packages/flutter/lib/src/widgets/editable_text.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:async';
import 'dart:math' as math;
import 'dart:ui' as ui hide TextStyle;

import 'package:characters/characters.dart' show CharacterRange, StringCharacters;
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart' show DragStartBehavior;
import 'package:flutter/rendering.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter/services.dart';

import 'actions.dart';
import 'autofill.dart';
import 'automatic_keep_alive.dart';
import 'basic.dart';
import 'binding.dart';
import 'constants.dart';
import 'debug.dart';
import 'default_selection_style.dart';
import 'focus_manager.dart';
import 'focus_scope.dart';
import 'focus_traversal.dart';
import 'framework.dart';
import 'localizations.dart';
import 'media_query.dart';
import 'scroll_configuration.dart';
import 'scroll_controller.dart';
import 'scroll_physics.dart';
import 'scrollable.dart';
import 'shortcuts.dart';
import 'text.dart';
import 'text_editing_intents.dart';
import 'text_selection.dart';
import 'ticker_provider.dart';
import 'widget_span.dart';

export 'package:flutter/services.dart' show SelectionChangedCause, TextEditingValue, TextSelection, TextInputType, SmartQuotesType, SmartDashesType;

/// Signature for the callback that reports when the user changes the selection
/// (including the cursor location).
typedef SelectionChangedCallback = void Function(TextSelection selection, SelectionChangedCause? cause);

/// Signature for the callback that reports the app private command results.
typedef AppPrivateCommandCallback = void Function(String, Map<String, dynamic>);

// The time it takes for the cursor to fade from fully opaque to fully
// transparent and vice versa. A full cursor blink, from transparent to opaque
// to transparent, is twice this duration.
const Duration _kCursorBlinkHalfPeriod = Duration(milliseconds: 500);

// The time the cursor is static in opacity before animating to become
// transparent.
const Duration _kCursorBlinkWaitForStart = Duration(milliseconds: 150);

// Number of cursor ticks during which the most recently entered character
// is shown in an obscured text field.
const int _kObscureShowLatestCharCursorTicks = 3;

// The minimum width of an iPad screen. The smallest iPad is currently the
// iPad Mini 6th Gen according to ios-resolution.com.
const double _kIPadWidth = 1488.0;

/// A controller for an editable text field.
///
/// Whenever the user modifies a text field with an associated
/// [TextEditingController], the text field updates [value] and the controller
/// notifies its listeners. Listeners can then read the [text] and [selection]
/// properties to learn what the user has typed or how the selection has been
/// updated.
///
/// Similarly, if you modify the [text] or [selection] properties, the text
/// field will be notified and will update itself appropriately.
///
/// A [TextEditingController] can also be used to provide an initial value for a
/// text field. If you build a text field with a controller that already has
/// [text], the text field will use that text as its initial value.
///
/// The [value] (as well as [text] and [selection]) of this controller can be
/// updated from within a listener added to this controller. Be aware of
/// infinite loops since the listener will also be notified of the changes made
/// from within itself. Modifying the composing region from within a listener
/// can also have a bad interaction with some input methods. Gboard, for
/// example, will try to restore the composing region of the text if it was
/// modified programmatically, creating an infinite loop of communications
/// between the framework and the input method. Consider using
/// [TextInputFormatter]s instead for as-you-type text modification.
///
/// If both the [text] or [selection] properties need to be changed, set the
/// controller's [value] instead.
///
/// Remember to [dispose] of the [TextEditingController] when it is no longer
/// needed. This will ensure we discard any resources used by the object.
/// {@tool dartpad}
/// This example creates a [TextField] with a [TextEditingController] whose
/// change listener forces the entered text to be lower case and keeps the
/// cursor at the end of the input.
///
/// ** See code in examples/api/lib/widgets/editable_text/text_editing_controller.0.dart **
/// {@end-tool}
///
/// See also:
///
///  * [TextField], which is a Material Design text field that can be controlled
///    with a [TextEditingController].
///  * [EditableText], which is a raw region of editable text that can be
///    controlled with a [TextEditingController].
///  * Learn how to use a [TextEditingController] in one of our [cookbook recipes](https://flutter.dev/docs/cookbook/forms/text-field-changes#2-use-a-texteditingcontroller).
class TextEditingController extends ValueNotifier<TextEditingValue> {
  /// Creates a controller for an editable text field.
  ///
  /// This constructor treats a null [text] argument as if it were the empty
  /// string.
  TextEditingController({ String? text })
    : super(text == null ? TextEditingValue.empty : TextEditingValue(text: text));

