package certs

import (
	"encoding/json"
	"errors"
	"github.com/golang-jwt/jwt/v5"
	"github.com/rs/xid"
	"time"
)

type User struct {
	UserId int64 `json:"id"`
	jwt.RegisteredClaims
}

func NewUser() *User {
	return &User{}
}

// Token 获取token
func (u *User) Token(id int64, username string) (string, error) {
	u.UserId = id
	u.RegisteredClaims = jwt.RegisteredClaims{
		Issuer:    issuer,
		Subject:   username,
		ExpiresAt: jwt.NewNumericDate(u.Expired()),
		NotBefore: jwt.NewNumericDate(time.Now()),
		IssuedAt:  jwt.NewNumericDate(time.Now()),
		ID:        xid.New().String(),
	}

	var key = randomString(6)
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, u)

	//加密校验字符串
	token.Header[saltKey] = key
	token.Header[signKey] = mmd5(key)

	return token.SignedString([]byte(key))
}

// Parse 解析token
func (u *User) Parse(tokenString string) (err error) {
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		salt, sign, ok := checkHeaderSign(token.Header)
		if !ok || mmd5(salt) != sign {
			return nil, errors.New("key invalid")
		}

		return []byte(salt), nil
	})

	if err != nil {
		return
	}

	if user, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
		b, _ := json.Marshal(user)
		_ = json.Unmarshal(b, u)
		return
	}

	if errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet) {
		return ExpiredErr
	}

	return InvalidToken
}

func (u *User) Expired() time.Time {
	return time.Now().AddDate(0, 0, 7)
}