<?php

/*
Plugin Name: Custom fields
Description: Container module for post metadata.
Version: 1.0
Author: Janis Elsts

ModuleID: custom_field
ModuleCategory: container
ModuleClassName: blcPostMetaManager
*/

//Note : If it ever becomes necessary to check metadata on objects other than posts, it will
//be fairly easy to extract a more general metadata container class from blcPostMeta.

/**
 * blcPostMeta - A link container class for post metadata (AKA custom fields).
 *
 * Due to the way metadata works, this container differs significantly from other containers :
 *  - container_field is equal to meta name, and container_id holds the ID of the post.
 *  - There is one synch. record per post that determines the synch. state of all metadata fields of that post.
 *  - Unlinking simply deletes the meta entry in question without involving the parser.
 *  - The list of parse-able $fields is not fixed. Instead, it's initialized based on the
 *    custom field list defined in Settings -> Link Checker.
 *  - The $wrapped_object is an array (and isn't really used for anything).
 *  - update_wrapped_object() does nothing.
 *
 * @package Broken Link Checker
 * @access public
 */
class blcPostMeta extends blcContainer {

	var $meta_type = 'post';

	/**
	 * Retrieve all metadata fields of the post associated with this container.
	 * The results are cached in the internal $wrapped_object variable.
	 *
	 * @param bool $ensure_consistency
	 * @return object The wrapped object.
	 */
	function get_wrapped_object( $ensure_consistency = false ) {
		if ( is_null( $this->wrapped_object ) || $ensure_consistency ) {
			$this->wrapped_object = get_metadata( $this->meta_type, $this->container_id );
		}

		return $this->wrapped_object;
	}

	function update_wrapped_object() {
		trigger_error( 'Function blcPostMeta::update_wrapped_object() does nothing and should not be used.', E_USER_WARNING );
	}

	/**
	 * Get the value of the specified metadata field of the object wrapped by this container.
	 *
	 * @access protected
	 *
	 * @param string $field Field name. If omitted, the value of the default field will be returned.
	 * @return array
	 */
	function get_field( $field = '', $single = false ) {
		$get_only_first_field = ( 'metadata' !== $this->fields[ $field ] );

		//override the get only first by a param
		if ( $single ) {
			$get_only_first_field = true;
		}

		return get_metadata( $this->meta_type, $this->container_id, $field, $get_only_first_field );
	}

	/**
	 * Update the value of the specified metadata field of the object wrapped by this container.
	 *
	 * @access protected
	 *
	 * @param string $field Meta name.
	 * @param string $new_value New meta value.
	 * @param string $old_value old meta value.
	 * @return bool|WP_Error True on success, an error object if something went wrong.
	 */
	function update_field( $field, $new_value, $old_value = '' ) {

		//necessary for metas that store more than one value in a key
		$meta_value     = $this->get_field( $field, true );
		$new_meta_value = $meta_value;
		if ( is_array( $meta_value ) ) {
			foreach ( $meta_value as $key => $meta ) {
				if ( $meta === $old_value ) {
					$new_meta_value[ $key ] = $new_value;
				}
			}
			$new_value = $new_meta_value;
			$old_value = $meta_value;
		}

		//update the medatadata
		$rez = update_metadata( $this->meta_type, $this->container_id, $field, $new_value, $old_value );
		if ( $rez ) {
			return true;
		} else {
			return new WP_Error(
				'metadata_update_failed',
				sprintf(
					__( "Failed to update the meta field '%1\$s' on %2\$s [%3\$d]", 'broken-link-checker' ),
					$field,
					$this->meta_type,
					$this->container_id
				)
			);
		}
	}

	/**
	 * "Unlink"-ing a custom fields removes all metadata fields that contain the specified URL.
	 *
	 * @param string $field_name
	 * @param blcParser $parser
	 * @param string $url
	 * @param string $raw_url
	 * @return bool|WP_Error True on success, or an error object if something went wrong.
	 */
	function unlink( $field_name, $parser, $url, $raw_url = '' ) {
		if ( 'metadata' !== $this->fields[ $field_name ] ) {
			return parent::unlink( $field_name, $parser, $url, $raw_url );
		}

		$rez = delete_metadata( $this->meta_type, $this->container_id, $field_name, $raw_url );
		if ( $rez ) {
			return true;
		} else {
			return new WP_Error(
				'metadata_delete_failed',
				sprintf(
					__( "Failed to delete the meta field '%1\$s' on %2\$s [%3\$d]", 'broken-link-checker' ),
					$field_name,
					$this->meta_type,
					$this->container_id
				)
			);
		}
	}

