system.module

<?php
// $Id$

/**
 * @file
 * Configuration system that lets administrators modify the workings of the site.
 */

define('VERSION', '5.0-dev');

/**
 * Implementation of hook_help().
 */
function system_help($section) {
  global $base_url;

  switch ($section) {
    case 'admin/help#system':
      $output = '<p>'. t('The system module provides system-wide defaults such as running jobs at a particular time, and storing web pages to improve efficiency. The ability to run scheduled jobs makes administering the web site more usable, as administrators do not have to manually start jobs. The storing of web pages, or caching, allows the site to efficiently re-use web pages and improve web site performance. The settings module provides control over preferences, behaviours including visual and operational settings.') .'</p>';
      $output .= '<p>'. t('Some modules require regularly scheduled actions, such as cleaning up logfiles. Cron, which stands for chronograph, is a periodic command scheduler executing commands at intervals specified in seconds. It can be used to control the execution of daily, weekly and monthly jobs (or anything with a period measured in seconds). The aggregator module periodically updates feeds using cron. Ping periodically notifies services of new content on your site. Search periodically indexes the content on your site. Automating tasks is one of the best ways to keep a system running smoothly, and if most of your administration does not require your direct involvement, cron is an ideal solution. Cron can, if necessary, also be run manually.') .'</p>';
      $output .= '<p>'. t("There is a caching mechanism which stores dynamically generated web pages in a database. By caching a web page, the system module does not have to create the page each time someone wants to view it, instead it takes only one SQL query to display it, reducing response time and the server's load. Only pages requested by <em>anonymous</em> users are cached. In order to reduce server load and save bandwidth, the system module stores and sends cached pages compressed.") .'</p>';
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="@system">System page</a>.', array('@system' => 'http://drupal.org/handbook/modules/system/')) .'</p>';
      return $output;
    case 'admin':
      return '<p>'. t('Welcome to the administration section. Here you may control how your site functions.') .'</p>';
    case 'admin/by-module':
      return '<p>'. t('This page shows you all available administration tasks for each module.') .'</p>';
    case 'admin/build/themes':
      return '<p>'. t('Select which themes are available to your users and specify the default theme. To configure site-wide display settings, click the "configure" task above. Alternately, to override these settings in a specific theme, click the "configure" link for the corresponding theme. Note that different themes may have different regions available for rendering content like blocks. If you want consistency in what your users see, you may wish to enable only one theme.') .'</p>';
    case 'admin/build/themes/settings':
      return '<p>'. t('These options control the default display settings for your entire site, across all themes. Unless they have been overridden by a specific theme, these settings will be used.') .'</p>';
    case 'admin/build/themes/settings/'. arg(3):
      $reference = explode('.', arg(3), 2);
      $theme = array_pop($reference);
      return '<p>'. t('These options control the display settings for the <code>%template</code> theme. When your site is displayed using this theme, these settings will be used. By clicking "Reset to defaults," you can choose to use the <a href="@global">global settings</a> for this theme.', array('%template' => $theme, '@global' => url('admin/build/themes/settings'))) .'</p>';
    case 'admin/build/modules':
      return t('<p>Modules are plugins for Drupal that extend its core functionality. Here you can select which modules are enabled. Click on the name of the module in the navigation menu for their individual configuration pages. Once a module is enabled, new <a href="@permissions">permissions</a> might be made available. Modules can automatically be temporarily disabled to reduce server load when your site becomes extremely busy by enabling the throttle.module and checking throttle. The auto-throttle functionality must be enabled on the <a href="@throttle">throttle configuration page</a> after having enabled the throttle module.</p>
<p>It is important that <a href="@update-php">update.php</a> is run every time a module is updated to a newer version.</p><p>You can find all administration tasks belonging to a particular module on the <a href="@by-module">administration by module page</a>.</p>', array('@permissions' => url('admin/user/access'), '@throttle' => url('admin/settings/throttle'), '@update-php' => $base_url .'/update.php', '@by-module' => url('admin/by-module')));
    case 'admin/build/modules/uninstall':
      return '<p>'. t('The uninstall process removes all data related to a module. To uninstall a module, you must first disable it. Not all modules support this feature.') .'</p>';
    case 'admin/logs/status':
      return '<p>'. t("Here you can find a short overview of your Drupal site's parameters as well as any problems detected with your installation. It is useful to copy/paste this information when you need support.") .'</p>';
  }
}

/**
 * Implementation of hook_perm().
 */
function system_perm() {
  return array('administer site configuration', 'access administration pages', 'select different theme');
}

/**
 * Implementation of hook_elements().
 */
function system_elements() {
  // Top level form
  $type['form'] = array('#method' => 'post', '#action' => request_uri());

