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

namespace KnockKnock.Lib
{
	internal class Connection
	{
		public delegate void SocketReceivedEvent(Connection sender, byte[] data);
		public delegate void SocketEvent(Connection sender);

		public SocketReceivedEvent Received;
		public SocketEvent Closed;

		const int BUFFER_SIZE = 1024;

		Socket socket;
		byte[] buffer = new byte[BUFFER_SIZE];

		public Connection(Socket socket)
		{
			this.socket = socket;
		}

		public void Open()
		{
			this.socket.BeginReceive(this.buffer, 0, BUFFER_SIZE, SocketFlags.None, this.SocketReceive, null);
		}

		public void Close()
		{
			this.socket.Close();
		}

		public void Send(byte[] data)
		{
			try
			{
				this.socket.Send(data);
			}
			catch
			{
				this.Closed(this);
			}
		}

		protected void SocketReceive(IAsyncResult result)
		{
			int read;
			try
			{
				read = socket.EndReceive(result);
			}
			catch
			{
				Closed(this);
				return;
			}

			if (read == 0)
			{
				// Connection closed
				Closed(this);
			}
			else
			{
				byte[] received = new byte[read];
				Array.Copy(this.buffer, 0, received, 0, read);
				Received(this, received);
				try
				{
					socket.BeginReceive(this.buffer, 0, BUFFER_SIZE, SocketFlags.None, this.SocketReceive, null);
				}
				catch
				{
					Closed(this);
				}
			}
		}
	}
}