	/**
	 * Change a meta field containing the specified URL to a new URL.
	 *
	 * @param string $field_name Meta name
	 * @param blcParser $parser
	 * @param string $new_url New URL.
	 * @param string $old_url
	 * @param string $old_raw_url Old meta value.
	 * @param null $new_text
	 * @return string|WP_Error The new value of raw_url on success, or an error object if something went wrong.
	 */
	function edit_link( $field_name, $parser, $new_url, $old_url = '', $old_raw_url = '', $new_text = null ) {
		/*
		FB::log(sprintf(
			'Editing %s[%d]:%s - %s to %s',
			$this->container_type,
			$this->container_id,
			$field_name,
			$old_url,
			$new_url
		));
		*/

		if ( 'metadata' !== $this->fields[ $field_name ] ) {
			return parent::edit_link( $field_name, $parser, $new_url, $old_url, $old_raw_url, $new_text );
		}

		if ( empty( $old_raw_url ) ) {
			$old_raw_url = $old_url;
		}

		//Get the current values of the field that needs to be edited.
		//The default metadata parser ignores them, but we're still going
		//to set this argument to a valid value in case someone writes a
		//custom meta parser that needs it.
		$old_value = $this->get_field( $field_name );

		//Get the new field value (a string).
		$edit_result = $parser->edit( $old_value, $new_url, $old_url, $old_raw_url );
		if ( is_wp_error( $edit_result ) ) {
			return $edit_result;
		}

		//Update the field with the new value returned by the parser.
		//Notice how $old_raw_url is used instead of $old_value. $old_raw_url contains the entire old
		//value of the metadata field (see blcMetadataParser::parse()) and thus can be used to
		//differentiate between multiple meta fields with identical names.
		$update_result = $this->update_field( $field_name, $edit_result['content'], $old_raw_url );
		if ( is_wp_error( $update_result ) ) {
			return $update_result;
		}

		//Return the new "raw" URL.
		return $edit_result['raw_url'];
	}

	/**
	 * Get the default link text to use for links found in a specific container field.
	 *
	 * @param string $field
	 * @return string
	 */
	function default_link_text( $field = '' ) {
		//Just use the field name. There's no way to know how the links inside custom fields are
		//used, so no way to know the "real" link text. Displaying the field name at least gives
		//the user a clue where to look if they want to find/modify the field.
		return $field;
	}

	function ui_get_source( $container_field = '', $context = 'display' ) {
		if ( ! post_type_exists( get_post_type( $this->container_id ) ) ) {
			//Error: Invalid post type. The user probably removed a CPT without removing the actual posts.
			$post_html = '';

			$post = get_post( $this->container_id );
			if ( $post ) {
				$post_html .= sprintf(
					'<span class="row-title">%s</span><br>',
					get_the_title( $post )
				);
			}
			$post_html .= sprintf(
				'Invalid post type "%s"',
				htmlentities( $this->container_type )
			);

			return $post_html;
		}

		$post_html = sprintf(
			'<a class="row-title" href="%s" title="%s">%s</a>',
			esc_url( $this->get_edit_url() ),
			esc_attr( __( 'Edit this post' ) ),
			get_the_title( $this->container_id )
		);

		return $post_html;
	}

	function ui_get_action_links( $container_field ) {
		$actions = array();
		if ( ! post_type_exists( get_post_type( $this->container_id ) ) ) {
			return $actions;
		}

		if ( current_user_can( 'edit_post', $this->container_id ) ) {
			$actions['edit'] = '<span class="edit"><a href="' . $this->get_edit_url() . '" title="' . esc_attr( __( 'Edit this item' ) ) . '">' . __( 'Edit' ) . '</a>';

			if ( $this->current_user_can_delete() ) {
				if ( $this->can_be_trashed() ) {
					$actions['trash'] = sprintf(
						"<span><a class='submitdelete' title='%s' href='%s'>%s</a>",
						esc_attr( __( 'Move this item to the Trash' ) ),
						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' ) ),
						get_delete_post_link( $this->container_id, '', true ),
						__( 'Delete' )
					);
				}
			}
		}
		$actions['view'] = '<span class="view"><a href="' . esc_url( get_permalink( $this->container_id ) ) . '" title="' . esc_attr( sprintf( __( 'View "%s"', 'broken-link-checker' ), get_the_title( $this->container_id ) ) ) . '" rel="permalink">' . __( 'View' ) . '</a>';

		return $actions;
	}

	/**
	 * 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 = get_post( $this->container_id );

		if ( ! $post ) {
			return '';
		}

		$context = 'display';