  // Inputs
  $type['checkbox'] = array('#input' => TRUE, '#return_value' => 1);
  $type['submit'] = array('#input' => TRUE, '#name' => 'op', '#button_type' => 'submit', '#executes_submit_callback' => TRUE);
  $type['button'] = array('#input' => TRUE, '#name' => 'op', '#button_type' => 'submit', '#executes_submit_callback' => FALSE);
  $type['textfield'] = array('#input' => TRUE, '#size' => 60, '#maxlength' => 128, '#autocomplete_path' => FALSE);
  $type['password'] = array('#input' => TRUE, '#size' => 30);
  $type['password_confirm'] = array('#input' => TRUE, '#process' => array('expand_password_confirm' => array()));
  $type['textarea'] = array('#input' => TRUE, '#cols' => 60, '#rows' => 5);
  $type['radios'] = array('#input' => TRUE, '#process' => array('expand_radios' => array()));
  $type['radio'] = array('#input' => TRUE);
  $type['checkboxes'] = array('#input' => TRUE, '#process' => array('expand_checkboxes' => array()), '#tree' => TRUE);
  $type['select'] = array('#input' => TRUE);
  $type['weight'] = array('#input' => TRUE, '#delta' => 10, '#default_value' => 0, '#process' => array('process_weight' => array()));
  $type['date'] = array('#input' => TRUE, '#process' => array('expand_date' => array()), '#validate' => array('date_validate' => array()));
  $type['file'] = array('#input' => TRUE, '#size' => 60);

  // Form structure
  $type['item'] = array();
  $type['hidden'] = array('#input' => TRUE);
  $type['value'] = array('#input' => TRUE);
  $type['markup'] = array('#prefix' => '', '#suffix' => '');
  $type['fieldset'] = array('#collapsible' => FALSE, '#collapsed' => FALSE);
  $type['token'] = array('#input'=> TRUE);
  return $type;
}

/**
 * Implementation of hook_menu().
 */
function system_menu($may_cache) {
  $items = array();

  if ($may_cache) {
    $items[] = array('path' => 'system/files', 'title' => t('File download'),
      'callback' => 'file_download',
      'access' => TRUE,
      'type' => MENU_CALLBACK);

    $access = user_access('administer site configuration');

    $items[] = array('path' => 'admin', 'title' => t('Administer'),
      'access' => user_access('access administration pages'),
      'callback' => 'system_main_admin_page',
      'weight' => 9);
    $items[] = array('path' => 'admin/compact', 'title' => t('Compact mode'),
      'access' => user_access('access administration pages'),
      'callback' => 'system_admin_compact_page',
      'type' => MENU_CALLBACK);
    $items[] = array('path' => 'admin/by-task', 'title' => t('By task'),
      'callback' => 'system_main_admin_page',
      'type' => MENU_DEFAULT_LOCAL_TASK);
    $items[] = array('path' => 'admin/by-module', 'title' => t('By module'),
      'callback' => 'system_admin_by_module',
      'type' => MENU_LOCAL_TASK,
      'weight' => 2);

    // menu items that are basically just menu blocks
    $items[] = array(
      'path' => 'admin/settings',
      'title' => t('Site configuration'),
      'description' => t('Adjust basic site configuration options.'),
      'position' => 'right',
      'weight' => -5,
      'callback' => 'system_settings_overview',
      'access' => $access);

    $items[] = array('path' => 'admin/build',
      'title' => t('Site building'),
      'description' => t('Control how your site looks and feels.'),
      'position' => 'right',
      'weight' => -10,
      'callback' => 'system_admin_menu_block_page',
      'access' => $access);

    $items[] = array(
      'path' => 'admin/settings/admin',
      'title' => t('Administration theme'),
      'description' => t('Settings for how your administrative pages should look.'),
      'position' => 'left',
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_admin_theme_settings'),
      'block callback' => 'system_admin_theme_settings',
      'access' => $access);

    // Themes:
    $items[] = array(
      'path' => 'admin/build/themes',
      'title' => t('Themes'),
      'description' => t('Change which theme your site uses or allows users to set.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_themes'),
      'access' => $access);

    $items[] = array(
      'path' => 'admin/build/themes/select',
      'title' => t('List'),
      'description' => t('Select the default theme.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_themes'),
      'access' => $access,
      'type' => MENU_DEFAULT_LOCAL_TASK,
      'weight' => -1);

    $items[] = array('path' => 'admin/build/themes/settings',
      'title' => t('Configure'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_theme_settings'),
      'access' => $access,
      'type' => MENU_LOCAL_TASK);

    // Theme configuration subtabs
    $items[] = array('path' => 'admin/build/themes/settings/global', 'title' => t('Global settings'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_theme_settings'),
      'access' => $access,
      'type' => MENU_DEFAULT_LOCAL_TASK,
      'weight' => -1);

    foreach (list_themes() as $theme) {
      if ($theme->status) {
        $items[] = array('path' => 'admin/build/themes/settings/'. $theme->name, 'title' => $theme->name,
        'callback' => 'drupal_get_form', 'callback arguments' => array('system_theme_settings', $theme->name),
        'access' => $access, 'type' => MENU_LOCAL_TASK);
      }
    }

