Govor/Govor.API/Hubs/ChatsHub.cs

using Govor.API.Services;
using Govor.Application.Interfaces;
using Govor.Application.Interfaces.Messages;
using Govor.Application.Interfaces.Messages.Parameters;
using Govor.Contracts.Requests.SignalR;
using Govor.Contracts.Responses.SignalR;
using Govor.Core.Models;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;

namespace Govor.API.Hubs;

[Authorize] // api/chats
public class ChatsHub : Hub
{
    private readonly ILogger<ChatsHub> _logger;
    private readonly IMessageCommandService _messageCommandService;
    private readonly IUserGroupsService _userService;

    public ChatsHub(ILogger<ChatsHub> logger, IMessageCommandService messageCommandService, IUserGroupsService userService)
    {
        _logger = logger;
        _messageCommandService = messageCommandService;
        _userService = userService;
    }

    public override async Task OnConnectedAsync()
    {
        var userId = GetUserId();
        if (userId == Guid.Empty)
        {
            _logger.LogWarning("User connected with invalid UserID claim.");
            Context.Abort(); // Abort connection if userID is invalid
            return;
        }

        // Add user to their own group (for private messages and notifications)
        await Groups.AddToGroupAsync(Context.ConnectionId, userId.ToString());
        _logger.LogInformation("User {UserId} connected with ConnectionId {ConnectionId} and added to their group",
            userId, Context.ConnectionId);

        var userGroups = await _userService.GetUserGroupsAsync(userId);
        foreach (var group in userGroups)
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, $"group_{group.Id}");
        }

        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        var userId =
            GetUserId(suppressException: true); // Suppress exception if userID is not found (e.g. connection aborted early)
        if (userId != Guid.Empty)
        {
            // Remove user from their own group
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, userId.ToString());
            _logger.LogInformation(
                "User {UserId} disconnected with ConnectionId {ConnectionId} and removed from their group", userId,
                Context.ConnectionId);

            var userGroups =
                await _userService
                    .GetUserGroupsAsync(
                        userId); // This might be problematic if the service relies on the user being connected
            foreach (var group in userGroups)
            {
                await Groups.RemoveFromGroupAsync(Context.ConnectionId, $"group_{group.Id}");
            }
        }
        else if (exception != null)
        {
            _logger.LogWarning(exception,
                "User disconnected with an exception and invalid UserID claim. ConnectionId: {ConnectionId}",
                Context.ConnectionId);
        }
        else
        {
            _logger.LogInformation(
                "User disconnected with no exception and invalid UserID claim. ConnectionId: {ConnectionId}",
                Context.ConnectionId);
        }

        await base.OnDisconnectedAsync(exception);
    }

    public async Task Send(MessageRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.EncryptedContent) &&
            (request.MediaAttachments == null || !request.MediaAttachments.Any()))
        {
            _logger.LogWarning("Empty message (no content and no attachments) received from user {UserId}",
                GetUserId());
            throw new ArgumentException("Message cannot be empty (must have content or attachments).");
        }

        var senderId = GetUserId();
        _logger.LogInformation("Message send initiated by {SenderId} to {RecipientId} of type {RecipientType}",
            senderId, request.RecipientId, request.RecipientType);

        var sendMessageParams = new SendMessage(EncryptContent: request.EncryptedContent,
            ReplyToMessageId: request.ReplyToMessageId, FromUserId: senderId, RecipientId: request.RecipientId,
            RecipientType: request.RecipientType, SendAt: DateTime.UtcNow,
            Media: request.MediaAttachments?.Select(f => new SendMedia(f.MediaId, f.EncryptedKey)) ??
                   Array.Empty<SendMedia>());

        var result = await _messageCommandService.SendMessageAsync(sendMessageParams);

        if (!result.IsSuccess || result.Message.Id == Guid.Empty)
        {
            _logger.LogError(result.Exception,
                "Failed to send message from {SenderId} to {RecipientId}. Error: {ErrorMessage}", senderId,
                request.RecipientId, result.Exception?.Message ?? "Unknown error");
            if (result.Exception != null)
                throw result.Exception;
            throw new HubException("Failed to send message due to an internal error.");
        }

        var messageResponse = new UserMessageResponse // Assuming a response DTO
        {
            MessageId = result.Message.Id,
            SenderId = result.Message.SenderId,
            RecipientId = result.Message.RecipientId,
            RecipientType = result.Message.RecipientType,
            EncryptedContent = result.Message.EncryptedContent,
            SentAt = result.Message.SentAt,
            IsEdited = false,
            MediaAttachments = result.Message.MediaAttachments.Select(m => m.MediaFile).ToList(),
            ReplyToMessageId = request.ReplyToMessageId
        };

        // Notify recipient (user or group)
        if (request.RecipientType == RecipientType.User)
        {
            // Send to the recipient's personal group
            await Clients.Group(request.RecipientId.ToString()).SendAsync("ReceiveMessage", messageResponse);
        }
        else if (request.RecipientType == RecipientType.Group)
        {
            // Send to all members of the group, including the sender if they are part of the group via a different connection
            await Clients.Group($"group_{request.RecipientId}").SendAsync("ReceiveMessage", messageResponse);
        }

        // Notify sender (confirmation) on their connection
        await Clients.Caller.SendAsync("MessageSent",
            messageResponse); // Or use "ReceiveMessage" if the sender should also just get it like anyone else

        _logger.LogInformation(
            "Message {MessageId} sent successfully from {SenderId} to {RecipientId} ({RecipientType})",
            result.Message.Id, senderId, request.RecipientId, request.RecipientType);
    }

    public async Task Remove(RemoveMessageRequest request)
    {
    }

    public async Task Edit(EditMessageRequest request)
    {
    }

    private Guid GetUserId(bool suppressException = false)
    {
        var userIdClaim = Context.User?.FindFirst("userId")?.Value;
        if (string.IsNullOrEmpty(userIdClaim) || !Guid.TryParse(userIdClaim, out var userId))
        {
            if (!suppressException)
            {
                _logger.LogError("Could not retrieve sender userId. Claim was: {UserIDClaim}", userIdClaim);
                throw new UnauthorizedAccessException("userID claim is missing or invalid.");
            }

            return Guid.Empty;
        }

        return userId;
    }
}