package main

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

// User represents an admin user for authentication
type User struct {
	ID           int
	Username     string
	PasswordHash string
	CreatedAt    time.Time
}

// HashPassword hashes a plain password using bcrypt
func HashPassword(password string) (string, error) {
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	return string(hash), err
}

// CheckPasswordHash compares a plain password with a bcrypt hash
func CheckPasswordHash(password, hash string) bool {
	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password)) == nil
}

// JWT secret key (should be loaded from config in production)
var jwtSecret = []byte("replace_this_with_a_secure_secret")

// GenerateJWT generates a JWT token for a user
func GenerateJWT(username string) (string, error) {
	claims := jwt.MapClaims{
		"username": username,
		"exp":      time.Now().Add(24 * time.Hour).Unix(),
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(jwtSecret)
}

// ValidateJWT validates a JWT token and returns the username if valid
func ValidateJWT(tokenString string) (string, error) {
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		return jwtSecret, nil
	})
	if err != nil || !token.Valid {
		return "", err
	}
	claims, ok := token.Claims.(jwt.MapClaims)
	if !ok {
		return "", err
	}
	username, ok := claims["username"].(string)
	if !ok {
		return "", err
	}
	return username, nil
}