<?php
/**
 * @file
 *
 * Define rules to redirect the user to a different domain.
 * The common use-case is to setup sub-domains for mobile sites.
 * In this case you can configure ThemeKey Redirect to detect mobile clients and
 * redirect the user accordingly. In ThemeKey itself you have to configure rules
 * to select a mobile theme depending on the sub-domain.
 *
 * Cookie states:
 *  - 0: No redirect happened, keep on evaluating redirect rule chain on further
 *       requests. Note: if cookie is not set the state is 0 as well.
 *  - 1: Redirect happened. Optionally provide the user the choice to switch back.
 *  - 2: Redirect completed and no further redirects will happen until the
 *       browser gets closed.
 *
 * Initial State, user visits Domain A:
 *  Domain A 0, Domain B 0
 *
 * User gets redirected to Domain B and is allowed to switch back manually:
 *  Domain A 0, Domain B 1 (set via php before page delivery)
 *  Domain A 0, Domain B 2 (set via javascript after page delivery and a switch back link has been shown)
 *
 * If user clicks switch back link:
 *  Domain A 2 (set via php before page delivery), Domain B 2
 *
 *
 * Initial State, user visits Domain A:
 *  Domain A 0, Domain B 0
 *
 * User gets redirected to Domain B and is not allowed to switch back manually:
 *  Domain A 0, Domain B 1 (set via php before page delivery)
 *  Domain A 0, Domain B 2 (set via javascript after page delivery)
 *
 *
 * Initial State, user visits Domain A:
 *  Domain A 0, Domain B 0
 *
 * User gets redirected to Domain B and "Don't evaluate the rule chain again if the user comes back after a redirect." is turned on:
 *  Domain A 2 (set via php before page delivery), Domain B 1 (set via php before page delivery)
 *  Domain A 2, Domain B 2 (set via javascript after page delivery)
 */

/**
 * Implements hook_menu().
 */
function themekey_redirect_menu() {
  $items = array();

  $items['admin/config/user-interface/themekey/redirects'] = array(
    'title' => 'Redirecting Rule Chain',
    'description' => 'Set up rules to redirect the user, depending on Drupal paths or different properties.',
    'access callback' => 'user_access',
    'access arguments' => array('administer theme assignments'),
    'file' => 'themekey_redirect_admin.inc',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('themekey_redirect_rule_chain_form'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
  $items['admin/config/user-interface/themekey/redirects/delete'] = array(
    'title' => 'Delete ThemeKey Redirect Rule',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('themekey_redirect_admin_delete_rule_confirm', 1),
    'access callback' => 'user_access',
    'access arguments' => array('administer theme assignments'),
    'file' => 'themekey_redirect_admin.inc',
    'type' => MENU_CALLBACK,
  );
  $items['admin/config/user-interface/themekey/settings/redirects'] = array(
    'title' => 'Redirect',
    'access callback' => 'user_access',
    'access arguments' => array('administer themekey settings'),
    'file' => 'themekey_redirect_admin.inc',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('themekey_redirect_settings_form'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 9,
  );
  $items['themekey/redirect_callback'] = array(
    'title' => 'ThemeKey Redirect Callback',
    'page callback' => 'themekey_redirect_callback',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
    'delivery callback' => 'drupal_json_output',
  );

  return $items;
}

/**
 * Implements hook_theme().
 */
function themekey_redirect_theme() {
  $items = array(
    'themekey_redirect_rule_chain_form' => array(
      'file' => 'themekey_redirect_admin.inc',
      'render element' => 'form',
    ),
    'themekey_redirect_domain_selector_links' => array(
      'template' => 'themekey_redirect_domain_selector_links',
      'variables' => array(
        'links' => array(),
      ),
    ),
  );
  return $items;
}

/**
 * Implements hook_themekey_disabled_paths().
 */
function themekey_redirect_themekey_disabled_paths() {
  return array('themekey/redirect_callback');
}

function themekey_redirect_format_rule_as_string($themekey_property_id) {
  module_load_include('inc', 'themekey', 'themekey_build');
  return themekey_abstract_format_rule_as_string($themekey_property_id, array(
    'rule' => themekey_redirect_rule_get($themekey_property_id),
  ));
}

/**
 * Loads ThemeKey rule from database.
 *
 * @param $id
 *   id of the rule to be loaded from database
 *
 * @return
 *   the rule as associative array or NULL
 */
function themekey_redirect_rule_get($id) {
  return themekey_abstract_rule_get('themekey_redirect_rules', $id);
}

