<?php

/**
 * The manager to rule all (post) managers.
 *
 * This class dynamically registers container modules for the available post types
 * (including custom post types) and does stuff that pertain to all of them, such
 * as handling save/delete hooks and (re)creating synch records.
 *
 * @package Broken Link Checker
 * @author Janis Elsts
 * @access private
 */
class blcPostTypeOverlord {
	public $enabled_post_types    = array();  //Post types currently selected for link checking
	public $enabled_post_statuses = array( 'publish' ); //Only posts that have one of these statuses shall be checked

	var $plugin_conf;
	var $resynch_already_done = false;

	/**
	 * Class "constructor". Can't use an actual constructor due to how PHP4 handles object references.
	 *
	 * Specifically, this class is a singleton. The function needs to pass $this to several other
	 * functions (to set up hooks), which will store the reference for later use. However, it appears
	 * that in PHP4 the actual value of $this is thrown away right after the constructor finishes, and
	 * `new` returns a *copy* of $this. The result is that getInstance() won't be returning a ref.
	 * to the same object as is used for hook callbacks. And that's horrible.
	 *
	 * Sets up hooks that monitor added/modified/deleted posts and registers
	 * virtual modules for all post types.
	 *
	 * @return void
	 */
	function init() {
		$this->plugin_conf = blc_get_configuration();

		if ( isset( $this->plugin_conf->options['enabled_post_statuses'] ) ) {
			$this->enabled_post_statuses = $this->plugin_conf->options['enabled_post_statuses'];
		}

		//Register a virtual container module for each enabled post type
		$module_manager = blcModuleManager::getInstance();

		$post_types = get_post_types( array(), 'objects' );
		$exceptions = array( 'revision', 'nav_menu_item', 'attachment' );

		foreach ( $post_types as $data ) {
			$post_type = $data->name;

			if ( in_array( $post_type, $exceptions ) ) {
				continue;
			}

			$module_manager->register_virtual_module(
				$post_type,
				array(
					'Name'            => $data->labels->name,
					'ModuleCategory'  => 'container',
					'ModuleContext'   => 'all',
					'ModuleClassName' => 'blcAnyPostContainerManager',
				)
			);
		}

		if ( ! WPMUDEV_BLC\App\Options\Settings\Model::instance()->get( 'use_legacy_blc_version' ) ) {
			if ( ! WPMUDEV_BLC\Core\Utils\Utilities::is_subsite() ) {
				return;
			}
			//return;
		}

		//These hooks update the synch & instance records when posts are added, deleted or modified.
		add_action( 'delete_post', array( &$this, 'post_deleted' ) );
		add_action( 'save_post', array( &$this, 'post_saved' ) );
		//We also treat post trashing/untrashing as delete/save.
		add_action( 'trashed_post', array( &$this, 'post_deleted' ) );
		add_action( 'untrash_post', array( &$this, 'post_saved' ) );

		//Highlight and nofollow broken links in posts & pages
		if ( $this->plugin_conf->options['mark_broken_links'] || $this->plugin_conf->options['nofollow_broken_links'] ) {
			add_filter( 'the_content', array( &$this, 'hook_the_content' ) );
			if ( $this->plugin_conf->options['mark_broken_links'] && ! empty( $this->plugin_conf->options['broken_link_css'] ) ) {
				add_action( 'wp_head', array( &$this, 'hook_wp_head' ) );
			}
		}
	}

	/**
	 * Retrieve an instance of the overlord class.
	 *
	 * @return blcPostTypeOverlord
	 */
	static function getInstance() {
		static $instance = null;
		if ( is_null( $instance ) ) {
			$instance = new blcPostTypeOverlord;
			$instance->init();
		}
		return $instance;
	}

	/**
	 * Notify the overlord that a post type is active.
	 *
	 * Called by individual instances of blcAnyPostContainerManager to let
	 * the overlord know that they've been created. Since a module instance
	 * is only created if the module is active, this event indicates that
	 * the user has enabled the corresponding post type for link checking.
	 *
	 * @param string $post_type
	 * @return void
	 */
	function post_type_enabled( $post_type ) {
		if ( ! in_array( $post_type, $this->enabled_post_types ) ) {
			$this->enabled_post_types[] = $post_type;
		}
	}

