package auth

import (
	"errors"
	"time"

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

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

type TokenService struct {
	secret    []byte
	accessTTL time.Duration
}

func NewTokenService(secret string, accessTTL time.Duration) TokenService {
	return TokenService{
		secret:    []byte(secret),
		accessTTL: accessTTL,
	}
}

func (s TokenService) IssueAccessToken(userID string, email string, role string) (string, error) {
	if len(s.secret) == 0 {
		return "", errors.New("jwt secret is not configured")
	}

	now := time.Now()
	claims := Claims{
		UserID: userID,
		Email:  email,
		Role:   role,
		RegisteredClaims: jwt.RegisteredClaims{
			Subject:   userID,
			IssuedAt:  jwt.NewNumericDate(now),
			ExpiresAt: jwt.NewNumericDate(now.Add(s.accessTTL)),
		},
	}

	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(s.secret)
}

func (s TokenService) ParseAccessToken(tokenValue string) (Claims, error) {
	if len(s.secret) == 0 {
		return Claims{}, errors.New("jwt secret is not configured")
	}

	token, err := jwt.ParseWithClaims(tokenValue, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		if token.Method != jwt.SigningMethodHS256 {
			return nil, errors.New("unexpected signing method")
		}
		return s.secret, nil
	})
	if err != nil {
		return Claims{}, err
	}

	claims, ok := token.Claims.(*Claims)
	if !ok || !token.Valid {
		return Claims{}, errors.New("invalid token")
	}

	return *claims, nil
}