<?php
/**
 *
 * @file
 * Saves the collapsed state of a Drupal collapsible fieldset.
 *
 * Besides saving the state of collapsible fieldsets this module improves
 * the usability of Drupal's main module page (admin/modules) by adding
 * expand and collapse all links to top of the page.
 *
 * Notes:
 * - All collapsible fieldsets should be generated using theme('fieldset', array('element' => $element));
 *   but you can also use static HTML. (See README.txt)
 *
 * Fieldset helper state manager:
 *
 * - The 'state manager' stores the state of all collapsible fieldsets in a
 *   cookie.
 *
 * - The state manager dramatically reduces the cookie's size, by converting the
 *   fieldset's element #id and its related path to an auto incremented numeric id.
 *
 * - The state management is controlled by the fieldset_helper_state_manager
 *   PHP functions and the FieldsetHelperStateManager JavaScript object which
 *   isolates the API so that it can copied, renamed, and re-used.
 *
 *
 * Related discussions
 * - @link http://drupal.org/node/114130 Is it possible to get Fieldset Collapsed/Collapsible to remember settings? @endlink
 * - @link http://drupal.org/node/209006 would be nice to save/show fieldset states @endlink
 * - @link http://drupal.org/node/198529 In modules listing: collapse fieldsets @endlink
 * - @link http://drupal.org/node/49103 Give fieldsets an id @endlink
 * - @link http://drupal.org/node/118343 Adding a collapsible fieldset to your nodes @endlink
 * - @link http://drupal.org/node/321779 Use Drupal JS Libraries : Your own collapsible fieldset @endlink
 *
 * Similar modules
 * - @link http://drupal.org/project/autosave Autosave @endlink
 * - @link http://drupal.org/project/util Utility @endlink
 */

module_load_include('inc', 'fieldset_helper', 'fieldset_helper.theme');


////////////////////////////////////////////////////////////////////////////////
// Hooks
////////////////////////////////////////////////////////////////////////////////

/**
 * Implements hook_permission().
 */
function fieldset_helper_permission() {
  return array(
    'save fieldset state' => array(
      'title' => t('Save fieldset state'),
      'description' => t('Allows users to save the state of collapsible fieldsets.'),
    ),
  );
}

/**
 * Implements hook_menu().
 */
function fieldset_helper_menu() {
  $items['admin/config/user-interface/fieldset_helper'] = array(
    'title' => 'Fieldset helper',
    'description' =>  'Settings to save FAPI collapsible fieldset state',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('fieldset_helper_admin_settings'),
    'file' => 'fieldset_helper.admin.inc',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_NORMAL_ITEM,
  );

  $items['admin/config/user-interface/fieldset_helper/view'] = array(
    'title' => 'Settings',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 0,
  );

  $items['admin/config/user-interface/fieldset_helper/test'] = array(
    'title' => 'Test',
    'description' =>  'Test page for saving FAPI collapsible fieldset state',
    'page callback' => 'fieldset_helper_test',
    'file' => 'fieldset_helper.admin.inc',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );

  return $items;
}

/**
 * Implements hook_fieldset_helper_path_alter().
 */
function fieldset_helper_fieldset_helper_path_alter(&$path) {
  // Force all node form (add and edit) fieldsets to share their state.
  if (variable_get('fieldset_helper_node_form_state', 1) == 1) {
    if (preg_match('#^(node/[^/]+/edit|node/add/[^/]+)$#', $path)) {
      $path = 'node/form';
    }
  }
}

////////////////////////////////////////////////////////////////////////////////
// Alter js function.
////////////////////////////////////////////////////////////////////////////////

/**
 * Implements hook_js_alter().
 */
function fieldset_helper_js_alter(&$javascript) {
  static $altered;
  if ($altered !== TRUE && fieldset_helper_number_of_collapsible_fieldset() !== 0) {
    // Immediately set $altered to avoid recursions when using drupal_add_js().
    $altered = TRUE;

    // Make sure to add 'misc/form.js'.
    if (!isset($javascript['misc/form.js'])) {
      drupal_add_js('misc/form.js');
    }