	/**
	* Remove the synch. record and link instances associated with a post when it's deleted
	*
	* @param int $post_id
	* @return void
	*/
	function post_deleted( $post_id ) {
		global $wpdb;

		$post_id = intval( $post_id );
		//Get the container type matching the type of the deleted post
		$post = get_post( $post_id );
		if ( ! $post ) {
			return;
		}
		//Get the associated container object
		$post_type      = get_post_type( $post );
		$post_container = blcContainerHelper::get_container( array( $post_type, $post_id ) );

		if ( $post_container ) {
			//Delete the container
			$post_container->delete();

			// Firstly: See if we have any current instances
			$q_current_instance_ids = $wpdb->prepare(
				'SELECT instance_id FROM `' . $wpdb->prefix . 'blc_instances` WHERE container_id = %d AND container_type = %s',
				$post_id,
				$post_type
			);

			$current_instance_ids_results = $wpdb->get_results( $q_current_instance_ids, ARRAY_A );

			if ( $wpdb->num_rows == 0 ) {
				// No current instances present, skip cleanup at once
				return;
			}

			$current_instance_ids = wp_list_pluck( $current_instance_ids_results, 'instance_id' );

			// Secondly: Get all link_ids used in our current instances
			$q_current_link_ids = 'SELECT DISTINCT link_id FROM `' . $wpdb->prefix . 'blc_instances` WHERE instance_id IN (\'' . implode( "', '", $current_instance_ids ) . '\')';

			$q_current_link_ids_results = $wpdb->get_results( $q_current_link_ids, ARRAY_A );

			$current_link_ids = wp_list_pluck( $q_current_link_ids_results, 'link_id' );

			// Go ahead and remove blc_instances for this container, blc_cleanup_links( $current_link_ids ) will find and remove any dangling links in the blc_links table
			$wpdb->query( 'DELETE FROM `' . $wpdb->prefix . 'blc_instances` WHERE instance_id IN (\'' . implode( "', '", $current_instance_ids ) . '\')' );

			//Clean up any dangling links
			blc_cleanup_links( $current_link_ids );
		}
	}

	/**
	 * When a post is saved or modified, mark it as unparsed.
	 *
	 * @param int $post_id
	 * @return void
	 */
	function post_saved( $post_id ) {
		//Get the container type matching the type of the deleted post
		$post = get_post( $post_id );
		if ( ! $post ) {
			return;
		}

		//Only check links in currently enabled post types
		if ( ! in_array( $post->post_type, $this->enabled_post_types ) ) {
			return;
		}

		//Only check posts that have one of the allowed statuses
		if ( ! in_array( $post->post_status, $this->enabled_post_statuses ) ) {
			return;
		}

		//Get the container & mark it as unparsed
		$args           = array( $post->post_type, intval( $post_id ) );
		$post_container = blcContainerHelper::get_container( $args );

		$post_container->mark_as_unsynched();
	}


	/**
	 * Create or update synchronization records for all posts.
	 *
	 * @param string $container_type
	 * @param bool $forced If true, assume that all synch. records are gone and will need to be recreated from scratch.
	 * @return void
	 */
	function resynch( $container_type = '', $forced = false ) {
		global $wpdb; /** @var wpdb $wpdb */
		global $blclog;

		//Resynch is expensive in terms of DB performance. Thus we only do it once, processing
		//all post types in one go and ignoring any further resynch requests during this pageload.
		//BUG: This might be a problem if there ever is an actual need to run resynch twice or
		//more per pageload.
		if ( $this->resynch_already_done ) {
			$blclog->log( sprintf( '...... Skipping "%s" resyncyh since all post types were already synched.', $container_type ) );
			return;
		}

		if ( empty( $this->enabled_post_types ) ) {
			$blclog->warn( sprintf( '...... Skipping "%s" resyncyh since no post types are enabled.', $container_type ) );
			return;
		}

