packages/flutter/lib/src/material/search_bar_theme.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 'dart:ui' show lerpDouble;

import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';

import 'material_state.dart';
import 'theme.dart';

// Examples can assume:
// late BuildContext context;

/// Defines default property values for descendant [SearchBar] widgets.
///
/// Descendant widgets obtain the current [SearchBarThemeData] object using
/// `SearchBarTheme.of(context)`. Instances of [SearchBarThemeData] can be customized
/// with [SearchBarThemeData.copyWith].
///
/// Typically a [SearchBarThemeData] is specified as part of the overall [Theme]
/// with [ThemeData.searchBarTheme].
///
/// All [SearchBarThemeData] properties are `null` by default. When null, the
/// [SearchBar] will use the values from [ThemeData] if they exist, otherwise it
/// will provide its own defaults based on the overall [Theme]'s colorScheme.
/// See the individual [SearchBar] properties for details.
///
/// See also:
///
///  * [ThemeData], which describes the overall theme information for the
///    application.
@immutable
class SearchBarThemeData with Diagnosticable {
  /// Creates a theme that can be used for [ThemeData.searchBarTheme].
  const SearchBarThemeData({
    this.elevation,
    this.backgroundColor,
    this.shadowColor,
    this.surfaceTintColor,
    this.overlayColor,
    this.side,
    this.shape,
    this.padding,
    this.textStyle,
    this.hintStyle,
    this.constraints,
  });

  /// Overrides the default value of the [SearchBar.elevation].
  final MaterialStateProperty<double?>? elevation;

  /// Overrides the default value of the [SearchBar.backgroundColor].
  final MaterialStateProperty<Color?>? backgroundColor;

  /// Overrides the default value of the [SearchBar.shadowColor].
  final MaterialStateProperty<Color?>? shadowColor;

  /// Overrides the default value of the [SearchBar.surfaceTintColor].
  final MaterialStateProperty<Color?>? surfaceTintColor;

  /// Overrides the default value of the [SearchBar.overlayColor].
  final MaterialStateProperty<Color?>? overlayColor;

  /// Overrides the default value of the [SearchBar.side].
  final MaterialStateProperty<BorderSide?>? side;

  /// Overrides the default value of the [SearchBar.shape].
  final MaterialStateProperty<OutlinedBorder?>? shape;

  /// Overrides the default value for [SearchBar.padding].
  final MaterialStateProperty<EdgeInsetsGeometry?>? padding;

  /// Overrides the default value for [SearchBar.textStyle].
  final MaterialStateProperty<TextStyle?>? textStyle;

  /// Overrides the default value for [SearchBar.hintStyle].
  final MaterialStateProperty<TextStyle?>? hintStyle;

  /// Overrides the value of size constraints for [SearchBar].
  final BoxConstraints? constraints;

  /// Creates a copy of this object but with the given fields replaced with the
  /// new values.
  SearchBarThemeData copyWith({
    MaterialStateProperty<double?>? elevation,
    MaterialStateProperty<Color?>? backgroundColor,
    MaterialStateProperty<Color?>? shadowColor,
    MaterialStateProperty<Color?>? surfaceTintColor,
    MaterialStateProperty<Color?>? overlayColor,
    MaterialStateProperty<BorderSide?>? side,
    MaterialStateProperty<OutlinedBorder?>? shape,
    MaterialStateProperty<EdgeInsetsGeometry?>? padding,
    MaterialStateProperty<TextStyle?>? textStyle,
    MaterialStateProperty<TextStyle?>? hintStyle,
    BoxConstraints? constraints,
  }) {
    return SearchBarThemeData(
      elevation: elevation ?? this.elevation,
      backgroundColor: backgroundColor ?? this.backgroundColor,
      shadowColor: shadowColor ?? this.shadowColor,
      surfaceTintColor: surfaceTintColor ?? this.surfaceTintColor,
      overlayColor: overlayColor ?? this.overlayColor,
      side: side ?? this.side,
      shape: shape ?? this.shape,
      padding: padding ?? this.padding,
      textStyle: textStyle ?? this.textStyle,
      hintStyle: hintStyle ?? this.hintStyle,
      constraints: constraints ?? this.constraints,
    );
  }

  /// Linearly interpolate between two [SearchBarThemeData]s.
  ///
  /// {@macro dart.ui.shadow.lerp}
  static SearchBarThemeData? lerp(SearchBarThemeData? a, SearchBarThemeData? b, double t) {
    if (identical(a, b)) {
      return a;
    }
    return SearchBarThemeData(
      elevation: MaterialStateProperty.lerp<double?>(a?.elevation, b?.elevation, t, lerpDouble),
      backgroundColor: MaterialStateProperty.lerp<Color?>(a?.backgroundColor, b?.backgroundColor, t, Color.lerp),
      shadowColor: MaterialStateProperty.lerp<Color?>(a?.shadowColor, b?.shadowColor, t, Color.lerp),
      surfaceTintColor: MaterialStateProperty.lerp<Color?>(a?.surfaceTintColor, b?.surfaceTintColor, t, Color.lerp),
      overlayColor: MaterialStateProperty.lerp<Color?>(a?.overlayColor, b?.overlayColor, t, Color.lerp),
      side: _lerpSides(a?.side, b?.side, t),
      shape: MaterialStateProperty.lerp<OutlinedBorder?>(a?.shape, b?.shape, t, OutlinedBorder.lerp),
      padding: MaterialStateProperty.lerp<EdgeInsetsGeometry?>(a?.padding, b?.padding, t, EdgeInsetsGeometry.lerp),
      textStyle: MaterialStateProperty.lerp<TextStyle?>(a?.textStyle, b?.textStyle, t, TextStyle.lerp),
      hintStyle: MaterialStateProperty.lerp<TextStyle?>(a?.hintStyle, b?.hintStyle, t, TextStyle.lerp),
      constraints: BoxConstraints.lerp(a?.constraints, b?.constraints, t),
    );
  }

