using System.Collections.Concurrent;
using System.Net.WebSockets;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System;
using System.Collections.Generic;
using System.Linq;

namespace Syc.Basic.Web.WMS
{
    // WebSocketManager.cs
    public class WebSocketManager
    {
        private readonly ConcurrentDictionary<string,System.Net.WebSockets.WebSocket> _sockets = new();
        private static Lazy<WebSocketManager> socketManager = new Lazy<WebSocketManager>(() => new WebSocketManager());
        public static WebSocketManager SocketManager => socketManager.Value; 
        public void AddSocket(System.Net.WebSockets.WebSocket socket, string connectionId)
        {
            _sockets.TryAdd(connectionId, socket);
        }

        public async Task RemoveSocket(string connectionId)
        {
            if (_sockets.TryRemove(connectionId, out var socket))
            {
                await socket.CloseAsync(
                    WebSocketCloseStatus.NormalClosure,
                    "Connection closed",
                    CancellationToken.None);
            }
        }

        public async Task SendMessageAsync(string connectionId, string message)
        {
            if (_sockets.TryGetValue(connectionId, out var socket))
            {
                var buffer = Encoding.UTF8.GetBytes(message);
                await socket.SendAsync(
                    new ArraySegment<byte>(buffer),
                    WebSocketMessageType.Text,
                    true,
                    CancellationToken.None);
            }
        }

        public async Task BroadcastAsync(string message)
        {
            List<string> keys = new List<string>();
            foreach (var pair in _sockets)
            {
                if (pair.Value.State == WebSocketState.Open)
                {
                    try
                    {
                        await SendMessageAsync(pair.Key, message);
                    }
                    catch (Exception ex)
                    {
                        keys.Add(pair.Key);
                    }
                }
            }

            if (keys.Any())
            {
                foreach (var item in keys)
                {
                    _sockets.Remove(item,out _);
                }
            }
        }
    }
}