// --------------------------------------------------------------------------------------------------------------------

// <copyright file="MessageClient.cs" company="Alexey Zakharov">

//   This file is part of SocketsLight Framework.

//

//   SocketsLight Framework is free software: you can redistribute it and/or modify

//   it under the terms of the GNU General Public License as published by 

//   the Free Software Foundation, either version 3 of the License, or 

//   (at your option) any later version. 

//   

//   SocketsLight Framework is distributed in the hope that it will be useful, 

//   but WITHOUT ANY WARRANTY; without even the implied warranty of 

//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 

//   GNU General Public License for more details. 

//   

//   You should have received a copy of the GNU General Public License 

//   along with Foobar.  If not, see http://www.gnu.org/license.

// </copyright>

// <summary>

//   Defines the MessageClient type.

// </summary>

// --------------------------------------------------------------------------------------------------------------------



namespace Witcraft.SocketsLight.Client

{

    using System;

    using System.Collections.Generic;

    using System.ComponentModel;

    using System.Linq;

    using System.Net;

    using System.Net.Sockets;

    using System.Windows;



    using Witcraft.SocketsLight.Server;



    /// <summary>

    /// Send and recives messages.

    /// </summary>

    public class MessageClient : IMessageClient

    {

        /// <summary>

        /// Used to aggregate message frames.

        /// </summary>

        private List<byte> messageBuffer = new List<byte>();



        /// <summary>

        /// Serialize and deserialize messages.

        /// </summary>

        private IMessageSerializer messageSerializer;



        /// <summary>

        /// Port which will be used for message transfer.

        /// </summary>

        private int port;



        /// <summary>

        /// Socket which will be used for message transfer.

        /// </summary>

        private Socket socket;



        /// <summary>

        /// Initializes a new instance of the <see cref="MessageClient"/> class.

        /// </summary>

        /// <param name="port">

        /// </param>

        /// <param name="messageSerializer">

        /// </param>

        public MessageClient(int port, IMessageSerializer messageSerializer)

        {

            this.port = port;

            this.messageSerializer = messageSerializer;

            this.socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

        }



        /// <summary>

        /// Prevents a default instance of the <see cref="MessageClient"/> class from being created.

        /// </summary>

        private MessageClient()

        {

        }



        /// <summary>

        /// Occurs when client has connected to message server

        /// </summary>

        public event EventHandler<AsyncCompletedEventArgs> ConnectCompleted;



        /// <summary>

        /// Occure if connection with message server has been lost.

        /// </summary>

        public event EventHandler<EventArgs> ConnectionLost;



        /// <summary>

        /// Occurs when new message have been recieved.

        /// </summary>

        public event EventHandler<MessageRecievedEventArgs> MessageRecieved;



        /// <summary>

        /// Occurs when message is sent

        /// </summary>

        public event EventHandler<AsyncCompletedEventArgs> SendCompleted;



        /// <summary>

        /// Indicates if client is connected to message server.

        /// </summary>

        public bool Connected

        {

            get

            {

                return this.socket.Connected;

            }

        }



        /// <summary>

        /// Connect to message server async.

        /// </summary>

        /// <param name="state">

        /// </param>

        public void ConnectAsync()

        {

            this.ConnectAsync(null);

        }



        /// <summary>

        /// Connect to message server async.

        /// </summary>

        /// <param name="state">

        /// </param>

        public void ConnectAsync(object state)

        {

            if (!this.Connected)

            {

                var endPoint = new DnsEndPoint(Application.Current.Host.Source.DnsSafeHost, this.port);

                var args = new SocketAsyncEventArgs { UserToken = state, RemoteEndPoint = endPoint };

                args.Completed += this.OnSocketConnected;

                this.socket.ConnectAsync(args);

            }

        }



        /// <summary>

        /// Disconnect from message server.

        /// </summary>

        public void Disconnect()

        {

            this.socket.Close();

        }



        /// <summary>

        /// Send message.

        /// </summary>

        /// <param name="message">

        /// </param>

        public void SendMessageAsync(Message message)

        {

            this.SendMessageAsync(message, null);

        }



        /// <summary>

        /// Send message.

