package utils

import (
	"time"

	"github.com/golang-jwt/jwt/v4"
)

type JWTUtil struct {
	secretKey string
}

type Claims struct {
	UserID uint   `json:"user_id"`
	Email  string `json:"email"`
	Role   string `json:"role"`
	jwt.RegisteredClaims
}

func NewJWTUtil(secretKey string) *JWTUtil {
	return &JWTUtil{secretKey: secretKey}
}

func (j *JWTUtil) GenerateToken(userID uint, email, role string) (string, error) {
	claims := Claims{
		UserID: userID,
		Email:  email,
		Role:   role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(24 * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(j.secretKey))
}

func (j *JWTUtil) ValidateToken(tokenString string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(j.secretKey), nil
	})

	if err != nil {
		return nil, err
	}

	if claims, ok := token.Claims.(*Claims); ok && token.Valid {
		return claims, nil
	}

	return nil, jwt.ErrInvalidKey
}