using System;
using System.Net.Sockets;
using System.IO;
using System.Text;
using ConsoleApp.TelnetSamples;

namespace Samples.Telnet
{
    public class StreamTelnetClient : ITelnetClient
    {
        private TcpClient _client;
        private NetworkStream _stream;
        private StreamReader _reader;
        private StreamWriter _writer;

        public string Connect(string ip, int port = 23)
        {
            try
            {
				Close();

				_client = new TcpClient(ip, port);

				// 스트림 생성
				_stream = _client.GetStream();
				_reader = new StreamReader(_stream);
				_writer = new StreamWriter(_stream);
				_writer.AutoFlush = true;

				return Read();
			}
            catch (Exception)
            {
                throw;
            }
        }

        public string Read()
        {
            try
            {
				StringBuilder sb = new StringBuilder();
				byte[] readBuffer = new byte[1024];
				while (true)
				{
					int bytesRead = _reader.BaseStream.Read(readBuffer, 0, readBuffer.Length);
					if (bytesRead < 1)
						break;

					string data = Encoding.ASCII.GetString(readBuffer, 0, bytesRead);
					sb.Append(data);

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

				// 에코 삭제
				string read = sb.ToString();
				int rnIdx = read.IndexOf("\r\n");

				return read.Substring(rnIdx + 1);
			}
            catch (Exception)
            {
                throw;
            }
		}

        public string SendCommand(string command)
        {
            try
            {
				_writer.WriteLine(command);

				return Read();
			}
            catch (Exception)
            {
                throw;
            }
        }

        public void Close()
        {
            try
            {
                if (_client == null)
                    return;

				if (_stream != null)
				{
					_stream.Flush();
					_stream.Close();
				}

				_client.Close();
				_client.Dispose();
			}
            catch (Exception)
            {
                throw;
            }
        }
    }
}