		//WP 3.0
		if ( 'display' === $context ) {
			$action = '&amp;action=edit';
		} else {
			$action = '&action=edit';
		}

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

		return apply_filters( 'get_edit_post_link', admin_url( sprintf( $post_type_object->_edit_link . $action, $post->ID ) ), $post->ID, $context );
	}

	/**
	 * Get the base URL of the container. For custom fields, the base URL is the permalink of
	 * the post that the field is attached to.
	 *
	 * @return string
	 */
	function base_url() {
		return get_permalink( $this->container_id );
	}

	/**
	 * Delete or trash the post corresponding to this container. If trash is enabled,
	 * will always move the post to the trash instead of deleting.
	 *
	 * @return bool|WP_error
	 */
	function delete_wrapped_object() {
		if ( EMPTY_TRASH_DAYS ) {
			return $this->trash_wrapped_object();
		} else {
			if ( wp_delete_post( $this->container_id ) ) {
				return true;
			} else {
				return new WP_Error(
					'delete_failed',
					sprintf(
						__( 'Failed to delete post "%1$s" (%2$d)', 'broken-link-checker' ),
						get_the_title( $this->container_id ),
						$this->container_id
					)
				);
			}
		}
	}

	/**
	 * Move the post corresponding to this custom field 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 ( 'trash' === $post->post_status ) {
			//Prevent conflicts between post and custom field containers trying to trash the same post.
			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
				)
			);
		}
	}

	function current_user_can_delete() {
		$post             = get_post( $this->container_id );
		$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;
	}
}

class blcPostMetaManager extends blcContainerManager {
	var $container_class_name  = 'blcPostMeta';
	var $meta_type             = 'post';
	protected $selected_fields = array();

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

		//Figure out which custom fields we're interested in.
		if ( is_array( $this->plugin_conf->options['custom_fields'] ) ) {
			$prefix_formats = array(
				'html' => 'html',
				'url'  => 'metadata',
			);
			foreach ( $this->plugin_conf->options['custom_fields'] as $meta_name ) {
				//The user can add an optional "format:" prefix to specify the format of the custom field.
				$parts = explode( ':', $meta_name, 2 );
				if ( ( count( $parts ) == 2 ) && in_array( $parts[0], $prefix_formats ) ) {
					$this->selected_fields[ $parts[1] ] = $prefix_formats[ $parts[0] ];
				} else {
					$this->selected_fields[ $meta_name ] = 'metadata';
				}
			}
		}

		//Intercept 2.9+ style metadata modification actions
		add_action( "added_{$this->meta_type}_meta", array( $this, 'meta_modified' ), 10, 4 );
		add_action( "updated_{$this->meta_type}_meta", array( $this, 'meta_modified' ), 10, 4 );
		add_action( "deleted_{$this->meta_type}_meta", array( $this, 'meta_modified' ), 10, 4 );

		//When a post is deleted, also delete the custom field container associated with it.
		add_action( 'delete_post', array( $this, 'post_deleted' ) );
		add_action( 'trash_post', array( $this, 'post_deleted' ) );

		//Re-parse custom fields when a post is restored from trash
		add_action( 'untrashed_post', array( $this, 'post_untrashed' ) );
	}


	/**
	 * Get a list of parseable fields.
	 *
	 * @return array
	 */
	function get_parseable_fields() {
		return $this->selected_fields;
	}

	/**
	 * 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 blcPostMeta indexed by "container_type|container_id"
	 */
	function get_containers( $containers, $purpose = '', $load_wrapped_objects = false ) {
		$containers = $this->make_containers( $containers );

		/*
		When links from custom fields are displayed in Tools -> Broken Links,
		each one also shows the title of the post that the custom field(s)
		belong to. Thus it makes sense to pre-cache the posts beforehand - it's
		faster to load them all at once than to make a separate query for each
		one later.

		So make a list of involved post IDs and load them.

		Calling get_posts() will automatically populate the post cache, so we
		don't need to actually store the results anywhere in the container object().
		*/
		$preload = $load_wrapped_objects || in_array( $purpose, array( BLC_FOR_DISPLAY ) );
		if ( $preload ) {
			$post_ids = array();
			foreach ( $containers as $container ) {
				$post_ids[] = $container->container_id;
			}

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

		return $containers;
	}

	/**
	 * Create or update synchronization records for all containers managed by this class.
	 *
	 * @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 ) {
		global $wpdb; /** @var wpdb $wpdb */
		global $blclog;

