package utils

import (
	"errors"
	"strings"
	"time"

	"github.com/dgrijalva/jwt-go"
)

const (
	userIDKey = "userId"
	ipKey     = "ip"
	uaKey     = "ua"
)

type IPClaims struct {
	Ip     string
	Expire time.Duration
	UA     string
}

func GenerateIpToken(claims IPClaims, secret string) (string, error) {
	return generateToken(jwt.MapClaims{
		ipKey:    claims.Ip,
		uaKey:    claims.UA,
		"exp":    Now().Add(claims.Expire).Unix(),
		"issuer": "com.butterfly",
		"sub":    "asign",
		"aud":    "public",
	}, []byte(secret))
}

func ParseIpToken(tokenString string, secret string) (pass bool, ip, ua string, err error) {
	t, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		return []byte(secret), nil
	})
	var isExpire *bool
	if vErr, ok := err.(*jwt.ValidationError); ok {
		e := vErr.Errors&jwt.ValidationErrorExpired > 0
		isExpire = &e
	}
	if err != nil || isExpire == nil {
		return
	}
	var ok bool
	var jc jwt.MapClaims
	jc, ok = t.Claims.(jwt.MapClaims)
	if !ok {
		err = errors.New("parse token fail")
		return
	}
	ip, ok = jc[ipKey].(string)
	if !ok {
		err = errors.New("parse token fail")
		return
	}
	ua, ok = jc[uaKey].(string)
	if !ok {
		err = errors.New("parse token fail")
		return
	}
	pass = true
	return
}

type UserClaims struct {
	UserID int64
	Expire time.Duration
}

func generateToken(claims jwt.MapClaims, secret []byte) (string, error) {
	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(secret)
}

func GenerateUserToken(claims UserClaims, secret string) (string, error) {
	return generateToken(jwt.MapClaims{
		userIDKey: claims.UserID,
		"exp":     Now().Add(claims.Expire).Unix(),
		"issuer":  "com.butterfly",
		"sub":     "asign",
		"aud":     "public",
	}, []byte(secret))
}

// ParseToken 解析Token
func ParseUserToken(token string, secret string) (userId int64, newToken string, err error) {
	t, err := jwt.Parse(token, func(token *jwt.Token) (interface{}, error) {
		return []byte(secret), nil
	})
	var isExpire *bool
	if vErr, ok := err.(jwt.ValidationError); ok {
		e := vErr.Errors&jwt.ValidationErrorExpired > 0
		isExpire = &e
	}
	if err != nil && isExpire == nil {
		return
	}

	jc, ok := t.Claims.(jwt.MapClaims)
	if !ok {
		err = errors.New("unknown token error1")
		return
	}

	id, ok := jc[userIDKey].(float64)
	if !ok {
		err = errors.New("unknown token error1")
		return
	}
	userId = int64(id)
	if isExpire != nil && *isExpire {
		newToken, err = GenerateUserToken(UserClaims{UserID: userId, Expire: 30 * 24 * time.Hour}, secret)
		return
	}
	err = nil
	return
}

// Strips 'Bearer ' prefix from bearer token string
func StripBearerPrefixFromTokenString(tok string) string {
	if len(tok) > 6 && strings.ToUpper(tok[0:7]) == "BEARER " {
		return tok[7:]
	} else {
		return tok
	}
}