    // Make sure to add 'misc/collapse.js'.
    if (!isset($javascript['misc/collapse.js'])) {
      drupal_add_js('misc/collapse.js');
    }

    // Add 'fieldset_helper.js'.
    $fieldset_helper_js = drupal_get_path('module', 'fieldset_helper') . '/fieldset_helper.js';
    if (!isset($javascript[$fieldset_helper_js])) {
      drupal_add_js($fieldset_helper_js );
    }

    // Add settings. (includes lookups ids and cookie duration)
    $settings['fieldset_helper_state_manager'] = array(
      'ids' => fieldset_helper_state_manager_get_lookup_id(),
      'cookie_duration' => variable_get('fieldset_helper_cookie_duration', 0),
    );
    drupal_add_js($settings, 'setting');
  }
}


////////////////////////////////////////////////////////////////////////////////
// General and utility functions
////////////////////////////////////////////////////////////////////////////////

/**
 * Get default collapsible attribute for the current path.
 */
function fieldset_helper_default_collapsible() {
  static $default_collapsible;
  if (isset($default_collapsible)) {
    return $default_collapsible;
  }

  $pages = variable_get('fieldset_helper_default_collapsible_pages', '*');

  if (empty($pages)) {
    $default_collapsible = FALSE;
  }
  elseif (trim($pages) == '*') {
    $default_collapsible = TRUE;
  }
  else {
    $default_collapsible = drupal_match_path($_GET['q'], $pages);
  }

  return $default_collapsible;
}

/**
 * Get default collapsed state for the current page.
 */
function fieldset_helper_default_collapsed() {
  static $default_collapsed;
  if (isset($default_collapsed)) {
    return $default_collapsed;
  }

  $pages = variable_get('fieldset_helper_default_collapsed_pages', 'admin/modules');

  if (empty($pages)) {
    $default_collapsed = FALSE;
  }
  elseif (trim($pages) == '*') {
    $default_collapsed = TRUE;
  }
  else {
    $default_collapsed = drupal_match_path($_GET['q'], $pages);
  }

  return $default_collapsed;
}

/**
 * Track the number of collapsible fieldsets on the page.
 */
function fieldset_helper_number_of_collapsible_fieldset($count = 0, $reset = FALSE) {
  static $number_of_collapsible_fieldset;
  if (!isset($number_of_collapsible_fieldset) || $reset === TRUE) {
    $number_of_collapsible_fieldset = 0;
  }
  $number_of_collapsible_fieldset += $count;
  return $number_of_collapsible_fieldset;
}


////////////////////////////////////////////////////////////////////////////////
// State manager functions.
////////////////////////////////////////////////////////////////////////////////

/**
 * Check if a path matches any pattern in a set of patterns.
 *
 * @return
 *   The path to save current page's element to.
 */
function fieldset_helper_state_manager_get_path() {
  static $path;

  if (isset($path)) {
    return $path;
  }

  $path = $_GET['q'];

  if ($pages = variable_get('fieldset_helper_global_pages', '')) {
    $pages = preg_split('/\s+/', $pages);
    foreach ($pages as $page) {
      $pattern = '/^' . str_replace('\*', '.*', preg_quote($page, '/') ) . '$/';
      if (preg_match($pattern, $path)) {
        $path = $page;
        break;
      }
    }
  }

  // Run all hook implementations for hook_fieldset_helper_path_alter().
  foreach (module_implements('fieldset_helper_path_alter') as $module) {
    $function = $module . '_fieldset_helper_path_alter';
    $function($path);
  }

  return $path;
}

/**
 * Check if a fieldset id matches any global id patterns.
 *
 * @param $element_id
 *   The DOM element id.
 * @param $path
 *   Default path if no match is found.
 * @return
 *   The elements path (*, $_GET['q'], or custom).
 */
function fieldset_helper_state_manager_get_element_path($element_id, $path) {
  static $global_patterns;

  if (!isset($global_patterns )) {
    $global_ids = variable_get('fieldset_helper_global_ids', '');
    $global_patterns = '/^(' . preg_replace(array('/(\r\n?|\n)/', '/\\\\\*/'), array('|', '.*'), preg_quote($global_ids, '/')) . ')$/';
  }