  /// Creates a controller for an editable text field from an initial [TextEditingValue].
  ///
  /// This constructor treats a null [value] argument as if it were
  /// [TextEditingValue.empty].
  TextEditingController.fromValue(TextEditingValue? value)
    : assert(
        value == null || !value.composing.isValid || value.isComposingRangeValid,
        'New TextEditingValue $value has an invalid non-empty composing range '
        '${value.composing}. It is recommended to use a valid composing range, '
        'even for readonly text fields',
      ),
      super(value ?? TextEditingValue.empty);

  /// The current string the user is editing.
  String get text => value.text;
  /// Setting this will notify all the listeners of this [TextEditingController]
  /// that they need to update (it calls [notifyListeners]). For this reason,
  /// this value should only be set between frames, e.g. in response to user
  /// actions, not during the build, layout, or paint phases.
  ///
  /// This property can be set from a listener added to this
  /// [TextEditingController]; however, one should not also set [selection]
  /// in a separate statement. To change both the [text] and the [selection]
  /// change the controller's [value].
  set text(String newText) {
    value = value.copyWith(
      text: newText,
      selection: const TextSelection.collapsed(offset: -1),
      composing: TextRange.empty,
    );
  }

  @override
  set value(TextEditingValue newValue) {
    assert(
      !newValue.composing.isValid || newValue.isComposingRangeValid,
      'New TextEditingValue $newValue has an invalid non-empty composing range '
      '${newValue.composing}. It is recommended to use a valid composing range, '
      'even for readonly text fields',
    );
    super.value = newValue;
  }

  /// Builds [TextSpan] from current editing value.
  ///
  /// By default makes text in composing range appear as underlined. Descendants
  /// can override this method to customize appearance of text.
  TextSpan buildTextSpan({required BuildContext context, TextStyle? style , required bool withComposing}) {
    assert(!value.composing.isValid || !withComposing || value.isComposingRangeValid);
    // If the composing range is out of range for the current text, ignore it to
    // preserve the tree integrity, otherwise in release mode a RangeError will
    // be thrown and this EditableText will be built with a broken subtree.
    if (!value.isComposingRangeValid || !withComposing) {
      return TextSpan(style: style, text: text);
    }
    final TextStyle composingStyle = style?.merge(const TextStyle(decoration: TextDecoration.underline))
        ?? const TextStyle(decoration: TextDecoration.underline);
    return TextSpan(
      style: style,
      children: <TextSpan>[
        TextSpan(text: value.composing.textBefore(value.text)),
        TextSpan(
          style: composingStyle,
          text: value.composing.textInside(value.text),
        ),
        TextSpan(text: value.composing.textAfter(value.text)),
      ],
    );
  }

  /// The currently selected [text].
  ///
  /// If the selection is collapsed, then this property gives the offset of the
  /// cursor within the text.
  TextSelection get selection => value.selection;
  /// Setting this will notify all the listeners of this [TextEditingController]
  /// that they need to update (it calls [notifyListeners]). For this reason,
  /// this value should only be set between frames, e.g. in response to user
  /// actions, not during the build, layout, or paint phases.
  ///
  /// This property can be set from a listener added to this
  /// [TextEditingController]; however, one should not also set [text]
  /// in a separate statement. To change both the [text] and the [selection]
  /// change the controller's [value].
  ///
  /// If the new selection is of non-zero length, or is outside the composing
  /// range, the composing range is cleared.
  set selection(TextSelection newSelection) {
    if (!isSelectionWithinTextBounds(newSelection))
      throw FlutterError('invalid text selection: $newSelection');
    final TextRange newComposing =
        newSelection.isCollapsed && _isSelectionWithinComposingRange(newSelection)
            ? value.composing
            : TextRange.empty;
    value = value.copyWith(selection: newSelection, composing: newComposing);
  }

  /// Set the [value] to empty.
  ///
  /// After calling this function, [text] will be the empty string and the
  /// selection will be collapsed at zero offset.
  ///
  /// Calling this will notify all the listeners of this [TextEditingController]
  /// that they need to update (it calls [notifyListeners]). For this reason,
  /// this method should only be called between frames, e.g. in response to user
  /// actions, not during the build, layout, or paint phases.
  void clear() {
    value = const TextEditingValue(selection: TextSelection.collapsed(offset: 0));
  }

