package http

import (
	"crypto/tls"
	"fmt"
	"io"
	"io/ioutil"
	logger "log"
	"net"
	"runtime/debug"
	"strconv"
	"strings"
	"time"

	server "github.com/snail007/goproxy/core/cs/server"
	"github.com/snail007/goproxy/core/lib/kcpcfg"
	"github.com/snail007/goproxy/services"
	"github.com/snail007/goproxy/utils/datasize"
	"github.com/snail007/goproxy/utils/dnsx"
	"github.com/snail007/goproxy/utils/iolimiter"
	"github.com/snail007/goproxy/utils/jumper"
	"github.com/snail007/goproxy/utils/lb"
	"github.com/snail007/goproxy/utils/mapx"

	"github.com/snail007/goproxy/utils"
	"github.com/snail007/goproxy/utils/conncrypt"

	"golang.org/x/crypto/ssh"
)

type HTTPArgs struct {
	Parent                *[]string
	CertFile              *string
	KeyFile               *string
	CaCertFile            *string
	CaCertBytes           []byte
	CertBytes             []byte
	KeyBytes              []byte
	Local                 *string
	Always                *bool
	HTTPTimeout           *int
	Interval              *int
	Blocked               *string
	Direct                *string
	AuthFile              *string
	Auth                  *[]string
	AuthURL               *string
	AuthURLOkCode         *int
	AuthURLTimeout        *int
	AuthURLRetry          *int
	ParentType            *string
	LocalType             *string
	Timeout               *int
	CheckParentInterval   *int
	SSHKeyFile            *string
	SSHKeyFileSalt        *string
	SSHPassword           *string
	SSHUser               *string
	SSHKeyBytes           []byte
	SSHAuthMethod         ssh.AuthMethod
	KCP                   kcpcfg.KCPConfigArgs
	LocalIPS              *[]string
	DNSAddress            *string
	DNSTTL                *int
	LocalKey              *string
	ParentKey             *string
	LocalCompress         *bool
	ParentCompress        *bool
	CloseIntelligent      *bool
	LoadBalanceMethod     *string
	LoadBalanceTimeout    *int
	LoadBalanceRetryTime  *int
	LoadBalanceHashTarget *bool
	LoadBalanceOnlyHA     *bool

	RateLimit      *string
	RateLimitBytes float64
	BindListen     *bool
	Debug          *bool
	Jumper         *string
}
type HTTP struct {
	cfg            HTTPArgs
	checker        utils.Checker
	basicAuth      utils.BasicAuth
	sshClient      *ssh.Client
	lockChn        chan bool
	domainResolver dnsx.DomainResolver
	isStop         bool
	serverChannels []*server.ServerChannel
	userConns      mapx.ConcurrentMap
	log            *logger.Logger
	lb             *lb.Group
	jumper         *jumper.Jumper
}

func NewHTTP() services.Service {
	return &HTTP{
		cfg:            HTTPArgs{},
		checker:        utils.Checker{},
		basicAuth:      utils.BasicAuth{},
		lockChn:        make(chan bool, 1),
		isStop:         false,
		serverChannels: []*server.ServerChannel{},
		userConns:      mapx.NewConcurrentMap(),
	}
}
func (s *HTTP) CheckArgs() (err error) {

	if len(*s.cfg.Parent) == 1 && (*s.cfg.Parent)[0] == "" {
		(*s.cfg.Parent) = []string{}
	}
	if len(*s.cfg.Parent) > 0 && *s.cfg.ParentType == "" {
		err = fmt.Errorf("parent type unkown,use -T <tls|tcp|ssh|kcp>")
		return
	}
	if *s.cfg.ParentType == "tls" || *s.cfg.LocalType == "tls" {
		s.cfg.CertBytes, s.cfg.KeyBytes, err = utils.TlsBytes(*s.cfg.CertFile, *s.cfg.KeyFile)
		if err != nil {
			return
		}
		if *s.cfg.CaCertFile != "" {
			s.cfg.CaCertBytes, err = ioutil.ReadFile(*s.cfg.CaCertFile)
			if err != nil {
				err = fmt.Errorf("read ca file error,ERR:%s", err)
				return
			}
		}
	}
	if *s.cfg.ParentType == "ssh" {
		if *s.cfg.SSHUser == "" {
			err = fmt.Errorf("ssh user required")
			return
		}
		if *s.cfg.SSHKeyFile == "" && *s.cfg.SSHPassword == "" {
			err = fmt.Errorf("ssh password or key required")
			return
		}

