package utils

import (
	"errors"
	"time"

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

var jwtSecret = []byte("your-secret-key-change-this-in-production") // TODO: Move to env var

// Claims represents JWT custom claims
type Claims struct {
	UserID     int    `json:"userId"`
	Identifier string `json:"identifier"`
	Role       string `json:"role"`
	jwt.RegisteredClaims
}

// GenerateJWT generates a new JWT token for a user
func GenerateJWT(userID int, identifier string, role string) (string, error) {
	expirationTime := time.Now().Add(24 * time.Hour) // 24 hours

	claims := &Claims{
		UserID:     userID,
		Identifier: identifier,
		Role:       role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(expirationTime),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}

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

// ValidateJWT validates a JWT token and returns the claims
func ValidateJWT(tokenString string) (*Claims, error) {
	claims := &Claims{}

	token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("invalid signing method")
		}
		return jwtSecret, nil
	})

	if err != nil {
		return nil, err
	}

	if !token.Valid {
		return nil, errors.New("invalid token")
	}

	return claims, nil
}