package trojan

import (
	"fmt"
	"foo/common"
	"foo/component/outbound/dialer"
	"foo/component/outbound/dialer/transport/tls"
	"foo/component/outbound/dialer/transport/ws"
	"github.com/mzz2017/softwind/protocol"
	"github.com/mzz2017/softwind/transport/grpc"
	"gopkg.in/yaml.v3"
	"net"
	"net/url"
	"strconv"
	"strings"
)

func init() {
	dialer.FromLinkRegister("trojan", NewTrojan)
	dialer.FromLinkRegister("trojan-go", NewTrojan)
	dialer.FromClashRegister("trojan", NewTrojanFromClashObj)
}

type Trojan struct {
	Name          string `json:"name"`
	Server        string `json:"server"`
	Port          int    `json:"port"`
	Password      string `json:"password"`
	Sni           string `json:"sni"`
	Type          string `json:"type"`
	Encryption    string `json:"encryption"`
	Host          string `json:"host"`
	Path          string `json:"path"`
	ServiceName   string `json:"serviceName"`
	AllowInsecure bool   `json:"allowInsecure"`
	Protocol      string `json:"protocol"`
}

func NewTrojan(link string) (*dialer.Dialer, error) {
	s, err := ParseTrojanURL(link)
	if err != nil {
		return nil, err
	}
	return s.Dialer()
}

func NewTrojanFromClashObj(o *yaml.Node) (*dialer.Dialer, error) {
	s, err := ParseClash(o)
	if err != nil {
		return nil, err
	}
	return s.Dialer()
}

func (s *Trojan) Dialer() (*dialer.Dialer, error) {
	d := dialer.SymmetricDirect
	u := url.URL{
		Scheme: "tls",
		Host:   net.JoinHostPort(s.Server, strconv.Itoa(s.Port)),
		RawQuery: url.Values{
			"sni": []string{s.Sni},
		}.Encode(),
	}
	var err error
	if s.Type != "grpc" {
		// grpc contains tls
		if d, err = tls.NewTls(u.String(), d); err != nil {
			return nil, err
		}
	}
	// "tls,ws,ss,trojanc"
	switch s.Type {
	case "ws":
		u = url.URL{
			Scheme: "ws",
			Host:   net.JoinHostPort(s.Server, strconv.Itoa(s.Port)),
			RawQuery: url.Values{
				"host": []string{s.Host},
				"path": []string{s.Path},
			}.Encode(),
		}
		if d, err = ws.NewWs(u.String(), d); err != nil {
			return nil, err
		}
	case "grpc":
		serviceName := s.ServiceName
		if serviceName == "" {
			serviceName = "GunService"
		}
		d = &grpc.Dialer{
			NextDialer:  &protocol.DialerConverter{Dialer: d},
			ServiceName: serviceName,
			ServerName:  s.Sni,
		}
	}
	if strings.HasPrefix(s.Encryption, "ss;") {
		fields := strings.SplitN(s.Encryption, ";", 3)
		if d, err = protocol.NewDialer("shadowsocks", d, protocol.Header{
			ProxyAddress: net.JoinHostPort(s.Server, strconv.Itoa(s.Port)),
			Cipher:       fields[1],
			Password:     fields[2],
			IsClient:     false,
		}); err != nil {
			return nil, err
		}
	}
	if d, err = protocol.NewDialer("trojanc", d, protocol.Header{
		ProxyAddress: net.JoinHostPort(s.Server, strconv.Itoa(s.Port)),
		Password:     s.Password,
		IsClient:     true,
	}); err != nil {
		return nil, err
	}
	return dialer.NewDialer(d, true, s.Name, s.Protocol, s.ExportToURL()), nil
}