		if *s.cfg.SSHPassword != "" {
			s.cfg.SSHAuthMethod = ssh.Password(*s.cfg.SSHPassword)
		} else {
			var SSHSigner ssh.Signer
			s.cfg.SSHKeyBytes, err = ioutil.ReadFile(*s.cfg.SSHKeyFile)
			if err != nil {
				err = fmt.Errorf("read key file ERR: %s", err)
				return
			}
			if *s.cfg.SSHKeyFileSalt != "" {
				SSHSigner, err = ssh.ParsePrivateKeyWithPassphrase(s.cfg.SSHKeyBytes, []byte(*s.cfg.SSHKeyFileSalt))
			} else {
				SSHSigner, err = ssh.ParsePrivateKey(s.cfg.SSHKeyBytes)
			}
			if err != nil {
				err = fmt.Errorf("parse ssh private key fail,ERR: %s", err)
				return
			}
			s.cfg.SSHAuthMethod = ssh.PublicKeys(SSHSigner)
		}
	}
	if *s.cfg.RateLimit != "0" && *s.cfg.RateLimit != "" {
		var size uint64
		size, err = datasize.Parse(*s.cfg.RateLimit)
		if err != nil {
			err = fmt.Errorf("parse rate limit size error,ERR:%s", err)
			return
		}
		s.cfg.RateLimitBytes = float64(size)
	}
	if *s.cfg.Jumper != "" {
		if *s.cfg.ParentType != "tls" && *s.cfg.ParentType != "tcp" {
			err = fmt.Errorf("jumper only worked of -T is tls or tcp")
			return
		}
		var j jumper.Jumper
		j, err = jumper.New(*s.cfg.Jumper, time.Millisecond*time.Duration(*s.cfg.Timeout))
		if err != nil {
			err = fmt.Errorf("parse jumper fail, err %s", err)
			return
		}
		s.jumper = &j
	}
	return
}
func (s *HTTP) InitService() (err error) {
	s.InitBasicAuth()
	//init lb
	if len(*s.cfg.Parent) > 0 {
		s.checker = utils.NewChecker(*s.cfg.HTTPTimeout, int64(*s.cfg.Interval), *s.cfg.Blocked, *s.cfg.Direct, s.log, *s.cfg.CloseIntelligent)
		s.InitLB()
	}
	if *s.cfg.DNSAddress != "" {
		s.domainResolver = dnsx.NewDomainResolver(*s.cfg.DNSAddress, *s.cfg.DNSTTL, s.log)
	}
	if *s.cfg.ParentType == "ssh" {
		err = s.ConnectSSH()
		if err != nil {
			err = fmt.Errorf("init service fail, ERR: %s", err)
			return
		}
		go func() {
			defer func() {
				if e := recover(); e != nil {
					fmt.Printf("crashed, err: %s\nstack:%s", e, string(debug.Stack()))
				}
			}()
			//循环检查ssh网络连通性
			for {
				if s.isStop {
					return
				}
				conn, err := utils.ConnectHost(s.Resolve(s.lb.Select("", *s.cfg.LoadBalanceOnlyHA)), *s.cfg.Timeout*2)
				if err == nil {
					conn.SetDeadline(time.Now().Add(time.Millisecond * time.Duration(*s.cfg.Timeout)))
					_, err = conn.Write([]byte{0})
					conn.SetDeadline(time.Time{})
				}
				if err != nil {
					if s.sshClient != nil {
						s.sshClient.Close()
						if s.sshClient.Conn != nil {
							s.sshClient.Conn.Close()
						}
					}
					s.log.Printf("ssh offline, retrying...")
					s.ConnectSSH()
				} else {
					conn.Close()
				}
				time.Sleep(time.Second * 3)
			}
		}()
	}
	return
}
func (s *HTTP) StopService() {
	defer func() {
		e := recover()
		if e != nil {
			s.log.Printf("stop http(s) service crashed,%s", e)
		} else {
			s.log.Printf("service http(s) stopped")
		}
		s.basicAuth = utils.BasicAuth{}
		s.cfg = HTTPArgs{}
		s.checker = utils.Checker{}
		s.domainResolver = dnsx.DomainResolver{}
		s.lb = nil
		s.lockChn = nil
		s.log = nil
		s.jumper = nil
		s.serverChannels = nil
		s.sshClient = nil
		s.userConns = nil
		s = nil
	}()
	s.isStop = true
	if len(*s.cfg.Parent) > 0 {
		s.checker.Stop()
	}
	if s.sshClient != nil {
		s.sshClient.Close()
	}
	for _, sc := range s.serverChannels {
		if sc.Listener != nil && *sc.Listener != nil {
			(*sc.Listener).Close()
		}
		if sc.UDPListener != nil {
			(*sc.UDPListener).Close()
		}
	}
	if s.lb != nil {
		s.lb.Stop()
	}
}
func (s *HTTP) Start(args interface{}, log *logger.Logger) (err error) {
	s.log = log
	s.cfg = args.(HTTPArgs)
	if err = s.CheckArgs(); err != nil {
		return
	}

