/// Application-wide configuration constants
class AppConstants {
  AppConstants._();

  // App Info
  static const String appName = 'Retail POS';
  static const String appVersion = '1.0.0';

  // Defaults
  static const String defaultCurrency = 'USD';
  static const String defaultLanguage = 'en';
  static const double defaultTaxRate = 0.0;

  // Pagination
  static const int defaultPageSize = 20;
  static const int maxPageSize = 100;

  // Cache
  static const Duration cacheExpiration = Duration(hours: 24);
  static const int maxCacheSize = 100;

  // Business Rules
  static const int minStockThreshold = 5;
  static const int maxCartItemQuantity = 999;
  static const double minTransactionAmount = 0.01;

  // Spacing and Sizes
  static const double defaultPadding = 16.0;
  static const double smallPadding = 8.0;
  static const double largePadding = 24.0;
  static const double borderRadius = 12.0;
  static const double buttonHeight = 48.0;
  static const double textFieldHeight = 56.0;

  // Animation Durations
  static const Duration shortAnimationDuration = Duration(milliseconds: 200);
  static const Duration mediumAnimationDuration = Duration(milliseconds: 400);
  static const Duration longAnimationDuration = Duration(milliseconds: 600);
}