  /// Set the composing region to an empty range.
  ///
  /// The composing region is the range of text that is still being composed.
  /// Calling this function indicates that the user is done composing that
  /// region.
  ///
  /// Calling this will notify all the listeners of this [TextEditingController]
  /// that they need to update (it calls [notifyListeners]). For this reason,
  /// this method should only be called between frames, e.g. in response to user
  /// actions, not during the build, layout, or paint phases.
  void clearComposing() {
    value = value.copyWith(composing: TextRange.empty);
  }

  /// Check that the [selection] is inside of the bounds of [text].
  bool isSelectionWithinTextBounds(TextSelection selection) {
    return selection.start <= text.length && selection.end <= text.length;
  }

  /// Check that the [selection] is inside of the composing range.
  bool _isSelectionWithinComposingRange(TextSelection selection) {
    return selection.start >= value.composing.start && selection.end <= value.composing.end;
  }
}

/// Toolbar configuration for [EditableText].
///
/// Toolbar is a context menu that will show up when user right click or long
/// press the [EditableText]. It includes several options: cut, copy, paste,
/// and select all.
///
/// [EditableText] and its derived widgets have their own default [ToolbarOptions].
/// Create a custom [ToolbarOptions] if you want explicit control over the toolbar
/// option.
class ToolbarOptions {
  /// Create a toolbar configuration with given options.
  ///
  /// All options default to false if they are not explicitly set.
  const ToolbarOptions({
    this.copy = false,
    this.cut = false,
    this.paste = false,
    this.selectAll = false,
  }) : assert(copy != null),
       assert(cut != null),
       assert(paste != null),
       assert(selectAll != null);

  /// Whether to show copy option in toolbar.
  ///
  /// Defaults to false. Must not be null.
  final bool copy;

  /// Whether to show cut option in toolbar.
  ///
  /// If [EditableText.readOnly] is set to true, cut will be disabled regardless.
  ///
  /// Defaults to false. Must not be null.
  final bool cut;

  /// Whether to show paste option in toolbar.
  ///
  /// If [EditableText.readOnly] is set to true, paste will be disabled regardless.
  ///
  /// Defaults to false. Must not be null.
  final bool paste;

  /// Whether to show select all option in toolbar.
  ///
  /// Defaults to false. Must not be null.
  final bool selectAll;
}

