using System.Collections.Concurrent;
using System.Net;
using System.Net.WebSockets;
using System.Text;

namespace SimpleWebChat.ConHost
{
    public static class SimpleWebChatServerModule
    {
        private static readonly ConcurrentDictionary<int, WebSocket> TextChatSessions = new();
        private static readonly List<byte[]> HistoryMessage = new();

        public static void ProcessRequest(HttpListenerContext context, int currentSessionId)
        {
            WebSocket sck = null;
            try
            {
                var wsc = context.AcceptWebSocketAsync("swcp").Result;
                Console.WriteLine($"Request #{currentSessionId:00000} TextChat WebSocket Session Start");
                sck = TextChatSessions[currentSessionId] = wsc.WebSocket;

                var buffer = new byte[1024];

                var r = sck.ReceiveAsync(buffer, default).Result;
                var s = Encoding.UTF8.GetString(buffer, 0, r.Count);

                byte[][] copy;
                lock (HistoryMessage) copy = HistoryMessage.ToArray();

                foreach (var item in copy)
                {
                    sck.SendAsync(item, WebSocketMessageType.Text, true, default).Wait();
                }

                sck.BroadCastFaf($"SYS{Environment.NewLine}" +
                    $"  Session #{currentSessionId:X4}({s}) Connected.{Environment.NewLine}" +
                    $"  Now number of online session: {TextChatSessions.Count}");

                while (true)
                {
                    r = sck.ReceiveAsync(buffer, default).Result;
                    if (r.Count == 0)
                    {
                        break;
                    }
                    else
                    {
                        s = Encoding.UTF8.GetString(buffer, 0, r.Count);
                        sck.BroadCastFaf($"#{currentSessionId:X4}{Environment.NewLine}  {s}");
                    }
                }
            }
            catch (Exception)
            {
                try
                {
                    if (sck != null && sck.State != WebSocketState.Aborted)
                    {
                        sck.CloseAsync(WebSocketCloseStatus.InternalServerError, "Error", default).Wait();
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            }

            TextChatSessions.TryRemove(currentSessionId, out _);
            sck.BroadCastFaf($"SYS{Environment.NewLine}" +
                         $"  Session #{currentSessionId:X4} Disconnected.{Environment.NewLine}" +
                         $"  Now number of online session: {TextChatSessions.Count}");
        }

        private static void BroadCastFaf(this WebSocket sck, string content)
        {
            var now = DateTime.Now;
            string text = $"{now} {content}";
            var buf = Encoding.UTF8.GetBytes(text);

            lock (HistoryMessage)
            {
                HistoryMessage.Add(buf);
                while (HistoryMessage.Count >= ConfigFile.Instance.HistoryMessageLength)
                {
                    HistoryMessage.RemoveAt(0);
                }
            }

            var all = TextChatSessions.Values.ToArray();
            foreach (var s in all)
            {
                try
                {
                    s.SendAsync(text);
                }
                catch
                {
                    //FUCK ERR
                }
            }
        }

        private static Task SendAsync(this WebSocket sck, string text) => sck.SendAsync(Encoding.UTF8.GetBytes(text), WebSocketMessageType.Text, true, default);
    }
}