package ssr

import (
	"errors"
	"net"
	"strconv"
	"strings"

	shadowsocksr "github.com/sun8911879/shadowsocksR"
	"github.com/sun8911879/shadowsocksR/obfs"
	"github.com/sun8911879/shadowsocksR/protocol"
	"github.com/sun8911879/shadowsocksR/ssr"

	"github.com/nadoo/glider/common/log"
	"github.com/nadoo/glider/common/socks"
	"github.com/nadoo/glider/proxy"
)

func init() {
	proxy.RegisterDialer("ssr", CreateDialer)
}

// Dialer struct
type Dialer struct {
	*SSR
	dialer proxy.Dialer
}

// NewDialer returns a proxy dialer
func NewDialer(s string, dialer proxy.Dialer) (*Dialer, error) {
	h, err := NewSSR(s)
	if err != nil {
		return nil, err
	}

	d := &Dialer{SSR: h, dialer: dialer}
	return d, nil
}

// CreateDialer returns a proxy dialer
func CreateDialer(s string, dialer proxy.Dialer) (proxy.Dialer, error) {
	return NewDialer(s, dialer)
}

// Addr returns dialer's address
func (s *Dialer) Addr() string {
	if s.addr == "" {
		return s.dialer.Addr()
	}
	return s.addr
}

// NextDialer returns the next dialer
func (s *Dialer) NextDialer(dstAddr string) proxy.Dialer { return s.dialer.NextDialer(dstAddr) }

// Dial establishes a connection to the addr
func (s *Dialer) Dial(network, addr string) (net.Conn, error) {
	target := socks.ParseAddr(addr)
	if target == nil {
		return nil, errors.New("[ssr] unable to parse address: " + addr)
	}

	cipher, err := shadowsocksr.NewStreamCipher(s.EncryptMethod, s.EncryptPassword)
	if err != nil {
		return nil, err
	}

	c, err := s.dialer.Dial("tcp", s.addr)
	if err != nil {
		log.F("[ssr] dial to %s error: %s", s.addr, err)
		return nil, err
	}

	ssrconn := shadowsocksr.NewSSTCPConn(c, cipher)
	if ssrconn.Conn == nil || ssrconn.RemoteAddr() == nil {
		return nil, errors.New("[ssr] nil connection")
	}

	// should initialize obfs/protocol now
	rs := strings.Split(ssrconn.RemoteAddr().String(), ":")
	port, _ := strconv.Atoi(rs[1])

	ssrconn.IObfs = obfs.NewObfs(s.Obfs)
	if ssrconn.IObfs == nil {
		return nil, errors.New("[ssr] unsupported obfs type: " + s.Obfs)
	}

	obfsServerInfo := &ssr.ServerInfoForObfs{
		Host:   rs[0],
		Port:   uint16(port),
		TcpMss: 1460,
		Param:  s.ObfsParam,
	}
	ssrconn.IObfs.SetServerInfo(obfsServerInfo)

	ssrconn.IProtocol = protocol.NewProtocol(s.Protocol)
	if ssrconn.IProtocol == nil {
		return nil, errors.New("[ssr] unsupported protocol type: " + s.Protocol)
	}

	protocolServerInfo := &ssr.ServerInfoForObfs{
		Host:   rs[0],
		Port:   uint16(port),
		TcpMss: 1460,
		Param:  s.ProtocolParam,
	}
	ssrconn.IProtocol.SetServerInfo(protocolServerInfo)

	if s.ObfsData == nil {
		s.ObfsData = ssrconn.IObfs.GetData()
	}
	ssrconn.IObfs.SetData(s.ObfsData)

	if s.ProtocolData == nil {
		s.ProtocolData = ssrconn.IProtocol.GetData()
	}
	ssrconn.IProtocol.SetData(s.ProtocolData)

	if _, err := ssrconn.Write(target); err != nil {
		ssrconn.Close()
		return nil, err
	}

	return ssrconn, err
}

// DialUDP returns a PacketConn to the addr
func (s *Dialer) DialUDP(network, addr string) (net.PacketConn, net.Addr, error) {
	return nil, nil, errors.New("[ssr] udp not supported now")
}