/// A basic text input field.
///
/// This widget interacts with the [TextInput] service to let the user edit the
/// text it contains. It also provides scrolling, selection, and cursor
/// movement. This widget does not provide any focus management (e.g.,
/// tap-to-focus).
///
/// ## Handling User Input
///
/// Currently the user may change the text this widget contains via keyboard or
/// the text selection menu. When the user inserted or deleted text, you will be
/// notified of the change and get a chance to modify the new text value:
///
/// * The [inputFormatters] will be first applied to the user input.
///
/// * The [controller]'s [TextEditingController.value] will be updated with the
///   formatted result, and the [controller]'s listeners will be notified.
///
/// * The [onChanged] callback, if specified, will be called last.
///
/// ## Input Actions
///
/// A [TextInputAction] can be provided to customize the appearance of the
/// action button on the soft keyboard for Android and iOS. The default action
/// is [TextInputAction.done].
///
/// Many [TextInputAction]s are common between Android and iOS. However, if a
/// [textInputAction] is provided that is not supported by the current
/// platform in debug mode, an error will be thrown when the corresponding
/// EditableText receives focus. For example, providing iOS's "emergencyCall"
/// action when running on an Android device will result in an error when in
/// debug mode. In release mode, incompatible [TextInputAction]s are replaced
/// either with "unspecified" on Android, or "default" on iOS. Appropriate
/// [textInputAction]s can be chosen by checking the current platform and then
/// selecting the appropriate action.
///
/// {@template flutter.widgets.EditableText.lifeCycle}
/// ## Lifecycle
///
/// Upon completion of editing, like pressing the "done" button on the keyboard,
/// two actions take place:
///
///   1st: Editing is finalized. The default behavior of this step includes
///   an invocation of [onChanged]. That default behavior can be overridden.
///   See [onEditingComplete] for details.
///
///   2nd: [onSubmitted] is invoked with the user's input value.
///
/// [onSubmitted] can be used to manually move focus to another input widget
/// when a user finishes with the currently focused input widget.
///
/// When the widget has focus, it will prevent itself from disposing via
/// [AutomaticKeepAliveClientMixin.wantKeepAlive] in order to avoid losing the
/// selection. Removing the focus will allow it to be disposed.
/// {@endtemplate}
///
/// Rather than using this widget directly, consider using [TextField], which
/// is a full-featured, material-design text input field with placeholder text,
/// labels, and [Form] integration.
///
/// ## Text Editing [Intent]s and Their Default [Action]s
///
/// This widget provides default [Action]s for handling common text editing
/// [Intent]s such as deleting, copying and pasting in the text field. These
/// [Action]s can be directly invoked using [Actions.invoke] or the
/// [Actions.maybeInvoke] method. The default text editing keyboard [Shortcuts]
/// also use these [Intent]s and [Action]s to perform the text editing
/// operations they are bound to.
///
/// The default handling of a specific [Intent] can be overridden by placing an
/// [Actions] widget above this widget. See the [Action] class and the
/// [Action.overridable] constructor for more information on how a pre-defined
/// overridable [Action] can be overridden.
///
/// ### Intents for Deleting Text and Their Default Behavior
///
/// | **Intent Class**                 | **Default Behavior when there's selected text**      | **Default Behavior when there is a [caret](https://en.wikipedia.org/wiki/Caret_navigation) (The selection is [TextSelection.collapsed])**  |
/// | :------------------------------- | :--------------------------------------------------- | :----------------------------------------------------------------------- |
/// | [DeleteCharacterIntent]          | Deletes the selected text                            | Deletes the user-perceived character before or after the caret location. |
/// | [DeleteToNextWordBoundaryIntent] | Deletes the selected text and the word before/after the selection's [TextSelection.extent] position | Deletes from the caret location to the previous or the next word boundary |
/// | [DeleteToLineBreakIntent]        | Deletes the selected text, and deletes to the start/end of the line from the selection's [TextSelection.extent] position | Deletes from the caret location to the logical start or end of the current line |
///
/// ### Intents for Moving the [Caret](https://en.wikipedia.org/wiki/Caret_navigation)
///
/// | **Intent Class**                                                                     | **Default Behavior when there's selected text**                  | **Default Behavior when there is a caret ([TextSelection.collapsed])**  |
/// | :----------------------------------------------------------------------------------- | :--------------------------------------------------------------- | :---------------------------------------------------------------------- |
/// | [ExtendSelectionByCharacterIntent](`collapseSelection: true`)                       | Collapses the selection to the logical start/end of the selection | Moves the caret past the user-perceived character before or after the current caret location.  |
/// | [ExtendSelectionToNextWordBoundaryIntent](`collapseSelection: true`)                | Collapses the selection to the word boundary before/after the selection's [TextSelection.extent] position | Moves the caret to the previous/next word boundary.  |