    // Modules:
    $items[] = array('path' => 'admin/build/modules',
      'title' => t('Modules'),
      'description' => t('Enable or disable add-on modules for your site.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_modules'),
      'access' => $access);
    $items[] = array('path' => 'admin/build/modules/list',
      'title' => t('List'),
      'type' => MENU_DEFAULT_LOCAL_TASK,
      'access' => $access);
    $items[] = array('path' => 'admin/build/modules/list/confirm',
      'title' => t('List'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_modules'),
      'type' => MENU_CALLBACK,
      'access' => $access);
    $items[] = array('path' => 'admin/build/modules/uninstall',
      'title' => t('Uninstall'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_modules_uninstall'),
      'type' => MENU_LOCAL_TASK,
      'access' => $access);
    $items[] = array('path' => 'admin/build/modules/uninstall/confirm',
      'title' => t('Uninstall'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_modules_uninstall'),
      'type' => MENU_CALLBACK,
      'access' => $access);

    // Settings:
    $items[] = array(
      'path' => 'admin/settings/site-information',
      'title' => t('Site information'),
      'description' => t('Change basic site information, such as the site name, slogan, e-mail address, mission, front page and more.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_site_information_settings'));
    $items[] = array(
      'path' => 'admin/settings/error-reporting',
      'title' => t('Error reporting'),
      'description' => t('Control how Drupal deals with errors including 403/404 errors as well as PHP error reporting.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_error_reporting_settings'));
    $items[] = array(
      'path' => 'admin/settings/performance',
      'title' => t('Performance'),
      'description' => t('Enable or disable page caching for anonymous users, and enable or disable CSS preprocessor.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_performance_settings'));
    $items[] = array(
      'path' => 'admin/settings/file-system',
      'title' => t('File system'),
      'description' => t('Tell Drupal where to store uploaded files and how they are accessed.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_file_system_settings'));
    $items[] = array(
      'path' => 'admin/settings/image-toolkit',
      'title' => t('Image toolkit'),
      'description' => t('Choose which image toolkit to use if you have installed optional toolkits.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_image_toolkit_settings'));
    $items[] = array(
      'path' => 'admin/content/rss-publishing',
      'title' => t('RSS publishing'),
      'description' => t('Configure the number of items per feed and whether feeds should be titles/teasers/full-text.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_rss_feeds_settings'));
    $items[] = array(
      'path' => 'admin/settings/date-time',
      'title' => t('Date and time'),
      'description' => t("Settings for how Drupal displays date and time, as well as the system's default timezone."),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_date_time_settings'));
    $items[] = array(
      'path' => 'admin/settings/site-maintenance',
      'title' => t('Site maintenance'),
      'description' => t('Take the site off-line for maintenance or bring it back online.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_site_maintenance_settings'));
    $items[] = array(
      'path' => 'admin/settings/clean-urls',
      'title' => t('Clean URLs'),
      'description' => t('Enable or disable clean URLs for your site.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('system_clean_url_settings'));


    // Logs:
    $items[] = array(
      'path' => 'admin/logs',
      'title' => t('Logs'),
      'description' => t('View system logs and other status information.'),
      'callback' => 'system_admin_menu_block_page',
      'weight' => 5,
      'position' => 'left');
    $items[] = array(
      'path' => 'admin/logs/status',
      'title' => t('Status report'),
      'description' => t("Get a status report about your site's operation and any detected problems."),
      'callback' => 'system_status',
      'weight' => 10,
      'access' => $access);
    $items[] = array(
      'path' => 'admin/logs/status/run-cron',
      'title' => t('Run cron'),
      'callback' => 'system_run_cron',
      'type' => MENU_CALLBACK);
    $items[] = array(
      'path' => 'admin/logs/status/php',
      'title' => t('PHP'),
      'callback' => 'system_php',
      'type' => MENU_CALLBACK);
    $items[] = array(
      'path' => 'admin/logs/status/sql',
      'title' => t('SQL'),
      'callback' => 'system_sql',
      'type' => MENU_CALLBACK);
  }
  else {
    /**
     * Use the administrative theme if the user is looking at a page in the admin/* path.
     */
    if (arg(0) == 'admin') {
      global $custom_theme;
      $custom_theme = variable_get('admin_theme', '0');
      drupal_add_css(drupal_get_path('module', 'system') .'/admin.css', 'module');
    }

