<?php

/**
 * @file
 *
 * Reminder module.
 */

/**
 * Implements hook_menu()
 */
function reminder_menu() {
  $items['reminder/%'] = array(
    'title'            => 'Reminder page',
    'description'      => 'Access a reminder page',
    'page callback'    => 'reminder_page',
    'page arguments'   => array(1),
    'access arguments' => array('show reminder'),
    'file'             => 'reminder.pages.inc',
    'type'             => MENU_CALLBACK,
  );

  $items['reminder/%/unsubscribe'] = array(
    'title'            => 'Unsubscribe page',
    'description'      => 'Unsubscribe from a reminder',
    'page callback'    => 'reminder_unsubscribe',
    'page arguments'   => array(1),
    'access arguments' => array('show reminder'),
    'file'             => 'reminder.pages.inc',
    'type'             => MENU_CALLBACK,
  );

  $items['reminder/%/log'] = array(
    'title' => 'Log page',
    'description' => 'Show logs',
    'page callback' => 'reminder_logpage',
    'page arguments' => array(1),
    'access arguments' => array('show reminder'),
    'file' => 'reminder.pages.inc',
    'type' => MENU_CALLBACK,
  );  

  $items['reminder/%/denounce'] = array(
    'title' => 'Log page',
    'description' => 'Show logs',
    'page callback' => 'reminder_denounce',
    'page arguments' => array(1),
    'access arguments' => array('show reminder'),
    'file' => 'reminder.pages.inc',
    'type' => MENU_CALLBACK,
  );  

  $items['user/%user/reminder'] = array(
    'title'            => 'My reminders',
    'description'      => 'List of my reminders',
    'page callback'    => 'reminder_mypage',
    'access callback'  => '_reminder_access_userreminders',
    'access arguments' => array(1),
    'file'             => 'reminder.pages.inc',
    'type'             => MENU_SUGGESTED_ITEM,
  );

  return $items;
}

/**
 * Implements hook_perm()
 */
function reminder_permission() {
  return array(
    'access all reminders' => array(
      'title' => t("Access all reminders"),
      'restrict access' => TRUE,
    ),
    'access own reminders' => array(
      'title' => t("Access own reminders"),
    ),
    'show reminder' => array(
      'title' => t("Access reminders"),
    ),
  );
}

/**
 * Implements hook_node_info()
 */
function reminder_node_info() {
  return array(
    'reminder'      => array(
      'name'        => t('Reminder'),
      'base'        => 'reminder',
      'description' => t("Create a reminder for a business lunch, a meeting or a movie night."),
      'has_title'   => TRUE,
      'title_label' => t('Your reminder'),
    )
  );
}

/**
 * Implementation of hook_form_alter()
 */
function reminder_form_alter(&$form, $form_state, $form_id) {
  // Remove preview button from reminder node form
  if ($form_id == 'reminder_node_form') {
    unset($form['actions']['preview']);
  }
}

/**
 * Implementation of hook_node_access()
 */
function reminder_node_access($node, $op, $account) {
  if (is_object($node) && $node->type == 'reminder') {
    switch ($op) {
      // disabling the edit page: we don't give access to any user
      // reason: we're using custom urls to update the nodes, and only
      // the owner of the reminder has the custom admin url
      case 'update':
        return FALSE;

      case 'delete':
        return user_access('delete reminder', $account) && ($account->uid == $node->uid);
    }
  }
}

/**
 * Implementation of hook_node_form()
 */
function reminder_form(&$node) {
  global $user;

  $type         = node_type_get_type($node);
  $format_until = 'Y-m-d H:i';
  $reminder     = isset($node->nid) ? reminder_get_reminder($node->nid, TRUE) : array();

  if ($type->has_title) {
    $form['title'] = array(
      '#type' => 'textfield',
      '#title' => check_plain($type->title_label),
      '#required' => TRUE,
      '#default_value' => $node->title,
      '#weight' => -5
    );
  }

  $form['description'] = array(
      '#type' => 'textarea',
      '#title' => t('Add some description'),
      '#default_value' => isset($reminder['description']) ? $reminder['description']: '',
      '#rows' => 5
  );

  if ((isset($node->nid) && $node->uid == 0) || $user->uid == 0) {
    $form['anonym'] = array(
      '#type' => 'fieldset',
      '#title' => t('Add your name and email'),
      '#tree' => TRUE,
    );

