package web

import (
	"context"
	"fmt"
	"git.makemake.in/kzkzzzz/mycommon/mylog"
	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/binding"
	"github.com/go-playground/locales/en"
	ut "github.com/go-playground/universal-translator"
	"github.com/go-playground/validator/v10"
	enTr "github.com/go-playground/validator/v10/translations/en"
	"github.com/spf13/cast"
	"gorm.io/gorm"
	"log"
	"net/http"
	"net/netip"
	"proxyport/app/db"
	"proxyport/app/forward"
	"proxyport/app/model"
	"proxyport/app/static"
	"reflect"
	"regexp"
	"strings"
	"time"
)

var Config = &Cfg{}

type Cfg struct {
	ListenAddr string
	User       string
	Password   string
	WebName    string
}

func Start(ctx context.Context) {
	InitGinTrans()

	engine := gin.Default()

	if Config.User != "" && Config.Password != "" {
		engine.Use(gin.BasicAuth(gin.Accounts{
			Config.User: Config.Password,
		}))
	}

	static.LoadStatic(engine)
	engine.Use(cors())

	engine.GET("/", func(ctx *gin.Context) {
		ctx.HTML(http.StatusOK, "index.html", nil)
	})

	engine.GET("/GetConfig", GetConfig)
	engine.GET("/List", List)
	engine.POST("/Create", Create)
	engine.POST("/Update", Update)
	engine.POST("/Delete", Delete)
	engine.POST("/SwitchStatus", SwitchStatus)

	hs := &http.Server{
		Addr:    Config.ListenAddr,
		Handler: engine,
	}

	go func() {
		log.Printf("http listen on %s", hs.Addr)
		mylog.Warn(hs.ListenAndServe())
	}()

	<-ctx.Done()
	hs.Close()

}

func cors() gin.HandlerFunc {
	return func(ctx *gin.Context) {
		ctx.Header("Access-Control-Allow-Origin", "*")
		ctx.Header("Access-Control-Allow-Methods", "GET, POST")

		ctx.Header("Access-Control-Allow-Headers", "Content-Type")

		if ctx.Request.Method == http.MethodOptions {
			ctx.AbortWithStatus(http.StatusOK)
		} else {
			ctx.Next()
		}
	}
}

func GetConfig(ctx *gin.Context) {
	success(ctx, gin.H{
		"web_name": Config.WebName,
	})
}

func List(ctx *gin.Context) {
	data := make([]*model.Forward, 0)

	err := db.DB().Table("forward").Select("*").Order("update_time desc").Find(&data).Error
	if err != nil {
		fail(ctx, err)
		return
	}
	success(ctx, data)
}

func Create(ctx *gin.Context) {
	type Req struct {
		TargetAddr  string `json:"target_addr" binding:"min=1"`
		LocalPort   int    `json:"local_port" binding:"required"`
		Name        string `json:"name" binding:"required"`
		ForwardType int    `json:"protocol" binding:"oneof=0 1"`
		Status      int    `json:"status" binding:"oneof=0 1"`
	}

	req := &Req{}
	err := ctx.ShouldBindJSON(req)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = checkAddr(fmt.Sprintf("0.0.0.0:%d", req.LocalPort))
	if err != nil {
		fail(ctx, err)
		return
	}

	targetAddr, err := parseAddrList(req.TargetAddr)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = checkUnique(0, req.LocalPort, req.ForwardType)
	if err != nil {
		fail(ctx, err)
		return
	}

	now := time.Now()

	err = db.DB().Transaction(func(tx *gorm.DB) error {
		mForward := &model.Forward{
			LocalPort:  req.LocalPort,
			TargetAddr: targetAddr,
			Name:       req.Name,
			Protocol:   req.ForwardType,
			Status:     1,
			CreateTime: now.Format(time.DateTime),
			UpdateTime: now.Format(time.DateTime),
		}

		err := tx.Table("forward").Create(mForward).Error
		if err != nil {
			return err
		}

		err = forward.ListenerManager.Add(mForward)
		if err != nil {
			return err
		}

		return nil
	})

	if err != nil {
		fail(ctx, err)
		return
	}

	success(ctx, "ok")
}

func Update(ctx *gin.Context) {
	type Req struct {
		Id         int    `json:"id" binding:"required"`
		TargetAddr string `json:"target_addr" binding:"min=1"`
		LocalPort  int    `json:"local_port" binding:"required"`
		Name       string `json:"name" binding:"required"`
		Protocol   int    `json:"protocol" binding:"oneof=0 1"`
		Status     int    `json:"status" binding:"oneof=0 1"`
	}

	req := &Req{}
	err := ctx.ShouldBindJSON(req)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = checkAddr(fmt.Sprintf("0.0.0.0:%d", req.LocalPort))
	if err != nil {
		fail(ctx, err)
		return
	}

	targetAddr, err := parseAddrList(req.TargetAddr)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = checkUnique(req.Id, req.LocalPort, req.Protocol)
	if err != nil {
		fail(ctx, err)
		return
	}

	current, err := getForwardById(req.Id)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = db.DB().Transaction(func(tx *gorm.DB) error {
		mForward := &model.Forward{
			LocalPort:  req.LocalPort,
			TargetAddr: targetAddr,
			Name:       req.Name,
			Protocol:   req.Protocol,
			UpdateTime: time.Now().Format(time.DateTime),
		}

		err = tx.Table("forward").Select("*").Omit("create_time", "status").Where("id = ?", req.Id).
			Limit(1).
			Updates(mForward).Error

		if err != nil {
			return err
		}

		forward.ListenerManager.Remove(current)

		if current.Status == 1 {
			err = forward.ListenerManager.Add(mForward)
			if err != nil {
				return err
			}
		}
		return nil
	})

