Add Premium key validation [PREMIUM-4]

lib/API/Endpoints/v1/Services.php

@@ -64,4 +64,57 @@ class Services extends APIEndpoint {
 
     return $this->errorResponse(array(APIError::BAD_REQUEST => $error));
   }
+
+  function verifyPremiumKey($data = array()) {
+    $key = isset($data['key']) ? trim($data['key']) : null;
+
+    if(!$key) {
+      return $this->badRequest(array(
+        APIError::BAD_REQUEST  => __('Please specify a key.', 'mailpoet')
+      ));
+    }
+
+    try {
+      $result = $this->bridge->checkPremiumKey($key);
+    } catch(\Exception $e) {
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
+
+    $state = !empty($result['state']) ? $result['state'] : null;
+
+    $success_message = null;
+    if($state == Bridge::PREMIUM_KEY_VALID) {
+      $success_message = __('Your Premium API key is valid!', 'mailpoet');
+    } elseif($state == Bridge::PREMIUM_KEY_EXPIRING) {
+      $success_message = sprintf(
+        __('Your Premium key expires on %s!', 'mailpoet'),
+        Carbon::createFromTimestamp(strtotime($result['data']['expire_at']))
+          ->format('Y-m-d')
+      );
+    }
+
+    if($success_message) {
+      return $this->successResponse(array('message' => $success_message));
+    }
+
+    switch($state) {
+      case Bridge::PREMIUM_KEY_INVALID:
+        $error = __('Your Premium key is invalid!', 'mailpoet');
+        break;
+      case Bridge::PREMIUM_KEY_USED:
+        $error = __('Your Premium key is already used on another site!', 'mailpoet');
+        break;
+      default:
+        $code = !empty($result['code']) ? $result['code'] : Bridge::CHECK_ERROR_UNKNOWN;
+        $error = sprintf(
+          __('Error validating Premium key, please try again later (code: %s)', 'mailpoet'),
+          $code
+        );
+        break;
+    }
+
+    return $this->errorResponse(array(APIError::BAD_REQUEST => $error));
+  }
 }

lib/API/Endpoints/v1/Settings.php

@@ -3,7 +3,6 @@ namespace MailPoet\API\Endpoints\v1;
 
 use MailPoet\API\Endpoint as APIEndpoint;
 use MailPoet\API\Error as APIError;
-use MailPoet\Mailer\Mailer as MailerConfig;
 use MailPoet\Models\Setting;
 use MailPoet\Services\Bridge;
 
@@ -24,13 +23,8 @@ class Settings extends APIEndpoint {
       foreach($settings as $name => $value) {
         Setting::setValue($name, $value);
       }
-      if(!empty($settings[MailerConfig::MAILER_CONFIG_SETTING_NAME]['mailpoet_api_key'])
-          && Bridge::isMPSendingServiceEnabled()
-      ) {
       $bridge = new Bridge();
-        $result = $bridge->checkKey($settings[MailerConfig::MAILER_CONFIG_SETTING_NAME]['mailpoet_api_key']);
-        $bridge->updateSubscriberCount($result);
-      }
+      $bridge->onSettingsSave($settings);
       return $this->successResponse(Setting::getAll());
     }
   }

lib/Config/Menu.php

@@ -15,6 +15,7 @@ use MailPoet\Settings\Hosts;
 use MailPoet\Settings\Pages;
 use MailPoet\Subscribers\ImportExport\ImportExportFactory;
 use MailPoet\Util\License\Features\Subscribers as SubscribersFeature;
+use MailPoet\Util\License\License;
 use MailPoet\WP\DateTime;
 use MailPoet\WP\Notice as WPNotice;
 use MailPoet\WP\Readme;
@@ -28,6 +29,7 @@ class Menu {
     $subscribers_feature = new SubscribersFeature();
     $this->subscribers_over_limit = $subscribers_feature->check();
     $this->checkMailPoetAPIKey();
+    $this->checkPremiumKey();
   }
 
   function init() {
@@ -308,6 +310,8 @@ class Menu {
       'segments' => Segment::getSegmentsWithSubscriberCount(),
       'cron_trigger' => CronTrigger::getAvailableMethods(),
       'total_subscribers' => Subscriber::getTotalSubscribers(),
+      'premium_plugin_active' => License::getLicense(),
+      'premium_key_valid' => isset($this->premium_key_valid) ? $this->premium_key_valid : null,
       'pages' => Pages::getAll(),
       'flags' => $flags,
       'current_user' => wp_get_current_user(),
@@ -525,6 +529,15 @@ class Menu {
     }
   }
 