    $form['anonym']['user_name'] = array(
      '#type' => 'textfield',
      '#title' => t('Your name'),
      '#maxlength' => 100,
      '#description' => t('This is optional.'),
      '#default_value' => isset($reminder['anonym_name']) ? $reminder['anonym_name'] : '',
    );

    $form['anonym']['user_email'] = array(
      '#type' => 'textfield',
      '#title' => t('Your e-mail'),
      '#description' => t(''),
      '#maxlength' => 100,
      '#default_value' => isset($reminder['anonym_email']) ? $reminder['anonym_email'] : '',
    );

  }

  if (isset($node->nid)) {
    $reminder['subscriptions'] = reminder_get_subscriptions($node->nid);
  }

  $form['until'] = array(
     '#type'                => 'date_popup',
     '#title'               => 'Remind until',
     '#default_value'       => isset($reminder['until']) ? $reminder['until'] : date($format_until),
     '#date_format'         => $format_until,
     '#date_label_position' => 'within',
     '#date_increment'      => 60,
     '#date_year_range'     => '0:+20',
  );

  $form['frequency'] = array(
    '#type' => 'select',
    '#title' => t('Interval'),
    '#options' => array(
      'hourly'     => t('Hourly'),
      'daily'      => t('Daily'),
      'weekly'     => t('Weekly'),
      'monthly'    => t('Monthly'),
      'yearly'     => t('Yearly'),
      'decreasing' => t('Increasing (you get more reminders over time)'),
    ),
    '#default_value' => isset($reminder['frequency']) ? $reminder['frequency'] : 'hourly',
    '#description' => t('Choose the frequency a reminder should be sent to you and all subscribers.'),
  );

  $form['reminder_options'] = array(
    '#type' => 'fieldset',
    '#title' => t('Reminder options'),
    '#tree' => TRUE,
  );

  $form['reminder_options']['secure'] = array(
    '#type' => 'radios',
    '#title' => t('Show subscribed emails'),
    '#description' => t("Deny subscribers to see each other."),
    '#options' => array('0' => t('No'), '1' => t('Yes')),
    '#default_value' => isset($reminder['secure']) ? $reminder['secure'] : 0,
  );

  $form['reminder_options']['now'] = array(
    '#type' => 'radios',
    '#title' => t('Issue a reminder right now to all subscribers'),
    '#description' => t("Deny subscribers to see each other."),
    '#options' => array('0' => t('No'), '1' => t('Yes')),
    '#default_value' => 0,
  );

  $form['reminder_subscriptions'] = array(
    '#type' => 'textarea',
    '#title' => t('Subscribers'),
    '#description' => t('One valid email address per line.'),
    '#maxlength' => 100,
    '#default_value' => isset($reminder['subscriptions']) ? implode($reminder['subscriptions'], '\n'): NULL,
  );

  return $form;
}

/**
 * Form validation.
 *
 * @todo
 *   Throttling settings to avoid SPAM: max posts per
 *   hour and max recipients per post.
 *
 *   Validate name and email if not registered user.
 *   Date and interval validation.
 *   Test all fields.
 */
function reminder_validate($node, $form, &$form_state) {
  if ($form['type']['#value'] == 'reminder') {
    // TODO
    // valid_email_address()
  }
}

/**
 * Implementation of hook_node_submit()
 *
 * @todo
 *   Date, remind and subscribe widgets.
 *   Update subscribers, removing old ones.
 *   Optionally send unsubscription email for removed users.
 *   Redirect to reminder page.
 */
function reminder_node_submit($node, $form, &$form_state) {
  global $user;

  // No preview available.
  if (!$form_state['submitted']) {
    return;
  }

  if (isset($form_state['values']['anonym'])) {
    $anonym_name  = $form_state['values']['anonym']['user_name'];
    $anonym_email = $form_state['values']['anonym']['user_email'];
  }
  else {
    $anonym_name  = NULL;
    $anonym_email = NULL;
  }

  $node->title = $form_state['values']['title'];

  if ($node->nid == NULL) {
    $action = 'create';

    // Save basic data.
    node_save($node);

    // Generate the reminder urls and save them.
    $reminder_url = _reminder_generate_url('url', 10);
    $admin_url    = _reminder_generate_url('admin_url', 25);