    // Add the CSS for this module. We put this in !$may_cache so it is only
    // added once per request.
    drupal_add_css(drupal_get_path('module', 'system') .'/defaults.css', 'module');
    drupal_add_css(drupal_get_path('module', 'system') .'/system.css', 'module');
  }

  return $items;
}

/**
 * Implementation of hook_user().
 *
 * Allows users to individually set their theme and time zone.
 */
function system_user($type, $edit, &$user, $category = NULL) {
  if ($type == 'form' && $category == 'account') {
    $form['theme_select'] = system_theme_select_form(t('Selecting a different theme will change the look and feel of the site.'), $edit['theme'], 2);

    if (variable_get('configurable_timezones', 1)) {
      $zones = _system_zonelist();
      $form['timezone'] = array('#type'=>'fieldset', '#title' => t('Locale settings'), '#weight' => 6);
      $form['timezone']['timezone'] = array(
        '#type' => 'select', '#title' => t('Time zone'), '#default_value' => strlen($edit['timezone']) ? $edit['timezone'] : variable_get('date_default_timezone', 0),
        '#options' => $zones, '#description' => t('Select your current local time. Dates and times throughout this site will be displayed using this time zone.')
      );
    }

    return $form;
  }
}

/**
 * Provide the administration overview page.
 */
function system_main_admin_page($arg = NULL) {
  // If we received an argument, they probably meant some other page.
  // Let's 404 them since the menu system cannot be told we do not
  // accept arguments.
  if (isset($arg) && substr($arg, 0, 3) != 'by-') {
    return drupal_not_found();
  }

  // Check for status report errors.
  if (system_status(TRUE)) {
    drupal_set_message(t('One or more problems were detected with your Drupal installation. Check the <a href="@status">status report</a> for more information.', array('@status' => url('admin/logs/status'))), 'error');
  }


  $menu = menu_get_item(NULL, 'admin');
  usort($menu['children'], '_menu_sort');
  foreach ($menu['children'] as $mid) {
    $block = menu_get_item($mid);
    if ($block['block callback'] && function_exists($block['block callback'])) {
      $arguments = isset($block['block arguments']) ? $block['block arguments'] : array();
      $block['content'] .= call_user_func_array($block['block callback'], $arguments);
    }
    $block['content'] .= theme('admin_block_content', system_admin_menu_block($block));
    $blocks[] = $block;
  }

  return theme('admin_page', $blocks);
}

/**
 * Provide a single block on the administration overview page.
 */
function system_admin_menu_block($block) {
  $content = array();
  if (is_array($block['children'])) {
    usort($block['children'], '_menu_sort');
    foreach ($block['children'] as $mid) {
      $item = menu_get_item($mid);
      if (($item['type'] & MENU_VISIBLE_IN_TREE) && _menu_item_is_accessible($mid)) {
        $content[] = $item;
      }
    }
  }
  return $content;
}

/**
 * Provide a single block from the administration menu as a page.
 * This function is often a destination for these blocks.
 * For example, 'admin/content/types' needs to have a destination to be valid
 * in the Drupal menu system, but too much information there might be
 * hidden, so we supply the contents of the block.
 */
function system_admin_menu_block_page() {
  $menu = menu_get_item(NULL, $_GET['q']);
  $content = system_admin_menu_block($menu);

  $output = theme('admin_block_content', $content);
  return $output;
}

function system_admin_compact_page($mode = 'off') {
  global $user;
  user_save($user, array('admin_compact_mode' => ($mode == 'on')));
  drupal_goto('admin');
}

/**
 * This function allows selection of the theme to show in administration sections.
 */
function system_admin_theme_settings() {
  $themes = system_theme_data();
  ksort($themes);
  $options[0] = t('System default');
  foreach ($themes as $theme) {
    $options[$theme->name] = $theme->name;
  }

  $form['admin_theme'] = array(
    '#type' => 'select',
    '#options' => $options,
    '#title' => t('Administration theme'),
    '#description' => t('Choose which theme the administration pages should display in. If you choose "System default" the administration pages will use the same theme as the rest of the site.'),
    '#default_value' => variable_get('admin_theme', '0'),
  );

  // In order to give it our own submit, we have to give it the default submit
  // too because the presence of a #submit will prevent the default #submit
  // from being used. Also we want ours first.
  $form['#submit']['system_admin_theme_submit'] = array();
  $form['#submit']['system_settings_form_submit'] = array();
  return system_settings_form($form);
}


function system_admin_theme_submit($form_id, $form_values) {
  // If we're changing themes, make sure the theme has its blocks initialized.
  if ($form_values['admin_theme'] != variable_get('admin_theme', '0')) {
    $result = db_query("SELECT status FROM {blocks} WHERE theme = '%s'", $form_values['admin_theme']);
    if (!db_num_rows($result)) {
      system_initialize_theme_blocks($form_values['admin_theme']);
    }
  }
}