+  function checkPremiumKey(ServicesChecker $checker = null) {
+    if(self::isOnMailPoetAdminPage()) {
+      $show_notices = isset($_REQUEST['page'])
+        && stripos($_REQUEST['page'], 'mailpoet-newsletters') === false;
+      $checker = $checker ?: new ServicesChecker();
+      $this->premium_key_valid = $checker->isPremiumKeyValid($show_notices);
+    }
+  }
+
   private function getLimitPerPage($model = null) {
     if($model === null) {
       return Listing\Handler::DEFAULT_LIMIT_PER_PAGE;

lib/Config/ServicesChecker.php

@@ -5,6 +5,7 @@ use MailPoet\Models\Setting;
 use MailPoet\Models\Subscriber;
 use MailPoet\Services\Bridge;
 use MailPoet\Util\Helpers;
+use MailPoet\Util\License\License;
 use MailPoet\WP\Notice as WPNotice;
 
 if(!defined('ABSPATH')) exit;
@@ -46,4 +47,44 @@ class ServicesChecker {
 
     return true;
   }
+
+  function isPremiumKeyValid($display_error_notice = true) {
+    if(!Bridge::isPremiumKeySpecified()) {
+      return null;
+    }
+
+    $premium_plugin_active = License::getLicense();
+    $result = Setting::getValue(Bridge::PREMIUM_KEY_STATE_SETTING_NAME);
+    if(empty($result['state']) || $result['state'] == Bridge::PREMIUM_KEY_VALID) {
+      return true;
+    }
+
+    if($result['state'] == Bridge::PREMIUM_KEY_INVALID
+      || $result['state'] == Bridge::PREMIUM_KEY_USED
+    ) {
+      $error = Helpers::replaceLinkTags(
+        __('Warning! Your License Key is either invalid or expired. [link]Renew your License now[/link] to enjoy automatic updates and Premium support.', 'mailpoet'),
+        'https://account.mailpoet.com'
+      );
+      if($premium_plugin_active && $display_error_notice) {
+        WPNotice::displayError($error);
+      }
+      return false;
+    } elseif($result['state'] == Bridge::PREMIUM_KEY_EXPIRING
+      && !empty($result['data']['expire_at'])
+    ) {
+      $date = date('Y-m-d', strtotime($result['data']['expire_at']));
+      $error = Helpers::replaceLinkTags(
+        __('Your License Key is expiring! Don\'t forget to [link]renew your license[/link] by %s to keep enjoying automatic updates and Premium support.', 'mailpoet'),
+        'https://account.mailpoet.com'
+      );
+      $error = sprintf($error, $date);
+      if($premium_plugin_active && $display_error_notice) {
+        WPNotice::displayWarning($error);
+      }
+      return true;
+    }
+
+    return false;
+  }
 }

lib/Cron/Daemon.php

@@ -3,6 +3,7 @@ namespace MailPoet\Cron;
 use MailPoet\Cron\Workers\Scheduler as SchedulerWorker;
 use MailPoet\Cron\Workers\SendingQueue\SendingQueue as SendingQueueWorker;
 use MailPoet\Cron\Workers\Bounce as BounceWorker;
+use MailPoet\Cron\Workers\PremiumKeyCheck as PremiumKeyCheckWorker;
 use MailPoet\Cron\Workers\SendingServiceKeyCheck as SendingServiceKeyCheckWorker;
 
 if(!defined('ABSPATH')) exit;
@@ -50,6 +51,7 @@ class Daemon {
       $this->executeScheduleWorker();
       $this->executeQueueWorker();
       $this->executeSendingServiceKeyCheckWorker();
+      $this->executePremiumKeyCheckWorker();
       $this->executeBounceWorker();
     } catch(\Exception $e) {
       // continue processing, no need to handle errors
@@ -87,6 +89,11 @@ class Daemon {
     return $worker->process();
   }
 