  $path = preg_match($global_patterns, $element_id) ? '*' : $path;

  // Run all hook implementations for hook_fieldset_helper_element_path_alter().
  foreach (module_implements('fieldset_helper_element_path_alter') as $module) {
    $function = $module . '_fieldset_helper_element_path_alter';
    $function($element_id, $path);
  }

  return $path;
}

/**
 * Get the lookup id for the $element_id in the current path.
 *
 * @param $element_id
 *   The DOM element id.
 * @return
 *   The numeric auto generated look up id for the $element_id. If $element_id
 *   is not set then the entire lookup id table for the current page will returned.
 */
function fieldset_helper_state_manager_get_lookup_id($element_id = NULL) {
  static $lookup_id_table;

  $path = fieldset_helper_state_manager_get_path();

  // Load existing lookup ids for the current path from the database.
  if (!isset($lookup_id_table)) {
    $lookup_id_table = array();
    // Fetch lookup records for the current path. Use sorting to make sure global path (*) are last.
    $result = db_query("SELECT id, element_id FROM {fieldset_helper_state_manager} WHERE path=:path OR path='*' ORDER BY path DESC", array(':path' => $path));
    foreach ($result as $record) {
      $lookup_id_table[ $record->element_id ] = $record->id;
    }
  }

  // Create a new lookup id for element_id's not associated with the lookup id table.
  if ( $element_id != NULL && !isset($lookup_id_table[$element_id]) ) {
    // Get element path.
    $element_path = fieldset_helper_state_manager_get_element_path($element_id, $path);

    // Get id for path and element_id combination.
    $lookup_id = db_insert('fieldset_helper_state_manager')
      ->fields(array(
        'path' => $element_path,
        'element_id' => $element_id,
      ))
      ->execute();
    $lookup_id_table[$element_id] = $lookup_id;
  }

  // Return the look up id for the element id.
  return ($element_id == NULL) ? $lookup_id_table : $lookup_id_table[$element_id];
}

/**
 * Clear all the store lookup id for every form.
 */
function fieldset_helper_state_manager_clear_lookup_ids() {
  drupal_set_message(t('Fieldset lookup ids cleared.'));
  db_delete('fieldset_helper_state_manager')->execute();
}

/**
 * Get an associated array for lookup id and the element's state (1 or 0) from $_COOKIE['fieldset_helper_state_manager'].
 *
 * @param $clear
 *   Optional boolean when set to TRUE will clear any cached cookie states.
 */
function fieldset_helper_state_manager_get_cookie_states($clear = FALSE) {
  static $states;

  if (isset($states) && $clear == FALSE) {
    return $states;
  }

  $states = array();

  if (!isset($_COOKIE['fieldset_helper_state_manager'])) {
    return $states;
  }
  else {
    $values = explode('_', $_COOKIE['fieldset_helper_state_manager']);
    foreach ($values as $value) {
      $params = explode('.', $value);
      $states[ $params[0] ] = ($params[1] == '1') ? TRUE : FALSE ;
    }
    return $states;
  }
}

/**
 * Get fieldset's collapsed state.
 *
 * @param $element_id
 *   The DOM element id.
 * @param $default_value
 *   Boolean for default state value
 */
function fieldset_helper_state_manager_get_state($element_id, $default_value = FALSE) {
  // Always return the default value is state management is disabled for anonymous.
  if (user_is_anonymous() && variable_get('fieldset_helper_disable_state_anonymous', 0) == 1) {
    return $default_value;
  }

  // Get fieldset states and lookup ids
  $states = fieldset_helper_state_manager_get_cookie_states();
  $lookup_id = fieldset_helper_state_manager_get_lookup_id($element_id);

  // Return collapsed boolean value.
  if ( isset($states[$lookup_id])) {
    return ($states[$lookup_id]) ? TRUE : FALSE;
  }
  else {
    return ($default_value) ? TRUE : FALSE;
  }
}