  @override
  int get hashCode => Object.hash(
    elevation,
    backgroundColor,
    shadowColor,
    surfaceTintColor,
    overlayColor,
    side,
    shape,
    padding,
    textStyle,
    hintStyle,
    constraints,
  );

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    if (other.runtimeType != runtimeType) {
      return false;
    }
    return other is SearchBarThemeData
      && other.elevation == elevation
      && other.backgroundColor == backgroundColor
      && other.shadowColor == shadowColor
      && other.surfaceTintColor == surfaceTintColor
      && other.overlayColor == overlayColor
      && other.side == side
      && other.shape == shape
      && other.padding == padding
      && other.textStyle == textStyle
      && other.hintStyle == hintStyle
      && other.constraints == constraints;
  }

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<MaterialStateProperty<double?>>('elevation', elevation, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('backgroundColor', backgroundColor, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('shadowColor', shadowColor, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('surfaceTintColor', surfaceTintColor, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('overlayColor', overlayColor, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<BorderSide?>>('side', side, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<OutlinedBorder?>>('shape', shape, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<EdgeInsetsGeometry?>>('padding', padding, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<TextStyle?>>('textStyle', textStyle, defaultValue: null));
    properties.add(DiagnosticsProperty<MaterialStateProperty<TextStyle?>>('hintStyle', hintStyle, defaultValue: null));
    properties.add(DiagnosticsProperty<BoxConstraints>('constraints', constraints, defaultValue: null));
  }

  // Special case because BorderSide.lerp() doesn't support null arguments
  static MaterialStateProperty<BorderSide?>? _lerpSides(MaterialStateProperty<BorderSide?>? a, MaterialStateProperty<BorderSide?>? b, double t) {
    if (identical(a, b)) {
      return a;
    }
    return _LerpSides(a, b, t);
  }
}

class _LerpSides implements MaterialStateProperty<BorderSide?> {
  const _LerpSides(this.a, this.b, this.t);

  final MaterialStateProperty<BorderSide?>? a;
  final MaterialStateProperty<BorderSide?>? b;
  final double t;

  @override
  BorderSide? resolve(Set<MaterialState> states) {
    final BorderSide? resolvedA = a?.resolve(states);
    final BorderSide? resolvedB = b?.resolve(states);
    if (identical(resolvedA, resolvedB)) {
      return resolvedA;
    }
    if (resolvedA == null) {
      return BorderSide.lerp(BorderSide(width: 0, color: resolvedB!.color.withAlpha(0)), resolvedB, t);
    }
    if (resolvedB == null) {
      return BorderSide.lerp(resolvedA, BorderSide(width: 0, color: resolvedA.color.withAlpha(0)), t);
    }
    return BorderSide.lerp(resolvedA, resolvedB, t);
  }
}

/// Applies a search bar theme to descendant [SearchBar] widgets.
///
/// Descendant widgets obtain the current theme's [SearchBarTheme] object using
/// [SearchBarTheme.of]. When a widget uses [SearchBarTheme.of], it is automatically
/// rebuilt if the theme later changes.
///
/// A search bar theme can be specified as part of the overall Material theme using
/// [ThemeData.searchBarTheme].
///
/// See also:
///
///  * [SearchBarThemeData], which describes the actual configuration of a search bar
///    theme.
class SearchBarTheme extends InheritedWidget {
  /// Constructs a search bar theme that configures all descendant [SearchBar] widgets.
  const SearchBarTheme({
    super.key,
    required this.data,
    required super.child,
  });

  /// The properties used for all descendant [SearchBar] widgets.
  final SearchBarThemeData data;

  /// Returns the configuration [data] from the closest [SearchBarTheme] ancestor.
  /// If there is no ancestor, it returns [ThemeData.searchBarTheme].
  ///
  /// Typical usage is as follows:
  ///
  /// ```dart
  /// SearchBarThemeData theme = SearchBarTheme.of(context);
  /// ```
  static SearchBarThemeData of(BuildContext context) {
    final SearchBarTheme? searchBarTheme = context.dependOnInheritedWidgetOfExactType<SearchBarTheme>();
    return searchBarTheme?.data ?? Theme.of(context).searchBarTheme;
  }

  @override
  bool updateShouldNotify(SearchBarTheme oldWidget) => data != oldWidget.data;
}