package services

import (
	"errors"
	"time"

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

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

type AuthService struct {
	secretKey []byte
}

func NewAuthService(secret string) *AuthService {
	return &AuthService{secretKey: []byte(secret)}
}

func (s *AuthService) GenerateToken(userID int, email string) (string, error) {
	claims := Claims{
		UserID: userID,
		Email:  email,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(24 * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodES256, claims)
	return token.SignedString(s.secretKey)
}

func (s *AuthService) ValidateToken(tokenString string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return s.secretKey, 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")

}