		//Only check custom fields on selected post types. By default, that's "post" and "page".
		$post_types = array( 'post', 'page' );
		if ( class_exists( 'blcPostTypeOverlord' ) ) {
			$overlord   = blcPostTypeOverlord::getInstance();
			$post_types = array_merge( $post_types, $overlord->enabled_post_types );
			$post_types = array_unique( $post_types );
		}

		$escaped_post_types = "'" . implode( "', '", array_map( 'esc_sql', $post_types ) ) . "'";

		if ( $forced ) {
			//Create new synchronization records for all posts.
			$blclog->log( '...... Creating synch records for all custom fields on ' . $escaped_post_types );
			$start = microtime( true );
			$q     = "INSERT INTO {$wpdb->prefix}blc_synch(container_id, container_type, synched)
				  SELECT id, '{$this->container_type}', 0
				  FROM {$wpdb->posts}
				  WHERE
				  	{$wpdb->posts}.post_status = 'publish'
	 				AND {$wpdb->posts}.post_type IN ({$escaped_post_types})";
			$wpdb->query( $q ); //phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
			$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.
			$blclog->log( '...... Deleting custom field synch records corresponding to deleted posts' );
			$start = microtime( true );
			$q     = "DELETE synch.*
				  FROM
					 {$wpdb->prefix}blc_synch AS synch LEFT JOIN {$wpdb->posts} AS posts
					 ON posts.ID = synch.container_id
				  WHERE
					 synch.container_type = '{$this->container_type}' AND posts.ID IS NULL";
			$wpdb->query( $q ); //phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
			$blclog->log( sprintf( '...... %d rows deleted in %.3f seconds', $wpdb->rows_affected, microtime( true ) - $start ) );

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

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

	/**
	 * Mark custom fields as unsynched when they're modified or deleted.
	 *
	 * @param array|int $meta_id
	 * @param int $object_id
	 * @param string $meta_key
	 * @param string $meta_value
	 * @return void
	 */
	function meta_modified( $meta_id, $object_id = 0, $meta_key = '', $meta_value = '' ) {
		global $wpdb; /** @var wpdb $wpdb */

		//If object_id isn't specified then the hook was probably called from the
		//stupidly inconsistent delete_meta() function in /wp-admin/includes/post.php.
		if ( empty( $object_id ) ) {
			//We must manually retrieve object_id and meta_key from the DB.
			if ( is_array( $meta_id ) ) {
				$meta_id = array_shift( $meta_id );
			}

			$meta = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->postmeta WHERE meta_id = %d", $meta_id ), ARRAY_A );
			if ( empty( $meta ) ) {
				return;
			}

			$object_id = $meta['post_id'];
			$meta_key  = $meta['meta_key'];
		}

		//Metadata changes only matter to us if the modified key
		//is one that the user wants checked.
		if ( empty( $this->selected_fields ) ) {
			return;
		}
		if ( ! array_key_exists( $meta_key, $this->selected_fields ) ) {
			return;
		}

		//Skip revisions. We only care about custom fields on the main post.
		$post = get_post( $object_id );
		if ( empty( $post ) || ! isset( $post->post_type ) || ( 'revision' === $post->post_type ) ) {
			return;
		}

		$container = blcContainerHelper::get_container( array( $this->container_type, intval( $object_id ) ) );
		$container->mark_as_unsynched();
	}

	/**
	 * Delete custom field synch. records when the post that they belong to is deleted.
	 *
	 * @param int $post_id
	 * @return void
	 */
	function post_deleted( $post_id ) {
		//Get the associated container object

		$container = blcContainerHelper::get_container( array( $this->container_type, intval( $post_id ) ) );
		if ( null != $container ) {
			//Delete it
			$container->delete();
			//Clean up any dangling links
			blc_cleanup_links();
		}
	}

	/**
	* When a post is restored, mark all of its custom fields as unparsed.
	* Called via the 'untrashed_post' action.
	*
	* @param int $post_id
	* @return void
	*/
	function post_untrashed( $post_id ) {
		//Get the associated container object
		$container = blcContainerHelper::get_container( array( $this->container_type, intval( $post_id ) ) );
		$container->mark_as_unsynched();
	}

	/**
	 * Get the message to display after $n posts have been deleted.
	 *
	 * @uses blcAnyPostContainerManager::ui_bulk_delete_message()
	 *
	 * @param int $n Number of deleted posts.
	 * @return string A delete confirmation message, e.g. "5 posts were moved to the trash"
	 */
	function ui_bulk_delete_message( $n ) {
		return blcAnyPostContainerManager::ui_bulk_delete_message( $n );
	}

	/**
	 * 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 ) {
		return blcAnyPostContainerManager::ui_bulk_trash_message( $n );
	}
}