/// | [ExtendSelectionToNextWordBoundaryOrCaretLocationIntent](`collapseSelection: true`) | Collapses the selection to the word boundary before/after the selection's [TextSelection.extent] position, or [TextSelection.base], whichever is closest in the given direction | Moves the caret to the previous/next word boundary.  |
/// | [ExtendSelectionToLineBreakIntent](`collapseSelection: true`)                       | Collapses the selection to the start/end of the line at the selection's [TextSelection.extent] position | Moves the caret to the start/end of the current line .|
/// | [ExtendSelectionVerticallyToAdjacentLineIntent](`collapseSelection: true`)          | Collapses the selection to the position closest to the selection's [TextSelection.extent], on the previous/next adjacent line | Moves the caret to the closest position on the previous/next adjacent line. |
/// | [ExtendSelectionToDocumentBoundaryIntent](`collapseSelection: true`)                | Collapses the selection to the start/end of the document | Moves the caret to the start/end of the document. |
///
/// #### Intents for Extending the Selection
///
/// | **Intent Class**                                                                     | **Default Behavior when there's selected text**                  | **Default Behavior when there is a caret ([TextSelection.collapsed])**  |
/// | :----------------------------------------------------------------------------------- | :--------------------------------------------------------------- | :---------------------------------------------------------------------- |
/// | [ExtendSelectionByCharacterIntent](`collapseSelection: false`)                       | Moves the selection's [TextSelection.extent] past the user-perceived character before/after it |
/// | [ExtendSelectionToNextWordBoundaryIntent](`collapseSelection: false`)                | Moves the selection's [TextSelection.extent] to the previous/next word boundary |
/// | [ExtendSelectionToNextWordBoundaryOrCaretLocationIntent](`collapseSelection: false`) | Moves the selection's [TextSelection.extent] to the previous/next word boundary, or [TextSelection.base] whichever is closest in the given direction | Moves the selection's [TextSelection.extent] to the previous/next word boundary. |
/// | [ExtendSelectionToLineBreakIntent](`collapseSelection: false`)                       | Moves the selection's [TextSelection.extent] to the start/end of the line |
/// | [ExtendSelectionVerticallyToAdjacentLineIntent](`collapseSelection: false`)          | Moves the selection's [TextSelection.extent] to the closest position on the previous/next adjacent line |
/// | [ExtendSelectionToDocumentBoundaryIntent](`collapseSelection: false`)                | Moves the selection's [TextSelection.extent] to the start/end of the document |
/// | [SelectAllTextIntent]  | Selects the entire document |
///
/// ### Other Intents
///
/// | **Intent Class**                        | **Default Behavior**                                 |
/// | :-------------------------------------- | :--------------------------------------------------- |
/// | [DoNothingAndStopPropagationTextIntent] | Does nothing in the input field, and prevents the key event from further propagating in the widget tree. |
/// | [ReplaceTextIntent]                     | Replaces the current [TextEditingValue] in the input field's [TextEditingController], and triggers all related user callbacks and [TextInputFormatter]s. |
/// | [UpdateSelectionIntent]                 | Updates the current selection in the input field's [TextEditingController], and triggers the [onSelectionChanged] callback. |
/// | [CopySelectionTextIntent]               | Copies or cuts the selected text into the clipboard |
/// | [PasteTextIntent]                       | Inserts the current text in the clipboard after the caret location, or replaces the selected text if the selection is not collapsed. |
///
/// ## Gesture Events Handling
///
/// This widget provides rudimentary, platform-agnostic gesture handling for
/// user actions such as tapping, long-pressing and scrolling when
/// [rendererIgnoresPointer] is false (false by default). To tightly conform
/// to the platform behavior with respect to input gestures in text fields, use
/// [TextField] or [CupertinoTextField]. For custom selection behavior, call
/// methods such as [RenderEditable.selectPosition],
/// [RenderEditable.selectWord], etc. programmatically.
///
/// {@template flutter.widgets.editableText.showCaretOnScreen}
/// ## Keep the caret visible when focused
///
/// When focused, this widget will make attempts to keep the text area and its
/// caret (even when [showCursor] is `false`) visible, on these occasions:
///
///  * When the user focuses this text field and it is not [readOnly].
///  * When the user changes the selection of the text field, or changes the
///    text when the text field is not [readOnly].
///  * When the virtual keyboard pops up.
/// {@endtemplate}
///
/// See also:
///
///  * [TextField], which is a full-featured, material-design text input field
///    with placeholder text, labels, and [Form] integration.
class EditableText extends StatefulWidget {
  /// Creates a basic text input control.
  ///
  /// The [maxLines] property can be set to null to remove the restriction on
  /// the number of lines. By default, it is one, meaning this is a single-line
  /// text field. [maxLines] must be null or greater than zero.
  ///
  /// If [keyboardType] is not set or is null, its value will be inferred from
  /// [autofillHints], if [autofillHints] is not empty. Otherwise it defaults to
  /// [TextInputType.text] if [maxLines] is exactly one, and
  /// [TextInputType.multiline] if [maxLines] is null or greater than one.
  ///
  /// The text cursor is not shown if [showCursor] is false or if [showCursor]
  /// is null (the default) and [readOnly] is true.
