(function() {
  'use strict';
  window.Whisper = window.Whisper || {};
  Whisper.ReadSyncs = new (Backbone.Collection.extend({
    forMessage: function(message) {
      var receipt = this.findWhere({
        sender: message.get('source'),
        timestamp: message.get('sent_at'),
      });
      if (receipt) {
        console.log('Found early read sync for message');
        this.remove(receipt);
        return receipt;
      }
    },
    onReceipt: function(receipt) {
      var messages = new Whisper.MessageCollection();
      return messages.fetchSentAt(receipt.get('timestamp')).then(
        function() {
          var message = messages.find(function(message) {
            return (
              message.isIncoming() &&
              message.isUnread() &&
              message.get('source') === receipt.get('sender')
            );
          });
          const notificationForMessage = message
            ? Whisper.Notifications.findWhere({ messageId: message.id })
            : null;
          const removedNotification = Whisper.Notifications.remove(
            notificationForMessage
          );
          const receiptSender = receipt.get('sender');
          const receiptTimestamp = receipt.get('timestamp');
          const wasMessageFound = Boolean(message);
          const wasNotificationFound = Boolean(notificationForMessage);
          const wasNotificationRemoved = Boolean(removedNotification);
          console.log('Receive read sync:', {
            receiptSender,
            receiptTimestamp,
            wasMessageFound,
            wasNotificationFound,
            wasNotificationRemoved,
          });
          return message
            ? message.markRead(receipt.get('read_at')).then(
                function() {
                  // This notification may result in messages older than this one being
                  //   marked read. We want those messages to have the same expire timer
                  //   start time as this one, so we pass the read_at value through.
                  this.notifyConversation(message, receipt.get('read_at'));
                  this.remove(receipt);
                }.bind(this)
              )
            : Promise.resolve();
        }.bind(this)
      );
    },
    notifyConversation: function(message, readAt) {
      var conversation = ConversationController.get({
        id: message.get('conversationId'),
      });

      if (conversation) {
        conversation.onReadMessage(message, readAt);
      }
    },
  }))();
})();