/*
 * Returns a fieldset containing the theme select form.
 *
 * @param $description
 *    description of the fieldset
 * @param $default_value
 *    default value of theme radios
 * @param $weight
 *    weight of the fieldset
 * @return
 *    a form array
 */
function system_theme_select_form($description = '', $default_value = '', $weight = 0) {
  if (user_access('select different theme')) {
    foreach (list_themes() as $theme) {
      if ($theme->status) {
        $enabled[] = $theme;
      }
    }

    if (count($enabled) > 1) {
      ksort($enabled);

      $form['themes'] = array(
        '#type' => 'fieldset',
        '#title' => t('Theme configuration'),
        '#description' => $description,
        '#collapsible' => TRUE,
        '#theme' => 'system_theme_select_form'
      );

      foreach ($enabled as $info) {
        // For the default theme, revert to an empty string so the user's theme updates when the site theme is changed.
        $info->key = $info->name == variable_get('theme_default', 'garland') ? '' : $info->name;

        $info->screenshot = dirname($info->filename) . '/screenshot.png';
        $screenshot = file_exists($info->screenshot) ? theme('image', $info->screenshot, t('Screenshot for %theme theme', array('%theme' => $info->name)), '', array('class' => 'screenshot'), FALSE) : t('no screenshot');

        $form['themes'][$info->key]['screenshot'] = array('#value' => $screenshot);
        $form['themes'][$info->key]['description'] = array('#type' => 'item', '#title' => $info->name,  '#value' => dirname($info->filename) . ($info->name == variable_get('theme_default', 'garland') ? '<br /> <em>'. t('(site default theme)') .'</em>' : ''));
        $options[$info->key] = '';
      }

      $form['themes']['theme'] = array('#type' => 'radios', '#options' => $options, '#default_value' => $default_value ? $default_value : '');
      $form['#weight'] = $weight;
      return $form;
    }
  }
}

function theme_system_theme_select_form($form) {
  foreach (element_children($form) as $key) {
    $row = array();
    if (is_array($form[$key]['description'])) {
      $row[] = drupal_render($form[$key]['screenshot']);
      $row[] = drupal_render($form[$key]['description']);
      $row[] = drupal_render($form['theme'][$key]);
    }
    $rows[] = $row;
  }

  $header = array(t('Screenshot'), t('Name'), t('Selected'));
  $output = theme('table', $header, $rows);
  return $output;
}

function _system_zonelist() {
  $timestamp = time();
  $zonelist = array(-11, -10, -9.5, -9, -8, -7, -6, -5, -4, -3.5, -3, -2, -1, 0, 1, 2, 3, 3.5, 4, 5, 5.5, 5.75, 6, 6.5, 7, 8, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.75, 13, 14);
  $zones = array();
  foreach ($zonelist as $offset) {
    $zone = $offset * 3600;
    $zones[$zone] = format_date($timestamp, 'custom', variable_get('date_format_long', 'l, F j, Y - H:i') . ' O', $zone);
  }
  return $zones;
}

function system_site_information_settings() {
  $form['site_name'] = array(
    '#type' => 'textfield',
    '#title' => t('Name'),
    '#default_value' => variable_get('site_name', 'Drupal'),
    '#description' => t('The name of this web site.'),
    '#required' => TRUE
  );
  $form['site_mail'] = array(
    '#type' => 'textfield',
    '#title' => t('E-mail address'),
    '#default_value' => variable_get('site_mail', ini_get('sendmail_from')),
    '#description' => t('A valid e-mail address for this website, used by the auto-mailer during registration, new password requests, notifications, etc.')
  );
  $form['site_slogan'] = array(
    '#type' => 'textfield',
    '#title' => t('Slogan'),
    '#default_value' => variable_get('site_slogan', ''),
    '#description' => t('The slogan of this website. Some themes display a slogan when available.')
  );

  $form['site_mission'] = array(
    '#type' => 'textarea',
    '#title' => t('Mission'),
    '#default_value' => variable_get('site_mission', ''),
    '#description' => t('Your site\'s mission statement or focus.')
  );
  $form['site_footer'] = array(
    '#type' => 'textarea',
    '#title' => t('Footer message'),
    '#default_value' => variable_get('site_footer', ''),
    '#description' => t('This text will be displayed at the bottom of each page. Useful for adding a copyright notice to your pages.')
  );
  $form['anonymous'] = array(
    '#type' => 'textfield',
    '#title' => t('Anonymous user'),
    '#default_value' => variable_get('anonymous', t('Anonymous')),
    '#description' => t('The name used to indicate anonymous users.')
  );
  $form['site_frontpage'] = array(
    '#type' => 'textfield',
    '#title' => t('Default front page'),
    '#default_value' => variable_get('site_frontpage', 'node'),
    '#size' => 40,
    '#description' => t('The home page displays content from this relative URL. If unsure, specify "node".'),
    '#field_prefix' => url(NULL, NULL, NULL, TRUE) . (variable_get('clean_url', 0) ? '' : '?q=')
  );

