public ICollection <Model.ChatRoom> GetChatRoomsForUser(Guid userId)
{
var chatRoomUsers = _chatRoomUserRepository.Where(x => x.UserId == userId);
if (!chatRoomUsers.Any())
{
return(new List <Model.ChatRoom>());
}
var chatRoomUserIds = chatRoomUsers.Select(x => x.ChatRoomId).Distinct().ToList();
var rooms = _chatRoomRepository.Where(x => chatRoomUserIds.Contains(x.Id)).ToList();
return(rooms);
}