  ///
  /// The [controller], [focusNode], [obscureText], [autocorrect], [autofocus],
  /// [showSelectionHandles], [enableInteractiveSelection], [forceLine],
  /// [style], [cursorColor], [cursorOpacityAnimates],[backgroundCursorColor],
  /// [enableSuggestions], [paintCursorAboveText], [selectionHeightStyle],
  /// [selectionWidthStyle], [textAlign], [dragStartBehavior], [scrollPadding],
  /// [dragStartBehavior], [toolbarOptions], [rendererIgnoresPointer],
  /// [readOnly], and [enableIMEPersonalizedLearning] arguments must not be null.
  EditableText({
    super.key,
    required this.controller,
    required this.focusNode,
    this.readOnly = false,
    this.obscuringCharacter = '•',
    this.obscureText = false,
    this.autocorrect = true,
    SmartDashesType? smartDashesType,
    SmartQuotesType? smartQuotesType,
    this.enableSuggestions = true,
    required this.style,
    StrutStyle? strutStyle,
    required this.cursorColor,
    required this.backgroundCursorColor,
    this.textAlign = TextAlign.start,
    this.textDirection,
    this.locale,
    this.textScaleFactor,
    this.maxLines = 1,
    this.minLines,
    this.expands = false,
    this.forceLine = true,
    this.textHeightBehavior,
    this.textWidthBasis = TextWidthBasis.parent,
    this.autofocus = false,
    bool? showCursor,
    this.showSelectionHandles = false,
    this.selectionColor,
    this.selectionControls,
    TextInputType? keyboardType,
    this.textInputAction,
    this.textCapitalization = TextCapitalization.none,
    this.onChanged,
    this.onEditingComplete,
    this.onSubmitted,
    this.onAppPrivateCommand,
    this.onSelectionChanged,
    this.onSelectionHandleTapped,
    List<TextInputFormatter>? inputFormatters,
    this.mouseCursor,
    this.rendererIgnoresPointer = false,
    this.cursorWidth = 2.0,
    this.cursorHeight,
    this.cursorRadius,
    this.cursorOpacityAnimates = false,
    this.cursorOffset,
    this.paintCursorAboveText = false,
    this.selectionHeightStyle = ui.BoxHeightStyle.tight,
    this.selectionWidthStyle = ui.BoxWidthStyle.tight,
    this.scrollPadding = const EdgeInsets.all(20.0),
    this.keyboardAppearance = Brightness.light,
    this.dragStartBehavior = DragStartBehavior.start,
    bool? enableInteractiveSelection,
    this.scrollController,
    this.scrollPhysics,
    this.autocorrectionTextRectColor,
    ToolbarOptions? toolbarOptions,
    this.autofillHints = const <String>[],
    this.autofillClient,
    this.clipBehavior = Clip.hardEdge,
    this.restorationId,
    this.scrollBehavior,
    this.scribbleEnabled = true,
    this.enableIMEPersonalizedLearning = true,
  }) : assert(controller != null),
       assert(focusNode != null),
       assert(obscuringCharacter != null && obscuringCharacter.length == 1),
       assert(obscureText != null),
       assert(autocorrect != null),
       smartDashesType = smartDashesType ?? (obscureText ? SmartDashesType.disabled : SmartDashesType.enabled),
       smartQuotesType = smartQuotesType ?? (obscureText ? SmartQuotesType.disabled : SmartQuotesType.enabled),
       assert(enableSuggestions != null),
       assert(showSelectionHandles != null),
       assert(readOnly != null),
       assert(forceLine != null),
       assert(style != null),
       assert(cursorColor != null),
       assert(cursorOpacityAnimates != null),
       assert(paintCursorAboveText != null),
       assert(backgroundCursorColor != null),
       assert(selectionHeightStyle != null),
       assert(selectionWidthStyle != null),
       assert(textAlign != null),
       assert(maxLines == null || maxLines > 0),
       assert(minLines == null || minLines > 0),
       assert(
         (maxLines == null) || (minLines == null) || (maxLines >= minLines),
         "minLines can't be greater than maxLines",
       ),
       assert(expands != null),
       assert(
         !expands || (maxLines == null && minLines == null),
         'minLines and maxLines must be null when expands is true.',
       ),
       assert(!obscureText || maxLines == 1, 'Obscured fields cannot be multiline.'),
       assert(autofocus != null),
       assert(rendererIgnoresPointer != null),
       assert(scrollPadding != null),
       assert(dragStartBehavior != null),
       enableInteractiveSelection = enableInteractiveSelection ?? (!readOnly || !obscureText),
       toolbarOptions = toolbarOptions ??
           (obscureText
               ? (readOnly
                   // No point in even offering "Select All" in a read-only obscured
                   // field.
                   ? const ToolbarOptions()
                   // Writable, but obscured.
                   : const ToolbarOptions(
                       selectAll: true,
                       paste: true,
                     ))
               : (readOnly
                   // Read-only, not obscured.
                   ? const ToolbarOptions(
                       selectAll: true,
                       copy: true,
                     )
                   // Writable, not obscured.
                   : const ToolbarOptions(
                       copy: true,
                       cut: true,
                       selectAll: true,
                       paste: true,
                     ))),
       assert(clipBehavior != null),
       assert(enableIMEPersonalizedLearning != null),
       _strutStyle = strutStyle,
       keyboardType = keyboardType ?? _inferKeyboardType(autofillHints: autofillHints, maxLines: maxLines),
       inputFormatters = maxLines == 1
           ? <TextInputFormatter>[
               FilteringTextInputFormatter.singleLineFormatter,
               ...inputFormatters ?? const Iterable<TextInputFormatter>.empty(),
             ]
           : inputFormatters,
       showCursor = showCursor ?? !readOnly;