/**
 * Implements hook_init().
 */
function themekey_redirect_init() {
  if (themekey_is_active()) { // Not active if ThemeKey Redirect ajax callback is requested.
    // Ensure to have javascript based switching for anonymous users in page cache.
    themekey_redirect_add_js();

    if (isset($_GET['themekey_redirect'])) {
      // Don't cache the page if query param 'themekey_redirect' is set.
      drupal_page_is_cacheable(FALSE);

      switch ($_GET['themekey_redirect']) {
        case 'active':
          // User has been redirected.
          setcookie('themekey_redirect_state', 1, 0, '/');
          break;
        case 'avoid':
          //User manually selected a domain. No further redirects.
          setcookie('themekey_redirect_state', 2, 0, '/');
          break;
      }
    }
  }
}

function themekey_redirect_add_js() {
  drupal_add_library('system', 'jquery.cookie');
  drupal_add_js(array('ThemeKeyRedirect' => array(
    'checkOnce' => variable_get('themekey_redirect_check_once', FALSE),
    'redirectOnce' => variable_get('themekey_redirect_redirect_once', FALSE),
  )), 'setting');
  drupal_add_js(drupal_get_path('module', 'themekey_redirect') . '/themekey_redirect.js');
}

function themekey_redirect_match_rules() {
  require_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'themekey') . '/themekey_base.inc';
  $parameters = themekey_get_global_parameters();
  $result = themekey_match_rule_childs($parameters, array(
    'table' => 'themekey_redirect_rules',
    'format_rule_as_string_callback' => 'themekey_redirect_format_rule_as_string',
    'check_enabled_callback' => 'themekey_redirect_check_different_url',
    'stop_on_check_enabled_false' => TRUE,
  ));

  if (is_array($result) && 'default' != $result['theme']) {
    drupal_alter('themekey_redirect', $result['theme'], $result['rules_matched']);

    $last_rule = array_pop($result['rules_matched']);
    $query_string = themekey_query_string();

    return url(
      $result['theme'] .
        (
          $last_rule->append_path ?
            (
              variable_get('themekey_redirect_compatible_path', FALSE) ? '/index.php?q=' . $_GET['q'] .
                (
                  $query_string ? '&' . $query_string : ''
                ) : request_uri()
            ) : ''
        ),
      array('query' => array('themekey_redirect' => 'active')) // If we redirect to a non-drupal site, the query should not break anything.
    );
  }

  return FALSE;
}

function themekey_redirect_callback() {
  // Don't cache this JSON response.
  drupal_page_is_cacheable(FALSE);
  // Clean-up the URI path for rule matching and response by overriding
  // $_GET['q'] and $_SERVER['REQUEST_URI'].
  $_GET['q'] = implode('/', func_get_args());
  // If the path is empty, we're at the front page.
  if (empty($_GET['q'])) {
    $_GET['q'] = variable_get('site_frontpage', 'node');
  }

  // Coder module complains "the use of REQUEST_URI is prone to XSS exploits and
  // does not work on IIS; use request_uri() instead [security_12]". But we have
  // to override (or set) the REQUEST_URI here which is not an security issue.
  // The rule in coder module is about reading $_SERVER['REQUEST_URI'] and not
  // about setting it.
  // @ignore security_12
  $_SERVER['REQUEST_URI'] = str_replace('themekey/redirect_callback/', '', request_uri());
  return themekey_redirect_match_rules();
}

/**
 * Implements hook_help().
 */
function themekey_redirect_help($path, $arg) {
  switch ($path) {
    case 'admin/config/user-interface/themekey/redirects':
      if (!function_exists('themekey_help_properties_form')) {
        module_load_include('inc', 'themekey', 'themekey_help');
      }
      $properties_form = drupal_get_form('themekey_help_properties_form', TRUE);
      $operators_form = drupal_get_form('themekey_help_operators_form', TRUE);
      $text_1 = t('For every page request, Drupal steps through this Redirecting Rule Chain until an activated rule matches or it reaches the end. If a rule matches, the redirect associated with this rule will be performed.');

      return '<p>' . $text_1 . '</p> ' .
        drupal_render($properties_form) .
        drupal_render($operators_form);
  }
}

/**
 * Avoid a redirect loop by not redirecting to current domain.
 *
 * @param $url
 * @return bool
 */
function themekey_redirect_check_different_url($url) {
  $parts = parse_url($url);
  $host = $parts['host'];
  if (isset($parts['port']) && ($parts['port'] != 80) && ($parts['port'] != 443)) {
    $host .= ':' . $parts['port'];
  }

  return (
    $host != $_SERVER['HTTP_HOST']
  );
}

/**
 * Implements hook_themekey_page_cache_support_alter().
 */
function themekey_redirect_themekey_page_cache_support_alter(&$page_cache, $key, $form_id) {
  if ('themekey_redirect_rule_chain_form' == $form_id) {
    $page_cache = THEMEKEY_PAGECACHE_SUPPORTED;
  }
}