	if err = s.InitService(); err != nil {
		return
	}

	if len(*s.cfg.Parent) > 0 {
		s.log.Printf("use %s parent %v [ %s ]", *s.cfg.ParentType, *s.cfg.Parent, strings.ToUpper(*s.cfg.LoadBalanceMethod))
	}

	for _, addr := range strings.Split(*s.cfg.Local, ",") {
		if addr != "" {
			host, port, _ := net.SplitHostPort(addr)
			p, _ := strconv.Atoi(port)
			sc := server.NewServerChannel(host, p, s.log)
			if *s.cfg.LocalType == "tcp" {
				err = sc.ListenTCP(s.callback)
			} else if *s.cfg.LocalType == "tls" {
				err = sc.ListenTLS(s.cfg.CertBytes, s.cfg.KeyBytes, s.cfg.CaCertBytes, s.callback)
			} else if *s.cfg.LocalType == "kcp" {
				err = sc.ListenKCP(s.cfg.KCP, s.callback, s.log)
			}
			if err != nil {
				return
			}
			s.log.Printf("%s http(s) proxy on %s", *s.cfg.LocalType, (*sc.Listener).Addr())
			s.serverChannels = append(s.serverChannels, &sc)
		}
	}
	return
}

func (s *HTTP) Clean() {
	s.StopService()
}
func (s *HTTP) callback(inConn net.Conn) {
	defer func() {
		if err := recover(); err != nil {
			s.log.Printf("http(s) conn handler crashed with err : %s \nstack: %s", err, string(debug.Stack()))
		}
	}()
	if *s.cfg.LocalCompress {
		inConn = utils.NewCompConn(inConn)
	}
	if *s.cfg.LocalKey != "" {
		inConn = conncrypt.New(inConn, &conncrypt.Config{
			Password: *s.cfg.LocalKey,
		})
	}
	var err interface{}
	var req utils.HTTPRequest
	req, err = utils.NewHTTPRequest(&inConn, 4096, s.IsBasicAuth(), &s.basicAuth, s.log)
	if err != nil {
		if err != io.EOF {
			s.log.Printf("decoder error , from %s, ERR:%s", inConn.RemoteAddr(), err)
		}
		utils.CloseConn(&inConn)
		return
	}
	address := req.Host
	host, _, _ := net.SplitHostPort(address)
	useProxy := false
	if !utils.IsInternalIP(host, *s.cfg.Always) {
		useProxy = true
		if len(*s.cfg.Parent) == 0 {
			useProxy = false
		} else if *s.cfg.Always {
			useProxy = true
		} else {
			var isInMap bool
			useProxy, isInMap, _, _ = s.checker.IsBlocked(address)
			if !isInMap {
				s.checker.Add(address, s.Resolve(address))
			}
			//s.log.Printf("blocked ? : %v, %s , fail:%d ,success:%d", useProxy, address, n, m)
		}
	}

