<?php
// $Id: r4032login.module,v 1.3.2.10 2010-11-07 21:14:32 deekayen Exp $

/**
 * @file
 * Redirect denied pages to the user login form.
 */

/**
 * Implementation of hook_menu().
 */
function r4032login_menu() {
  $items = array();
  $items['r4032login'] = array(
    'page callback' => 'r4032login_redirect',
    'access callback' => 'r4032login_access',
    'type' => MENU_CALLBACK
  );
  $items['admin/settings/r4032login'] = array(
    'title' => 'Redirect 403 to User Login',
    'description' => 'Toggle display of denied message on login page.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('r4032login_admin_settings'),
    'access callback' => 'user_access',
    'access arguments' => array('administer site configuration')
  );
  return $items;
}

/**
 * Without an access callback on the menu item for r4032login_redirect,
 * the redirect will be 403 and just have the default access denied page anyway.
 */
function r4032login_access() {
  return TRUE;
}

function r4032login_admin_settings() {
  $form = array();
  $form['r4032login_display_denied_message'] = array(
    '#type' => 'textarea',
    '#title' => t('Display access denied message on login page'),
    '#default_value' => variable_get('r4032login_display_denied_message', 'Access denied. You must login to view this page.')
  );
  $form['r4032login_user_register_message'] = array(
    '#type' => 'textfield',
    '#title' => t('User register message'),
    '#description' => t('The message to display when a logged-in user tries to register another account through the !new_account. Drupal does not allow it, so regular users must log out first. Administrators should create new users in !link.', array('!new_account' => l(t('new account registration form'), 'user/register'), '!link' => l(t('User management'), 'admin/user/user/create'))),
    '#default_value' => variable_get('r4032login_user_register_message', t('You are not authorized to access this page.'))
  );
  return system_settings_form($form);
}

/**
 * Implementation of hook_theme().
 */
function r4032login_theme() {
  return array(
    'r4032login_denied' => array(
      'arguments' => array()
    ),
    'r4032login_user_register' => array(
      'arguments' => array()
    )
  );
}

/**
 * MENU_CALLBACK for /4032login
 *
 * Redirect anonymous users from 403 Access Denied pages to the /user/login page
 * with a message explaining that they must login to view the requested page
 * and a query string parameter appended to the url to return after login.
 */
function r4032login_redirect() {
  global $user;
  if (user_is_anonymous()) {
    if (variable_get('r4032login_display_denied_message', 'Access denied. You must login to view this page.')) {
      drupal_set_message(variable_get('r4032login_display_denied_message', 'Access denied. You must login to view this page.'), 'error');
    }
    // A special case for the homepage.
    if (empty($_REQUEST['q'])) {
      $_REQUEST['q'] = '<front>';
    }
    // Check for path prefix and strip it out if its found.
    $path = _r4032login_remove_language(drupal_urlencode($_REQUEST['q']));
    // using drupal_goto() with destination set causes a recursive redirect loop
    header('Location: '. url('user/login', array('query' => 'destination='. $path, 'absolute' => TRUE)), TRUE, 302);
    exit;
  }
  // checking arg() returns r4032login
  elseif ($_REQUEST['q'] == 'user/register') {
    print theme('page', theme('r4032login_user_register'));
    exit;
  }
  else {
    print theme('page', theme('r4032login_denied'));
    exit;
  }
}

/**
 * Special handling for sites that use localization.
 *
 * @see http://drupal.org/node/339120
 */
function _r4032login_remove_language($destination) {
  $prefix = arg(0, $destination);
  $languages = language_list();

  while (list(, $lang) = each($languages)) {
    if (strcasecmp($prefix, $lang->language) == 0) {
      return substr($destination, strlen($prefix) + 1); // remove prefix and slash
    }
  }
  return $destination;
}

function theme_r4032login_denied() {
  drupal_set_title(t('Access denied'));
  return '<p>'. t('You are not authorized to access this page.') .'</p>';
}

function theme_r4032login_user_register() {
  drupal_set_title(t('Access denied'));
  return '<p>'. variable_get('r4032login_user_register_message', t('You are not authorized to access this page.')) .'</p>';
}