func ParseTrojanURL(u string) (data *Trojan, err error) {
	//trojan://password@server:port#escape(remarks)
	t, err := url.Parse(u)
	if err != nil {
		err = fmt.Errorf("invalid trojan format")
		return
	}
	allowInsecure := t.Query().Get("allowInsecure")
	sni := t.Query().Get("peer")
	if sni == "" {
		sni = t.Query().Get("sni")
	}
	if sni == "" {
		sni = t.Hostname()
	}
	port, err := strconv.Atoi(t.Port())
	if err != nil {
		return nil, dialer.InvalidParameterErr
	}
	data = &Trojan{
		Name:          t.Fragment,
		Server:        t.Hostname(),
		Port:          port,
		Password:      t.User.Username(),
		Sni:           sni,
		AllowInsecure: allowInsecure == "1" || allowInsecure == "true",
		Protocol:      "trojan",
	}
	if t.Query().Get("type") != "" {
		t.Scheme = "trojan-go"
	}
	if t.Scheme == "trojan-go" {
		data.Protocol = "trojan-go"
		data.Encryption = t.Query().Get("encryption")
		data.Host = t.Query().Get("host")
		data.Path = t.Query().Get("path")
		data.Type = t.Query().Get("type")
		data.ServiceName = t.Query().Get("serviceName")
		if data.Type == "grpc" && data.ServiceName == "" {
			data.ServiceName = data.Path
		}
		data.AllowInsecure = false
	}
	return data, nil
}

func ParseClash(o *yaml.Node) (data *Trojan, err error) {
	type WSOptions struct {
		Path                string            `yaml:"path,omitempty"`
		Headers             map[string]string `yaml:"headers,omitempty"`
		MaxEarlyData        int               `yaml:"max-early-data,omitempty"`
		EarlyDataHeaderName string            `yaml:"early-data-header-name,omitempty"`
	}
	type GrpcOptions struct {
		GrpcServiceName string `proxy:"grpc-service-name,omitempty"`
	}
	type TrojanOption struct {
		Name           string      `yaml:"name"`
		Server         string      `yaml:"server"`
		Port           int         `yaml:"port"`
		Password       string      `yaml:"password"`
		ALPN           []string    `yaml:"alpn,omitempty"`
		SNI            string      `yaml:"sni,omitempty"`
		SkipCertVerify bool        `yaml:"skip-cert-verify,omitempty"`
		UDP            bool        `yaml:"udp,omitempty"`
		Network        string      `yaml:"network,omitempty"`
		GrpcOpts       GrpcOptions `yaml:"grpc-opts,omitempty"`
		WSOpts         WSOptions   `yaml:"ws-opts,omitempty"`
	}
	var option TrojanOption
	if err = o.Decode(&option); err != nil {
		return nil, err
	}
	proto := "trojan"
	if option.Network != "" && option.Network != "origin" {
		proto = "trojan-go"
	}
	return &Trojan{
		Name:          option.Name,
		Server:        option.Server,
		Port:          option.Port,
		Password:      option.Password,
		Sni:           option.SNI,
		Type:          option.Network,
		Encryption:    "",
		Host:          option.WSOpts.Headers["Host"],
		Path:          option.WSOpts.Path,
		AllowInsecure: option.SkipCertVerify,
		ServiceName:   option.GrpcOpts.GrpcServiceName,
		Protocol:      proto,
	}, nil
}

func (t *Trojan) ExportToURL() string {
	u := &url.URL{
		Scheme:   "trojan",
		User:     url.User(t.Password),
		Host:     net.JoinHostPort(t.Server, strconv.Itoa(t.Port)),
		Fragment: t.Name,
	}
	q := u.Query()
	if t.AllowInsecure {
		q.Set("allowInsecure", "1")
	}
	common.SetValue(&q, "sni", t.Sni)

	if t.Protocol == "trojan-go" {
		u.Scheme = "trojan-go"
		common.SetValue(&q, "host", t.Host)
		common.SetValue(&q, "encryption", t.Encryption)
		common.SetValue(&q, "type", t.Type)
		common.SetValue(&q, "path", t.Path)
	}
	u.RawQuery = q.Encode()
	return u.String()
}