	s.log.Printf("use proxy : %v, %s", useProxy, address)

	lbAddr, err := s.OutToTCP(useProxy, address, &inConn, &req)
	if err != nil {
		if len(*s.cfg.Parent) == 0 {
			s.log.Printf("connect to %s fail, ERR:%s", address, err)
		} else {
			s.log.Printf("connect to %s parent %v fail", *s.cfg.ParentType, lbAddr)
		}
		utils.CloseConn(&inConn)
	}
}
func (s *HTTP) OutToTCP(useProxy bool, address string, inConn *net.Conn, req *utils.HTTPRequest) (lbAddr string, err interface{}) {
	inAddr := (*inConn).RemoteAddr().String()
	inLocalAddr := (*inConn).LocalAddr().String()
	//防止死循环
	if s.IsDeadLoop(inLocalAddr, req.Host) {
		utils.CloseConn(inConn)
		err = fmt.Errorf("dead loop detected , %s", req.Host)
		return
	}
	var outConn net.Conn
	tryCount := 0
	maxTryCount := 5
	for {
		if s.isStop {
			return
		}
		if useProxy {
			// s.log.Printf("%v", s.outPool)
			selectAddr := (*inConn).RemoteAddr().String()
			if utils.LBMethod(*s.cfg.LoadBalanceMethod) == lb.SELECT_HASH && *s.cfg.LoadBalanceHashTarget {
				selectAddr = address
			}
			lbAddr = s.lb.Select(selectAddr, *s.cfg.LoadBalanceOnlyHA)
			outConn, err = s.GetParentConn(lbAddr)
		} else {
			outConn, err = s.GetDirectConn(s.Resolve(address), inLocalAddr)
		}
		tryCount++
		if err == nil || tryCount > maxTryCount {
			break
		} else {
			s.log.Printf("connect to %s , err:%s,retrying...", lbAddr, err)
			time.Sleep(time.Second * 2)
		}
	}
	if err != nil {
		s.log.Printf("connect to %s , err:%s", lbAddr, err)
		utils.CloseConn(inConn)
		return
	}
	if *s.cfg.ParentCompress {
		outConn = utils.NewCompConn(outConn)
	}
	if *s.cfg.ParentKey != "" {
		outConn = conncrypt.New(outConn, &conncrypt.Config{
			Password: *s.cfg.ParentKey,
		})
	}

	outAddr := outConn.RemoteAddr().String()
	//outLocalAddr := outConn.LocalAddr().String()
	if req.IsHTTPS() && (!useProxy || *s.cfg.ParentType == "ssh") {
		//https无上级或者上级非代理,proxy需要响应connect请求,并直连目标
		err = req.HTTPSReply()
	} else {
		//https或者http,上级是代理,proxy需要转发
		outConn.SetDeadline(time.Now().Add(time.Millisecond * time.Duration(*s.cfg.Timeout)))
		//直连目标或上级非代理或非SNI,,清理HTTP头部的代理头信息
		if (!useProxy || *s.cfg.ParentType == "ssh") && !req.IsSNI {
			_, err = outConn.Write(utils.RemoveProxyHeaders(req.HeadBuf))
		} else {
			_, err = outConn.Write(req.HeadBuf)
		}
		outConn.SetDeadline(time.Time{})
		if err != nil {
			s.log.Printf("write to %s , err:%s", lbAddr, err)
			utils.CloseConn(inConn)
			return
		}
	}

	if s.cfg.RateLimitBytes > 0 {
		outConn = iolimiter.NewReaderConn(outConn, s.cfg.RateLimitBytes)
	}

