using System;
using System.Threading.Tasks;
using Vinno.IUS.Common.IO;
using Vinno.IUS.Common.Network.Tcp;
using Vinno.IUS.Common.Network.Tcp.Extensions;
using Vinno.IUS.Common.Network.IO;

namespace Vinno.IUS.Common.Network.Channels
{
    public class ClientChannel:Channel
    {
        private readonly ITcp _tcp;

        private int _readTimeoutTranscationLevel;
        private int _writeTimeoutTranscationLevel;

        /// <summary>
        /// Gets the total data transfered include send and receive.
        /// </summary>
        public long DataTransfered { get; private set; }

        public ClientChannel(int channelId, ITcp tcp):base(channelId)
        {
            _tcp = tcp;
            Remote = _tcp.Remote;
            Local = _tcp.Local;
        }      

        /// <summary>
        /// Read and validate the header from remote.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected override void ReadHeader(int timeout = 0)
        {
            //Notice that when network is shutdown, it may not know it's shutdown,
            //But when read data from socket, it will read 0 byte, that's can used for
            //Check if network is shutdown.
            using (new ReadTimeoutTranscation(this, timeout))
            {
                //ReadBinary may throw exception when network is shutdown, and readed data length is zero.
                var headerData = _tcp.ReadBinary(8);
                ValidateHeader(headerData);
                DataTransfered += 8;
            }
        }

        /// <summary>
        /// Read and validate the header from remote by async way.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected override async Task ReadHeaderAsync(int timeout = 0)
        {
            //Notice that when network is shutdown, it may not know it's shutdown,
            //But when read data from socket, it will read 0 byte, that's can used for
            //Check if network is shutdown.
            using (new ReadTimeoutTranscation(this, timeout))
            {
                //ReadBinary may throw exception when network is shutdown, and read data length is zero.
                var headerData = await _tcp.ReadBinaryAsync(8).ConfigureAwait(false);
                ValidateHeader(headerData);
                DataTransfered += 8;
            }
        }

        /// <summary>
        /// Write the header before write buffer.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected override void WriteHeader(int timeout = 0)
        {
            using (new WriteTimeoutTranscation(this, timeout))
            {
                var headerData = GetHeaderData();
                //Write header
                _tcp.WriteBinary(headerData);
                DataTransfered += 8;
            }
        }

        /// <summary>
        /// Write the header before write buffer by async way.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected override async Task WriteHeaderAsync(int timeout = 0)
        {
            using (new WriteTimeoutTranscation(this, timeout))
            {
                var headerData = GetHeaderData();
                //Write header
                await _tcp.WriteBinaryAsync(headerData).ConfigureAwait(false);
                DataTransfered += 8;
            }
        }

        /// <summary>
        /// Read buffer from remote side.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        /// <returns>The buffer readed from network.</returns>
        protected IBuffer ReadBuffer(int timeout = 0)
        {
            using (new ReadTimeoutTranscation(this, timeout))
            {
                var reader = new BufferReader(_tcp.ReadStream);
                var buffer = reader.ReadBuffer();
                DataTransfered += buffer.Size;
                return buffer;
            }
        }

        /// <summary>
        /// Read buffer from remote side by async way.
        /// </summary>
        /// <param name="timeout">Wait forever if the value is 0</param>
        /// <returns>The buffer readed from network.</returns>
        protected async Task<IBuffer> ReadBufferAsync(int timeout = 0)
        {
            using (new ReadTimeoutTranscation(this, timeout))
            {
                var reader = new AsyncBufferReader(_tcp.ReadStream);
                var buffer = await reader.ReadBufferAsync().ConfigureAwait(false);
                DataTransfered += buffer.Size;
                return buffer;
            }
        }

        /// <summary>
        /// Write buffer to remote side.
        /// </summary>
        /// <param name="buffer">The buffer to be writen</param>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected void WriteBuffer(IBuffer buffer, int timeout = 0)
        {
            using (new WriteTimeoutTranscation(this, timeout))
            {
                var writer = new BufferWriter(_tcp.WriteStream);
                writer.WriteBuffer(buffer);
                DataTransfered += buffer.Size;
            }
        }

        /// <summary>
        /// Write buffer to remote side by async way.
        /// </summary>
        /// <param name="buffer">The buffer to be writen</param>
        /// <param name="timeout">Wait forever if the value is 0</param>
        protected async Task WriteBufferAsync(IBuffer buffer, int timeout = 0)
        {
            using (new WriteTimeoutTranscation(this, timeout))
            {
                var writer = new AsyncBufferWriter(_tcp.WriteStream);
                await writer.WriteBufferAsync(buffer).ConfigureAwait(false);
                DataTransfered += buffer.Size;
            }
        }

        protected override void OnClosed()
        {
            _tcp.Disconnect();
            base.OnClosed();
        }

        public override string ToString()
        {
            return $"{Remote}<->{Local}";
        }

        private class ReadTimeoutTranscation : IDisposable
        {
            private readonly ClientChannel _channel;

            public ReadTimeoutTranscation(ClientChannel channel, int timeout)
            {
                _channel = channel;
                if (_channel._readTimeoutTranscationLevel == 0)
                {
                    try
                    {
                        _channel._tcp.ReadTimeout = timeout;
                    }
                    catch
                    {
                        //DO Nothing.
                    }

                }
                _channel._readTimeoutTranscationLevel++;
            }

            public void Dispose()
            {
                _channel._readTimeoutTranscationLevel--;
                if (_channel._readTimeoutTranscationLevel == 0)
                {
                    try
                    {
                        _channel._tcp.ReadTimeout = 0;
                    }
                    catch
                    {
                        //DO Nothing.
                    }

                }
            }
        }

        private class WriteTimeoutTranscation : IDisposable
        {
            private readonly ClientChannel _channel;

            public WriteTimeoutTranscation(ClientChannel channel, int timeout)
            {
                _channel = channel;
                if (_channel._writeTimeoutTranscationLevel == 0)
                {
                    try
                    {
                        _channel._tcp.SendTimeout = timeout;
                    }
                    catch
                    {
                        //DO Nothing.
                    }
                }
                _channel._writeTimeoutTranscationLevel++;
            }

            public void Dispose()
            {
                _channel._writeTimeoutTranscationLevel--;
                if (_channel._writeTimeoutTranscationLevel == 0)
                {
                    try
                    {
                        _channel._tcp.SendTimeout = 0;
                    }
                    catch
                    {
                        //DO Nothing.
                    }
                }
            }
        }
    }
}