<?php

/**
 * @file
 * Mailchimp module.
 */

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

  $items['admin/config/services/mailchimp'] = array(
    'title' => 'MailChimp',
    'description' => 'Manage MailChimp Settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('mailchimp_admin_settings'),
    'access arguments' => array('administer mailchimp'),
    'file' => 'includes/mailchimp.admin.inc',
    'type' => MENU_NORMAL_ITEM,
  );
  $items['admin/config/services/mailchimp/global'] = array(
    'title' => 'Global Settings',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['mailchimp/webhook'] = array(
    'title' => 'MailChimp webhooks endpoint',
    'page callback' => 'mailchimp_process_webhook',
    'access callback' => 'mailchimp_process_webhook_access',
    'access arguments' => array(2),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function mailchimp_permission() {
  return array(
    'administer mailchimp' => array(
      'title' => t('administer mailchimp'),
      'description' => t('TODO Add a description for administer mailchimp'),
    ),
  );
}

/**
 * Check if the given email is subscribed to the given list. Simple
 *   wrapper around mailchimp_get_memberinfo().
 *
 * @param  $list_id
 * @param  $email
 *
 * @return bool
 */
function mailchimp_is_subscribed($list_id, $email) {
  $subscribed = FALSE;
  $memberinfo = mailchimp_get_memberinfo($list_id, $email);
  if (isset($memberinfo['status']) && $memberinfo['status'] == 'subscribed') {
    $subscribed = TRUE;
  }

  return $subscribed;
}

/**
 * Subscribe a user to a given list.
 */
function mailchimp_subscribe_user($list, $email, $merge_vars, $message = TRUE, $mcapi = NULL) {
  $success = FALSE;
  if ($mcapi || $mcapi = mailchimp_get_api_object()) {
    $double_optin = $list->settings['doublein'];

    $success = $mcapi->listSubscribe($list->mc_list_id, $email, $merge_vars, 'html', $double_optin, TRUE);

    if ($message && $success && $double_optin) {
      drupal_set_message(t('You have chosen to subscribe to %list. An email will be sent to your address. Click the link in the email to confirm the subscription.',
        array('%list' => $list->label)));
    }
    elseif ($message && $success) {
      drupal_set_message(t('You have subscribed to %list.', array('%list' => $list->label)));
    }

    // clear user cache, just in case there's some cruft leftover
    mailchimp_cache_clear_user($list->mc_list_id, $email);

    if ($success) {
      watchdog('mailchimp', '@email was subscribed to list @list.',
        array('@email' => $merge_vars['EMAIL'], '@list' => $list->label), WATCHDOG_NOTICE
      );
    }
    else {
      watchdog('mailchimp', 'A problem occurred subscribing @email to list @list. Message: @msg', array(
          '@email' => $merge_vars['EMAIL'],
          '@list' => $list->label,
          '@msg' => $mcapi->errorMessage,
        ), WATCHDOG_WARNING);
    }
  }

  return $success;
}

/**
 * Update a user in a given list.
 */
function mailchimp_update_user($list, $email, $merge_vars, $message = TRUE, $mcapi = NULL) {
  $success = FALSE;
  if ($mcapi || $mcapi = mailchimp_get_api_object()) {

    $success = $mcapi->listUpdateMember($list->mc_list_id, $email, $merge_vars);

    if ($success && $message) {
      drupal_set_message(t('You have updated your settings in %list.', array('%list' => $list->label)));
    }

    // clear user cache
    mailchimp_cache_clear_user($list->mc_list_id, $email);

    if ($success) {
      watchdog('mailchimp', '@email was updated in list @list.',
        array('@email' => $merge_vars['EMAIL'], '@list' => $list->label), WATCHDOG_NOTICE
      );
    }
    else {
      watchdog('mailchimp', 'A problem occurred subscribing @email to list @list. Message: @msg', array(
          '@email' => $merge_vars['EMAIL'],
          '@list' => $list->label,
          '@msg' => $mcapi->errorMessage,
        ), WATCHDOG_WARNING);
    }
  }

  return $success;
}

/**
 * Unsubscribe a user from the given list.
 *
 * @param object $list 
 * @param string $email 
 * @param bool $message 
 * @param object $mcapi 
 * @param book $delete 
 *   Indicates whether an email should be deleted or just unsubscribed.
 * @return bool
 */
function mailchimp_unsubscribe_user($list, $email, $message = TRUE, $mcapi = NULL, $delete = FALSE) {
  $success = FALSE;
  if ($mcapi || $mcapi = mailchimp_get_api_object()) {
    if (mailchimp_is_subscribed($list->mc_list_id, $email)) {
      $success = $mcapi->listUnsubscribe($list->mc_list_id, $email, $delete, FALSE, FALSE);
      if ($message && $success) {
        drupal_set_message(t('You have unsubscribed from %list.', array('%list' => $list->label)));
      }

      // clear user cache
      mailchimp_cache_clear_user($list->mc_list_id, $email);
    }
  }

  return $success;
}

/**
 * Get a Mailchimp API object for communication with the mailchimp server.
 */
function mailchimp_get_api_object() {
  $q = new MCAPI(variable_get('mailchimp_api_key', ''));

