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

namespace FrameworkSL.Hubs.SysJob
{
    /// <summary>
    /// SysJobHub — server-push hub for real-time SysJob execution progress.
    ///
    /// Clients connect and are placed into a tenant-scoped group.
    /// SysJobExecutorQuartzJob injects IHubContext&lt;SysJobHub, ISysJobClient&gt; to push
    /// job lifecycle events (started / completed / retrying / failed) to all connected
    /// clients for that tenant.
    ///
    /// No client-initiated methods — this hub is server-push only.
    /// </summary>
    public class SysJobHub(ILogger<SysJobHub> _logger) : Hub<ISysJobClient>
    {
        // ── Group naming ──────────────────────────────────────────────────

        /// <summary>Tenant-scoped group — all connected clients for a given client/tenant.</summary>
        internal static string TenantGroup(int clientId) => $"sysjob:client:{clientId}";

        /// <summary>User-scoped group — used for targeted pushes (e.g. JobShared notifications).</summary>
        internal static string UserGroup(int userId) => $"sysjob:user:{userId}";

        // ── Connection lifecycle ──────────────────────────────────────────

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

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

            if (exception is not null)
                _logger.LogWarning(exception, "SysJobHub disconnected with error: {ConnectionId}",
                    Context.ConnectionId);

            await base.OnDisconnectedAsync(exception);
        }

        // ── Helper ────────────────────────────────────────────────────────

        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.");
        }
    }
}