using Microsoft.AspNetCore.SignalR;

namespace SignalRChat.Chat
{
    public class ChatHub:Hub
    {
        private static Dictionary<string,string> dictUsers = new Dictionary<string,string>();


        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);
        }

        /// <summary>
        /// 向客戶端發(fā)送信息
        /// </summary>
        /// <param name="msg"></param>
        /// <returns></returns>
        public Task Send(string msg) {
            return Clients.Caller.SendAsync("SendMessage",msg);
        }

        /// <summary>
        /// 登錄功能，將用戶ID和ConntectionId關(guān)聯(lián)起來
        /// </summary>
        /// <param name="userId"></param>
        public void Login(string userId) {
            if (!dictUsers.ContainsKey(userId)) {
                dictUsers[userId] = Context.ConnectionId;
            }
            Console.WriteLine($"{userId}登錄成功，ConnectionId={Context.ConnectionId}");
            //向所有用戶發(fā)送當(dāng)前在線的用戶列表
            Clients.All.SendAsync("Users", dictUsers.Keys.ToList());
        }

        /// <summary>
        /// 一對(duì)一聊天
        /// </summary>
        /// <param name="userId"></param>
        /// <param name="targetUserId"></param>
        /// <param name="msg"></param>
        public void Chat(string userId, string targetUserId, string msg)
        {
            string newMsg = $"{userId}|{msg}";//組裝后的消息體
            //如果當(dāng)前用戶在線
            if (dictUsers.ContainsKey(targetUserId))
            {
                Clients.Client(dictUsers[targetUserId]).SendAsync("ChatInfo",newMsg);
            }
            else {
                //如果當(dāng)前用戶不在線，正常是保存數(shù)據(jù)庫(kù)，等上線時(shí)加載，暫時(shí)不做處理
            }
        }

        /// <summary>
        /// 退出功能，當(dāng)客戶端退出時(shí)調(diào)用
        /// </summary>
        /// <param name="userId"></param>
        public void Logout(string userId)
        {
            if (dictUsers.ContainsKey(userId))
            {
                dictUsers.Remove(userId);
            }
            Console.WriteLine($"{userId}退出成功，ConnectionId={Context.ConnectionId}");
        }
    }
}

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();

app.MapControllers();
//2.映射路由
app.UseEndpoints(endpoints => {
    endpoints.MapHub<ChatHub>("/chat");
});

app.Run();

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

        private string targetUserName;

        public string TargetUserName
        {
            get { return targetUserName; }
            set { SetProperty(ref targetUserName , value); }
        }


        private string userName;

        public string UserName
        {
            get { return userName; }
            set
            {
                SetProperty(ref userName, value);
                Welcome = $"歡迎 {value} 來到聊天室";
            }
        }

        private string welcome;

        public string Welcome
        {
            get { return welcome; }
            set { SetProperty(ref welcome , value); }
        }

        private List<string> users;

        public List<string> Users
        {
            get { return users; }
            set {SetProperty(ref users , value); }
        }

        private RichTextBox richTextBox;

        private HubConnection hubConnection;

        public ChatViewModel() {

        }

        #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();
            //4.登錄
            Login();
            //
            if (obj != null) {
                var eventArgs = obj as RoutedEventArgs;

                var window= eventArgs.OriginalSource as ChatWindow;
                this.richTextBox = window.richTextBox;
            }
        }

        private IRelayCommand<string> sendCommand;

        public IRelayCommand<string> SendCommand
        {
            get {
                if (sendCommand == null) {
                    sendCommand = new RelayCommand<string>(Send);
                }
                return sendCommand; }
        }

        private void Send(string msg)
        {
            if (string.IsNullOrEmpty(msg)) {
                MessageBox.Show("發(fā)送的消息為空");
                return;
            }
            if (string.IsNullOrEmpty(this.TargetUserName)) {
                MessageBox.Show("發(fā)送的目標(biāo)用戶為空");
                return ;
            }
            hubConnection.InvokeAsync("Chat",this.UserName,this.TargetUserName,msg);
            if (this.richTextBox != null)
            {
                Run run = new Run();
                Run run1 = new Run();
                Paragraph paragraph = new Paragraph();
                Paragraph paragraph1 = new Paragraph();
                run.Foreground = Brushes.Blue;
                run.Text = this.UserName;
                run1.Foreground= Brushes.Black;
                run1.Text = msg;
                paragraph.Inlines.Add(run);
                paragraph1.Inlines.Add(run1);
                paragraph.LineHeight = 1;
                paragraph.TextAlignment = TextAlignment.Right;
                paragraph1.LineHeight = 1;
                paragraph1.TextAlignment = TextAlignment.Right;
                this.richTextBox.Document.Blocks.Add(paragraph);
                this.richTextBox.Document.Blocks.Add(paragraph1);
                this.richTextBox.ScrollToEnd();
            }
        }

        #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<List<string>>("Users", RefreshUsers);
            hubConnection.On<string>("ChatInfo",ReceiveInfos);
        }

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

        private void Login()
        {
            hubConnection.InvokeAsync("Login", this.UserName);
        }

        private void ReceiveInfos(string msg)
        {
            if (string.IsNullOrEmpty(msg)) {
                return;
            }
            if (this.richTextBox != null)
            {
                Run run = new Run();
                Run run1 = new Run();
                Paragraph paragraph = new Paragraph();
                Paragraph paragraph1 = new Paragraph();
                run.Foreground = Brushes.Red;
                run.Text = msg.Split("|")[0];
                run1.Foreground = Brushes.Black;
                run1.Text = msg.Split("|")[1];
                paragraph.Inlines.Add(run);
                paragraph1.Inlines.Add(run1);
                paragraph.LineHeight = 1;
                paragraph.TextAlignment = TextAlignment.Left;
                paragraph1.LineHeight = 1;
                paragraph1.TextAlignment = TextAlignment.Left;
                this.richTextBox.Document.Blocks.Add(paragraph);
                this.richTextBox.Document.Blocks.Add(paragraph1);
                this.richTextBox.ScrollToEnd();
            }
        }

        private void RefreshUsers(List<string> users) {
            this.Users = users;
        }
    }
}