using Microsoft.AspNetCore.SignalR;

namespace SignalRChat.Chat
{
    public class ChatHub:Hub
    {
        public override Task OnConnectedAsync()
        {
            Console.WriteLine($"ID:{Context.ConnectionId} 已連接");
            return base.OnConnectedAsync();
        }

        public override Task OnDisconnectedAsync(Exception? exception)
        {
            Console.WriteLine($"ID:{Context.ConnectionId} 已斷開");
            return base.OnDisconnectedAsync(exception);
        }
    }
}

using Microsoft.AspNetCore.SignalR;

namespace SignalRChat.Chat
{
    public class Worker
    {
        public static Worker Instance;

        private static readonly object locker=new object();

        private IHubContext<ChatHub> context;

        private System.Timers.Timer timer;

        public Worker(IHubContext<ChatHub> context) {
            this.context = context;
            timer= new System.Timers.Timer(500);//單位毫秒
            timer.Enabled=true;
            timer.AutoReset=true;//自動(dòng)重新
            timer.Elapsed += Timer_Elapsed;
            timer.Start();
        }

        private void Timer_Elapsed(object? sender, System.Timers.ElapsedEventArgs e)
        {
            //模擬數(shù)據(jù)，一般情況下，從數(shù)據(jù)庫獲取，然后通知到客戶端
            Dictionary<string, object> data = new Dictionary<string, object>();
            var online = new Random().Next(0, 100);
            var male = Math.Floor(new Random().NextSingle() * online);
            var female = online - male;
            data["online"]=online;
            data["male"] =male;
            data["female"] = female;
            context.Clients.All.SendAsync("Data",data);
        }

        public static void Register(IHubContext<ChatHub> context)
        {
            if (Instance == null)
            {
                lock (locker)
                {
                    if (Instance == null)
                    {
                        Instance = new Worker(context);
                    }
                }
            }
        }
    }
}

using Microsoft.AspNetCore.SignalR;
using SignalRChat.Chat;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
//1.添加SignalR服務(wù)
builder.Services.AddSignalR();
var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}
app.UseRouting();
app.UseHttpsRedirection();

app.UseAuthorization();
//在Use中注冊(cè)單例實(shí)例
app.Use(async (context, next) =>
{
    var hubContext = context.RequestServices
                            .GetRequiredService<IHubContext<ChatHub>>();
    Worker.Register(hubContext);//調(diào)用靜態(tài)方法注冊(cè)

    if (next != null)
    {
        await next.Invoke();
    }
});
app.MapControllers();
//2.映射路由
app.UseEndpoints(endpoints => {
    endpoints.MapHub<ChatHub>("/chat");
});

app.Run();

namespace SignalRClient
{
    public class ShowDataViewModel : ObservableObject
    {
        #region 屬性及構(gòu)造函數(shù)

        private int online;

        public int Online
        {
            get { return online; }
            set { SetProperty(ref online, value); }
        }

        private int male;

        public int Male
        {
            get { return male; }
            set { SetProperty(ref male, value); }
        }


        private int female;

        public int Female
        {
            get { return female; }
            set { SetProperty(ref female, value); }
        }

        private HubConnection hubConnection;

        public ShowDataViewModel()
        {

        }

        #endregion

        #region 命令

        private ICommand loadedCommand;

        public ICommand LoadedCommand
        {
            get
            {
                if (loadedCommand == null)
                {
                    loadedCommand = new RelayCommand<object>(Loaded);
                }
                return loadedCommand;
            }
        }

        private void Loaded(object obj)
        {
            //1.初始化
            InitInfo();
            //2.監(jiān)聽
            Listen();
            //3.連接
            Link();
        }

        #endregion

        /// <summary>
        /// 初始化Connection對(duì)象
        /// </summary>
        private void InitInfo()
        {
            hubConnection = new HubConnectionBuilder().WithUrl("https://localhost:7149/chat").WithAutomaticReconnect().Build();
            hubConnection.KeepAliveInterval = TimeSpan.FromSeconds(5);
        }

        /// <summary>
        /// 監(jiān)聽
        /// </summary>
        private void Listen()
        {
            hubConnection.On<Dictionary<string,object>>("Data", ReceiveInfos);
        }

        /// <summary>
        /// 連接
        /// </summary>
        private async void Link()
        {
            try
            {
                await hubConnection.StartAsync();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void ReceiveInfos(Dictionary<string, object> data)
        {
            if (data == null || data.Count < 1)
            {
                return;
            }
            int.TryParse(data["online"]?.ToString(),out int online);
            int.TryParse(data["male"]?.ToString(),out int male);
            int.TryParse(data["female"]?.ToString(),out int female);
            this.Online=online;
            this.Male = male;
            this.Female=female;
        }
    }
}