = array();

		foreach ( get_intermediate_image_sizes() as $size ) {
			if ( in_array( $size, array( 'thumbnail', 'medium', 'large' ) ) ) {
				$thumbnail_sizes[ $size ]['width']  = get_option( $size . '_size_w' );
				$thumbnail_sizes[ $size ]['height'] = get_option( $size . '_size_h' );
				$thumbnail_sizes[ $size ]['crop']   = ( 'thumbnail' == $size ) ? get_option( 'thumbnail_crop' ) : false;
			} elseif ( ! empty( $_wp_additional_image_sizes ) && ! empty( $_wp_additional_image_sizes[ $size ] ) ) {
				$thumbnail_sizes[ $size ]['width']  = $_wp_additional_image_sizes[ $size ]['width'];
				$thumbnail_sizes[ $size ]['height'] = $_wp_additional_image_sizes[ $size ]['height'];
				$thumbnail_sizes[ $size ]['crop']   = $_wp_additional_image_sizes[ $size ]['crop'];
			}
		}

		return $thumbnail_sizes;
	}

	/**
	 * AJAX handler that regenerates the thumbnails a single image attachment. Outputs JSON.
	 */
	public function ajax_process_image() {
		@error_reporting( 0 ); // Don't break the JSON result

		header( 'Content-type: application/json' );

		$id    = (int) $_REQUEST['id'];
		$image = get_post( $id );

		if ( ! $image || 'attachment' != $image->post_type || 'image/' != substr( $image->post_mime_type, 0, 6 ) ) {
			die( json_encode( array( 'error' => sprintf( __( 'Failed resize: %s is an invalid image ID.', 'regenerate-thumbnails' ), esc_html( $_REQUEST['id'] ) ) ) ) );
		}

		if ( ! current_user_can( $this->capability ) ) {
			$this->die_json_error_msg( $image->ID, __( "Your user account doesn't have permission to resize images", 'regenerate-thumbnails' ) );
		}

		$fullsizepath = get_attached_file( $image->ID );

		if ( false === $fullsizepath || ! file_exists( $fullsizepath ) ) {
			$this->die_json_error_msg( $image->ID, sprintf( __( 'The originally uploaded image file cannot be found at %s', 'regenerate-thumbnails' ), '<code>' . esc_html( $fullsizepath ) . '</code>' ) );
		}

		@set_time_limit( 900 ); // 5 minutes per image should be PLENTY

		$metadata = wp_generate_attachment_metadata( $image->ID, $fullsizepath );

		if ( is_wp_error( $metadata ) ) {
			$this->die_json_error_msg( $image->ID, $metadata->get_error_message() );
		}
		if ( empty( $metadata ) ) {
			$this->die_json_error_msg( $image->ID, __( 'Unknown failure reason.', 'regenerate-thumbnails' ) );
		}

		// If this fails, then it just means that nothing was changed (old value == new value)
		wp_update_attachment_metadata( $image->ID, $metadata );

		die( json_encode( array( 'success' => sprintf( __( '&quot;%1$s&quot; (ID %2$s) was successfully resized in %3$s seconds.', 'regenerate-thumbnails' ), esc_html( get_the_title( $image->ID ) ), $image->ID, timer_stop() ) ) ) );
	}

	/**
	 * Create a JSON error message and die.
	 *
	 * @param int    $id      The attachment ID.
	 * @param string $message The error message.
	 */
	public function die_json_error_msg( $id, $message ) {
		die( json_encode( array( 'error' => sprintf( __( '&quot;%1$s&quot; (ID %2$s) failed to resize. The error message was: %3$s', 'regenerate-thumbnails' ), esc_html( get_the_title( $id ) ), $id, $message ) ) ) );
	}

	/**
	 * Slash escape double quotes.
	 *
	 * @param string $string The string to escape.
	 *
	 * @return string The escaped string.
	 */
	public function esc_quotes( $string ) {
		return str_replace( '"', '\"', $string );
	}
}

/**
 * Returns the single instance of this plugin, creating one if needed.
 *
 * @return RegenerateThumbnails
 */
function RegenerateThumbnails() {
	return RegenerateThumbnails::instance();
}

/**
 * Initalize this plugin once all other plugins have finished loading.
 */
add_action( 'plugins_loaded', 'RegenerateThumbnails' );