		$escaped_post_types    = array_map( 'esc_sql', $this->enabled_post_types );
		$escaped_post_statuses = array_map( 'esc_sql', $this->enabled_post_statuses );

		if ( $forced ) {
			//Create new synchronization records for all posts.
			$blclog->log( '...... Creating synch records for these post types: ' . implode( ', ', $escaped_post_types ) . ' that have one of these statuses: ' . implode( ', ', $escaped_post_statuses ) );
			$start = microtime( true );
			$q     = "INSERT INTO {$wpdb->prefix}blc_synch(container_id, container_type, synched)
				  SELECT posts.id, posts.post_type, 0
				  FROM {$wpdb->posts} AS posts
				  WHERE
				  	posts.post_status IN (%s)
	 				AND posts.post_type IN (%s)";
			$q     = sprintf(
				$q,
				"'" . implode( "', '", $escaped_post_statuses ) . "'",
				"'" . implode( "', '", $escaped_post_types ) . "'"
			);
			$wpdb->query( $q );
			$blclog->log( sprintf( '...... %d rows inserted in %.3f seconds', $wpdb->rows_affected, microtime( true ) - $start ) );
		} else {
			//Delete synch records corresponding to posts that no longer exist.
			//Also delete posts that don't have enabled post status
			$blclog->log( '...... Deleting synch records for removed posts & post with invalid status' );
			$start            = microtime( true );
			$all_posts_id     = get_posts(
				array(
					'posts_per_page' => -1,
					'fields'         => 'ids',
					'post_type'      => $this->enabled_post_types,
					'post_status'    => $this->enabled_post_statuses,
				)
			);

			$q = "DELETE synch.* FROM {$wpdb->prefix}blc_synch AS synch WHERE synch.container_id NOT IN (%s)";

			$q     = sprintf(
				$q,
				"'" . implode( "', '", $all_posts_id ) . "'"
			);

			$wpdb->query( $q );
			$elapsed = microtime( true ) - $start;
			$blclog->debug( $q );
			$blclog->log( sprintf( '...... %d rows deleted in %.3f seconds', $wpdb->rows_affected, $elapsed ) );

			// //Delete records where the post status is not one of the enabled statuses.
			// $blclog->log( '...... Deleting synch records for posts that have a disallowed status' );
			// $start = microtime( true );
			// $all_posts_status     = get_posts(
			// 	array(
			// 		'posts_per_page' => -1,
			// 		'fields'         => 'ids',
			// 		'post_type'      => $this->enabled_post_types,
			// 		'post_status'    => $this->enabled_post_statuses,
			// 	)
			// );

			// $q     = "DELETE synch.*
			// 	  FROM
			// 		 {$wpdb->prefix}blc_synch AS synch
			// 	  WHERE
			// 		 posts.post_status NOT IN (%s)";
			// $q     = sprintf(
			// 	$q,
			// 	"'" . implode( "', '", $escaped_post_statuses ) . "'",
			// 	"'" . implode( "', '", wp_list_pluck( $all_posts, 'post_status' ) ) . "'",
			// );
			// $wpdb->query( $q );
			// $elapsed = microtime( true ) - $start;
			// $blclog->debug( $q );
			// $blclog->log( sprintf( '...... %d rows deleted in %.3f seconds', $wpdb->rows_affected, $elapsed ) );

			//Remove the 'synched' flag from all posts that have been updated
			//since the last time they were parsed/synchronized.
			$blclog->log( '...... Marking changed posts as unsynched' );
			$start = microtime( true );
			$q     = "UPDATE
					{$wpdb->prefix}blc_synch AS synch
					JOIN {$wpdb->posts} AS posts ON (synch.container_id = posts.ID and synch.container_type=posts.post_type)
				  SET
					synched = 0
				  WHERE
					synch.last_synch < posts.post_modified";
			$wpdb->query( $q );
			$elapsed = microtime( true ) - $start;
			$blclog->debug( $q );
			$blclog->log( sprintf( '...... %d rows updated in %.3f seconds', $wpdb->rows_affected, $elapsed ) );