  return system_settings_form($form);
}

function system_clean_url_settings() {
  // We check for clean URL support using an image on the client side.
  $form['clean_url'] = array(
    '#type' => 'radios',
    '#title' => t('Clean URLs'),
    '#default_value' => variable_get('clean_url', 0),
    '#options' => array(t('Disabled'), t('Enabled')),
    '#description' => t('This option makes Drupal emit "clean" URLs (i.e. without <code>?q=</code> in the URL.)'),
  );

  if (!variable_get('clean_url', 0)) {
    if (strpos(request_uri(), '?q=') !== FALSE) {
      $form['clean_url']['#description'] .= t(' Before enabling clean URLs, you must perform a test to determine if your server is properly configured. If you are able to see this page again after clicking the "Run the clean URL test" link, the test has succeeded and the radio buttons above will be available. If instead you are directed to a "Page not found" error, you will need to change the configuration of your server. The <a href="@handbook">handbook page on Clean URLs</a> has additional troubleshooting information. !run-test', array('@handbook' => 'http://drupal.org/node/15365', '!run-test' => '<a href ="'. base_path() . 'admin/settings/clean-urls">'. t('Run the clean URL test') .'</a>'));
      $form['clean_url']['#disabled'] = TRUE;
    }
    else {
      $form['clean_url']['#description'] .= t(' You have successfully demonstrated that clean URLs work on your server. You may enable/disable them as you wish.');
      $form['#collapsed'] = FALSE;
    }
  }

  return system_settings_form($form);
}

function system_error_reporting_settings() {

  $form['site_403'] = array(
    '#type' => 'textfield',
    '#title' => t('Default 403 (access denied) page'),
    '#default_value' => variable_get('site_403', ''),
    '#size' => 40,
    '#description' => t('This page is displayed when the requested document is denied to the current user. If unsure, specify nothing.'),
    '#field_prefix' => url(NULL, NULL, NULL, TRUE) . (variable_get('clean_url', 0) ? '' : '?q=')
  );

  $form['site_404'] = array(
    '#type' => 'textfield',
    '#title' => t('Default 404 (not found) page'),
    '#default_value' =>  variable_get('site_404', ''),
    '#size' => 40,
    '#description' => t('This page is displayed when no other content matches the requested document. If unsure, specify nothing.'),
    '#field_prefix' => url(NULL, NULL, NULL, TRUE) . (variable_get('clean_url', 0) ? '' : '?q=')
  );

  $form['error_level'] = array(
    '#type' => 'select', '#title' => t('Error reporting'), '#default_value' => variable_get('error_level', 1),
    '#options' => array(t('Write errors to the log'), t('Write errors to the log and to the screen')),
    '#description' =>  t('Where Drupal, PHP and SQL errors are logged. On a production server it is recommended that errors are only written to the error log. On a test server it can be helpful to write logs to the screen.')
  );

  $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200), 'format_interval');
  $period['1000000000'] = t('Never');
  $form['watchdog_clear'] = array(
    '#type' => 'select',
    '#title' => t('Discard log entries older than'),
    '#default_value' => variable_get('watchdog_clear', 604800),
    '#options' => $period,
    '#description' => t('The time log entries should be kept. Older entries will be automatically discarded. Requires crontab.')
  );

  return system_settings_form($form);
}

function system_performance_settings() {

  $description = '<p>'. t("The normal cache mode is suitable for most sites and does not cause any side effects. The aggressive cache mode causes Drupal to skip the loading (init) and unloading (exit) of enabled modules when serving a cached page. This results in an additional performance boost but can cause unwanted side effects.") .'</p>';

  $problem_modules = array_unique(array_merge(module_implements('init'), module_implements('exit')));
  sort($problem_modules);

  if (count($problem_modules) > 0) {
    $description .= '<p>'. t('<strong class="error">The following enabled modules are incompatible with aggressive mode caching and will not function properly: %modules</strong>', array('%modules' => implode(', ', $problem_modules))) .'.</p>';
  }
  else {
    $description .= '<p>'. t('<strong class="ok">Currently, all enabled modules are compatible with the aggressive caching policy.</strong> Please note, if you use aggressive caching and enable new modules, you will need to check this page again to ensure compatibility.') .'</p>';
  }
  $form['page_cache'] = array(
    '#type' => 'fieldset',
    '#title' => t('Page cache'),
    '#description' => t('Enabling the cache will offer a significant performance boost. Drupal can store and send compressed cached pages requested by <em>anonymous</em> users. By caching a web page, Drupal does not have to construct the page each time someone wants to view it.'),
  );

  $form['page_cache']['cache'] = array(
    '#type' => 'radios',
    '#title' => t('Caching mode'),
    '#default_value' => variable_get('cache', CACHE_DISABLED),
    '#options' => array(CACHE_DISABLED => t('Disabled'), CACHE_NORMAL => t('Normal (recommended, no side effects)'), CACHE_AGGRESSIVE => t('Aggressive (experts only, possible side effects)')),
    '#description' => $description
  );