/**
 * Implements hook_block().
 */
function themekey_redirect_block_info() {
  $blocks['domain_selector'] = array(
    'info' => t('ThemeKey Redirect Domain Selector'),
    'cache' => DRUPAL_CACHE_PER_PAGE,
  );

  return $blocks;
}

/**
 * Implements hook_block_configure().
 */
function themekey_redirect_block_configure($delta = '') {
  $form = array();

  switch ($delta) {
    case 'domain_selector':
      $form['domain_list'] = array(
        '#type' => 'textarea',
        '#title' => t('Domain Targets'),
        '#description' => t('One entry per line, format: url|link title. The url must include the protocol. Example: http://www.example.com|My Example Site'),
        '#default_value' => themekey_redirect_encode_domain_selector(variable_get('themekey_redirect_domain_selector', array())),
        '#element_validate' => array('themekey_redirect_domain_list_validate'),
        '#required' => TRUE,
      );

      $form['auto_hide'] = array(
        '#type' => 'checkbox',
        '#title' => t('Auto hide'),
        '#description' => t('If selected the user will only be asked once to return to a previous URL after the redirect.'),
        '#default_value' => variable_get('themekey_redirect_domain_selector_auto_hide', 1),
      );

      break;
  }

  $form['#validate'][] = 'themekey_redirect_block_validate';

  return $form;
}

/*
 * There's no hook_block_validate() in drupal. So we have to validate the form
 * on element level.
 */
function themekey_redirect_domain_list_validate($element) {
  if (!empty($element['#value'])) {
    $domain_selector = themekey_redirect_parse_domain_selector($element['#value']);
    foreach ($domain_selector as $url => $link) {
      @$parts = parse_url($url);
      if (!isset($parts['host']) || !isset($parts['scheme'])) {
        form_set_error('domain_list', t('The url %url is not valid.', array('%url' => $url)));
      }
    }
  }
}

/**
 * Implements hook_block_save().
 */
function themekey_redirect_block_save($delta = '', $edit = array()) {
  switch ($delta) {
    case 'domain_selector':
      variable_set('themekey_redirect_domain_selector', themekey_redirect_parse_domain_selector($edit['domain_list']));
      variable_set('themekey_redirect_domain_selector_auto_hide', !empty($edit['auto_hide']) ? 1 : 0);
      // fast deletion of page cache (truncate) for new css
      cache_clear_all('*', 'cache_page', TRUE);
      // and block cache
      cache_clear_all('*', 'cache_block', TRUE);
      break;
  }
}

/**
 * Implements hook_block_view().
 */
function themekey_redirect_block_view($delta = '') {
  $block = array();

  switch ($delta) {
    case 'domain_selector':
      if ($links = variable_get('themekey_redirect_domain_selector', array())) {
        $block['subject'] = t('You have been redirected automatically.');
        $block['content'] = theme('themekey_redirect_domain_selector_links', array('links' => $links));
        if (variable_get('themekey_redirect_domain_selector_auto_hide', 1)) {
          drupal_add_css(drupal_get_path('module', 'themekey_redirect') . '/themekey_redirect_domain_selector.css');
        }
      }
      break;
  }

  return $block;
}

function themekey_redirect_preprocess_themekey_redirect_domain_selector_links(&$vars) {
  $vars['links_rendered'] = array();
  foreach ($vars['links'] as $url => $link) {
    if (themekey_redirect_check_different_url($url)) {
      $vars['links_rendered'][] = l(t($link), $url . str_replace('themekey_redirect=active', '', request_uri()), array('query' => array('themekey_redirect' => 'avoid')));
    }
  }
}

function themekey_redirect_parse_domain_selector($domain_selector_string) {
  $domain_selector = array();
  $domain_selector_string = trim($domain_selector_string, " \r\n");
  $lines = explode("\n", $domain_selector_string);
  foreach ($lines as $line) {
    @list($url, $link) = explode('|', $line);
    $url = trim($url, " \r\n");
    $link = trim($link, " \r\n");
    $domain_selector[$url] = $link ? $link : $url;
  }
  return $domain_selector;
}

function themekey_redirect_encode_domain_selector($domain_selector) {
  $domain_selector_strings = array();
  foreach ($domain_selector as $url => $link) {
    $domain_selector_strings[] = $url . '|' . $link;
  }
  return implode("\n", $domain_selector_strings);
}