			//Create synch. records for posts that don't have them.
			$blclog->log( '...... Creating synch records for new posts' );
			$start = microtime( true );
			$q     = "INSERT INTO {$wpdb->prefix}blc_synch(container_id, container_type, synched)
				  SELECT posts.id, posts.post_type, 0
				  FROM
				    {$wpdb->posts} AS posts LEFT JOIN {$wpdb->prefix}blc_synch AS synch
					ON (synch.container_id = posts.ID and synch.container_type=posts.post_type)
				  WHERE
				  	posts.post_status IN (%s)
	 				AND posts.post_type IN (%s)
					AND synch.container_id IS NULL";
			$q     = sprintf(
				$q,
				"'" . implode( "', '", $escaped_post_statuses ) . "'",
				"'" . implode( "', '", $escaped_post_types ) . "'"
			);
			$wpdb->query( $q );
			$elapsed = microtime( true ) - $start;
			$blclog->debug( $q );
			$blclog->log( sprintf( '...... %d rows inserted in %.3f seconds', $wpdb->rows_affected, $elapsed ) );
		}

		$this->resynch_already_done = true;
	}

	/**
	 * Hook for the 'the_content' filter. Scans the current post and adds the 'broken_link'
	 * CSS class to all links that are known to be broken. Currently works only on standard
	 * HTML links (i.e. the '<a href=...' kind).
	 *
	 * @param string $content Post content
	 * @return string Modified post content.
	 */
	function hook_the_content( $content ) {
		global $post, $wpdb; /** @var wpdb $wpdb */
		if ( empty( $post ) || ! in_array( $post->post_type, $this->enabled_post_types ) ) {
			return $content;
		}

		//Retrieve info about all occurrences of broken links in the current post
		$q     = "
			SELECT instances.raw_url
			FROM {$wpdb->prefix}blc_instances AS instances JOIN {$wpdb->prefix}blc_links AS links
				ON instances.link_id = links.link_id
			WHERE
				instances.container_type = %s
				AND instances.container_id = %d
				AND links.broken = 1
				AND parser_type = 'link'
		";
		$q     = $wpdb->prepare( $q, $post->post_type, $post->ID );
		$links = $wpdb->get_results( $q, ARRAY_A );

		//Return the content unmodified if there are no broken links in this post.
		if ( empty( $links ) || ! is_array( $links ) ) {
			return $content;
		}

		//Put the broken link URLs in an array
		$broken_link_urls = array();
		foreach ( $links as $link ) {
			$broken_link_urls[] = $link['raw_url'];
		}

		//Iterate over all HTML links and modify the broken ones
		$parser = blcParserHelper::get_parser( 'link' );
		if ( $parser ) {
			$content = $parser->multi_edit( $content, array( &$this, 'highlight_broken_link' ), $broken_link_urls );
		}

		return $content;
	}

	/**
	 * Analyse a link and add 'broken_link' CSS class if the link is broken.
	 *
	 * @see blcHtmlLink::multi_edit()
	 *
	 * @param array $link Associative array of link data.
	 * @param array $broken_link_urls List of broken link URLs present in the current post.
	 * @return array|string The modified link
	 */
	function highlight_broken_link( $link, $broken_link_urls ) {
		if ( ! in_array( $link['href'], $broken_link_urls ) ) {
			//Link not broken = return the original link tag
			return $link['#raw'];
		}

		//Add 'broken_link' to the 'class' attribute (unless already present).
		if ( $this->plugin_conf->options['mark_broken_links'] ) {
			if ( isset( $link['class'] ) ) {
				$classes = explode( ' ', $link['class'] );
				if ( ! in_array( 'broken_link', $classes ) ) {
					$classes[]     = 'broken_link';
					$link['class'] = implode( ' ', $classes );
				}
			} else {
				$link['class'] = 'broken_link';
			}
		}

		//Nofollow the link (unless it's already nofollow'ed)
		if ( $this->plugin_conf->options['nofollow_broken_links'] ) {
			if ( isset( $link['rel'] ) ) {
				$relations = explode( ' ', $link['rel'] );
				if ( ! in_array( 'nofollow', $relations ) ) {
					$relations[] = 'nofollow';
					$link['rel'] = implode( ' ', $relations );
				}
			} else {
				$link['rel'] = 'nofollow';
			}
		}

		return $link;
	}

	/**
	 * A hook for the 'wp_head' action. Outputs the user-defined broken link CSS.
	 *
	 * @return void
	 */
	function hook_wp_head() {
		echo '<style type="text/css">',$this->plugin_conf->options['broken_link_css'],'</style>';
	}
}