	utils.IoBind((*inConn), outConn, func(err interface{}) {
		s.log.Printf("conn %s - %s released [%s]", inAddr, outAddr, req.Host)
		s.userConns.Remove(inAddr)
		if len(*s.cfg.Parent) > 0 {
			s.lb.DecreaseConns(lbAddr)
		}
	}, s.log)
	s.log.Printf("conn %s - %s connected [%s]", inAddr, outAddr, req.Host)
	if c, ok := s.userConns.Get(inAddr); ok {
		(*c.(*net.Conn)).Close()
	}
	s.userConns.Set(inAddr, inConn)
	if len(*s.cfg.Parent) > 0 {
		s.lb.IncreasConns(lbAddr)
	}
	return
}

func (s *HTTP) getSSHConn(host string) (outConn net.Conn, err interface{}) {
	maxTryCount := 1
	tryCount := 0
RETRY:
	if tryCount >= maxTryCount || s.isStop {
		return
	}
	wait := make(chan bool, 1)
	go func() {
		defer func() {
			if err == nil {
				err = recover()
			}
			wait <- true
		}()
		outConn, err = s.sshClient.Dial("tcp", host)
	}()
	select {
	case <-wait:
	case <-time.After(time.Second * 5):
		err = fmt.Errorf("ssh dial %s timeout", host)
	}
	if err != nil {
		s.log.Printf("connect ssh fail, ERR: %s, retrying...", err)
		e := s.ConnectSSH()
		if e == nil {
			tryCount++
			time.Sleep(time.Second * 3)
			goto RETRY
		} else {
			err = e
		}
	}
	return
}
func (s *HTTP) ConnectSSH() (err error) {
	select {
	case s.lockChn <- true:
	default:
		err = fmt.Errorf("can not connect at same time")
		return
	}
	config := ssh.ClientConfig{
		Timeout: time.Duration(*s.cfg.Timeout) * time.Millisecond,
		User:    *s.cfg.SSHUser,
		Auth:    []ssh.AuthMethod{s.cfg.SSHAuthMethod},
		HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error {
			return nil
		},
	}
	if s.sshClient != nil {
		s.sshClient.Close()
	}
	s.sshClient, err = ssh.Dial("tcp", s.Resolve(s.lb.Select("", *s.cfg.LoadBalanceOnlyHA)), &config)
	<-s.lockChn
	return
}