+  function executePremiumKeyCheckWorker() {
+    $worker = new PremiumKeyCheckWorker($this->timer);
+    return $worker->process();
+  }
+
   function executeBounceWorker() {
     $bounce = new BounceWorker($this->timer);
     return $bounce->process();

lib/Cron/Triggers/WordPress.php

@@ -5,6 +5,7 @@ use MailPoet\Cron\CronHelper;
 use MailPoet\Cron\Workers\Scheduler as SchedulerWorker;
 use MailPoet\Cron\Workers\SendingQueue\SendingQueue as SendingQueueWorker;
 use MailPoet\Cron\Workers\Bounce as BounceWorker;
+use MailPoet\Cron\Workers\PremiumKeyCheck as PremiumKeyCheckWorker;
 use MailPoet\Cron\Workers\SendingServiceKeyCheck as SendingServiceKeyCheckWorker;
 use MailPoet\Mailer\MailerLog;
 use MailPoet\Services\Bridge;
@@ -32,12 +33,17 @@ class WordPress {
     // sending service key check
     $sskeycheck_due_queues = SendingServiceKeyCheckWorker::getAllDueQueues();
     $sskeycheck_future_queues = SendingServiceKeyCheckWorker::getFutureQueues();
+    // premium key check
+    $premium_key_specified = Bridge::isPremiumKeySpecified();
+    $premium_keycheck_due_queues = PremiumKeyCheckWorker::getAllDueQueues();
+    $premium_keycheck_future_queues = PremiumKeyCheckWorker::getFutureQueues();
     // check requirements for each worker
     $sending_queue_active = (($scheduled_queues || $running_queues) && !$sending_limit_reached && !$sending_is_paused);
     $bounce_sync_active = ($mp_sending_enabled && ($bounce_due_queues || !$bounce_future_queues));
     $sending_service_key_check_active = ($mp_sending_enabled && ($sskeycheck_due_queues || !$sskeycheck_future_queues));
+    $premium_key_check_active = ($premium_key_specified && ($premium_keycheck_due_queues || !$premium_keycheck_future_queues));
 
-    return ($sending_queue_active || $bounce_sync_active || $sending_service_key_check_active);
+    return ($sending_queue_active || $bounce_sync_active || $sending_service_key_check_active || $premium_key_check_active);
   }
 