//Start up the post overlord
blcPostTypeOverlord::getInstance();


/**
 * Universal container item class used for all post types.
 *
 * @package Broken Link Checker
 * @author Janis Elsts
 * @access public
 */
class blcAnyPostContainer extends blcContainer {
	var $default_field = 'post_content';

	public $updating_urls = null;

	/**
	 * Get action links for this post.
	 *
	 * @param string $container_field Ignored.
	 * @return array of action link HTML.
	 */
	function ui_get_action_links( $container_field = '' ) {
		$actions = array();

		//Fetch the post (it should be cached already)
		$post = $this->get_wrapped_object();
		if ( ! $post ) {
			return $actions;
		}

		$post_type_object = get_post_type_object( $post->post_type );

		if ( ! $post_type_object ) {
			return $actions;
		}

		//Each post type can have its own cap requirements
		if ( current_user_can( $post_type_object->cap->edit_post, $this->container_id ) ) {
			$actions['edit'] = sprintf(
				'<span class="edit"><a href="%s" title="%s">%s</a>',
				$this->get_edit_url(),
				$post_type_object->labels->edit_item,
				__( 'Edit' )
			);

			//Trash/Delete link
			if ( current_user_can( $post_type_object->cap->delete_post, $this->container_id ) ) {
				if ( $this->can_be_trashed() ) {
					$actions['trash'] = sprintf(
						"<span class='trash'><a class='submitdelete' title='%s' href='%s'>%s</a>",
						esc_attr( __( 'Move this item to the Trash' ) ),
						esc_attr( get_delete_post_link( $this->container_id, '', false ) ),
						__( 'Trash' )
					);
				} else {
					$actions['delete'] = sprintf(
						"<span><a class='submitdelete' title='%s' href='%s'>%s</a>",
						esc_attr( __( 'Delete this item permanently' ) ),
						esc_attr( get_delete_post_link( $this->container_id, '', true ) ),
						__( 'Delete' )
					);
				}
			}
		}

		//View/Preview link
		$title = get_the_title( $this->container_id );
		if ( in_array( $post->post_status, array( 'pending', 'draft' ) ) ) {
			if ( current_user_can( $post_type_object->cap->edit_post, $this->container_id ) ) {
				$actions['view'] = sprintf(
					'<span class="view"><a href="%s" title="%s" rel="permalink">%s</a>',
					esc_url( add_query_arg( 'preview', 'true', get_permalink( $this->container_id ) ) ),
					esc_attr( sprintf( __( 'Preview &#8220;%s&#8221;' ), $title ) ),
					__( 'Preview' )
				);
			}
		} elseif ( 'trash' != $post->post_status ) {
			$actions['view'] = sprintf(
				'<span class="view"><a href="%s" title="%s" rel="permalink">%s</a>',
				esc_url( get_permalink( $this->container_id ) ),
				esc_attr( sprintf( __( 'View &#8220;%s&#8221;' ), $title ) ),
				__( 'View' )
			);
		}

		return $actions;
	}

	/**
	 * Get the HTML for displaying the post title in the "Source" column.
	 *
	 * @param string $container_field Ignored.
	 * @param string $context How to filter the output. Optional, defaults to 'display'.
	 * @return string HTML
	 */
	function ui_get_source( $container_field = '', $context = 'display' ) {
		$source = '<a class="row-title" href="%s" title="%s">%s</a>';
		$source = sprintf(
			$source,
			$this->get_edit_url(),
			esc_attr( __( 'Edit this item' ) ),
			get_the_title( $this->container_id )
		);

		return $source;
	}

	/**
	 * Get edit URL for this container. Returns the URL of the Dashboard page where the item
	 * associated with this container can be edited.
	 *
	 * @access protected
	 *
	 * @return string
	 */
	function get_edit_url() {
		/*
		The below is a near-exact copy of the get_post_edit_link() function.
		Unfortunately we can't just call that function because it has a hardcoded
		caps-check which fails when called from the email notification script
		executed by Cron.
		*/
		$post = $this->get_wrapped_object();
		if ( ! $post ) {
			return '';
		}

