<?php

/**
 * @file
 * Enable loading of Javascript and CSS data with AJAX loads.
 */

/**
 * Implementation of hook_menu().
 */
function ajax_load_init() {
  // Add on every page because we can't know in advance if an AJAX method
  // will be called.
  drupal_add_js(drupal_get_path('module', 'ajax_load') .'/ajax_load.js');
}

/**
 * Implementation of hook_theme_registry_alter().
 */
function ajax_load_theme_registry_alter(&$theme_registry) {
  // Prepend a template preprocess function to page.tpl.php.
  array_unshift($theme_registry['page']['preprocess functions'], '_ajax_load_preprocess_page');
}

/**
 * Template preprocess function for page.tpl.php.
 */
function _ajax_load_preprocess_page(&$variables) {
  $base_path = base_path();
  $resources = ajax_data_get_data();
  $js_settings = array();

  // Build the list of css files on the page when compression is enabled.
  if (variable_get('preprocess_css', FALSE)) {
    $files = array();
    foreach ($resources['css'] as $data) {
      foreach ($data as $paths) {
        foreach (array_keys($paths) as $path) {
          $files[$base_path . $path] = 1;
        }
      }
    }
    if (!empty($files)) {
      $js_settings['css'] = array_keys($files);
    }
  }

  // Build the list of javascript files on the page when compression is enabled.
  if (variable_get('preprocess_js', FALSE)) {
    $files = array();
    foreach ($resources['scripts'] as $type => $paths) {
      if (in_array($type, array('core', 'module', 'theme'))) {
        foreach (array_keys($paths) as $path) {
          $files[$base_path . $path] = 1;
        }
      }
    }
    if (!empty($files)) {
      $js_settings['scripts'] = array_keys($files);
    }
  }

  // Let the client-side know which individual files are present on the page
  // when compression is enabled.
  if (!empty($js_settings)) {
    drupal_add_js(array('AjaxLoad' => $js_settings), 'setting');
  }
}

/**
 * Implementation of hook_ajax_data_alter().
 */
function ajax_load_ajax_data_alter(&$data) {
  $extra = ajax_data_get_data();
  $array = FALSE;
  // Detect whether the data being altered is an array.
  if (is_array($data)) {
    $data = (object) $data;
    $array = TRUE;
  }
  $data->scripts = $extra['scripts'];
  $data->css = $extra['css'];
  if (!isset($data->__callbacks)) {
    $data->__callbacks = array();
  }
  // Set the AjaxLoad custom event as a callback.
  $data->__callbacks[] = 'Drupal.AjaxLoad.loadFiles';
  // Cast back to an array if necessary.
  if ($array) {
    $data = (array) $data;
  }
}

/**
 * Return an array of data representing the scripts and CSS files on a page.
 */
function ajax_data_get_data() {
  $return = array();
  $return['scripts'] = array();
  foreach (array('header', 'footer') as $scope) {
    $javascript = drupal_add_js(NULL, NULL, $scope);
    foreach ($javascript as $type => $data) {
      if (!$data) {
        unset($javascript[$type]);
      }
      elseif ($type == 'setting') {
        $javascript[$type] = call_user_func_array('array_merge_recursive', $data);
      }
    }
    $return['scripts'] = array_merge_recursive($return['scripts'], $javascript);
  }
  $return['css'] = drupal_add_css();

  // Allow the color.module alter the CSS array as if it was processed from
  // a regular page request. See phptemplate_preprocess_page() in garland.
  if (module_exists('color')) {
    init_theme();
    _color_page_alter($return);
  }

  // Deal with jQuery Update module, if exists.
  if (module_exists('jquery_update')) {
    ajax_load_jquery_update_preprocess($return);
  }

  return $return;
}

/**
 * Replace Drupal core's jquery.js with the new one from jQuery Update module.
 *
 * @see jquery_update_preprocess_page()
 */
function ajax_load_jquery_update_preprocess(&$variables) {
  // Only do this for pages that have JavaScript on them.
  if (!empty($variables['scripts'])) {
  
    // Perform the logic if either jQuery Update's jquery.js is newer than
    // core's, or if we're using a different compression type.
    if (variable_get('jquery_update_replace', TRUE) ||
        variable_get('jquery_update_compression_type', 'pack') != 'pack') {

      // Replace jquery.js first.
      $new_jquery = array(jquery_update_jquery_path() => $variables['scripts']['core']['misc/jquery.js']);
      $variables['scripts']['core'] = array_merge($new_jquery, $variables['scripts']['core']);
      unset($variables['scripts']['core']['misc/jquery.js']);

      // Loop through each of the required replacements.
      foreach (jquery_update_get_replacements() as $type => $replacements) {
        foreach ($replacements as $find => $replace) {
          // If the file to replace is loaded on this page...
          if (isset($variables['scripts'][$type][$find])) {
            // Create a new entry for the replacement file, and unset the original one.
            $replace = JQUERY_UPDATE_REPLACE_PATH . '/' . $replace;
            $variables['scripts'][$type][$replace] = $variables['scripts'][$type][$find];
            unset($variables['scripts'][$type][$find]);
          }
        }
      } 
    }
  }
}