   static function cleanup() {

lib/Cron/Workers/PremiumKeyCheck.php

@@ -0,0 +1,146 @@
+<?php
+namespace MailPoet\Cron\Workers;
+
+use Carbon\Carbon;
+use MailPoet\Cron\CronHelper;
+use MailPoet\Models\SendingQueue;
+use MailPoet\Models\Setting;
+use MailPoet\Services\Bridge;
+
+if(!defined('ABSPATH')) exit;
+
+class PremiumKeyCheck {
+  const TASK_TYPE = 'premium_key_check';
+  const UNAVAILABLE_SERVICE_RESCHEDULE_TIMEOUT = 60;
+
+  public $timer;
+  public $bridge;
+
+  function __construct($timer = false) {
+    $this->timer = ($timer) ? $timer : microtime(true);
+    // abort if execution limit is reached
+    CronHelper::enforceExecutionLimit($this->timer);
+  }
+
+  function initApi() {
+    if(!$this->bridge) {
+      $this->bridge = new Bridge();
+    }
+  }
+
+  function process() {
+    if(!Bridge::isPremiumKeySpecified()) {
+      return false;
+    }
+
+    $this->initApi();
+
+    $scheduled_queues = self::getScheduledQueues();
+    $running_queues = self::getRunningQueues();
+
+    if(!$scheduled_queues && !$running_queues) {
+      self::schedule();
+      return false;
+    }
+
+    foreach($scheduled_queues as $i => $queue) {
+      $this->prepareQueue($queue);
+    }
+    foreach($running_queues as $i => $queue) {
+      $this->processQueue($queue);
+    }
+
+    return true;
+  }
+
+  static function schedule() {
+    $already_scheduled = SendingQueue::where('type', self::TASK_TYPE)
+      ->whereNull('deleted_at')
+      ->where('status', SendingQueue::STATUS_SCHEDULED)
+      ->findMany();
+    if($already_scheduled) {
+      return false;
+    }
+    $queue = SendingQueue::create();
+    $queue->type = self::TASK_TYPE;
+    $queue->status = SendingQueue::STATUS_SCHEDULED;
+    $queue->priority = SendingQueue::PRIORITY_LOW;
+    $queue->scheduled_at = self::getNextRunDate();
+    $queue->newsletter_id = 0;
+    $queue->save();
+    return $queue;
+  }
+
+  function prepareQueue(SendingQueue $queue) {
+    $queue->status = null;
+    $queue->save();
+
+    // abort if execution limit is reached
+    CronHelper::enforceExecutionLimit($this->timer);
+
+    return true;
+  }
+
+  function processQueue(SendingQueue $queue) {
+    // abort if execution limit is reached
+    CronHelper::enforceExecutionLimit($this->timer);
+
+    try {
+      $premium_key = Setting::getValue(Bridge::PREMIUM_KEY_STATE_SETTING_NAME);
+      $result = $this->bridge->checkPremiumKey($premium_key);
+    } catch (\Exception $e) {
+      $result = false;
+    }
+
+    if(empty($result['code']) || $result['code'] == Bridge::CHECK_ERROR_UNAVAILABLE) {
+      // reschedule the check
+      $scheduled_at = Carbon::createFromTimestamp(current_time('timestamp'));
+      $queue->scheduled_at = $scheduled_at->addMinutes(
+        self::UNAVAILABLE_SERVICE_RESCHEDULE_TIMEOUT
+      );
+      $queue->save();
+      return false;
+    }
+
+    $queue->processed_at = current_time('mysql');
+    $queue->status = SendingQueue::STATUS_COMPLETED;
+    $queue->save();
+
+    return true;
+  }
+
+  static function getNextRunDate() {
+    $date = Carbon::createFromTimestamp(current_time('timestamp'));
+    // Random day of the next week
+    $date->setISODate($date->format('o'), $date->format('W') + 1, mt_rand(1, 7));
+    $date->startOfDay();
+    return $date;
+  }
+
+  static function getScheduledQueues($future = false) {
+    $dateWhere = ($future) ? 'whereGt' : 'whereLte';
+    return SendingQueue::where('type', self::TASK_TYPE)
+      ->$dateWhere('scheduled_at', Carbon::createFromTimestamp(current_time('timestamp')))
+      ->whereNull('deleted_at')
+      ->where('status', SendingQueue::STATUS_SCHEDULED)
+      ->findMany();
+  }
+
+  static function getRunningQueues() {
+    return SendingQueue::where('type', self::TASK_TYPE)
+      ->whereLte('scheduled_at', Carbon::createFromTimestamp(current_time('timestamp')))
+      ->whereNull('deleted_at')
+      ->whereNull('status')
+      ->findMany();
+  }
+
+  static function getAllDueQueues() {
+    $scheduled_queues = self::getScheduledQueues();
+    $running_queues = self::getRunningQueues();
+    return array_merge((array)$scheduled_queues, (array)$running_queues);
+  }
+
+  static function getFutureQueues() {
+    return self::getScheduledQueues(true);
+  }
+}

lib/Services/Bridge.php

@@ -9,6 +9,7 @@ if(!defined('ABSPATH')) exit;
 
 class Bridge {
   const API_KEY_STATE_SETTING_NAME = 'mta.mailpoet_api_key_state';
+  const PREMIUM_KEY_STATE_SETTING_NAME = 'premium.premium_key_state';
 
   const MAILPOET_KEY_VALID = 'valid';
   const MAILPOET_KEY_INVALID = 'invalid';
@@ -16,6 +17,13 @@ class Bridge {
 
   const MAILPOET_KEY_CHECK_ERROR = 'check_error';
 
+  const PREMIUM_KEY_VALID = 'valid';
+  const PREMIUM_KEY_INVALID = 'invalid';
+  const PREMIUM_KEY_EXPIRING = 'expiring';
+  const PREMIUM_KEY_USED = 'used';
+
+  const PREMIUM_KEY_CHECK_ERROR = 'check_error';
+
   const CHECK_ERROR_UNAVAILABLE = 503;
   const CHECK_ERROR_UNKNOWN = 'unknown';
 
@@ -31,6 +39,11 @@ class Bridge {
     }
   }
 
+  static function isPremiumKeySpecified() {
+    $key = Setting::getValue(self::PREMIUM_KEY_STATE_SETTING_NAME);
+    return !empty($key);
+  }
+
   function initApi($api_key) {
     if($this->api) {
       $this->api->setKey($api_key);
@@ -77,6 +90,50 @@ class Bridge {
     return $state;
   }
 