	if err != nil {
		fail(ctx, err)
		return
	}

	success(ctx, "ok")
}

func Delete(ctx *gin.Context) {
	type Req struct {
		Id int `json:"id" binding:"required"`
	}

	req := &Req{}
	err := ctx.ShouldBindJSON(req)
	if err != nil {
		fail(ctx, err)
		return
	}

	mForward, err := getForwardById(req.Id)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = db.DB().Table("forward").Select("*").Where("id = ?", req.Id).Limit(1).Delete(nil).Error
	if err != nil {
		fail(ctx, err)
		return
	}

	forward.ListenerManager.Remove(mForward)

	success(ctx, "ok")
}

var (
	hostReg   = regexp.MustCompile(`^[a-zA-Z0-9]+[a-zA-Z0-9\-.]*[a-zA-Z]+$`)
	letterReg = regexp.MustCompile(`[a-zA-Z\-]`)
	emptyReg  = regexp.MustCompile(`\s+`)
)

func checkAddr(addr string) error {
	addr = strings.TrimSpace(addr)

	if emptyReg.MatchString(addr) {
		return fmt.Errorf("addr format err: %s", addr)
	}

	sp := strings.SplitN(addr, ":", 2)

	if len(sp) != 2 {
		return fmt.Errorf("addr format err: %s", addr)
	}

	host := sp[0]
	port := sp[1]
	intPort := cast.ToInt(port)

	if intPort > 65535 || intPort < 10 {
		return fmt.Errorf("port [%s] out of range: 10 - 65535", port)
	}

	if !letterReg.MatchString(host) {
		_, err := netip.ParseAddrPort(addr)
		if err != nil {
			return fmt.Errorf("ip [%s] format err: %s", host, err)
		}

		return nil
	}

	if !hostReg.MatchString(host) {
		return fmt.Errorf("host [%s] format err", host)
	}

	return nil
}

func checkUnique(id, localPort, forwardType int) error {
	query := db.DB().Table("forward").
		Where("local_port = ?", localPort).
		Where("protocol = ?", forwardType)

	if id > 0 {
		query.Where("id != ?", id)
	}

	var res []int
	err := query.Select("id").Limit(1).Find(&res).Error
	if err != nil {
		return err
	}

	if len(res) > 0 {
		return fmt.Errorf("%s port: %d already use", forward.Protocol(forwardType).String(), localPort)
	}

	return nil
}

func getForwardById(id int) (*model.Forward, error) {
	if id <= 0 {
		return nil, fmt.Errorf("id err: %d", id)
	}
	mForward := &model.Forward{}
	err := db.DB().Table("forward").Select("*").Where("id = ?", id).First(mForward).Error
	if err != nil {
		return nil, err
	}

	return mForward, nil
}

func SwitchStatus(ctx *gin.Context) {
	type Req struct {
		Id     int `json:"id" binding:"required"`
		Status int `json:"status" binding:"oneof=0 1"`
	}

	req := &Req{}
	err := ctx.ShouldBindJSON(req)
	if err != nil {
		fail(ctx, err)
		return
	}

	mForward, err := getForwardById(req.Id)
	if err != nil {
		fail(ctx, err)
		return
	}

	err = db.DB().Transaction(func(tx *gorm.DB) error {
		err = tx.Table("forward").Where("id = ?", req.Id).Updates(map[string]any{
			"status": req.Status,
		}).Limit(1).Error

		if err != nil {
			return err
		}

		switch req.Status {
		case 1:
			err = forward.ListenerManager.Add(mForward)
			if err != nil {
				return err
			}
		default:
			forward.ListenerManager.Remove(mForward)
		}

		return nil
	})

	if err != nil {
		fail(ctx, err)
		return
	}

	success(ctx, "ok")
}

type apiRes struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
	Data    any    `json:"data"`
}

func success(ctx *gin.Context, data any) {
	ctx.JSON(http.StatusOK, &apiRes{
		Code:    0,
		Message: "ok",
		Data:    data,
	})
}

var ginTrans ut.Translator

func InitGinTrans() {
	v := binding.Validator.Engine().(*validator.Validate)
	v.RegisterTagNameFunc(func(fld reflect.StructField) string {
		nameSp := strings.SplitN(fld.Tag.Get("json"), ",", 2)
		if len(nameSp) == 0 {
			return fld.Name
		}

		name := nameSp[0]
		if name == "-" {
			return ""
		}

		if name != "" {
			return name
		}

		return fld.Name
	})
	enT := en.New()

	uni := ut.New(enT, enT)
	tr, _ := uni.GetTranslator("en")
	_ = enTr.RegisterDefaultTranslations(v, tr)

	ginTrans = tr
}

func fail(ctx *gin.Context, err error) {
	res := &apiRes{Code: 1}

	switch ve := err.(type) {
	case validator.ValidationErrors:
		if len(ve) > 0 {
			res.Message = ve[0].Translate(ginTrans)
		} else {
			res.Message = ve.Error()
		}

	default:
		res.Message = err.Error()
	}

	ctx.JSON(http.StatusOK, res)
}

var emptySplitReg = regexp.MustCompile(`\s*\n\s*`)

func parseAddrList(addrStr string) ([]string, error) {
	sp := emptySplitReg.Split(addrStr, -1)
	if len(sp) == 0 {
		return nil, fmt.Errorf("addr list is empty")
	}

	res := make([]string, 0)
	for i, _ := range sp {
		sp[i] = strings.TrimSpace(sp[i])

		if sp[i] == "" {
			continue
		}

		err := checkAddr(sp[i])
		if err != nil {
			return nil, err
		}

		res = append(res, sp[i])
	}

	return res, nil
}