using Core;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace Client
{
	internal class Singleton
	{
		public static Singleton Instance { get; set; } = new Singleton();

		public string Id { get; set; } = "";
		public string Nickname { get; set; } = "";
		public Socket Socket { get; } = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

		public event EventHandler? LoginResponsed;
		public event EventHandler? CreateRoomResponsed;
		public event EventHandler? RoomListResponsed;
		public event EventHandler? EnterRoomResponsed;

		public async Task ConnectAsync(string ip, int port)
		{
			IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(ip), port);
			await this.Socket.ConnectAsync(endPoint);
			ThreadPool.QueueUserWorkItem(ReceiveAsync, this.Socket);
		}

		public async Task<int> SendAsync(byte[] buffer, SocketFlags socketFlags)
		{
			return await this.Socket.SendAsync(buffer, socketFlags);
		}

		private async void ReceiveAsync(object? sender)
		{
			if (sender == null)
				return;

			Socket socket = (Socket)sender;
			byte[] headerBuffer = new byte[2];
			while (true)
			{
				// header buffer
				int n1 = await socket.ReceiveAsync(headerBuffer, SocketFlags.None);
				if (n1 < 1)
				{
					Console.WriteLine($"[{DateTime.Now}] Disconnect server: {socket.RemoteEndPoint}");
					socket.Dispose();
					return;
				}
				else if (n1 == 1)
				{
					await socket.ReceiveAsync(new ArraySegment<byte>(headerBuffer, 1, 1), SocketFlags.None);
				}

				// data buffer
				short dataSize = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(headerBuffer));
				byte[] dataBuffer = new byte[dataSize];

				int totalRecv = 0;
				while (totalRecv < dataSize)
				{
					int n2 = await socket.ReceiveAsync(new ArraySegment<byte>(dataBuffer, totalRecv, dataSize - totalRecv), SocketFlags.None);
					totalRecv += n2;
				}

				PacketType packetType = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(dataBuffer));
				if (packetType == PacketType.LoginResponse)
				{
					LoginResponsePacket packet = new LoginResponsePacket(dataBuffer);
					LoginResponsed?.Invoke(packet, EventArgs.Empty);
				}
				else if (packetType == PacketType.CreateRoomResponse)
				{
					CreateRoomResponsePacket packet = new CreateRoomResponsePacket(dataBuffer);
					CreateRoomResponsed?.Invoke(packet, EventArgs.Empty);
				}
				else if (packetType == PacketType.RoomListResponse)
				{
					RoomListResponsePacket packet = new RoomListResponsePacket(dataBuffer);
					RoomListResponsed?.Invoke(packet, EventArgs.Empty);
				}
				else if (packetType == PacketType.EnterRoomResponse)
				{
					EnterRoomResponsePacket packet = new EnterRoomResponsePacket(dataBuffer);
					EnterRoomResponsed?.Invoke(packet, EventArgs.Empty);
				}
			}
		}
	}
}