package auth

import (
	"errors"
	"time"

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

var jwtSecret []byte

func InitJWTSecret(secret string) {
	jwtSecret = []byte(secret)
}

type Claims struct {
	Username string `json:"username"`
	IsAdmin  bool   `json:"is_admin"`
	jwt.RegisteredClaims
}

func GenerateToken(username string, isAdmin bool) (string, error) {
	claims := Claims{
		Username: username,
		IsAdmin:  isAdmin,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(24 * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}

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

func 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 jwtSecret, 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")
}