+  function checkPremiumKey($key) {
+    $this->initApi($key);
+    $result = $this->api->checkPremiumKey();
+    return $this->processPremiumKeyCheckResult($result);
+  }
+
+  function processPremiumKeyCheckResult(array $result) {
+    $state_map = array(
+      200 => self::PREMIUM_KEY_VALID,
+      401 => self::PREMIUM_KEY_INVALID,
+      402 => self::PREMIUM_KEY_USED
+    );
+
+    $update_settings = false;
+
+    if(!empty($result['code']) && isset($state_map[$result['code']])) {
+      if($result['code'] == self::PREMIUM_KEY_VALID
+        && !empty($result['data']['expire_at'])
+      ) {
+        $key_state = self::PREMIUM_KEY_EXPIRING;
+      } else {
+        $key_state = $state_map[$result['code']];
+      }
+      $update_settings = true;
+    } else {
+      $key_state = self::PREMIUM_KEY_CHECK_ERROR;
+    }
+
+    $state = array(
+      'state' => $key_state,
+      'data' => !empty($result['data']) ? $result['data'] : null,
+      'code' => !empty($result['code']) ? $result['code'] : self::CHECK_ERROR_UNKNOWN
+    );
+
+    if($update_settings) {
+      Setting::setValue(
+        self::PREMIUM_KEY_STATE_SETTING_NAME,
+        $state
+      );
+    }
+
+    return $state;
+  }
+
   function updateSubscriberCount($result) {
     if(!empty($result['state'])
       && ($result['state'] === self::MAILPOET_KEY_VALID
@@ -93,4 +150,16 @@ class Bridge {
       array('state' => self::MAILPOET_KEY_INVALID)
     );
   }
+
+  function onSettingsSave($settings) {
+    $api_key_set = !empty($settings[Mailer::MAILER_CONFIG_SETTING_NAME]['mailpoet_api_key']);
+    $premium_key_set = !empty($settings['premium']['premium_key']);
+    if($api_key_set && self::isMPSendingServiceEnabled()) {
+      $result = $this->checkKey($settings[Mailer::MAILER_CONFIG_SETTING_NAME]['mailpoet_api_key']);
+      $this->updateSubscriberCount($result);
+    }
+    if($premium_key_set) {
+      $this->checkPremiumKey($settings['premium']['premium_key']);
+    }
+  }
 }

lib/Services/Bridge/API.php

@@ -15,6 +15,7 @@ class API {
   private $api_key;
 
   public $url_me = 'https://bridge.mailpoet.com/api/v0/me';
+  public $url_premium = 'https://bridge.mailpoet.com/api/v0/premium';
   public $url_messages = 'https://bridge.mailpoet.com/api/v0/messages';
   public $url_bounces = 'https://bridge.mailpoet.com/api/v0/bounces/search';
   public $url_stats = 'https://bridge.mailpoet.com/api/v0/stats';
@@ -46,6 +47,28 @@ class API {
     return array('code' => $code, 'data' => $body);
   }
 
+  function checkPremiumKey() {
+    $result = $this->request(
+      $this->url_premium,
+      array('site' => home_url())
+    );
+
+    $code = wp_remote_retrieve_response_code($result);
+    switch($code) {
+      case 200:
+        if($body = wp_remote_retrieve_body($result)) {
+          $body = json_decode($body, true);
+        }
+        break;
+      default:
+        $body = null;
+        break;
+    }
+
+    return array('code' => $code, 'data' => $body);
+  }
+
+
   function sendMessages($message_body) {
     $result = $this->request(
       $this->url_messages,

tests/unit/Services/BridgeTestMockAPI.php

@@ -13,12 +13,19 @@ class MockAPI {
   }
 
   function checkKey() {
-    // if key begins with these codes, return them
+    // if a key begins with these codes, return them
     $regex = '/^(401|402|503)/';
     $code = preg_match($regex, $this->api_key, $m) ? $m[1] : 200;
     return $this->processResponse($code);
   }
 
+  function checkPremiumKey() {
+    // if a key begins with these codes, return them
+    $regex = '/^(401|402|503)/';
+    $code = preg_match($regex, $this->api_key, $m) ? $m[1] : 200;
+    return $this->processPremiumResponse($code);
+  }
+
   function updateSubscriberCount($count) {
     return true;
   }
@@ -47,4 +54,22 @@ class MockAPI {
 
     return array('code' => $code, 'data' => $body);
   }
+
+  private function processPremiumResponse($code) {
+    switch($code) {
+      case 200:
+        $body = array(
+          'expire_at' => Carbon::createFromTimestamp(current_time('timestamp'))
+            ->addMonth()->format('c')
+        );
+        break;
+      case 401:
+      case 402:
+      default:
+        $body = null;
+        break;
+    }
+
+    return array('code' => $code, 'data' => $body);
+  }
 }

views/settings.html

@@ -19,6 +19,7 @@
         <a class="nav-tab" href="#signup"><%= __('Sign-up Confirmation') %></a>
         <a class="nav-tab" href="#mta"><%= __('Send With...') %></a>
         <a class="nav-tab" href="#advanced"><%= __('Advanced') %></a>
+        <a class="nav-tab" href="#premium"><%= __('Premium') %></a>
       </h2>
 