		$context = 'display';
		$action  = '&amp;action=edit';

		$post_type_object = get_post_type_object( $post->post_type );
		if ( ! $post_type_object ) {
			return '';
		}

		if ( 'wp_template' === $post->post_type || 'wp_template_part' === $post->post_type ) {
			$slug = urlencode( get_stylesheet() . '//' . $post->post_name );
			$link = admin_url( sprintf( $post_type_object->_edit_link, $post->post_type, $slug ) );
		} elseif ( 'wp_navigation' === $post->post_type ) {
			$link = admin_url( sprintf( $post_type_object->_edit_link, (string) $post->ID ) );
		} elseif ( $post_type_object->_edit_link ) {
			$link = admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) );
		}

		$post_type_object->_edit_link = str_replace( 'postType=%s&', '', $post_type_object->_edit_link );

		return apply_filters( 'get_edit_post_link', $link, $post->ID, $context );
	}

	/**
	 * Retrieve the post associated with this container.
	 *
	 * @access protected
	 *
	 * @param bool $ensure_consistency Set this to true to ignore the cached $wrapped_object value and retrieve an up-to-date copy of the wrapped object from the DB (or WP's internal cache).
	 * @return object Post data.
	 */
	function get_wrapped_object( $ensure_consistency = false ) {
		if ( $ensure_consistency || is_null( $this->wrapped_object ) ) {
			$this->wrapped_object = get_post( $this->container_id );
		}
		return $this->wrapped_object;
	}

	/**
	 * Update the post associated with this container.
	 *
	 * @access protected
	 *
	 * @return bool|WP_Error True on success, an error if something went wrong.
	 */
	function update_wrapped_object() {
		if ( is_null( $this->wrapped_object ) ) {
			return new WP_Error(
				'no_wrapped_object',
				__( 'Nothing to update', 'broken-link-checker' )
			);
		}

		$post                        = $this->wrapped_object;
		$post->blc_post_modified     = $post->post_modified;
		$post->blc_post_modified_gmt = $post->post_modified_gmt;
		$post_id                     = wp_update_post( $post, true );

		if ( is_wp_error( $post_id ) ) {
			return $post_id;
		} elseif ( $post_id == 0 ) {
			return new WP_Error(
				'update_failed',
				sprintf( __( 'Updating post %d failed', 'broken-link-checker' ), $this->container_id )
			);
		} else {
			$this->update_pagebuilders( $post_id );
			return true;
		}
	}

	/**
	 * Update the the links on pagebuilders
	 *
	 * @param int $post_id  Post ID of whose content to update.
	 */
	function update_pagebuilders( $post_id ) {
		if ( ! $post_id ) {
			return;
		}

		// support for elementor page builder.
		if ( class_exists( '\Elementor\Plugin' ) && \Elementor\Plugin::$instance->db->is_built_with_elementor( $post_id ) ) {
			if ( is_array( $this->updating_urls ) ) {
				if ( isset( $this->updating_urls['old_url'] ) && isset( $this->updating_urls['new_url'] ) ) {
					// Editing case.
					$old_url = $this->updating_urls['old_url'];
					$new_url = $this->updating_urls['new_url'];
					blcElementor::instance()->update_blc_links( $old_url, $new_url, $post_id );
				} else { // Unlinking case.
					foreach ( $this->updating_urls as $key => $link_info ) {
						$old_url = $link_info['#raw'];
						$new_url = $link_info['#new_raw'];

						if ( $old_url === $new_url ) {
							continue;
						}

						blcElementor::instance()->update_blc_links( $old_url, $new_url, $post_id );
					}
				}
			}
		}

