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

namespace FrameworkSL.Hubs.Dashboard
{
    /// <summary>
    /// DashboardHub — server-push hub so an open dashboard can refetch a widget's data the moment
    /// its underlying dataset actually changes (FFINANCE posting run, KPI posting run, a BRS
    /// instrument status change, a new Compliance alert, ...), instead of only on a manual reload
    /// or a fixed poll interval. Mirrors SysJobHub's own shape exactly.
    ///
    /// Clients connect and are placed into a tenant-scoped group — a dashboard's "did this
    /// dataset/OU change" question is tenant-wide, not per-user.
    ///
    /// No client-initiated methods — this hub is server-push only.
    /// </summary>
    public class DashboardHub(ILogger<DashboardHub> _logger) : Hub<IDashboardClient>
    {
        internal static string TenantGroup(int clientId) => $"dashboard:client:{clientId}";

        public override async Task OnConnectedAsync()
        {
            var login = GetLoginDTO();
            await Groups.AddToGroupAsync(Context.ConnectionId, TenantGroup(login.ClientId));
            _logger.LogInformation("DashboardHub connected: {ConnectionId} tenant {ClientId}",
                Context.ConnectionId, login.ClientId);
            await base.OnConnectedAsync();
        }

        public override async Task OnDisconnectedAsync(Exception? exception)
        {
            var login = GetLoginDTO();
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, TenantGroup(login.ClientId));

            if (exception is not null)
                _logger.LogWarning(exception, "DashboardHub 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.");
        }
    }
}