    // Save reminder options.
    $values = array(
      'nid'          => $node->nid,
      'uid'          => $user->uid,
      'until'        => $form_state['values']['until'],
      'frequency'    => $form_state['values']['frequency'],
      'secure'       => $form_state['values']['reminder_options']['secure'],
      'url'          => $reminder_url,
      'admin_url'    => $admin_url,
      'anonym_name'  => $anonym_name,
      'anonym_email' => $anonym_email,
      'description'  => $form_state['values']['description'],
    );

    $query = db_insert('reminder')->fields($values);
    $query->execute();

    // Save subscribers.
    foreach (reminder_parse_subscribers($node->reminder_subscriptions) as $subscriber) {
      $unsubscribe_url = _reminder_generate_url('unsubscribe_url', 30, 'reminder_subscriptions');
      $values = array(
        'email'           => $subscriber,
        'reminder_id'     => $node->nid,
        'unsubscribe_url' => $unsubscribe_url,
      );

      $query = db_insert('reminder_subscriptions')->fields($values)->execute();
    }
  }
  else {
    // Fetch existing options.
    $reminder     = reminder_get_reminder($node->nid);
    $reminder_url = $reminder['url'];
    $admin_url    = $reminder['admin_url'];
    $action       = 'update';

    // Update basic data.
    node_save($node);

    // Save reminder options
    db_update('reminder')->fields(array(
      'until'        => $form_state['values']['until'],
      'frequency'    => $form_state['values']['frequency'],
      'secure'       => $form_state['values']['reminder_options']['secure'],
      'anonym_name'  => $anonym_name,
      'anonym_email' => $anonym_email,
    ))->condition('nid', $node->nid)->execute();

    // Update subscribers, removing old ones.
    $current_subscriptions      = array();
    $current_subscriptions_data = reminder_get_subscriptions($node->nid);
    $new_subscriptions          = reminder_parse_subscribers($node->reminder_subscriptions);

    foreach ($current_subscriptions_data as $subscriber) {
      // We copy just the relevant data just for later use.
      $current_subscriptions[$subscriber['id']] = $subscriber['email'];

      // Unsubscribe user from reminder.
      if (!in_array($subscriber['email'], $new_subscriptions)) {
        db_delete('reminder_subscriptions')
          ->condition('id', $subscriber['id'])
          ->execute();
      }
    }

    foreach ($new_subscriptions as $subscriber) {
      if (!in_array($subscriber, $current_subscriptions)) {
        $unsubscribe_url = _reminder_generate_url('unsubscribe_url', 30, 'reminder_subscriptions');
        $values = array(
            'email'           => $subscriber,
            'reminder_id'     => $node->nid,
            'unsubscribe_url' => $unsubscribe_url,
            );
      }
    }

  }

  $mail = ($user->uid > 0) ? $mail = $user->mail : $form_state['values']['anonym']['user_email'];
  $name = ($user->uid > 0) ? $user->name : $form_state['values']['anonym']['user_name'];

  // Send message to reminder owner
  drupal_mail('reminder', $action .'_reminder', $mail, language_default(), array(
    "name"         => $name,
    "reminder_url" => $reminder_url,
    "admin_url"    => $admin_url,
    )
  );

  // Send reminder now.
  if (isset($form_state['reminder_options']['now']) && $form_state['reminder_options']['now'] != 0) {
    reminder_send($node->nid);
  }

  drupal_set_message(
      l(
        t("Reminder page URL: !url", array("!url" => url('reminder/' . $reminder_url, array("absolute" => TRUE)))),
        "reminder/" . $reminder_url
       )
  );

  drupal_set_message(
      l(
        t("Admin page URL: !url", array("!url" => url('reminder/' . $admin_url, array("absolute" => TRUE)))),
        "reminder/" . $admin_url
       )
  );

  drupal_set_message(t("Saved."));
}

/**
 * Implements hook_mail()
 *
 * @todo
 */
function reminder_mail($key, &$message, $params) {
   $subject             = t('Reminder information');
   $body                = t('Reminder URL: @url', array('@url' => $params['reminder_url']));
   $message['subject'] .= str_replace(array("\r", "\n"), '', $subject);
   $message['body'][]   = drupal_html_to_text($body);

   if ($key == 'create_reminder') {
   }
   else if ($key == 'update_reminder') {
   }
}

