<?php
/**
 * 
 *  Access to the execution flow
 * 
 */
class csscrush_hook {

    // Table of hooks and the functions attached to them
    static public $register = array();

    static public function add ( $hook, $fn_name ) {

        // Bail early is the named hook and callback combination is already loaded
        if ( isset( self::$register[ $hook ][ $fn_name ] ) ) {
            return;
        }

        // Register the hook and callback.
        // Store in associative array so no duplicates
        if ( function_exists( $fn_name ) ) {

            self::$register[ $hook ][ $fn_name ] = true;

            // If the callback is a plugin register the hook that it uses
            if ( strpos( $fn_name, csscrush_plugin::$prefix ) === 0 ) {

                $plugin_name = str_replace( '_', '-',
                    substr( $fn_name, strlen( csscrush_plugin::$prefix ) ) );
                csscrush_plugin::registerHook( $plugin_name, $hook );
            }
        }
    }

    static public function remove ( $hook, $fn_name ) {
        unset( self::$register[ $hook ][ $fn_name ] );
    }

    static public function run ( $hook, $arg_obj = null ) {

        // Run all callbacks attached to the hook
        if ( ! isset( self::$register[ $hook ] ) ) {
            return;
        }
        foreach ( array_keys( self::$register[ $hook ] ) as $fn_name ) {
            call_user_func( $fn_name, $arg_obj );
        }
    }
}