		// Support for Page Builder by SiteOrigin.
		if ( class_exists( '\SiteOrigin_Panels' ) && get_post_meta( $post_id, 'panels_data', true ) ) {
			if ( is_array( $this->updating_urls ) ) {
				if ( isset( $this->updating_urls['old_url'] ) && isset( $this->updating_urls['new_url'] ) ) {
					// Editing case.
					$old_url = $this->updating_urls['old_url'];
					$new_url = $this->updating_urls['new_url'];
					blcSiteOrigin::instance()->update_blc_links( $old_url, $new_url, $post_id );
				} else { // Unlinking case.
					foreach ( $this->updating_urls as $key => $link_info ) {
						$old_url = $link_info['#raw'];
						$new_url = $link_info['#new_raw'];

						if ( $old_url === $new_url ) {
							continue;
						}

						blcSiteOrigin::instance()->update_blc_links( $old_url, $new_url, $post_id );
					}
				}
			}
		}
	}


	/**
	 * Get the base URL of the container. For posts, the post permalink is used
	 * as the base URL when normalizing relative links.
	 *
	 * @return string
	 */
	function base_url() {
		return get_permalink( $this->container_id );
	}

	/**
	 * Delete or trash the post corresponding to this container.
	 * Will always move to trash instead of deleting if trash is enabled.
	 *
	 * @return bool|WP_error
	 */
	function delete_wrapped_object() {
		//Note that we don't need to delete the synch record and instances here -
		//wp_delete_post()/wp_trash_post() will run the post_delete/trash hook,
		//which will be caught by blcPostContainerManager, which will in turn
		//delete anything that needs to be deleted.
		if ( EMPTY_TRASH_DAYS ) {
			return $this->trash_wrapped_object();
		} else {
			if ( wp_delete_post( $this->container_id, true ) ) {
				return true;
			} else {
				return new WP_Error(
					'delete_failed',
					sprintf(
						__( 'Failed to delete post "%1$s" (%2$d)', 'broken-link-checker' ),
						get_the_title( $this->container_id ),
						$this->container_id
					)
				);
			}
		}
	}

	/**
	 * Move the post corresponding to this container to the Trash.
	 *
	 * @return bool|WP_Error
	 */
	function trash_wrapped_object() {
		if ( ! EMPTY_TRASH_DAYS ) {
			return new WP_Error(
				'trash_disabled',
				sprintf(
					__( 'Can\'t move post "%1$s" (%2$d) to the trash because the trash feature is disabled', 'broken-link-checker' ),
					get_the_title( $this->container_id ),
					$this->container_id
				)
			);
		}

		$post = get_post( $this->container_id );
		if ( $post->post_status == 'trash' ) {
			//Prevent conflicts between post and custom field containers trying to trash the same post.
			//BUG: Post and custom field containers shouldn't wrap the same object
			return true;
		}

		if ( wp_trash_post( $this->container_id ) ) {
			return true;
		} else {
			return new WP_Error(
				'trash_failed',
				sprintf(
					__( 'Failed to move post "%1$s" (%2$d) to the trash', 'broken-link-checker' ),
					get_the_title( $this->container_id ),
					$this->container_id
				)
			);
		}
	}

	/**
	 * Check if the current user can delete/trash this post.
	 *
	 * @return bool
	 */
	function current_user_can_delete() {
		$post             = $this->get_wrapped_object();
		$post_type_object = get_post_type_object( $post->post_type );
		return current_user_can( $post_type_object->cap->delete_post, $this->container_id );
	}

	function can_be_trashed() {
		return defined( 'EMPTY_TRASH_DAYS' ) && EMPTY_TRASH_DAYS;
	}
}

/**
 * Universal manager usable for most post types.
 *
 * @package Broken Link Checker
 * @access public
 */
class blcAnyPostContainerManager extends blcContainerManager {
	var $container_class_name = 'blcAnyPostContainer';
	var $fields               = array( 'post_content' => 'html', 'post_excerpt' => 'html' );

	function init() {
		parent::init();

		//Notify the overlord that the post/container type that this instance is
		//responsible for is enabled.
		$overlord = blcPostTypeOverlord::getInstance();
		$overlord->post_type_enabled( $this->container_type );
	}

