using GB5Shared.DTO.Framework.Login;
using Microsoft.AspNetCore.SignalR;
using Microsoft.Extensions.Logging;

namespace PERMSL.Hubs;

public class PermNotificationHub : Hub<IPermNotificationClient>
{
    private readonly ILogger<PermNotificationHub> _logger;

    public PermNotificationHub(ILogger<PermNotificationHub> logger) => _logger = logger;

    public override async Task OnConnectedAsync()
    {
        var login = GetLoginDTO();
        await Groups.AddToGroupAsync(Context.ConnectionId, HubGroup(login));
        _logger.LogInformation("PermNotification connected: {ConnectionId} employee {EmployeeId}",
            Context.ConnectionId, login.UserId);
        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        var login = GetLoginDTO();
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, HubGroup(login));
        if (exception is not null)
            _logger.LogWarning(exception, "PermNotification disconnected with error: {ConnectionId}",
                Context.ConnectionId);
        await base.OnDisconnectedAsync(exception);
    }

    private LoginDTO GetLoginDTO()
    {
        var http = Context.GetHttpContext()
            ?? throw new InvalidOperationException("Hub invoked outside HTTP context.");
        var raw = http.Request.Headers["Login"].FirstOrDefault()
            ?? throw new InvalidOperationException("Login header missing.");
        return System.Text.Json.JsonSerializer.Deserialize<LoginDTO>(raw)
            ?? throw new InvalidOperationException("Login header is invalid JSON.");
    }

    internal static string HubGroup(LoginDTO login) => $"perm:user:{login.UserId}";
}