<?php
// $Id: autosave.module,v 1.9 2009/11/06 00:41:16 ptalindstrom Exp $

/**
 * @file
 * Does background saves of node being edited.
 */

define('AUTOSAVE_PATH', drupal_get_path('module', 'autosave'));

/**
 * Implementation of hook_help().
 */
function autosave_help($path, $arg) {
  $output = '';
  switch ($path) {
    case 'admin/help#autosave':
      $output = '<p>'. t('The autosave module automatically saves a form after a period of time.') .'</p>';
      break;
  }
  return $output;
}

/**
 * Implementation of hook_menu().
 */
function autosave_menu() {
  $items['autosave/handler/%'] = array(
    'title'           => 'Autosave save',
    'page callback'   => 'autosave_save',
    'access callback' => 'autosave_save_access',
    'type'            => MENU_CALLBACK,
  );

  $items['admin/settings/autosave'] = array(
    'title'            => 'Autosave',
    'description'      => 'Configure autosave settings.',
    'page callback'    => 'drupal_get_form',
    'page arguments'   => array('autosave_admin_settings'),
    'access arguments' => array('administer nodes'),
  );
  return $items;
}

/**
 * Access callback for the form save menu callback.
 *
 *
 * For security reasons, we need to confirm that the user would have access
 * to the page where the form lives in the first place.  If they don't, they
 * should not be able to access its saved version.  We also check that the
 * form's token is correct to avoid CSRF attacks.
 *
 * Because the form data is not available to us, the only way we can access
 * the path is by checking $_POST directly.  Sux.
 *
 *  @return boolean
 *   True if this user should have access to save this form, false otherwise.
*/
function autosave_save_access() {
  $path = trim($_POST['autosave_path'], '/');
  $menu_item = menu_get_item($path);

  $token = isset($_POST['form_token'], $_POST['form_id']) && drupal_valid_token($_POST['form_token'], $_POST['form_id']);
  $menu = isset($menu_item['access']) ? $menu_item['access'] : FALSE;
  return $token && $menu;
}

/**
 * Menu callback; return the autosave module settings form.
 */
function autosave_admin_settings() {
  $form['autosave_period'] = array(
    '#type' => 'textfield',
    '#title' => t('Autosave after this amount seconds has passed'),
    '#default_value' => variable_get('autosave_period', 10),
  );

  $form['autosave_hidden'] = array(
    '#prefix' =>  '<div class="form-item"><label for="edit-autosave-hidden">'. t('Stealth Mode') . '</label>',
    '#type' => 'checkbox',
    '#title' => t('Run in stealth mode'),
    '#description' => t('If this check box is selected no popup will appear notifying user that the form has been autosaved.'),
    '#default_value' => variable_get('autosave_hidden', 0),
    '#suffix' => "</div>",
  );

  return system_settings_form($form);
}

/**
 * Implementation of hook_form_alter() for node_type_form
 */
function autosave_form_node_type_form_alter(&$form, $form_state) {
  $form['workflow']['autosave'] = array(
    '#type' => 'checkbox',
    '#title' => t('Enable Autosave to add/edit forms for this node type'),
    '#default_value' => variable_get('autosave_'. $form['#node_type']->type, 0),
    '#description' => t('Check this box to enable Autosave for this node type.')
  );
}

/**
 * Implementation of hook_form_alter().
 */
function autosave_form_alter(&$form, &$form_state, $form_id) {
  global $user;
  $path = $_GET['q'];
  
  if (stristr($form_id, '_node_form') && arg(0) != 'admin') {

    // check if this content_type has the autosave function enabled and make sure it's a node edit or add form
    if ((variable_get('autosave_'. $form['type']['#value'], 0))) {
      drupal_add_js(AUTOSAVE_PATH .'/autosave.js');
      drupal_add_js(AUTOSAVE_PATH .'/jquery.field.js');
      drupal_add_css(AUTOSAVE_PATH .'/autosave.css');

