package jwt

import (
	"errors"
	"time"

	"github.com/golang-jwt/jwt/v5"
)

// Claims JWT声明
type Claims struct {
	UserID uint `json:"user_id"`
	jwt.RegisteredClaims
}

// GenerateToken 生成Token
func GenerateToken(userID uint, secret string, expireSeconds int64) (string, int64, error) {
	expiresAt := time.Now().Add(time.Duration(expireSeconds) * time.Second)
	claims := Claims{
		UserID: userID,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(expiresAt),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			NotBefore: jwt.NewNumericDate(time.Now()),
		},
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	tokenString, err := token.SignedString([]byte(secret))
	if err != nil {
		return "", 0, err
	}
	return tokenString, expiresAt.Unix(), nil
}

// ParseToken 解析Token
func ParseToken(tokenString string, secret string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(secret), nil
	})
	if err != nil {
		return nil, err
	}
	if claims, ok := token.Claims.(*Claims); ok && token.Valid {
		return claims, nil
	}
	return nil, errors.New("invalid token")
}

// RefreshToken 刷新Token
func RefreshToken(tokenString string, secret string, expireSeconds int64) (string, int64, error) {
	claims, err := ParseToken(tokenString, secret)
	if err != nil {
		return "", 0, err
	}
	// 生成新Token
	return GenerateToken(claims.UserID, secret, expireSeconds)
}