/**
 * Implementation of hook_node_delete()
 */
function reminder_delete($node) {
  db_query("DELETE FROM {reminder} WHERE nid = :nid", array(':nid' => $node->nid));
  db_query("DELETE FROM {reminder_logs} WHERE nid = :nid", array(':nid' => $node->nid));
  db_query("DELETE FROM {reminder_subscriptions} WHERE reminder_id = :reminder_id", array(':reminder_id' => $node->nid));
  db_query("DELETE FROM {reminder_notifications} WHERE reminder_id = :reminder_id", array(':reminder_id' => $node->nid));
}

/**
 * Implements hook_cron()
 *
 * @todo
 *   Send periodic emails.
 */
function reminder_cron() {
  variable_set('reminder_cron_last_run', REQUEST_TIME);
}

/**
 * Send emails for all subscribers.
 *
 * @todo
 */
function reminder_send($nid) {
}

/**
 * Helper function to parse subscribers.
 *
 * @see http://stackoverflow.com/questions/1028553/how-to-get-email-address-from-a-long-string
 */
function reminder_parse_subscribers($subscribers) {
  foreach(preg_split('/ |,|;|\n/', $subscribers) as $token) {
    $email = filter_var(filter_var($token, FILTER_SANITIZE_EMAIL), FILTER_VALIDATE_EMAIL);

    if ($email !== false) {
      $emails[] = $email;
    }
  }

  return $emails;
}

/**
 * Helper function to generate a unique keychain
 *
 * @param $field
 *    The field to be unique
 * @param $length
 *    Lengh of the keychain
 * @return string
 */
function _reminder_generate_url($field, $length, $table = 'reminder') {
  $url = _reminder_keygen($length);
  $query = db_select($table, 'm')->fields('m');
  while ($query->condition($field, $url)->execute()->rowCount() > 0) {
    $url = _reminder_keygen($length);
  }
  return $url;
}

/**
 * Helper function to generate a keychain
 *
 * @param $length
 *    Lengh of the keychain
 * @return string
 */
function _reminder_keygen($length) {
  $pattern = "1234567890abcdefghijklmnopqrstuvwxyz";
  $key = $pattern{rand(0, 35)};
  for ($i = 1; $i < $length; $i++) {
    $key .= $pattern{rand(0, 35)};
  }
  return $key;
}

/**
 * Menu access callback.
 */
function _reminder_access_userreminders($account) {
  global $user;
  return user_access('access all reminders') || ($user->uid == $account->uid && user_access('access own reminders'));
}

/**
 * Get reminder data.
 *
 * @param $nid
 *   Reminder nid.
 *
 * @param $subscriptions
 *   Whether to fetch subscription information.
 *
 * @return
 *   Reminder result set.
 */
function reminder_get_reminder($nid, $subscriptions = FALSE) {
  // Schema
  include_once 'reminder.install';
  $schema = reminder_schema();
  $fields = array_keys($schema['reminder']['fields']);

  // Fetch existing options.
  $query = db_select('reminder', 'r');
  $query
    ->condition('r.nid', $nid)
    ->fields('r', $fields);

  $results = $query->execute()->fetchAll();

  // Sanitize the data before handing it off to the theme layer.
  foreach ($results as $entry) {
    // Return the first result as we just have one entry.
    $result = array_map('check_plain', (array) $entry);
    break;
  }

  if (!$subscriptions) {
    return $result;
  }

  $result['subscriptions'] = reminder_get_subscriptions($nid);
  return $result;
}

/**
 * Get subscription data.
 *
 * @param $nid
 *   Reminder nid.
 *
 * @return
 *   Subscriptions result set.
 */
function reminder_get_subscriptions($nid) {
  // Schema
  include_once 'reminder.install';
  $schema = reminder_schema();
  $fields = array_keys($schema['reminder_subscriptions']['fields']);

  // Fetch existing options.
  $query = db_select('reminder_subscriptions', 'r');
  $query
    ->condition('r.reminder_id', $nid) 
    ->fields('r', $fields);

  $results = $query->execute()->fetchAll();

  // Sanitize the data before handing it off to the theme layer.
  foreach ($results as $entry) {
    $results[] = array_map('check_plain', (array) $entry);
  }

  return $results;
}