  $period = drupal_map_assoc(array(0, 60, 180, 300, 600, 900, 1800, 2700, 3600, 10800, 21600, 32400, 43200, 86400), 'format_interval');
  $period[0] = t('none');
  $form['page_cache']['cache_lifetime'] = array(
    '#type' => 'select',
    '#title' => t('Minimum cache lifetime'),
    '#default_value' => variable_get('cache_lifetime', 0),
    '#options' => $period,
    '#description' => t('On high-traffic sites it can become necessary to enforce a minimum cache lifetime. The minimum cache lifetime is the minimum amount of time that will go by before the cache is emptied and recreated. A larger minimum cache lifetime offers better performance, but users will not see new content for a longer period of time.')
  );

  $form['bandwidth_optimizations'] = array(
    '#type' => 'fieldset',
    '#title' => t('Bandwidth optimizations'),
    '#description' => t('These options can help reduce both the size and number of requests made to your website. This can reduce the server load, the bandwidth used, and the average page loading time for your visitors.')
  );

  $directory = file_directory_path();
  $is_writable = is_dir($directory) && is_writable($directory) && (variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC) == FILE_DOWNLOADS_PUBLIC);
  $form['bandwidth_optimizations']['preprocess_css'] = array(
    '#type' => 'radios',
    '#title' => t('Aggregate and compress CSS files'),
    '#default_value' => variable_get('preprocess_css', FALSE) && $is_writable,
    '#disabled' => !$is_writable,
    '#options' => array(t('Disabled'), t('Enabled')),
    '#description' => t("Some Drupal modules include their own CSS files. When these modules are enabled, each module's CSS file adds an additional HTTP request to the page, which can increase the load time of each page. These HTTP requests can also slightly increase server load. It is recommended to only turn this option on when your site is in production, as it can interfere with theme development. This option is disabled if you have not set up your files directory, or if your download method is set to private."),
  );

  $form['#submit']['system_settings_form_submit'] = array();
  $form['#submit']['drupal_clear_css_cache'] = array();

  return system_settings_form($form);
}

function system_file_system_settings() {

  $form['file_directory_path'] = array(
    '#type' => 'textfield',
    '#title' => t('File system path'),
    '#default_value' => file_directory_path(),
    '#maxlength' => 255,
    '#description' => t('A file system path where the files will be stored. This directory has to exist and be writable by Drupal. If the download method is set to public this directory has to be relative to the Drupal installation directory, and be accessible over the web. When download method is set to private this directory should not be accessible over the web. Changing this location after the site has been in use will cause problems so only change this setting on an existing site if you know what you are doing.'),
    '#after_build' => array('system_check_directory'),
  );

  $form['file_directory_temp'] = array(
    '#type' => 'textfield',
    '#title' => t('Temporary directory'),
    '#default_value' => file_directory_temp(),
    '#maxlength' => 255,
    '#description' => t('Location where uploaded files will be kept during previews. Relative paths will be resolved relative to the Drupal installation directory.'),
    '#after_build' => array('system_check_directory'),
  );

  $form['file_downloads'] = array(
    '#type' => 'radios',
    '#title' => t('Download method'),
    '#default_value' => variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC),
    '#options' => array(FILE_DOWNLOADS_PUBLIC => t('Public - files are available using HTTP directly.'), FILE_DOWNLOADS_PRIVATE => t('Private - files are transferred by Drupal.')),
    '#description' => t('If you want any sort of access control on the downloading of files, this needs to be set to <em>private</em>. You can change this at any time, however all download URLs will change and there may be unexpected problems so it is not recommended.')
  );

  return system_settings_form($form);
}

function system_image_toolkit_settings() {
  $toolkits_available = image_get_available_toolkits();
  if (count($toolkits_available) > 1) {
    $form['image_toolkit'] = array(
      '#type' => 'radios',
      '#title' => t('Select an image processing toolkit'),
      '#default_value' => variable_get('image_toolkit', image_get_toolkit()),
      '#options' => $toolkits_available
    );

    return system_settings_form($form);
  }
  else {
    $form['error'] = array('#value' => '<p>'. t("No image toolkits found.  Drupal will use PHP's built-in GD library for image handling.") .'</p>');
    return $form;
  }
}

function system_rss_feeds_settings() {

  $form['feed_default_items'] = array(
    '#type' => 'select',
    '#title' => t('Number of items per feed'),
    '#default_value' => variable_get('feed_default_items', 10),
    '#options' => drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30)),
    '#description' => t('The default number of items to include in a feed.')
  );
  $form['feed_item_length'] = array(
    '#type' => 'select',
    '#title' => t('Display of XML feed items'),
    '#default_value' => variable_get('feed_item_length','teaser'),
    '#options' => array('title' => t('Titles only'), 'teaser' => t('Titles plus teaser'), 'fulltext' => t('Full text')),
    '#description' => t('Global setting for the length of XML feed items that are output by default.')
  );

  return system_settings_form($form);
}

function system_date_time_settings() {
  // Date settings:
  $zones = _system_zonelist();

