package auth

import (
	"encoding/json"
	"errors"
	"github.com/golang-jwt/jwt"
	"net/http"
	"time"
)

type UserInfo struct {
	UserId int64 `json:"user_id"`
}

// 签名key
var signKey = "FushenFGbhgfhgKgGH556HGlXrsfJKhhjYFGKLO=="
var expireTime = int64(3600)

// 生成token
func GenJwtToken(userInfo UserInfo) (token string, err error) {
	t := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"user_id": userInfo.UserId,
		"exp":     time.Now().Add(time.Second * time.Duration(expireTime)).Unix(), //过期时间
		"iss":     "fusen",
	})
	token, err = t.SignedString([]byte(signKey))
	if err != nil {
		return "", err
	}
	return
}

// 解释token
func ParseJwtToken(token string) (UserInfo, error) {
	t, err := jwt.ParseWithClaims(token, jwt.MapClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(signKey), nil
	})
	if err != nil {
		return UserInfo{}, err
	}
	d, err := json.Marshal(t.Claims)
	if err != nil {
		return UserInfo{}, err
	}
	var userInfo UserInfo
	if err = json.Unmarshal(d, &userInfo); err != nil {
		return UserInfo{}, err
	}
	return userInfo, nil
}

// 检测授权
func CheckAuth(r *http.Request) (UserInfo, error) {
	token := r.Header.Get("Authorization")
	if token == "" {
		return UserInfo{}, errors.New("token is required")
	}
	//解析token
	userInfo, err := ParseJwtToken(token)
	if err != nil {
		return UserInfo{}, err
	}
	return userInfo, nil
}