package token_model

import (
	"fmt"
	"github.com/astaxie/beego"
	"github.com/dgrijalva/jwt-go"
	"time"
)

type JwtUser struct {
	Id int64 `json:"id"`
}

// JWT -- json web token
// HEADER PAYLOAD SIGNATURE
// This struct is the PAYLOAD
type MyCustomClaims struct {
	JwtUser
	jwt.StandardClaims
}

//刷新jwt token
func RefreshToken(tokenString string) (string, error) {
	// first get previous token
	token, err := jwt.ParseWithClaims(
		tokenString,
		&MyCustomClaims{},
		func(token *jwt.Token) (interface{}, error) {
			return []byte(KEY), nil
		})
	claims, ok := token.Claims.(*MyCustomClaims)
	if !ok || !token.Valid {
		return "", err
	}
	mySigningKey := []byte(KEY)
	expireAt := time.Now().Add(time.Second * time.Duration(DEFAULT_EXPIRE_SECONDS)).Unix()
	newClaims := MyCustomClaims{
		claims.JwtUser,
		jwt.StandardClaims{
			ExpiresAt: expireAt,
			Issuer:    "",
			IssuedAt:  time.Now().Unix(),
		},
	}
	// generate new token with new claims
	newToken := jwt.NewWithClaims(jwt.SigningMethodHS256, newClaims)
	tokenStr, err := newToken.SignedString(mySigningKey)
	if err != nil {
		beego.BeeLogger.Error("generate new fresh json web token failed !! error :%v", err)
		return "", err
	}
	return tokenStr, err
}

//验证jtw token
func ValidateToken(tokenString string) (info JwtUser, err error) {
	token, err := jwt.ParseWithClaims(
		tokenString,
		&MyCustomClaims{},
		func(token *jwt.Token) (interface{}, error) {
			return []byte(KEY), nil
		})
	if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
		//fmt.Printf("%v %v", claims.User, claims.StandardClaims.ExpiresAt)
		//fmt.Println("token will be expired at ", time.Unix(claims.StandardClaims.ExpiresAt, 0))
		info = claims.JwtUser
	} else {
		beego.BeeLogger.Error("validate tokenString failed !!!:%v", err)
	}
	return info, err
}

//获取jwt token
func GenerateToken(info *JwtUser, expiredSeconds int) (tokenString string, err error) {
	if expiredSeconds == 0 {
		expiredSeconds = DEFAULT_EXPIRE_SECONDS
	}
	// Create the Claims
	mySigningKey := []byte(KEY)
	expireAt := time.Now().Add(time.Second * time.Duration(expiredSeconds)).Unix()
	beego.BeeLogger.Warn("token will be expired at %v ", time.Unix(expireAt, 0))

	// pass parameter to this func or not
	user := *info
	claims := MyCustomClaims{
		user,
		jwt.StandardClaims{
			ExpiresAt: expireAt,
			Issuer:    "",
			IssuedAt:  time.Now().Unix(),
		},
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	tokenStr, err := token.SignedString(mySigningKey)
	if err != nil {
		beego.BeeLogger.Error("generate json web token failed !! error : %v", err)
	} else {
		tokenString = tokenStr
	}
	return
}

// return this result to client then all later request should have header "Authorization: Bearer <token> "
func getHeaderTokenValue(tokenString string) string {
	//Authorization: Bearer <token>
	return fmt.Sprintf("Bearer %s", tokenString)
}