        /// </summary>

        /// <param name="message">

        /// </param>

        /// <param name="userState">

        /// </param>

        public void SendMessageAsync(Message message, object userState)

        {

            if ((this.socket == null) || (this.Connected == false))

            {

                // TODO : throw exception.

            }



            var args = new SocketAsyncEventArgs();



            byte[] serializedMessage = this.messageSerializer.Serialize(message);

            List<byte> messageByteList = serializedMessage.ToList();



            for (int i = 1023; i < serializedMessage.Length; i += 1023)

            {

                messageByteList.Insert(i, 0);

                i++;

            }



            messageByteList.Add(1);



            args.SetBuffer(messageByteList.ToArray(), 0, messageByteList.Count);

            args.Completed += this.SocketSendCompleted;

            args.UserToken = userState;



            this.socket.SendAsync(args);

        }



        /// <summary>

        /// </summary>

        /// <param name="e">

        /// </param>

        private void OnConnected(AsyncCompletedEventArgs e)

        {

            EventHandler<AsyncCompletedEventArgs> handler = this.ConnectCompleted;

            if (handler != null)

            {

                handler(this, e);

            }

        }



        /// <summary>

        /// </summary>

        /// <param name="e">

        /// </param>

        private void OnConnectionLost()

        {

            EventHandler<EventArgs> handler = this.ConnectionLost;

            if (handler != null)

            {

                handler(this, new EventArgs());

            }

        }



        /// <summary>

        /// </summary>

        /// <param name="e">

        /// </param>

        private void OnMessageRecieved(MessageRecievedEventArgs e)

        {

            EventHandler<MessageRecievedEventArgs> handler = this.MessageRecieved;

            if (handler != null)

            {

                handler(this, e);

            }

        }



        /// <summary>

        /// </summary>

        /// <param name="e">

        /// </param>

        private void OnSendCompleted(AsyncCompletedEventArgs e)

        {

            EventHandler<AsyncCompletedEventArgs> handler = this.SendCompleted;

            if (handler != null)

            {

                handler(this, e);

            }

        }



        /// <summary>

        /// </summary>

        /// <param name="sender">

        /// </param>

        /// <param name="e">

        /// </param>

        private void OnSocketConnected(object sender, SocketAsyncEventArgs e)

        {

            AsyncCompletedEventArgs asyncArgs;

            if (this.Connected)

            {

                var response = new byte[1024];

                e.SetBuffer(response, 0, response.Length);

                e.Completed -= this.OnSocketConnected;

                e.Completed += this.OnSocketReceive;



                this.socket.ReceiveAsync(e);

                asyncArgs = new AsyncCompletedEventArgs(null, false, e.UserToken);

                this.OnConnected(asyncArgs);

            }



            // TODO: Handle error while connection.

        }



        /// <summary>

        /// </summary>

        /// <param name="sender">

        /// </param>

        /// <param name="e">

        /// </param>

        private void OnSocketReceive(object sender, SocketAsyncEventArgs e)

        {

            if (e.BytesTransferred == 0)

            {

                this.OnConnectionLost();



                this.socket.Close();



                return;

            }



            this.messageBuffer.AddRange(e.Buffer.Take(e.BytesTransferred - 1));

            if (e.Buffer[e.BytesTransferred - 1] > 0)

            {

                this.OnMessageRecieved(

                    new MessageRecievedEventArgs(this.messageSerializer.Deserialize(this.messageBuffer.ToArray())));

                this.messageBuffer.Clear();

            }



            this.socket.ReceiveAsync(e);

        }



        /// <summary>

        /// </summary>

        /// <param name="sender">

        /// </param>

        /// <param name="e">

        /// </param>

        private void SocketSendCompleted(object sender, SocketAsyncEventArgs e)

        {

            if (e.SocketError == SocketError.Success)

            {

                this.OnSendCompleted(new AsyncCompletedEventArgs(null, false, e.UserToken));

            }



            // TODO: Handle error if send is not successful.

        }

    }

}