runable

lib/core/constants/performance_constants.dart

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+/// Performance-related constants for the retail POS app
+///
+/// This file contains all performance tuning parameters:
+/// - List/Grid performance settings
+/// - Cache configurations
+/// - Debounce/Throttle timings
+/// - Memory limits
+/// - Scroll performance settings
+
+class PerformanceConstants {
+  // Private constructor to prevent instantiation
+  PerformanceConstants._();
+
+  // ==================== List/Grid Performance ====================
+
+  /// Cache extent for ListView/GridView (pixels to preload)
+  static const double listCacheExtent = 500.0;
+
+  /// Number of items to preload in infinite scroll
+  static const int preloadItemThreshold = 5;
+
+  /// Maximum items to render at once in very large lists
+  static const int maxVisibleItems = 100;
+
+  /// Grid crossAxisCount for different screen widths
+  static int getGridColumnCount(double screenWidth) {
+    if (screenWidth < 600) return 2; // Mobile portrait
+    if (screenWidth < 900) return 3; // Mobile landscape / Small tablet
+    if (screenWidth < 1200) return 4; // Tablet
+    return 5; // Desktop
+  }
+
+  /// Grid childAspectRatio for product cards
+  static const double productCardAspectRatio = 0.75;
+
+  /// Grid childAspectRatio for category cards
+  static const double categoryCardAspectRatio = 1.0;
+
+  /// Grid spacing
+  static const double gridSpacing = 12.0;
+
+  // ==================== Debounce/Throttle Timings ====================
+
+  /// Search input debounce (ms) - wait before executing search
+  static const int searchDebounceDuration = 300;
+
+  /// Filter input debounce (ms)
+  static const int filterDebounceDuration = 200;
+
+  /// Auto-save debounce (ms)
+  static const int autoSaveDebounceDuration = 1000;
+
+  /// Scroll position throttle (ms)
+  static const int scrollThrottleDuration = 100;
+
+  /// Network retry debounce (ms)
+  static const int retryDebounceDuration = 500;
+
+  // ==================== Animation Durations ====================
+
+  /// Standard animation duration
+  static const int animationDuration = 300;
+
+  /// Fast animation duration
+  static const int fastAnimationDuration = 150;
+
+  /// Image fade-in duration
+  static const int imageFadeDuration = 300;
+
+  /// Shimmer animation duration
+  static const int shimmerDuration = 1500;
+
+  // ==================== Memory Management ====================
+
+  /// Maximum image cache size in memory (MB)
+  static const int maxImageMemoryCacheMB = 50;
+
+  /// Maximum image cache count in memory
+  static const int maxImageMemoryCacheCount = 100;
+
+  /// Maximum disk cache size (MB)
+  static const int maxDiskCacheMB = 200;
+
+  /// Database cache size limit (number of items)
+  static const int maxDatabaseCacheItems = 1000;
+
+  // ==================== Network Performance ====================
+
+  /// Network request timeout (seconds)
+  static const int networkTimeoutSeconds = 30;
+
+  /// Network connect timeout (seconds)
+  static const int networkConnectTimeoutSeconds = 15;
+
+  /// Network receive timeout (seconds)
+  static const int networkReceiveTimeoutSeconds = 30;
+
+  /// Maximum concurrent image downloads
+  static const int maxConcurrentImageDownloads = 3;
+
+  /// Retry attempts for failed requests
+  static const int maxRetryAttempts = 3;
+
+  /// Retry delay (seconds)
+  static const int retryDelaySeconds = 2;
+
+  // ==================== Batch Operations ====================
+
+  /// Batch size for database operations
+  static const int databaseBatchSize = 50;
+
+  /// Batch size for image preloading
+  static const int imagePreloadBatchSize = 10;
+
+  /// Pagination page size
+  static const int paginationPageSize = 20;
+
+  // ==================== Build Optimization ====================
+
+  /// Whether to use RepaintBoundary for grid items
+  static const bool useRepaintBoundaryForGridItems = true;
+
+  /// Whether to use const constructors aggressively
+  static const bool useConstConstructors = true;
+
+  /// Whether to enable performance overlay in debug mode
+  static const bool enablePerformanceOverlay = false;
+
+  // ==================== Hive Database Performance ====================
+
+  /// Compact database after this many operations
+  static const int databaseCompactThreshold = 100;
+
+  /// Use lazy box for large datasets
+  static const bool useLazyBoxForProducts = true;
+
+  /// Cache database queries
+  static const bool cacheQueries = true;
+
+  /// Maximum database file size (MB) before warning
+  static const int maxDatabaseSizeMB = 100;
+
+  // ==================== Scroll Performance ====================
+
+  /// Physics for better scroll performance
+  static const bool useBouncingScrollPhysics = true;
+
+  /// Scroll controller jump threshold (prevent jarring jumps)
+  static const double scrollJumpThreshold = 1000.0;
+
+  /// Enable scroll momentum
+  static const bool enableScrollMomentum = true;
+
+  // ==================== State Management Performance ====================
+
+  /// Provider auto-dispose delay (seconds)
+  static const int providerAutoDisposeDelay = 60;
+
+  /// Keep alive duration for cached providers (seconds)
+  static const int providerKeepAliveDuration = 300;
+
+  /// Use provider.select() for granular rebuilds
+  static const bool useGranularRebuild = true;
+
+  // ==================== Image Loading Performance ====================
+
+  /// Image loading placeholder height
+  static const double placeholderHeight = 200.0;
+
+  /// Use progressive JPEG loading
+  static const bool useProgressiveLoading = true;
+
+  /// Preload images for next page
+  static const bool preloadNextPageImages = true;
+
+  /// Maximum image resolution (width x height)
+  static const int maxImageWidth = 1920;
+  static const int maxImageHeight = 1920;
+
+  // ==================== Frame Rate Targets ====================
+
+  /// Target frame rate
+  static const int targetFPS = 60;
+
+  /// Budget per frame (milliseconds)
+  static const double frameBudgetMs = 16.67; // 60 FPS
+
+  /// Warning threshold for long frames (ms)
+  static const double longFrameThresholdMs = 32.0;
+
+  // ==================== Cart Performance ====================
+
+  /// Maximum cart items before pagination
+  static const int maxCartItemsBeforePagination = 50;
+
+  /// Cart calculation debounce (ms)
+  static const int cartCalculationDebounce = 100;
+
+  // ==================== Responsive Breakpoints ====================
+
+  /// Mobile breakpoint
+  static const double mobileBreakpoint = 600.0;
+
+  /// Tablet breakpoint
+  static const double tabletBreakpoint = 900.0;
+
+  /// Desktop breakpoint
+  static const double desktopBreakpoint = 1200.0;
+
+  // ==================== Helper Methods ====================
+
+  /// Get appropriate cache extent based on device
+  static double getCacheExtent(double screenHeight) {
+    // Cache 1.5x screen height
+    return screenHeight * 1.5;
+  }
+
+  /// Get appropriate batch size based on memory
+  static int getDynamicBatchSize(int totalItems) {
+    if (totalItems < 100) return 20;
+    if (totalItems < 500) return 50;
+    if (totalItems < 1000) return 100;
+    return 200;
+  }
+
+  /// Check if device can handle high performance mode
+  static bool shouldUseHighPerformanceMode(double screenWidth) {
+    return screenWidth >= tabletBreakpoint;
+  }
+}