  /// Controls the text being edited.
  final TextEditingController controller;

  /// Controls whether this widget has keyboard focus.
  final FocusNode focusNode;

  /// {@template flutter.widgets.editableText.obscuringCharacter}
  /// Character used for obscuring text if [obscureText] is true.
  ///
  /// Must be only a single character.
  ///
  /// Defaults to the character U+2022 BULLET (•).
  /// {@endtemplate}
  final String obscuringCharacter;

  /// {@template flutter.widgets.editableText.obscureText}
  /// Whether to hide the text being edited (e.g., for passwords).
  ///
  /// When this is set to true, all the characters in the text field are
  /// replaced by [obscuringCharacter], and the text in the field cannot be
  /// copied with copy or cut. If [readOnly] is also true, then the text cannot
  /// be selected.
  ///
  /// Defaults to false. Cannot be null.
  /// {@endtemplate}
  final bool obscureText;

  /// {@macro dart.ui.textHeightBehavior}
  final TextHeightBehavior? textHeightBehavior;

  /// {@macro flutter.painting.textPainter.textWidthBasis}
  final TextWidthBasis textWidthBasis;

  /// {@template flutter.widgets.editableText.readOnly}
  /// Whether the text can be changed.
  ///
  /// When this is set to true, the text cannot be modified
  /// by any shortcut or keyboard operation. The text is still selectable.
  ///
  /// Defaults to false. Must not be null.
  /// {@endtemplate}
  final bool readOnly;

  /// Whether the text will take the full width regardless of the text width.
  ///
  /// When this is set to false, the width will be based on text width, which
  /// will also be affected by [textWidthBasis].
  ///
  /// Defaults to true. Must not be null.
  ///
  /// See also:
  ///
  ///  * [textWidthBasis], which controls the calculation of text width.
  final bool forceLine;

  /// Configuration of toolbar options.
  ///
  /// By default, all options are enabled. If [readOnly] is true, paste and cut
  /// will be disabled regardless. If [obscureText] is true, cut and copy will
  /// be disabled regardless. If [readOnly] and [obscureText] are both true,
  /// select all will also be disabled.
  final ToolbarOptions toolbarOptions;

  /// Whether to show selection handles.
  ///
  /// When a selection is active, there will be two handles at each side of
  /// boundary, or one handle if the selection is collapsed. The handles can be
  /// dragged to adjust the selection.
  ///
  /// See also:
  ///
  ///  * [showCursor], which controls the visibility of the cursor.
  final bool showSelectionHandles;

  /// {@template flutter.widgets.editableText.showCursor}
  /// Whether to show cursor.
  ///
  /// The cursor refers to the blinking caret when the [EditableText] is focused.
  /// {@endtemplate}
  ///
  /// See also:
  ///
  ///  * [showSelectionHandles], which controls the visibility of the selection handles.
  final bool showCursor;

  /// {@template flutter.widgets.editableText.autocorrect}
  /// Whether to enable autocorrection.
  ///
  /// Defaults to true. Cannot be null.
  /// {@endtemplate}
  final bool autocorrect;

  /// {@macro flutter.services.TextInputConfiguration.smartDashesType}
  final SmartDashesType smartDashesType;

