package auth

import (
	"errors"
	"time"

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

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

type JWTService struct {
	secret string
	ttl    time.Duration
}

func NewJWTService(secret string, ttl time.Duration) *JWTService {
	return &JWTService{
		secret: secret,
		ttl:    ttl,
	}
}

// GenerateToken создаёт JWT токен для пользователя
func (j *JWTService) GenerateToken(userID, organizationID uuid.UUID, email, role string) (string, error) {
	claims := Claims{
		UserID:         userID,
		OrganizationID: organizationID,
		Email:          email,
		Role:           role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(j.ttl)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			NotBefore: jwt.NewNumericDate(time.Now()),
			Issuer:    "erp-mvp-core",
			Subject:   userID.String(),
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(j.secret))
}

// ValidateToken валидирует JWT токен и возвращает claims
func (j *JWTService) ValidateToken(tokenString string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return []byte(j.secret), nil
	})

	if err != nil {
		return nil, err
	}

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

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