package jwt

import (
	"time"

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

type Service struct {
	signer Signer
	expiry time.Duration
}

func NewService(signer Signer, exp time.Duration) *Service {
	return &Service{
		signer: signer,
		expiry: exp,
	}
}

// Generate creates a new JWT token for a given user ID and
// returns the token string along with its JTI(JWT IDentifier).
func (s *Service) Generate(userID int) (string, string, error) {
	jti := uuid.NewString()

	claims := jwt.MapClaims{
		"sub": userID,
		"jti": jti,
		"exp": time.Now().Add(s.expiry).Unix(),
		"iat": time.Now().Unix(),
	}

	token, err := s.signer.Sign(claims)
	return token, jti, err
}

// Validate verifies the JWT token and extracts the user ID and JTI(JWT IDentifier).
func (s *Service) Validate(token string) (int, string, error) {
	claims, err := s.signer.Verify(token)
	if err != nil {
		return 0, "", err
	}

	sub := int(claims.(jwt.MapClaims)["sub"].(float64))
	jti := claims.(jwt.MapClaims)["jti"].(string)

	return sub, jti, nil
}