  // set the timeout to something reasonsable to avoid taking down the Drupal site
  $q->setTimeout(60);

  // specify if a secure connection should be used wit the API
  $q->useSecure(variable_get('mailchimp_use_secure', TRUE));

  if ($q->errorCode) {
    watchdog('mailchimp', 'MCAPI Error: %errmsg', array('%errmsg' => $q->errorMessage), WATCHDOG_ERROR);
    return NULL;
  }

  return $q;
}

/**
 * Return all MailChimp lists for a given key. Lists are stored in the
 * cache.
 *
 * @param array $list_ids
 *   An array of list IDs to filter the results by.
 * @param bool $reset
 *   Force a cache reset.
 *
 * @return An array of list arrays.
 */
function mailchimp_get_lists($list_ids = array(), $reset = FALSE) {
  $cache = $reset ? NULL : cache_get('mailchimp_lists');
  $lists = array();
  // return cached lists
  if ($cache) {
    $lists = $cache->data;
  }
  // Query lists from the MC API and store in cache
  else {
    if ($q = mailchimp_get_api_object()) {
      $result = $q->lists(array(), 0, 100);
      if ($result['total'] > 0) {
        foreach ($result['data'] as $list) {
          // append mergefields
          $list['mergevars'] = $q->listMergeVars($list['id']);

          // append interest groups
          $list['intgroups'] = $q->listInterestGroupings($list['id']);

          $lists[$list['id']] = $list;
        }
      }
    }

    cache_set('mailchimp_lists', $lists, 'cache', CACHE_TEMPORARY);
  }

  // filter by given ids
  if (!empty($list_ids)) {
    foreach ($lists as $key => $list) {
      if (!in_array($key, $list_ids)) {
        unset($lists[$key]);
      }
    }
  }

  return $lists;
}

/**
 * Wrapper around mailchimp_get_lists() to return a single list.
 *
 * @param string $list_id
 *
 * @return array list
 */
function mailchimp_get_list($list_id) {
  $lists = mailchimp_get_lists(array($list_id));
  return reset($lists);
}

/**
 * Get the MailChimp memberinfo for a given email address and list. Results are cached
 * in the cache_mailchimp_user bin which is cleared by the MC web hooks system when
 * needed.
 *
 * @param string $list_id
 * @param string $email
 * @param bool $reset
 *
 * @return array memberinfo
 */
function mailchimp_get_memberinfo($list_id, $email, $reset = FALSE) {
  $cache = $reset ? NULL : cache_get($list_id . '-' . $email, 'cache_mailchimp_user');
  $memberinfo = array();

  // return cached lists
  if ($cache) {
    $memberinfo = $cache->data;
  }
  // Query lists from the MC API and store in cache
  else {
    if ($q = mailchimp_get_api_object()) {
      $result = $q->listMemberInfo($list_id, array($email));
      if ($result['success']) {
        $memberinfo = reset($result['data']);
      }
    }

    cache_set($list_id . '-' . $email, $memberinfo, 'cache_mailchimp_user', CACHE_PERMANENT);
  }

  return $memberinfo;
}

/**
 * Sets the member info in the cache.
 *
 * @param string $list_id
 * @param string $email
 */
function mailchimp_set_memberinfo($list_id, $email) {
  mailchimp_get_memberinfo($list_id, $email, TRUE);
}

/**
 * Clear a mailchimp user memberinfo cache
 *
 * @param  $list_id
 * @param  $email
 */
function mailchimp_cache_clear_user($list_id, $email) {
  cache_clear_all($list_id . '-' . $email, 'cache_mailchimp_user');
}

/**
 * Implements hook_flush_caches().
 */
function mailchimp_flush_caches() {
  return array('cache_mailchimp_user');
}

/**
 * Access callback for mailchimp_process_webhook().
 *
 * @param string $key
 *
 * @return bool
 */
function mailchimp_process_webhook_access($key) {
  return $key == mailchimp_webhook_key();
}

/**
 * Process a webhook post from MailChimp
 */
function mailchimp_process_webhook() {
  $data = $_POST['data'];
  switch ($_POST['type']) {
    case 'unsubscribe':
    case 'profile':
    case 'cleaned':
      mailchimp_cache_clear_user($data['list_id'], $data['email']);
      mailchimp_set_memberinfo($data['list_id'], $data['email']);
      break;

    case 'upemail':
      mailchimp_cache_clear_user($data['list_id'], $data['old_email']);
      mailchimp_set_memberinfo($data['list_id'], $data['new_email']);
      break;
  }

  // log event
  watchdog('mailchimp', 'Webhook type !type has been processed.',
    array('!type' => $_POST['type']), WATCHDOG_INFO
  );
}

/**
 * Generate a key to include in the webhook url based on a hash.
 *
 * @param string $list_id
 *
 * @return string
 */
function mailchimp_webhook_key() {
  return md5($GLOBALS['base_url']);
}

/**
 * Generate the webhook endpoint URL.
 *
 * @param string $list_id
 *
 * @return string
 */
function mailchimp_webhook_url() {
  return $GLOBALS['base_url'] . '/mailchimp/webhook/' . mailchimp_webhook_key();
}