using System;

namespace IFramework.Net.KCP
{
    public class KcpClient
    {
        private Kcp _kcp = null;
        private BufferQueue _buffer;
        private UInt32 _time = 0;
        public IKcpSocket socket;
        private ISessionListener _listen;

        public bool writeDelay;
        public bool ackNoDelay;

        public KcpClient(IKcpSocket client, ISessionListener listen)
        {
            _buffer = BufferQueue.Allocate(1024 * 32);
            this.socket = client;
            this._listen = listen;
            client.onMessage += Socket_onMessage;
        }

        private void Socket_onMessage(byte[] buffer, int offset, int length)
        {
            var inputN = _kcp.Input(buffer, offset, length, true, ackNoDelay);
            if (inputN < 0) return;
            _buffer.Clear();
            while (true)
            {
                var size = _kcp.PeekSize();
                if (size <= 0) break;

                _buffer.EnsureWritableBytes(size);

                var n = _kcp.Recv(_buffer.buffer, _buffer.writer, size);
                if (n > 0) _buffer.writer += n;
            }

            // 有数据待接收
            if (_buffer.canRead > 0)
            {
  
                _listen.OnMessage(socket,_buffer.buffer, _buffer.reader, _buffer.canRead);
                // 读完重置读写指针
                if (_buffer.reader == _buffer.writer)
                {
                    _buffer.Clear();
                }
            }

        }

        public void Connect(string host, int port)
        {
            _kcp = new Kcp((uint)(new Random().Next(1, Int32.MaxValue)), socket);
            _kcp.NoDelay(0, 30, 2, true);
            _kcp.stream = true;
            _buffer.Clear();
            socket.Connect(host,port);
        }

        public int Send(byte[] data, int index, int length)
        {
            var waitsnd = _kcp.waitToSend;
            if (waitsnd < _kcp.sendWindow && waitsnd < _kcp.RmtWnd)
            {

                var sendBytes = 0;
                do
                {
                    var n = Math.Min((int)_kcp.Mss, length - sendBytes);
                    _kcp.Send(data, index + sendBytes, n);
                    sendBytes += n;
                } while (sendBytes < length);

                waitsnd = _kcp.waitToSend;
                if (waitsnd >= _kcp.sendWindow || waitsnd >= _kcp.RmtWnd || !writeDelay)
                {
                    _kcp.Flush(false);
                }

                return length;
            }

            return 0;
        }
        public void Close()
        {
            _buffer.Clear();
            socket.Close();
        }
        public void Update()
        {
            if (0 == _time || _kcp.time >= _time)
            {
                _kcp.Update();
                _time = _kcp.Check();
            }
        }

    }
}