  // Date settings: possible date formats
  $dateshort = array('Y-m-d H:i', 'm/d/Y - H:i', 'd/m/Y - H:i', 'Y/m/d - H:i',
           'd.m.Y - H:i', 'm/d/Y - g:ia', 'd/m/Y - g:ia', 'Y/m/d - g:ia',
           'M j Y - H:i', 'j M Y - H:i', 'Y M j - H:i',
           'M j Y - g:ia', 'j M Y - g:ia', 'Y M j - g:ia');
  $datemedium = array('D, Y-m-d H:i', 'D, m/d/Y - H:i', 'D, d/m/Y - H:i',
          'D, Y/m/d - H:i', 'F j, Y - H:i', 'j F, Y - H:i', 'Y, F j - H:i',
          'D, m/d/Y - g:ia', 'D, d/m/Y - g:ia', 'D, Y/m/d - g:ia',
          'F j, Y - g:ia', 'j F Y - g:ia', 'Y, F j - g:ia', 'j. F Y - G:i');
  $datelong = array('l, F j, Y - H:i', 'l, j F, Y - H:i', 'l, Y,  F j - H:i',
        'l, F j, Y - g:ia', 'l, j F Y - g:ia', 'l, Y,  F j - g:ia', 'l, j. F Y - G:i');

  // Date settings: construct choices for user
  foreach ($dateshort as $f) {
    $dateshortchoices[$f] = format_date(time(), 'custom', $f);
  }
  foreach ($datemedium as $f) {
    $datemediumchoices[$f] = format_date(time(), 'custom', $f);
  }
  foreach ($datelong as $f) {
    $datelongchoices[$f] = format_date(time(), 'custom', $f);
  }

  $form['date_default_timezone'] = array(
    '#type' => 'select',
    '#title' => t('Default time zone'),
    '#default_value' => variable_get('date_default_timezone', 0),
    '#options' => $zones,
    '#description' => t('Select the default site time zone.')
  );

  $form['configurable_timezones'] = array(
    '#type' => 'radios',
    '#title' => t('Configurable time zones'),
    '#default_value' => variable_get('configurable_timezones', 1),
    '#options' => array(t('Disabled'), t('Enabled')),
    '#description' => t('Enable or disable user-configurable time zones. When enabled, users can set their own time zone and dates will be updated accordingly.')
  );

  $form['date_format_short'] = array(
    '#type' => 'select',
    '#title' => t('Short date format'),
    '#default_value' => variable_get('date_format_short', $dateshort[1]),
    '#options' => $dateshortchoices,
    '#description' => t('The short format of date display.')
  );

  $form['date_format_medium'] = array(
    '#type' => 'select',
    '#title' => t('Medium date format'),
    '#default_value' => variable_get('date_format_medium', $datemedium[1]),
    '#options' => $datemediumchoices,
    '#description' => t('The medium sized date display.')
  );

  $form['date_format_long'] = array(
    '#type' => 'select',
    '#title' => t('Long date format'),
    '#default_value' => variable_get('date_format_long', $datelong[0]),
    '#options' => $datelongchoices,
    '#description' => t('Longer date format used for detailed display.')
  );

  $form['date_first_day'] = array(
    '#type' => 'select',
    '#title' => t('First day of week'),
    '#default_value' => variable_get('date_first_day', 0),
    '#options' => array(0 => t('Sunday'), 1 => t('Monday'), 2 => t('Tuesday'), 3 => t('Wednesday'), 4 => t('Thursday'), 5 => t('Friday'), 6 => t('Saturday')),
    '#description' => t('The first day of the week for calendar views.')
  );

  return system_settings_form($form);
}

function system_site_maintenance_settings() {

  $form['site_offline'] = array(
    '#type' => 'radios',
    '#title' => t('Site status'),
    '#default_value' => variable_get('site_offline', 0),
    '#options' => array(t('Online'), t('Off-line')),
    '#description' => t('When set to "Online", all visitors will be able to browse your site normally. When set to "Off-line", only users with the "administer site configuration" permission will be able to access your site to perform maintenance; all other visitors will see the site off-line message configured below. Authorized users can log in during "Off-line" mode directly via the <a href="@user-login">user login</a> page.', array('@user-login' => url('user'))),
  );

  $form['site_offline_message'] = array(
    '#type' => 'textarea',
    '#title' => t('Site off-line message'),
    '#default_value' => variable_get('site_offline_message', t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => variable_get('site_name', 'Drupal')))),
    '#description' => t('Message to show visitors when the site is in off-line mode.')
  );