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

namespace EPD.Data
{
    public class SocketClientWrapper : IDisposable
    {
        public Action OnConnected;
        public Action OnDisconnected;
        public Action<byte[] /*data*/, int /*offset*/, int /*size*/> OnDataChanged;

        private static Object _lockerSender = new Object();

        public class ClientStateObject
        {
            public const int BufferSize = 16384;
            public Socket WorkSocket = null;
            public byte[] CacheBufferByteData = new byte[BufferSize];
        }

        private Socket socket;

        public bool IsConnected { get { return socket != null && socket.Connected; } }

        public SocketClientWrapper()
        {
        }

        ~SocketClientWrapper()
        {
            Dispose();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="address">127.0.0.1:15000</param>
        public void Connect(string ip, int port)
        {
            try
            {
                var remote = new IPEndPoint(IPAddress.Parse(ip), port);

                Dispose();

                socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                socket.BeginConnect(remote, ConnectCallback, socket);

            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error in Connect, " + ex.Message);
            }

        }
        private void ConnectCallback(IAsyncResult ar)
        {
            try
            {
                var client = (Socket)ar.AsyncState;
                client.EndConnect(ar);

                if (OnConnected != null)
                    OnConnected();

                System.Diagnostics.Trace.Write("Connected");

                var state = new ClientStateObject();
                state.WorkSocket = socket;

                socket.BeginReceive(state.CacheBufferByteData, 0, ClientStateObject.BufferSize, 0, ReceiveCallback, state);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error in ConnectCallback, " + ex.Message);
            }
        }

        public void Disconnect()
        {
            Dispose();

            if (OnDisconnected != null)
                OnDisconnected();
        }

        private void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                if (!IsConnected)
                    return;

                ClientStateObject state = (ClientStateObject)ar.AsyncState;
                Socket client = state.WorkSocket;

                int bytesRead = client.EndReceive(ar);
                if (bytesRead > 0)
                {
                    if (OnDataChanged != null)
                        OnDataChanged(state.CacheBufferByteData, 0, bytesRead);

                    client.BeginReceive(state.CacheBufferByteData, 0, ClientStateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error in ReceiveCallback, " + ex.Message);

                Disconnect();
            }
        }

        public bool Send(byte[] byteData)
        {
            try
            {
                if (!IsConnected)
                    return false;

                lock (_lockerSender)
                {
                    socket.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendCallback), socket);
                }

                return true;

            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error int Write, " + ex.Message);
            }

            return false;
        }

        private void SendCallback(IAsyncResult ar)
        {
            try
            {
                lock (_lockerSender)
                {
                    Socket client = (Socket)ar.AsyncState;

                    client.EndSend(ar);
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error in SendCallback, " + ex.Message);
            }
        }

        public void Dispose()
        {
            try
            {
                if (socket != null)
                {
                    if (IsConnected)
                    {
                        socket.Shutdown(SocketShutdown.Both);
                    }

                    socket.Close();
                    socket.Dispose();
                    socket = null;
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.Write("Error in Dispose, " + ex.Message);
            }
        }
    }
}