	/**
	 * Instantiate multiple containers of the container type managed by this class.
	 *
	 * @param array $containers Array of assoc. arrays containing container data.
	 * @param string $purpose An optional code indicating how the retrieved containers will be used.
	 * @param bool $load_wrapped_objects Preload wrapped objects regardless of purpose.
	 *
	 * @return array of blcPostContainer indexed by "container_type|container_id"
	 */
	function get_containers( $containers, $purpose = '', $load_wrapped_objects = false ) {
		global $blclog;
		$containers = $this->make_containers( $containers );

		//Preload post data if it is likely to be useful later
		$preload = $load_wrapped_objects || in_array( $purpose, array( BLC_FOR_DISPLAY, BLC_FOR_PARSING ) );
		if ( $preload ) {
			$post_ids = array();
			foreach ( $containers as $container ) {
				$post_ids[] = $container->container_id;
			}

			$args  = array( 'include' => implode( ',', $post_ids ) );
			$posts = get_posts( $args );

			foreach ( $posts as $post ) {
				$key = $this->container_type . '|' . $post->ID;
				if ( isset( $containers[ $key ] ) ) {
					$containers[ $key ]->wrapped_object = $post;
				}
			}
		}

		return $containers;
	}

	/**
	 * Create or update synchronization records for all posts.
	 *
	 * @param bool $forced If true, assume that all synch. records are gone and will need to be recreated from scratch.
	 * @return void
	 */
	function resynch( $forced = false ) {
		$overlord = blcPostTypeOverlord::getInstance();
		$overlord->resynch( $this->container_type, $forced );
	}

	/**
	 * Get the message to display after $n posts have been deleted.
	 *
	 * @param int $n Number of deleted posts.
	 * @return string A delete confirmation message, e.g. "5 posts were moved deleted"
	 */
	function ui_bulk_delete_message( $n ) {
		//Since the "Trash" feature has been introduced, calling wp_delete_post
		//doesn't actually delete the post (unless you set force_delete to True),
		//just moves it to the trash. So we pick the message accordingly.
		//(If possible, BLC *always* moves to trash instead of deleting permanently.)
		if ( function_exists( 'wp_trash_post' ) && EMPTY_TRASH_DAYS ) {
			return blcAnyPostContainerManager::ui_bulk_trash_message( $n );
		} else {
			$post_type_object = get_post_type_object( $this->container_type );
			$type_name        = '';

			if ( $this->container_type == 'post' || is_null( $post_type_object ) ) {
				$delete_msg = _n( '%d post deleted.', '%d posts deleted.', $n, 'broken-link-checker' );
			} elseif ( $this->container_type == 'page' ) {
				$delete_msg = _n( '%d page deleted.', '%d pages deleted.', $n, 'broken-link-checker' );
			} else {
				$delete_msg = _n( '%1$d "%2$s" deleted.', '%1$d "%2$s" deleted.', $n, 'broken-link-checker' );
				$type_name  = ( $n == 1 ? $post_type_object->labels->singular_name : $post_type_object->labels->name );
			}
			return sprintf( $delete_msg, $n, $type_name );
		}
	}


	/**
	 * Get the message to display after $n posts have been trashed.
	 *
	 * @param int $n Number of deleted posts.
	 * @return string A confirmation message, e.g. "5 posts were moved to trash"
	 */
	function ui_bulk_trash_message( $n ) {
		$post_type_object = get_post_type_object( $this->container_type );
		$type_name        = '';

		if ( $this->container_type == 'post' || is_null( $post_type_object ) ) {
			$delete_msg = _n( '%d post moved to the Trash.', '%d posts moved to the Trash.', $n, 'broken-link-checker' );
		} elseif ( $this->container_type == 'page' ) {
			$delete_msg = _n( '%d page moved to the Trash.', '%d pages moved to the Trash.', $n, 'broken-link-checker' );
		} else {
			$delete_msg = _n( '%1$d "%2$s" moved to the Trash.', '%1$d "%2$s" moved to the Trash.', $n, 'broken-link-checker' );
			$type_name  = ( $n == 1 ? $post_type_object->labels->singular_name : $post_type_object->labels->name );
		}
		return sprintf( $delete_msg, $n, $type_name );
	}
}
