<?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 = ''){
		$get_only_first_field = ($this->fields[$field] !== 'metadata');
		return get_metadata($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 = ''){
		$rez = update_metadata($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 '%s' on %s [%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 ( $this->fields[$field_name] !== 'metadata' ) {
			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 '%s' on %s [%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 ( $this->fields[$field_name] !== 'metadata' ) {
			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.
		*/ 
		
		if ( !($post = get_post( $this->container_id )) ){
			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 "%s" (%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 "%s" (%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.
			return true;
		}
		
		if ( wp_trash_post($this->container_id) ){
			return true;
		} else {
			return new WP_Error(
				'trash_failed',
				sprintf(
					__('Failed to move post "%s" (%d) to the trash', 'broken-link-checker'),
					get_the_title($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 );
	 		$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 );
			$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 );
			$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);
			$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) || ($post->post_type === 'revision') ) {
			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)) );
		//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);
	}
}