erp-platform/api/src/Kurs.Platform.HttpApi.Host/Classroom/ClassroomHub.cs

using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using Volo.Abp.Domain.Repositories;
using Kurs.Platform.Entities;
using Microsoft.Extensions.Logging;
using Volo.Abp.Guids;
using Volo.Abp.Users;

namespace Kurs.Platform.SignalR.Hubs;

[Authorize]
public class ClassroomHub : Hub
{
    private readonly IRepository<Classroom, Guid> _classSessionRepository;
    private readonly IRepository<ClassParticipant, Guid> _participantRepository;
    private readonly IRepository<ClassChat, Guid> _chatMessageRepository;
    private readonly ILogger<ClassroomHub> _logger;
    private readonly IGuidGenerator _guidGenerator;
    private readonly ICurrentUser _currentUser;

    public ClassroomHub(
        IRepository<Classroom, Guid> classSessionRepository,
        IRepository<ClassParticipant, Guid> participantRepository,
        IRepository<ClassChat, Guid> chatMessageRepository,
        ILogger<ClassroomHub> logger,
        IGuidGenerator guidGenerator,
        ICurrentUser currentUser)
    {
        _classSessionRepository = classSessionRepository;
        _participantRepository = participantRepository;
        _chatMessageRepository = chatMessageRepository;
        _logger = logger;
        _guidGenerator = guidGenerator;
        _currentUser = currentUser;
    }

    [HubMethodName("JoinClass")]
    public async Task JoinClassAsync(Guid sessionId, string userName)
    {
        var classSession = await _classSessionRepository.GetAsync(sessionId);

        if (!classSession.CanJoin())
        {
            await Clients.Caller.SendAsync("Error", "Cannot join this class at this time");
            return;
        }

        // Add to SignalR group
        await Groups.AddToGroupAsync(Context.ConnectionId, sessionId.ToString());

        // Update participant connection
        var participant = await _participantRepository.FirstOrDefaultAsync(
            x => x.SessionId == sessionId && x.UserId == _currentUser.Id
        );

        if (participant != null)
        {
            participant.UpdateConnectionId(Context.ConnectionId);
            await _participantRepository.UpdateAsync(participant);
        }

        // Notify others
        await Clients.Group(sessionId.ToString())
            .SendAsync("ParticipantJoined", _currentUser.Id, userName);
        _logger.LogInformation($"User {userName} joined class {sessionId}");
    }

    [HubMethodName("LeaveClass")]
    public async Task LeaveClassAsync(Guid sessionId)
    {
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, sessionId.ToString());
        await Clients.Group(sessionId.ToString())
            .SendAsync("ParticipantLeft", _currentUser);
        _logger.LogInformation($"User {_currentUser} left class {sessionId}");
    }

    public async Task SendSignalingMessageAsync(SignalingMessageDto message)
    {
        // Forward WebRTC signaling messages
        await Clients.User(message.ToUserId)
            .SendAsync("ReceiveSignalingMessage", message);
        _logger.LogInformation($"Signaling message sent from {message.FromUserId} to {message.ToUserId}");
    }

    public async Task SendChatMessageAsync(Guid sessionId, string message)
    {
        var userName = _currentUser.UserName;
        var userId = _currentUser.Id;

        // Check if user is teacher
        var participant = await _participantRepository.FirstOrDefaultAsync(
            x => x.SessionId == sessionId && x.UserId == userId
        );

        var isTeacher = participant?.IsTeacher ?? false;

        // Save message to database
        var chatMessage = new ClassChat(
            _guidGenerator.Create(),
            sessionId,
            userId,
            userName,
            message,
            isTeacher
        );

        await _chatMessageRepository.InsertAsync(chatMessage);

        // Send to all participants
        await Clients.Group(sessionId.ToString())
            .SendAsync("ChatMessage", new
            {
                Id = chatMessage.Id,
                SenderId = chatMessage.SenderId,
                SenderName = chatMessage.SenderName,
                Message = chatMessage.Message,
                Timestamp = chatMessage.Timestamp,
                IsTeacher = chatMessage.IsTeacher
            });
    }

    public async Task MuteParticipantAsync(Guid sessionId, Guid participantId, bool isMuted)
    {
        var teacherParticipant = await _participantRepository.FirstOrDefaultAsync(
            x => x.SessionId == sessionId && x.UserId == _currentUser.Id
        );

        if (teacherParticipant?.IsTeacher != true)
        {
            await Clients.Caller.SendAsync("Error", "Only teachers can mute participants");
            return;
        }

        var participant = await _participantRepository.FirstOrDefaultAsync(
            x => x.SessionId == sessionId && x.UserId == participantId
        );

        if (participant != null)
        {
            if (isMuted)
                participant.MuteAudio();
            else
                participant.UnmuteAudio();

            await _participantRepository.UpdateAsync(participant);

            // Notify the participant and others
            await Clients.Group(sessionId.ToString())
                .SendAsync("ParticipantMuted", participantId, isMuted);
        }
    }

    public override async Task OnDisconnectedAsync(Exception exception)
    {
        // Handle cleanup when user disconnects
        var userId = _currentUser.Id;
        if (userId.HasValue)
        {
            var participants = await _participantRepository.GetListAsync(
                x => x.UserId == userId.Value && x.ConnectionId == Context.ConnectionId
            );
            foreach (var participant in participants)
            {
                await Clients.Group(participant.SessionId.ToString())
                    .SendAsync("ParticipantLeft", userId.Value);
            }
        }

        await base.OnDisconnectedAsync(exception);
    }
}

public class SignalingMessageDto
{
    public string Type { get; set; } // offer, answer, ice-candidate
    public string FromUserId { get; set; }
    public string ToUserId { get; set; }
    public object Data { get; set; }
}