<?php

class P2_Mentions extends P2_Terms_In_Comments {
	var $names          = array();
	var $users          = array();
	var $mentions_regex = '/\B@([\w-\.]+)\b/';

	function P2_Mentions() {
		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 );

		parent::P2_Terms_In_Comments( P2_MENTIONS_TAXONOMY );
	}

	function init() {
		// Register P2 user taxonomy
		$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.
	 *
	 * @compat < 3.1: Use $wpdb and get_users of blog.
	 */
	function load_users() {
		global $wpdb; // < 3.1

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

		if ( function_exists( 'get_users' ) ) { // >= 3.1
			$users = get_users();
			foreach ( $users as $user ) {
				$this->users[ $user->ID ] = $user;
				$this->names[ $user->ID ] = $user->user_nicename;
			}
		} else {                                //  < 3.1
			$users      = get_users_of_blog();
			$user_ids   = '';

			foreach ( $users as $user ) {
				$this->users[ $user->ID ] = $user;
				$user_ids .= $user->ID;
			}
			foreach ( $wpdb->get_results( "SELECT ID, user_nicename from $wpdb->users WHERE ID IN($user_ids)" ) as $user ) {
				$this->users[ $user->ID ]['user_nicename'] = $user->user_nicename;
				$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();

		$this->load_users();
		return array_intersect( $matches[1], $this->names );
	}

	/**
	 * 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 ) {
		$names  = $this->find_mentions( $content );
		$slug   = P2_MENTIONS_SLUG;
		$search = is_search() ? substr( get_search_query( false ), 1 ) : '';

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

			$replacement    = "<a href='" . esc_url( home_url( "$slug/$name/" ) ) . "' class='$classes'>@$name</a>";
			$replacement    = apply_filters( 'p2_mention_link', $replacement, $name );
			$content        = preg_replace( "/@$name\b/i", $replacement, $content );
		}

		return $content;
	}

	/**
	 * 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'  => $user->user_nicename,
				'gravatar'  => get_avatar( $user->user_email, 32 ),
			);
		}

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

?>