using DXPSL.Common;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;

namespace DXPSL.Hubs;

// Real-time push for PO/ASN/Invoice status (Part 2/Part 3 of the DXP plan — "Universal Inbox").
// Caller identity is reconstructed ONLY from the validated JWT the ASP.NET Core JWT bearer
// middleware already attached to HttpContext.User (see Program.cs's OnMessageReceived hook that
// lets SignalR's WebSocket transport carry the token via ?access_token=, since browsers cannot
// set a custom Authorization header on the transport handshake) — never trusted from a hub
// method parameter, same rule CLAUDE.md states for every other Hub in this repo.
//
// [Authorize] is required here (unlike CLAUDE.md's CollabHub example, which relies on the
// internal LoginDTO-header trust model with no ASP.NET auth middleware in play at all) — DXPHub
// sits behind real JWT bearer middleware, and without this attribute SignalR would accept an
// unauthenticated connection (Context.User would just be an empty ClaimsPrincipal, silently
// landing in the "dxp:party:0" group instead of being rejected).
[Authorize]
public class DXPHub : Hub<IDXPHubClient>
{
    private readonly ILogger<DXPHub> _logger;

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

    public override async Task OnConnectedAsync()
    {
        var caller = DXPCallerContext.FromClaims(Context.User?.Claims ?? Enumerable.Empty<System.Security.Claims.Claim>());
        await Groups.AddToGroupAsync(Context.ConnectionId, PartyGroup(caller.DxpPartyId));
        _logger.LogInformation("DXPHub connected: {ConnectionId} party {DxpPartyId}",
            Context.ConnectionId, caller.DxpPartyId);
        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        var caller = DXPCallerContext.FromClaims(Context.User?.Claims ?? Enumerable.Empty<System.Security.Claims.Claim>());
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, PartyGroup(caller.DxpPartyId));
        if (exception is not null)
            _logger.LogWarning(exception, "DXPHub disconnected with error: {ConnectionId}", Context.ConnectionId);
        await base.OnDisconnectedAsync(exception);
    }

    // Group naming convention (Part 2 of the DXP plan): dxp:party:{dxpPartyId} — a party's
    // relevant notifications span every tenant it's linked to, so the group is keyed on the
    // global DxpPartyId, not per-tenant.
    public static string PartyGroup(int dxpPartyId) => $"dxp:party:{dxpPartyId}";
}