       <!-- basics -->
@@ -41,6 +42,11 @@
         <% include 'settings/advanced.html' %>
       </div>
 
+      <!-- premium -->
+      <div data-tab="premium" class="mailpoet_panel">
+        <% include 'settings/premium.html' %>
+      </div>
+
       <p class="submit mailpoet_settings_submit" style="display:none;">
         <input
           type="submit"

views/settings/premium.html

@@ -0,0 +1,112 @@
+<table class="form-table">
+  <tbody>
+    <!-- premium key -->
+    <tr>
+      <th scope="row">
+        <label for="mailpoet_premium_key">
+          <%= __('Premium License Key') %>
+        </label>
+        <p class="description">
+          <%= __('This key is used for automatic upgrades of your Premium features and access to support.') %>
+        </p>
+      </th>
+      <td>
+        <div>
+          <input
+            type="text"
+            class="regular-text"
+            id="mailpoet_premium_key"
+            name="premium[premium_key]"
+            value="<%=- settings.premium.premium_key -%>"
+          />
+          <a
+            id="mailpoet_premium_key_verify"
+            class="button-secondary"
+          ><%= __('Verify') %></a>
+        </div>
+        <div
+          class="mailpoet_premium_key_valid mailpoet_success"
+          <% if not(settings.premium.premium_key) or not(premium_key_valid) %>
+            style="display: none;"
+          <% endif %>
+        >
+          ✔ <%= __('Your license key has been successfully validated.') %>
+        </div>
+        <div
+          class="mailpoet_premium_key_invalid mailpoet_error"
+          <% if not(settings.premium.premium_key) or premium_key_valid %>
+            style="display: none;"
+          <% endif %>
+        >
+          ✗ <%= __('Your license key is invalid.') %>
+        </div>
+        <br/>
+        <div
+          <% if premium_plugin_active or not(premium_key_valid) %>
+            style="display: none;"
+          <% endif %>
+        >
+          <a class="button-primary" href="#"><%= __('Download Premium now.') %></a>
+          <span>
+            <%= __("[link]Read guide[/link] on how to install Premium.")
+              |replace({
+                '[link]': '<a target="_blank" href="http://beta.docs.mailpoet.com/article/194-instructions-to-install-the-premium-plugin">',
+                '[/link]': '</a>'
+                })
+              |raw
+            %>
+           </span>
+        </div>
+      </td>
+    </tr>
+  </tbody>
+</table>
+
+<script type="text/javascript">
+  jQuery(function($) {
+    $(function() {
+      // verifying premium key
+      $('#mailpoet_premium_key_verify').on('click', function() {
+        // get premium key
+        var key = $('#mailpoet_premium_key').val();
+
+        if(key.length === 0) {
+          // validation
+          return MailPoet.Notice.error(
+            '<%= __('Please specify a Premium key before validating it.') | escape('js') %>',
+            { scroll: true }
+          );
+        }
+
+        $('.mailpoet_premium_key_valid, .mailpoet_premium_key_invalid').hide();
+        MailPoet.Modal.loading(true);
+        MailPoet.Ajax.post({
+          api_version: window.mailpoet_api_version,
+          endpoint: 'services',
+          action: 'verifyPremiumKey',
+          data: {
+            key: key
+          }
+        }).always(function() {
+          MailPoet.Modal.loading(false);
+        }).done(function(response) {
+          // Hide server error notices
+          $('.mailpoet_notice_server').hide();
+          MailPoet.Notice.success(
+            response.data.message,
+            { scroll: true }
+          );
+          $('.mailpoet_premium_key_valid').show();
+        }).fail(function(response) {
+          if (response.errors.length > 0) {
+            MailPoet.Notice.error(
+              response.errors.map(function(error) { return error.message; }),
+              { scroll: true }
+            );
+            $('.mailpoet_premium_key_invalid').show();
+          }
+        });
+      });
+    });
+  });
+</script>