using System.Collections.Concurrent;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;

namespace F9WebAiTest.Api.Hubs;

/// <summary>在线用户登记表（用于判断用户是否在线，离线则走"拉取兜底"）</summary>
public static class OnlineUserRegistry
{
    private static readonly ConcurrentDictionary<long, byte> _users = new();

    public static void Add(long userId) => _users[userId] = 0;

    public static void Remove(long userId) => _users.TryRemove(userId, out _);

    public static bool IsOnline(long userId) => _users.ContainsKey(userId);
}

/// <summary>通知推送 Hub（客户端连接后按 UserId 标识，服务端用 Clients.User(userId) 定向推送）</summary>
public class NotificationHub : Hub
{
    public override async Task OnConnectedAsync()
    {
        var userId = GetUserId();
        if (userId > 0) OnlineUserRegistry.Add(userId);
        await base.OnConnectedAsync();
    }
    public override async Task OnDisconnectedAsync(Exception exception)
    {
        var userId = GetUserId();
        if (userId > 0) OnlineUserRegistry.Remove(userId);
        await base.OnDisconnectedAsync(exception);
    }

    private long GetUserId()
    {
        var raw = Context.User?.FindFirst("id")?.Value;
        return long.TryParse(raw, out var id) ? id : 0;
    }
}

/// <summary>自定义用户标识：使用 JWT 中的 "id" 声明作为 SignalR 的 UserIdentifier</summary>
public class NotificationUserIdProvider : IUserIdProvider
{
    public string GetUserId(HubConnectionContext connection)
        => connection.User?.FindFirst("id")?.Value ?? connection.ConnectionId;
}