Nexus.Reader/src/NexusReader.Infrastructure/RealTime/SyncHub.cs

using MediatR;
using Microsoft.AspNetCore.SignalR;
using Microsoft.AspNetCore.Authorization;
using NexusReader.Application.Commands.Sync;

namespace NexusReader.Infrastructure.RealTime;

[Authorize]
public class SyncHub : Hub
{
    private readonly IMediator _mediator;

    public SyncHub(IMediator mediator)
    {
        _mediator = mediator;
    }

    public async Task UpdateProgress(string pageId)
    {
        var userId = Context.UserIdentifier;
        if (!string.IsNullOrEmpty(userId))
        {
            await _mediator.Send(new UpdateReadingProgressCommand(pageId, userId));
        }
    }

    public override async Task OnConnectedAsync()
    {
        var userId = Context.UserIdentifier;
        if (!string.IsNullOrEmpty(userId))
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, $"User_{userId}");
        }
        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        var userId = Context.UserIdentifier;
        if (!string.IsNullOrEmpty(userId))
        {
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, $"User_{userId}");
        }
        await base.OnDisconnectedAsync(exception);
    }
}