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

namespace MailServer.SMTPServer
{
    public delegate void ReceivedLineEventHandler(string line);

    class SmtpSession
    {
        public event ReceivedLineEventHandler NewLine;

        private TcpClient Client { get; set; }
        public IPEndPoint IPEndPoint { get; private set; }
        private NetworkStream Stream { get; set; }
        private Encoding Encoding = Encoding.ASCII;
        private string Others;
        private Thread Worker;
        private bool Active = true;
        private int SessionID { get; set; }

        public SmtpSession(TcpClient client)
        {
            Client = client;
            IPEndPoint = (IPEndPoint)client.Client.RemoteEndPoint;
            Stream = client.GetStream();
            Others = "";
            SessionID = new Random(123).Next(10000, 99999);
            Logging.AddLogMessage(Logging.LoggingType.INFO, "New SMTPSession with id '" + SessionID + "' started");
            Worker = new Thread(ReadClientInput);
            Worker.Start();
        }

        public void SendExtensionResponse(Extensions extension) => SendResponse("250-" + extension.ToString());

        public void SendResponse(ResponseCodes responseCode) => SendResponse(responseCode, "");

        public void SendResponse(ResponseCodes responseCode, string args) => SendResponse(((int)responseCode).ToString() + " " + args);
       

        public void SendResponse(string response)
        {
            Logging.AddLogMessage(Logging.LoggingType.INFO, response);
            response += '\r' + '\n';
            var bytes = Encoding.UTF8.GetBytes(response);
            Stream.Write(bytes, 0, bytes.Length);
        }

        private void ReadClientInput()
        {
            while (Active)
            {
                if (Stream.DataAvailable)
                {
                    byte[] buffer = new byte[Client.ReceiveBufferSize];
                    var readed = Stream.Read(buffer, 0, buffer.Length);

                    var str = Encoding.GetString(buffer, 0, readed);
                    lock (Others)
                    {
                        Others += str;
                    }

                    CheckLines();
                }
                else
                {
                    Thread.Sleep(10);
                }
            }

        }

        private bool r = false;

        private void CheckLines()
        {
            lock (Others)
            {
                var line = "";
                foreach (char c in Others)
                {
                    if (c.Equals('\r'))
                    {
                        r = true;
                    }
                    else if (r && c.Equals('\n'))
                    {
                        //Console.WriteLine(line);
                        Logging.AddLogMessage(Logging.LoggingType.DEBUG, "Seession " + SessionID + ": received line: " + line);
                        NewLine(line);
                        line = "";
                    }
                    else
                    {
                        line += c;
                        r = false;
                    }
                }
                Others = line;
            }
        }

        public void CloseAll()
        {
            Stream.Dispose();
            Client.Dispose();
            Active = false;
        }
    }
}