dev/tools/gen_defaults/lib/app_bar_template.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'template.dart';

class AppBarTemplate extends TokenTemplate {
  const AppBarTemplate(super.blockName, super.fileName, super.tokens)
    : super(
      colorSchemePrefix: '_colors.',
      textThemePrefix: '_textTheme.',
    );

  @override
  String generate() => '''
class _${blockName}DefaultsM3 extends AppBarTheme {
  _${blockName}DefaultsM3(this.context)
    : super(
      elevation: ${elevation('md.comp.top-app-bar.small.container')},
      scrolledUnderElevation: ${elevation('md.comp.top-app-bar.small.on-scroll.container')},
      titleSpacing: NavigationToolbar.kMiddleSpacing,
      toolbarHeight: ${tokens['md.comp.top-app-bar.small.container.height']},
    );

  final BuildContext context;
  late final ThemeData _theme = Theme.of(context);
  late final ColorScheme _colors = _theme.colorScheme;
  late final TextTheme _textTheme = _theme.textTheme;

  @override
  Color? get backgroundColor => ${componentColor('md.comp.top-app-bar.small.container')};

  @override
  Color? get foregroundColor => ${color('md.comp.top-app-bar.small.headline.color')};

  @override
  Color? get shadowColor => ${colorOrTransparent('md.comp.top-app-bar.small.container.shadow-color')};

  @override
  Color? get surfaceTintColor => ${colorOrTransparent('md.comp.top-app-bar.small.container.surface-tint-layer.color')};

  @override
  IconThemeData? get iconTheme => IconThemeData(
    color: ${componentColor('md.comp.top-app-bar.small.leading-icon')},
    size: ${tokens['md.comp.top-app-bar.small.leading-icon.size']},
  );

  @override
  IconThemeData? get actionsIconTheme => IconThemeData(
    color: ${componentColor('md.comp.top-app-bar.small.trailing-icon')},
    size: ${tokens['md.comp.top-app-bar.small.trailing-icon.size']},
  );

  @override
  TextStyle? get toolbarTextStyle => _textTheme.bodyMedium;

  @override
  TextStyle? get titleTextStyle => ${textStyle('md.comp.top-app-bar.small.headline')};
}

// Variant configuration
class _MediumScrollUnderFlexibleConfig with _ScrollUnderFlexibleConfig {
  _MediumScrollUnderFlexibleConfig(this.context);

  final BuildContext context;
  late final ThemeData _theme = Theme.of(context);
  late final ColorScheme _colors = _theme.colorScheme;
  late final TextTheme _textTheme = _theme.textTheme;

  static const double collapsedHeight = ${tokens['md.comp.top-app-bar.small.container.height']};
  static const double expandedHeight = ${tokens['md.comp.top-app-bar.medium.container.height']};

  @override
  TextStyle? get collapsedTextStyle =>
    ${textStyle('md.comp.top-app-bar.small.headline')}?.apply(color: ${color('md.comp.top-app-bar.small.headline.color')});

  @override
  TextStyle? get expandedTextStyle =>
    ${textStyle('md.comp.top-app-bar.medium.headline')}?.apply(color: ${color('md.comp.top-app-bar.medium.headline.color')});

  @override
  EdgeInsetsGeometry? get collapsedTitlePadding => const EdgeInsetsDirectional.fromSTEB(48, 0, 16, 0);

  @override
  EdgeInsetsGeometry? get collapsedCenteredTitlePadding => const EdgeInsets.fromLTRB(16, 0, 16, 0);

  @override
  EdgeInsetsGeometry? get expandedTitlePadding => const EdgeInsets.fromLTRB(16, 0, 16, 20);
}

class _LargeScrollUnderFlexibleConfig with _ScrollUnderFlexibleConfig {
  _LargeScrollUnderFlexibleConfig(this.context);

  final BuildContext context;
  late final ThemeData _theme = Theme.of(context);
  late final ColorScheme _colors = _theme.colorScheme;
  late final TextTheme _textTheme = _theme.textTheme;

  static const double collapsedHeight = ${tokens['md.comp.top-app-bar.small.container.height']};
  static const double expandedHeight = ${tokens['md.comp.top-app-bar.large.container.height']};

  @override
  TextStyle? get collapsedTextStyle =>
    ${textStyle('md.comp.top-app-bar.small.headline')}?.apply(color: ${color('md.comp.top-app-bar.small.headline.color')});

  @override
  TextStyle? get expandedTextStyle =>
    ${textStyle('md.comp.top-app-bar.large.headline')}?.apply(color: ${color('md.comp.top-app-bar.large.headline.color')});

  @override
  EdgeInsetsGeometry? get collapsedTitlePadding => const EdgeInsetsDirectional.fromSTEB(48, 0, 16, 0);

  @override
  EdgeInsetsGeometry? get collapsedCenteredTitlePadding => const EdgeInsets.fromLTRB(16, 0, 16, 0);

  @override
  EdgeInsetsGeometry? get expandedTitlePadding => const EdgeInsets.fromLTRB(16, 0, 16, 28);
}
''';
}