func (s *HTTP) InitBasicAuth() (err error) {
	if *s.cfg.DNSAddress != "" {
		s.basicAuth = utils.NewBasicAuth(&(*s).domainResolver, s.log)
	} else {
		s.basicAuth = utils.NewBasicAuth(nil, s.log)
	}
	if *s.cfg.AuthURL != "" {
		s.basicAuth.SetAuthURL(*s.cfg.AuthURL, *s.cfg.AuthURLOkCode, *s.cfg.AuthURLTimeout, *s.cfg.AuthURLRetry)
		s.log.Printf("auth from %s", *s.cfg.AuthURL)
	}
	if *s.cfg.AuthFile != "" {
		var n = 0
		n, err = s.basicAuth.AddFromFile(*s.cfg.AuthFile)
		if err != nil {
			err = fmt.Errorf("auth-file ERR:%s", err)
			return
		}
		s.log.Printf("auth data added from file %d , total:%d", n, s.basicAuth.Total())
	}
	if len(*s.cfg.Auth) > 0 {
		n := s.basicAuth.Add(*s.cfg.Auth)
		s.log.Printf("auth data added %d, total:%d", n, s.basicAuth.Total())
	}
	return
}
func (s *HTTP) InitLB() {
	configs := lb.BackendsConfig{}
	for _, addr := range *s.cfg.Parent {
		_addrInfo := strings.Split(addr, "@")
		_addr := _addrInfo[0]
		weight := 1
		if len(_addrInfo) == 2 {
			weight, _ = strconv.Atoi(_addrInfo[1])
		}
		configs = append(configs, &lb.BackendConfig{
			Address:       _addr,
			Weight:        weight,
			ActiveAfter:   1,
			InactiveAfter: 2,
			Timeout:       time.Duration(*s.cfg.LoadBalanceTimeout) * time.Millisecond,
			RetryTime:     time.Duration(*s.cfg.LoadBalanceRetryTime) * time.Millisecond,
		})
	}
	LB := lb.NewGroup(utils.LBMethod(*s.cfg.LoadBalanceMethod), configs, &s.domainResolver, s.log, *s.cfg.Debug)
	s.lb = &LB
}
func (s *HTTP) IsBasicAuth() bool {
	return *s.cfg.AuthFile != "" || len(*s.cfg.Auth) > 0 || *s.cfg.AuthURL != ""
}
func (s *HTTP) IsDeadLoop(inLocalAddr string, host string) bool {
	inIP, inPort, err := net.SplitHostPort(inLocalAddr)
	if err != nil {
		return false
	}
	outDomain, outPort, err := net.SplitHostPort(host)
	if err != nil {
		return false
	}
	if inPort == outPort {
		var outIPs []net.IP
		if *s.cfg.DNSAddress != "" {
			outIPs = []net.IP{net.ParseIP(s.Resolve(outDomain))}
		} else {
			outIPs, err = utils.LookupIP(outDomain)
		}
		if err == nil {
			for _, ip := range outIPs {
				if ip.String() == inIP {
					return true
				}
			}
		}
		interfaceIPs, err := utils.GetAllInterfaceAddr()
		for _, ip := range *s.cfg.LocalIPS {
			interfaceIPs = append(interfaceIPs, net.ParseIP(ip).To4())
		}
		if err == nil {
			for _, localIP := range interfaceIPs {
				for _, outIP := range outIPs {
					if localIP.Equal(outIP) {
						return true
					}
				}
			}
		}
	}
	return false
}
func (s *HTTP) Resolve(address string) string {
	if *s.cfg.DNSAddress == "" {
		return address
	}
	ip, err := s.domainResolver.Resolve(address)
	if err != nil {
		s.log.Printf("dns error %s , ERR:%s", address, err)
		return address
	}
	return ip
}
func (s *HTTP) GetParentConn(address string) (conn net.Conn, err error) {
	if *s.cfg.ParentType == "tls" {
		if s.jumper == nil {
			var _conn tls.Conn
			_conn, err = utils.TlsConnectHost(address, *s.cfg.Timeout, s.cfg.CertBytes, s.cfg.KeyBytes, s.cfg.CaCertBytes)
			if err == nil {
				conn = net.Conn(&_conn)
			}
		} else {
			conf, err := utils.TlsConfig(s.cfg.CertBytes, s.cfg.KeyBytes, s.cfg.CaCertBytes)
			if err != nil {
				return nil, err
			}
			var _c net.Conn
			_c, err = s.jumper.Dial(address, time.Millisecond*time.Duration(*s.cfg.Timeout))
			if err == nil {
				conn = net.Conn(tls.Client(_c, conf))
			}
		}

	} else if *s.cfg.ParentType == "kcp" {
		conn, err = utils.ConnectKCPHost(address, s.cfg.KCP)
	} else if *s.cfg.ParentType == "ssh" {
		var e interface{}
		conn, e = s.getSSHConn(address)
		if e != nil {
			err = fmt.Errorf("%s", e)
		}
	} else {
		if s.jumper == nil {
			conn, err = utils.ConnectHost(address, *s.cfg.Timeout)
		} else {
			conn, err = s.jumper.Dial(address, time.Millisecond*time.Duration(*s.cfg.Timeout))
		}
	}
	return
}
func (s *HTTP) GetDirectConn(address string, localAddr string) (conn net.Conn, err error) {
	if !*s.cfg.BindListen {
		return utils.ConnectHost(address, *s.cfg.Timeout)
	}
	ip, _, _ := net.SplitHostPort(localAddr)
	if utils.IsInternalIP(ip, false) {
		return utils.ConnectHost(address, *s.cfg.Timeout)
	}
	local, _ := net.ResolveTCPAddr("tcp", ip+":0")
	d := net.Dialer{
		Timeout:   time.Millisecond * time.Duration(*s.cfg.Timeout),
		LocalAddr: local,
	}
	conn, err = d.Dial("tcp", address)
	return
}