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

namespace TelnetCommunicator.Telnet
{
    public class TAP
    {
        string _ip;
        int _port;

        public EventHandler<Exception> ErrorHandler;

        public TAP(string ip, int port)
        {
            _ip = ip;
            _port = port;
        }

        public async Task<string> SendMessage(string  message)
        {
            using (TcpClient client = new TcpClient())
            {
                try
                {
                    string response = "";
                    await client.ConnectAsync(_ip, _port);
                    using (NetworkStream stream = client.GetStream())
                    {
                        // First Message
                        response += await ReceiveMessage(stream);

                        byte[] sendData = Encoding.ASCII.GetBytes(message + "\r\n");
                        await stream.WriteAsync(sendData, 0, sendData.Length);

                        response += await ReceiveMessage(stream);
                    }

                    return response;
                }
                catch (Exception ex)
                {
                    if (this.ErrorHandler != null)
                        this.ErrorHandler(this, ex);

                    return "ERROR";
                }
            }
        }

        private async Task<string> ReceiveMessage(NetworkStream stream)
        {
            StringBuilder sb = new StringBuilder();
            byte[] receiveData = new byte[1024];

            while (true)
            {
                int bytesRead = await stream.ReadAsync(receiveData, 0, receiveData.Length);
                if (bytesRead < 1)
                    break;

                string response = Encoding.ASCII.GetString(receiveData, 0, bytesRead);
                sb.Append(response);

                if (response.EndsWith("\r\n>"))
                    break;
            }

            return sb.ToString();
        }
    }
}