r-a-y

class BP_Blog_Post_Fav {

    var $activity_id;

    function init() {
        add_action( 'the_post', array( &$this, 'get_blog_post_activity_id' ) );
    }

    function get_blog_post_activity_id() {
        global $current_blog, $post;

        if( isset($post->ID) ) :
            $activity_id = bp_activity_get_activity_id( array(
            'user_id' => $post->post_author,
            'type' => 'new_blog_post',
            'component' => 'blogs',
            'item_id' => $current_blog->blog_id,
            'secondary_item_id' => $post->ID) );

            $this->activity_id = $activity_id;

            if( !empty($this->activity_id) ) {
                add_filter( 'bp_get_activity_favorite_link', array( &$this, 'bp_get_activity_favorite_link' ) );
                add_filter( 'bp_get_activity_unfavorite_link', array( &$this, 'bp_get_activity_unfavorite_link' ) );
                add_filter( 'bp_get_activity_is_favorite', array( &$this, 'bp_get_activity_is_favorite' ) );
            }

        endif;

    }

    function bp_get_activity_favorite_link() {
        global $current_blog;

        if( $current_blog->blog_id != BP_ROOT_BLOG )
            switch_to_blog( BP_ROOT_BLOG );

        $nonce = wp_nonce_url( site_url( BP_ACTIVITY_SLUG . '/favorite/' . $this->activity_id . '/' ), 'mark_favorite' );

        if( $current_blog->blog_id != BP_ROOT_BLOG )
            restore_current_blog();

        return $nonce;
    }

    function bp_get_activity_unfavorite_link() {
        global $current_blog;

        if( $current_blog->blog_id != BP_ROOT_BLOG )
            switch_to_blog( BP_ROOT_BLOG );

        $nonce = wp_nonce_url( site_url( BP_ACTIVITY_SLUG . '/unfavorite/' . $this->activity_id . '/' ), 'unmark_favorite' );

        if( $current_blog->blog_id != BP_ROOT_BLOG )
            restore_current_blog();

        return $nonce;
    }

    function bp_get_activity_is_favorite() {
        global $bp;

        return in_array( $this->activity_id, (array)bp_activity_get_user_favorites($bp->loggedin_user->id) );
    }
}
$my_bp_favorite = new BP_Blog_Post_Fav();
$my_bp_favorite->init();