package auth

import (
	"time"

	"git.linuxforward.com/byom/byom-golang-lib/pkg/errors"
	"github.com/golang-jwt/jwt/v5"
)

type JWTService struct {
	secretKey []byte
}

func NewJWTService(secretKey string) *JWTService {
	return &JWTService{
		secretKey: []byte(secretKey),
	}
}

func (s *JWTService) GenerateToken(userID string, duration time.Duration) (string, error) {
	claims := jwt.MapClaims{
		"user_id": userID,
		"exp":     time.Now().Add(duration).Unix(),
		"iat":     time.Now().Unix(),
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	signedToken, err := token.SignedString(s.secretKey)
	if err != nil {
		return "", errors.NewAuthError("generate", err)
	}

	return signedToken, nil
}

func (s *JWTService) ValidateToken(tokenString string) (jwt.MapClaims, error) {
	if tokenString == "" {
		return nil, errors.NewAuthError("validate", errors.ErrInvalidInput)
	}

	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.NewAuthError("validate", errors.ErrInvalidInput)
		}
		return s.secretKey, nil
	})

	if err != nil {
		return nil, errors.NewAuthError("parse", err)
	}

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

	return nil, errors.NewAuthError("validate", errors.ErrInvalidInput)
}