package auth

import (
	"errors"
	"time"

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

type JWTService struct {
	secretKey []byte
	issuer    string
}

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

func (s *JWTService) HashPassword(password string) (string, error) {
	bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	return string(bytes), err
}

func (s *JWTService) VerifyPassword(hash, password string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
	return err == nil
}

func (s *JWTService) GenerateToken(userID, tenantID string, roles []string) (string, error) {
	claims := jwt.MapClaims{
		"sub":    userID,
		"tenant": tenantID,
		"roles":  roles,
		"iss":    s.issuer,
		"exp":    time.Now().Add(time.Hour * 24).Unix(), // 24 hours
		"iat":    time.Now().Unix(),
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(s.secretKey)
}

func (s *JWTService) ValidateToken(tokenString string) (map[string]interface{}, error) {
	token, err := jwt.Parse(tokenString, 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.(jwt.MapClaims); ok && token.Valid {
		return claims, nil
	}

	return nil, errors.New("invalid token")
}