package kcp

import (
	"net"

	"github.com/pkg/errors"
	kcp "github.com/xtaci/kcp-go"
)

type client struct {
	DataShard    int
	ParityShard  int
	DSCP         int
	SockBuf      int
	AckNodelay   bool
	NoDelay      int
	Interval     int
	Resend       int
	NoCongestion int
	SndWnd       int
	RcvWnd       int
	MTU          int
}

func NewClient() *client {
	return &client{
		DataShard:    10,
		ParityShard:  3,
		DSCP:         0,
		SockBuf:      4194304,
		NoDelay:      0,
		Interval:     50,
		Resend:       0,
		NoCongestion: 0,
		SndWnd:       0,
		RcvWnd:       0,
		MTU:          1350,
	}
}

func (c *client) Dial(server string) (net.Conn, error) {
	conn, err := kcp.DialWithOptions(server, nil, c.DataShard, c.ParityShard)
	if err != nil {
		return nil, errors.Wrap(err, "dial")
	}

	conn.SetStreamMode(true)
	conn.SetWriteDelay(false)
	conn.SetNoDelay(c.NoDelay, c.Interval, c.Resend, c.NoCongestion)
	conn.SetWindowSize(c.SndWnd, c.RcvWnd)
	conn.SetMtu(c.MTU)
	conn.SetACKNoDelay(c.AckNodelay)

	if err := conn.SetDSCP(c.DSCP); err != nil {
		return nil, errors.Wrap(err, "SetDSCP")
	}
	if err := conn.SetReadBuffer(c.SockBuf); err != nil {
		return nil, errors.Wrap(err, "SetReadBuffer")
	}
	if err := conn.SetWriteBuffer(c.SockBuf); err != nil {
		return nil, errors.Wrap(err, "SetWriteBuffer")
	}

	return conn, nil
}