      // if WYSIWYG module is enabled; lets let JS know this
      if (module_exists('wysiwyg')) $settings['autosave']['wysiwyg'] = 1;
      else $settings['autosave']['wysiwyg'] = 0;
      
      // add security token
      $token = drupal_get_token($form_id);
      
      $settings['autosave']['url'] = url('autosave/handler/' . $token);
      $settings['autosave']['period'] = variable_get('autosave_period', 10);
      $settings['autosave']['autosave_path'] = $path;
      $settings['autosave']['hidden'] = variable_get('autosave_hidden', 0);
      
      // If an autosaved version of the form exists, make it available via javascript.
      if ($autosaved_form = autosave_get_autosaved_form($form_id, $path, $user->uid)) {
        //$autosaved_form_id = $form['type']['#value'] ? $form['type']['#value'] .'_node_form' : 'node_form';
        $settings['autosave'] = array_merge($settings['autosave'], array(
          'serialized' => unserialize($autosaved_form['serialized']),
          'saved_date' => format_date($autosaved_form['timestamp'], 'medium'),
        ));
      }
      drupal_add_js($settings, 'setting');
    }
  }
}

/**
 * Menu callback; autosaves the node.
 */
function autosave_save() {
  global $user;
  $path = $_POST['autosave_path'];
  $form_id = $_POST['form_id'];

  // Not all variables need to be serialized.
  //    - for Drupal 6 version need to remove op and form_build_id
  unset($_POST['autosave_path'], $_POST['op'], $_POST['form_build_id']);
  $serialized = serialize($_POST);

  // check if node has just been saved - if it has then it's because AS ajax fired off as user was submitting
  // if it had just been submitted - no need to AS now
  //    - easy to figure out if we are submitting an edit to existing node
  //    - little harder if we have just added a node
  $path_args = explode("/", $path);

  // update case
  if (is_numeric($path_args[1])) {
    $submitted = node_load($path_args[1]);
  }

  // add case
  else {
    $submitted = new stdClass();
    $submitted->changed = db_result(db_query("SELECT created FROM {node} WHERE uid = %d and type = '%s' ORDER BY created DESC LIMIT 1", $user->uid, str_replace("-", "_", $path_args[2])));
  }

  if (!$submitted || (time() - $submitted->changed) > 10) {
    // Currently, each user can have only one autosave form at a particular path.
    db_query("DELETE FROM {autosaved_forms} WHERE form_id = '%s' AND path = '%s' AND uid = %d", $form_id, $path, $user->uid);
    db_query("INSERT INTO {autosaved_forms} (form_id, path, uid, timestamp, serialized) VALUES ('%s', '%s', %d, %d, '%s')", $form_id, $path, $user->uid, time(), $serialized);
  }

  exit();
}

/**
 * Get the autosaved form at a particular path for a user.
 *
 * @param string $form_id
 *   The form_id of the form.
 * @param string $path
 *   The the internal Drupal path where the form is located
 * @param string $uid
 *   Drupal UID of the user
 * @return
 *   An array containing the serialized values of the autosaved form and the timestamp of when the form was autosaved.
 */
function autosave_get_autosaved_form($form_id, $path, $uid) {
  $result = db_query("SELECT form_id, serialized, timestamp FROM {autosaved_forms} WHERE form_id = '%s' AND path = '%s' AND uid = %d", $form_id, $path, $uid);

  while ($data = db_fetch_object($result)) {
    $form['serialized'] = $data->serialized;
    $form['timestamp'] = $data->timestamp;
  }
  return $form;
}

/**
 * Implementation of hook_nodeapi().
 *
 * Delete autosave table entry on successful submit (add or update) of node
 *
 */
function autosave_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
  if ($op == 'presave') {
      // we remove ALL edits for that page (not just the users) to avoid:
      //  - user1 asaves but doesnt submit
      //  - user2 edits same node and submits
      //  - user1 comes back to edit -> user1 SHOULD lose edits since user2 has precedence
      db_query("DELETE FROM {autosaved_forms} WHERE form_id = '%s' AND path = '%s'", $node->form_id, $_GET['q']);
  }
}
