/// API configuration constants for the Retail POS application
class ApiConstants {
  // Private constructor to prevent instantiation
  ApiConstants._();

  // ===== Base URL Configuration =====
  /// Base URL for the API
  /// Development: http://localhost:3000
  /// Production: TODO - Replace with actual production URL
  static const String baseUrl = 'http://103.188.82.191:5000';

  /// API version prefix
  static const String apiVersion = '/api';

  /// Full base URL with version
  static String get fullBaseUrl => '$baseUrl$apiVersion';

  // ===== Timeout Configuration =====
  /// Connection timeout in milliseconds (30 seconds)
  static const int connectTimeout = 30000;

  /// Receive timeout in milliseconds (30 seconds)
  static const int receiveTimeout = 30000;

  /// Send timeout in milliseconds (30 seconds)
  static const int sendTimeout = 30000;

  // ===== Retry Configuration =====
  /// Maximum number of retry attempts for failed requests
  static const int maxRetries = 3;

  /// Delay between retry attempts in milliseconds (1 second)
  static const int retryDelay = 1000;

  // ===== Endpoint Paths =====

  // Authentication Endpoints
  /// POST - Login user
  static const String login = '/auth/login';

  /// POST - Register new user
  static const String register = '/auth/register';

  /// GET - Get current user profile (requires auth)
  static const String profile = '/auth/profile';

  /// POST - Refresh access token (requires auth)
  static const String refreshToken = '/auth/refresh';

  // Products Endpoints
  /// GET - Fetch all products (with pagination and filters)
  static const String products = '/products';

  /// GET - Fetch single product by ID
  /// Use: '${ApiConstants.products}/:id'
  static String productById(String id) => '$products/$id';

  /// GET - Fetch products by category
  /// Use: '${ApiConstants.products}/category/:categoryId'
  static String productsByCategory(String categoryId) =>
      '$products/category/$categoryId';

  /// GET - Search products
  /// Query params: ?q=searchTerm
  static const String searchProducts = '$products/search';

  /// POST - Sync products (bulk update/create)
  static const String syncProducts = '$products/sync';

  // Categories Endpoints
  /// GET - Fetch all categories
  static const String categories = '/categories';

  /// GET - Fetch single category by ID
  /// Use: '${ApiConstants.categories}/:id'
  static String categoryById(String id) => '$categories/$id';

  /// GET - Fetch category with its products
  /// Use: '${ApiConstants.categories}/:id/products'
  static String categoryWithProducts(String id) => '$categories/$id/products';

  /// POST - Sync categories (bulk update/create)
  static const String syncCategories = '$categories/sync';

  // Transactions Endpoints (for future use)
  /// POST - Create new transaction
  static const String transactions = '/transactions';

  /// GET - Fetch transaction history
  static const String transactionHistory = '$transactions/history';

  // Settings Endpoints (for future use)
  /// GET - Fetch app settings
  static const String settings = '/settings';

  /// PUT - Update app settings
  static const String updateSettings = settings;

  // ===== Request Headers =====
  /// Content-Type header key
  static const String contentType = 'Content-Type';

  /// Content-Type value for JSON
  static const String applicationJson = 'application/json';

  /// Authorization header key
  static const String authorization = 'Authorization';

  /// Accept header key
  static const String accept = 'Accept';

  // ===== API Keys and Authentication =====
  /// API key header name (if using API key authentication)
  static const String apiKeyHeader = 'X-API-Key';

  /// TODO: Store API key securely (use flutter_secure_storage in production)
  static const String apiKey = 'your-api-key-here';

  // ===== Status Codes =====
  /// Success status codes
  static const int statusOk = 200;
  static const int statusCreated = 201;
  static const int statusNoContent = 204;

  /// Client error status codes
  static const int statusBadRequest = 400;
  static const int statusUnauthorized = 401;
  static const int statusForbidden = 403;
  static const int statusNotFound = 404;
  static const int statusUnprocessableEntity = 422;
  static const int statusTooManyRequests = 429;

  /// Server error status codes
  static const int statusInternalServerError = 500;
  static const int statusBadGateway = 502;
  static const int statusServiceUnavailable = 503;
  static const int statusGatewayTimeout = 504;

  // ===== Cache Configuration =====
  /// Cache duration for products (in hours)
  static const int productsCacheDuration = 24;

  /// Cache duration for categories (in hours)
  static const int categoriesCacheDuration = 24;

  // ===== Pagination =====
  /// Default page size for paginated requests
  static const int defaultPageSize = 20;

  /// Maximum page size
  static const int maxPageSize = 100;

  // ===== Mock/Development Configuration =====
  /// Use mock data instead of real API (for development/testing)
  static const bool useMockData = false;

  /// Mock API delay in milliseconds
  static const int mockApiDelay = 500;
}