Window class matching material 3 guidelines.

windowclass.dart

import 'package:flutter/widgets.dart'
    show BoxConstraints, BuildContext, MediaQuery;

/// BoxConstraints matching the material3 guidelines
const BoxConstraints materialBoxConstraints = BoxConstraints(maxWidth: 840);

/// https://m3.material.io/foundations/layout/applying-layout/window-size-classes
enum WindowClass implements Comparable<WindowClass> {
  small(_smallWidth),
  medium(_mediumWidth),
  expanded(_expandedWidth),
  large(_largeWidth),
  extraLarge(_extraLargeWidth);

  static const double _smallWidth = 600;
  static const double _mediumWidth = 840;
  static const double _expandedWidth = 1200;
  static const double _largeWidth = 1600;
  static const double _extraLargeWidth = double.infinity;

  final double maxWidth;

  const WindowClass(this.maxWidth);

  bool operator <(WindowClass other) => maxWidth < other.maxWidth;
  bool operator <=(WindowClass other) => maxWidth <= other.maxWidth;
  bool operator >(WindowClass other) => maxWidth > other.maxWidth;
  bool operator >=(WindowClass other) => maxWidth >= other.maxWidth;

  @override
  int compareTo(WindowClass other) => maxWidth.compareTo(other.maxWidth);

  /// This function returns the matching WindowClass given the current BuildContext.
  ///
  /// Usage:
  /// ```dart
  /// final windowClass = WindowClass.of(context);
  ///
  /// if (windowClass < WindowClass.medium) {
  ///   doSomeThing();
  /// }
  /// ```
  static WindowClass of(BuildContext context) {
    final screenWidth = MediaQuery.sizeOf(context).width;

    return switch (screenWidth) {
      < _smallWidth => WindowClass.small,
      < _mediumWidth => WindowClass.medium,
      < _expandedWidth => WindowClass.expanded,
      < _largeWidth => WindowClass.large,
      _ => WindowClass.extraLarge,
    };
  }
}