module.exports = Ferdium => {
  const getMessages = () => {
    let count = 0;

    const unreadRed = document.querySelector('.unread-red');
    if (unreadRed !== null) {
      switch (unreadRed.classList[1]) {
        case 'fa-num1':
          count = 1;
          break;
        case 'fa-num2':
          count = 2;
          break;
        case 'fa-num3':
          count = 3;
          break;
        case 'fa-num4':
          count = 4;
          break;
        case 'fa-num5':
          count = 5;
          break;
        default: {
          // fa-num5plus
          const convUnread = document.querySelectorAll('.conv-unread:not(.func-unread__muted)');
          if (convUnread.length === 0)
            count = 6; // 5+
          else
            for (const convUnreadItem of convUnread) {
              switch (convUnreadItem.classList[1]) {
                case 'fa-1_24_Line':
                  count = count + 1;
                  break;
                case 'fa-2_24_Line':
                  count = count + 2;
                  break;
                case 'fa-3_24_Line':
                  count = count + 3;
                  break;
                case 'fa-4_24_Line':
                  count = count + 4;
                  break;
                case 'fa-5_24_Line':
                  count = count + 5;
                  break;
                default: // fa-5plus_24_Line
                  count = count + 6;
              }
            }
        }
      }
    }
    Ferdium.setBadge(count);
  };
  Ferdium.loop(getMessages);
};