package service

import (
	"context"
	"time"

	"github.com/golang-jwt/jwt/v5"
	"golang.org/x/crypto/bcrypt"
)

type AuthService struct {
	users     UserRepository
	jwtSecret []byte
	jwtTTL    time.Duration
}

func NewAuthService(users UserRepository, jwtSecret string, jwtTTL time.Duration) *AuthService {
	return &AuthService{users: users, jwtSecret: []byte(jwtSecret), jwtTTL: jwtTTL}
}

func (s *AuthService) Register(ctx context.Context, email, password, name string) (int64, error) {
	if email == "" || password == "" || name == "" {
		return 0, ErrBadRequest
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return 0, err
	}
	u, err := s.users.Create(ctx, email, string(hash), name)
	if err != nil {
		return 0, err
	}
	return u.ID, nil
}

func (s *AuthService) Login(ctx context.Context, email, password string) (string, error) {
	u, err := s.users.FindByEmail(ctx, email)
	if err != nil {
		return "", ErrUnauthorized
	}
	if bcrypt.CompareHashAndPassword([]byte(u.PasswordHash), []byte(password)) != nil {
		return "", ErrUnauthorized
	}
	claims := jwt.MapClaims{
		"sub": u.ID,
		"exp": time.Now().Add(s.jwtTTL).Unix(),
	}
	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(s.jwtSecret)
}