<?php
/*
 +--------------------------------------------------------------------+
 | CiviCRM version 4.6                                                |
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC (c) 2004-2014                                |
 +--------------------------------------------------------------------+
 | This file is a part of CiviCRM.                                    |
 |                                                                    |
 | CiviCRM is free software; you can copy, modify, and distribute it  |
 | under the terms of the GNU Affero General Public License           |
 | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
 |                                                                    |
 | CiviCRM is distributed in the hope that it will be useful, but     |
 | WITHOUT ANY WARRANTY; without even the implied warranty of         |
 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
 | See the GNU Affero General Public License for more details.        |
 |                                                                    |
 | You should have received a copy of the GNU Affero General Public   |
 | License and the CiviCRM Licensing Exception along                  |
 | with this program; if not, contact CiviCRM LLC                     |
 | at info[AT]civicrm[DOT]org. If you have questions about the        |
 | GNU Affero General Public License or the licensing of CiviCRM,     |
 | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
 +--------------------------------------------------------------------+
 */

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC (c) 2004-2014
 * $Id$
 *
 */
class CRM_Utils_Hook_WordPress extends CRM_Utils_Hook {

  /**
   * @var bool
   */
  private $isBuilt = FALSE;

  /**
   * @var array(string)
   */
  private $allModules = NULL;

  /**
   * @var array(string)
   */
  private $civiModules = NULL;

  /**
   * @var array(string)
   */
  private $wordpressModules = NULL;

  /**
   * @var array(string)
   */
  private $hooksThatReturn = array(
    'civicrm_upgrade',
    'civicrm_caseSummary',
    'civicrm_dashboard',
  );

  /**
   * Invoke hooks
   *
   * @param int $numParams
   *   Number of parameters to pass to the hook.
   * @param mixed $arg1
   *   Parameter to be passed to the hook.
   * @param mixed $arg2
   *   Parameter to be passed to the hook.
   * @param mixed $arg3
   *   Parameter to be passed to the hook.
   * @param mixed $arg4
   *   Parameter to be passed to the hook.
   * @param mixed $arg5
   *   Parameter to be passed to the hook.
   * @param mixed $arg6
   *   Parameter to be passed to the hook.
   * @param string $fnSuffix
   *   Function suffix, this is effectively the hook name.
   *
   * @return mixed
   */
  public function invoke(
    $numParams,
    &$arg1, &$arg2, &$arg3, &$arg4, &$arg5, &$arg6,
    $fnSuffix
  ) {

    /**
     * do_action_ref_array is the default way of calling WordPress hooks
     * because for the most part no return value is wanted. However, this is
     * only generally true, so using do_action_ref_array() is only called for those
     * hooks which do not require a return value. We exclude the following, which
     * are incompatible with the WordPress Plugin API:
     *
     * civicrm_upgrade
     * http://wiki.civicrm.org/confluence/display/CRMDOC43/hook_civicrm_upgrade
     *
     * civicrm_caseSummary
     * http://wiki.civicrm.org/confluence/display/CRMDOC43/hook_civicrm_caseSummary
     *
     * civicrm_dashboard
     * http://wiki.civicrm.org/confluence/display/CRMDOC43/hook_civicrm_dashboard
     */

    // distinguish between types of hook
    if (!in_array($fnSuffix, $this->hooksThatReturn)) {

      // only pass the arguments that have values
      $args = array_slice(
        array(&$arg1, &$arg2, &$arg3, &$arg4, &$arg5, &$arg6),
        0,
        $numParams
      );

      /**
       * Use WordPress Plugins API to modify $args
       *
       * Because $args are passed as references to the WordPress callbacks,
       * runHooks subsequently receives appropriately modified parameters.
       */

      // protect from REST calls
      if (function_exists('do_action_ref_array')) {
        do_action_ref_array($fnSuffix, $args);
      }

    }

    /**
     * The following is based on the logic of the Joomla hook file by allowing
     * WordPress callbacks to do their stuff before runHooks gets called.
     *
     * It also follows the logic of the Drupal hook file by building the "module"
     * (read "plugin") list and then calling runHooks directly. This should avoid
     * the need for the post-processing that the Joomla hook file does.
     *
     * Note that hooks which require a return value are incompatible with the
     * signature of apply_filters_ref_array and must therefore be called in
     * global scope, like in Drupal. It's not ideal, but plugins can always route
     * these calls to methods in their classes.
     *
     * At some point, those hooks could be pre-processed and called via the WordPress
     * Plugin API, but it would change their signature and require the CiviCRM docs
     * to be rewritten for those calls in WordPress. So it's been done this way for
     * now. Ideally these hooks will be deprecated in favour of hooks that do not
     * require return values.
     */

    // build list of registered plugin codes
    $this->buildModuleList();

    // Call runHooks the same way Drupal does
    $moduleResult = $this->runHooks(
      $this->allModules,
      $fnSuffix,
      $numParams,
      $arg1, $arg2, $arg3, $arg4, $arg5, $arg6
    );

    // finally, return
    return empty($moduleResult) ? TRUE : $moduleResult;

  }


  /**
   * Build the list of plugins ("modules" in CiviCRM terminology) to be processed for hooks.
   * We need to do this to preserve the CiviCRM hook signatures for hooks that require
   * a return value, since the WordPress Plugin API seems to be incompatible with them.
   *
   * Copied and adapted from: CRM/Utils/Hook/Drupal6.php
   */
  public function buildModuleList() {
    if ($this->isBuilt === FALSE) {

      if ($this->wordpressModules === NULL) {

        // include custom PHP file - copied from parent->commonBuildModuleList()
        $config = CRM_Core_Config::singleton();
        if (!empty($config->customPHPPathDir) &&
          file_exists("{$config->customPHPPathDir}/civicrmHooks.php")
        ) {
          @include_once 'civicrmHooks.php';
        }

        // initialise with the pre-existing 'wordpress' prefix
        $this->wordpressModules = array('wordpress');

        /**
         * Use WordPress Plugin API to build list
         * a plugin simply needs to declare its "unique_plugin_code" thus:
         * add_filter('civicrm_wp_plugin_codes', 'function_that_returns_my_unique_plugin_code');
         */

        // protect from REST calls
        if (function_exists('apply_filters')) {
          $this->wordpressModules = apply_filters('civicrm_wp_plugin_codes', $this->wordpressModules);
        }

      }

      if ($this->civiModules === NULL) {
        $this->civiModules = array();
        $this->requireCiviModules($this->civiModules);
      }

      $this->allModules = array_merge((array) $this->wordpressModules, (array) $this->civiModules);
      if ($this->wordpressModules !== NULL && $this->civiModules !== NULL) {
        // both CRM and CMS have bootstrapped, so this is the final list
        $this->isBuilt = TRUE;
      }

    }
  }

}