public function findMessages($state = false)
{
$user_id = $this->id;
$unreadMessages = Message::whereHas('messageStates', function ($q) use(&$user_id, &$state) {
$q->where('user_id', '=', $user_id);
if ($state) {
$q->where('state', '=', MessageState::indexOf($state));
}
})->with('conversation')->get();
return $unreadMessages;
}
