<?php
/**
 * Mentions.
 *
 * @package P2
 * @since P2 1.3.1
 */


/**
 * Handler for the mentions taxonomy.
 *
 * @package P2
 * @since unknown
 */
class P2_Mentions extends P2_Terms_In_Comments {
	var $names          = array();
	var $users          = array();
	var $mentions_regex = '/\B@([\w\.]+)\b/';

	function __construct() {
		p2_maybe_define( 'P2_MENTIONS_TAXONOMY', 'mentions', 'p2_mentions_taxonomy' );
		p2_maybe_define( 'P2_MENTIONS_SLUG',     'mentions', 'p2_mentions_slug'     );

		// Hooks
		add_action( 'init',              array( &$this, 'init'            ), 0 );
		add_filter( 'the_content',       array( &$this, 'mention_links'   ), 5 );
		add_filter( 'comment_text',      array( &$this, 'mention_links'   ), 5 );
		add_filter( 'p2_found_mentions', array( &$this, 'filter_mentions' ), 5 );

		parent::__construct( P2_MENTIONS_TAXONOMY );
	}

	/**
	 * Register P2 mentions taxonomy.
	 */
	function init() {
		$taxonomy_args = apply_filters( 'p2_mentions_taxonomy_args', array(
			'show_ui'           => false,
			'show_in_nav_menus' => false,
			'rewrite'           => array( 'slug' => P2_MENTIONS_SLUG ),
		) );

		register_taxonomy( P2_MENTIONS_TAXONOMY, 'post', $taxonomy_args );
	}

	/**
	 * Generates array of users indexed by user ID, and
	 * an array of user_nicenames, indexed by user ID.
	 *
	 * @return array An array of user objects indexed by user ID.
	 */
	function load_users() {

		// Cache the user information.
		if ( ! empty( $this->users ) )
	 		return $this->users;

		$users = get_users();
		foreach ( $users as $user ) {
			$this->users[ $user->ID ] = $user;
			$this->names[ $user->ID ] = $user->user_nicename;
		}

		return $this->users;
	}

	function update_post_terms( $post_id, $post ) {
		return $this->find_mentions( $post->post_content );
	}

	function update_comment_terms( $comment_id, $comment ) {
		return $this->find_mentions( $comment->comment_content );
	}

	function find_mentions( $content ) {
		if ( ! preg_match_all( $this->mentions_regex, $content, $matches ) )
			return array();

		// Filters found mentions. Passes original found mentions and content as args.
		return apply_filters( 'p2_found_mentions', $matches[1], $matches[1], $content );
	}

	function filter_mentions( $mentions ) {
		$this->load_users();
		return array_intersect( $mentions, $this->names );
	}

	static function wp_html_split( $input ) {
		static $regex;
		if ( ! isset( $regex ) && function_exists( 'get_html_split_regex' ) )
			$regex = get_html_split_regex();
		if ( ! isset( $regex ) ) {
			$comments =
				  '!'           // Start of comment, after the <.
				. '(?:'         // Unroll the loop: Consume everything until --> is found.
				.     '-(?!->)' // Dash not followed by end of comment.
				.     '[^\-]*+' // Consume non-dashes.
				. ')*+'         // Loop possessively.
				. '(?:-->)?';   // End of comment. If not found, match all input.

			$cdata =
				  '!\[CDATA\['  // Start of comment, after the <.
				. '[^\]]*+'     // Consume non-].
				. '(?:'         // Unroll the loop: Consume everything until ]]> is found.
				.     '](?!]>)' // One ] not followed by end of comment.
				.     '[^\]]*+' // Consume non-].
				. ')*+'         // Loop possessively.
				. '(?:]]>)?';   // End of comment. If not found, match all input.

			$escaped =
				  '(?='           // Is the element escaped?
				.    '!--'
				. '|'
				.    '!\[CDATA\['
				. ')'
				. '(?(?=!-)'      // If yes, which type?
				.     $comments
				. '|'
				.     $cdata
				. ')';

			$regex =
				  '/('              // Capture the entire match.
				.     '<'           // Find start of element.
				.     '(?'          // Conditional expression follows.
				.         $escaped  // Find end of escaped element.
				.     '|'           // ... else ...
				.         '[^>]*>?' // Find end of normal element.
				.     ')'
				. ')/';
		}
		return preg_split( $regex, $input, -1, PREG_SPLIT_DELIM_CAPTURE );
	}

	function mention_link_callback( $matches ) {
		global $current_user;

		$name = $matches[1];
		if ( !in_array( $name, $this->names ) )
			return $matches[0];

		$slug   = P2_MENTIONS_SLUG;
		$search = is_search() ? substr( get_search_query( false ), 1 ) : '';

		$classes = 'mention';
		// If we're searching for this name, highlight it.
		if ( $name === $search )
			$classes .= ' mention-highlight';

		if ( is_user_logged_in() && $name === $current_user->user_login )
			$classes .= ' mention-current-user';

		$url = get_term_link( $name, P2_MENTIONS_TAXONOMY );
		$url = apply_filters( 'p2_mention_url', $url, $name );
		if ( is_wp_error( $url ) || ! $url ) {
			return $matches[0];
		}

		$replacement = "<a href='" . esc_url( $url ) . "' class='$classes'>@$name</a>";
		return apply_filters( 'p2_mention_link', $replacement, $name );
	}

	/**
	 * Parses and links mentions within a string.
	 * Run on the_content.
	 *
	 * @param string $content The content.
	 * @return string The linked content.
	 */
	function mention_links( $content ) {
		global $current_user;

		if ( !preg_match( $this->mentions_regex, $content ) )
			return $content;

		$this->load_users();
		$textarr = self::wp_html_split( $content );
		foreach( $textarr as &$element ) {
			if ( '' == $element || '<' === $element[0] || false === strpos( $element, '@' ) ) {
				continue;
			}
			$element = preg_replace_callback( $this->mentions_regex, array( $this, 'mention_link_callback' ), $element );
		}
		return implode( $textarr );
	}

	/**
	 * Generates the user information for the mentions autocomplete feature.
	 *
	 * @return array User information.
	 */
	function user_suggestion() {

		// Membership check
		$user = wp_get_current_user();
		if ( function_exists( 'is_user_member_of_blog' ) && ! is_user_member_of_blog( $user->ID ) )
			return;

		// Capability check
		if ( ! current_user_can( 'edit_posts' ) )
			return;

		$this->load_users();

		$js_users = array();

		foreach( $this->users as $user ) {
			$js_users[] = array(
				'name'      => $user->display_name,
				'username'  => ( isset( $user->user_nicename ) ? $user->user_nicename : $user->display_name ),
				'gravatar'  => get_avatar( $user->user_email, 32 ),
			);
		}

		return apply_filters( 'p2_user_suggestion', $js_users );
	}
}