  /// {@macro flutter.services.TextInputConfiguration.smartQuotesType}
  final SmartQuotesType smartQuotesType;

  /// {@macro flutter.services.TextInputConfiguration.enableSuggestions}
  final bool enableSuggestions;

  /// The text style to use for the editable text.
  final TextStyle style;

  /// {@template flutter.widgets.editableText.strutStyle}
  /// The strut style used for the vertical layout.
  ///
  /// [StrutStyle] is used to establish a predictable vertical layout.
  /// Since fonts may vary depending on user input and due to font
  /// fallback, [StrutStyle.forceStrutHeight] is enabled by default
  /// to lock all lines to the height of the base [TextStyle], provided by
  /// [style]. This ensures the typed text fits within the allotted space.
  ///
  /// If null, the strut used will inherit values from the [style] and will
  /// have [StrutStyle.forceStrutHeight] set to true. When no [style] is
  /// passed, the theme's [TextStyle] will be used to generate [strutStyle]
  /// instead.
  ///
  /// To disable strut-based vertical alignment and allow dynamic vertical
  /// layout based on the glyphs typed, use [StrutStyle.disabled].
  ///
  /// Flutter's strut is based on [typesetting strut](https://en.wikipedia.org/wiki/Strut_(typesetting))
  /// and CSS's [line-height](https://www.w3.org/TR/CSS2/visudet.html#line-height).
  /// {@endtemplate}
  ///
  /// Within editable text and text fields, [StrutStyle] will not use its standalone
  /// default values, and will instead inherit omitted/null properties from the
  /// [TextStyle] instead. See [StrutStyle.inheritFromTextStyle].
  StrutStyle get strutStyle {
    if (_strutStyle == null) {
      return StrutStyle.fromTextStyle(style, forceStrutHeight: true);
    }
    return _strutStyle!.inheritFromTextStyle(style);
  }
  final StrutStyle? _strutStyle;

  /// {@template flutter.widgets.editableText.textAlign}
  /// How the text should be aligned horizontally.
  ///
  /// Defaults to [TextAlign.start] and cannot be null.
  /// {@endtemplate}
  final TextAlign textAlign;

  /// {@template flutter.widgets.editableText.textDirection}
  /// The directionality of the text.
  ///
  /// This decides how [textAlign] values like [TextAlign.start] and
  /// [TextAlign.end] are interpreted.
  ///
  /// This is also used to disambiguate how to render bidirectional text. For
  /// example, if the text is an English phrase followed by a Hebrew phrase,
  /// in a [TextDirection.ltr] context the English phrase will be on the left
  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
  /// context, the English phrase will be on the right and the Hebrew phrase on
  /// its left.
  ///
  /// Defaults to the ambient [Directionality], if any.
  /// {@endtemplate}
  final TextDirection? textDirection;

  /// {@template flutter.widgets.editableText.textCapitalization}
  /// Configures how the platform keyboard will select an uppercase or
  /// lowercase keyboard.
  ///
  /// Only supports text keyboards, other keyboard types will ignore this
  /// configuration. Capitalization is locale-aware.
  ///
  /// Defaults to [TextCapitalization.none]. Must not be null.
  ///
  /// See also:
  ///
  ///  * [TextCapitalization], for a description of each capitalization behavior.
  ///
  /// {@endtemplate}
  final TextCapitalization textCapitalization;

  /// Used to select a font when the same Unicode character can
  /// be rendered differently, depending on the locale.
  ///
  /// It's rarely necessary to set this property. By default its value
  /// is inherited from the enclosing app with `Localizations.localeOf(context)`.
  ///
  /// See [RenderEditable.locale] for more information.
  final Locale? locale;

  /// {@template flutter.widgets.editableText.textScaleFactor}
  /// The number of font pixels for each logical pixel.
  ///
  /// For example, if the text scale factor is 1.5, text will be 50% larger than
  /// the specified font size.
  ///
  /// Defaults to the [MediaQueryData.textScaleFactor] obtained from the ambient
  /// [MediaQuery], or 1.0 if there is no [MediaQuery] in scope.
  /// {@endtemplate}
  final double? textScaleFactor;

  /// The color to use when painting the cursor.
  ///
  /// Cannot be null.
  final Color cursorColor;

  /// The color to use when painting the autocorrection Rect.
  ///
  /// For [CupertinoTextField]s, the value is set to the ambient
  /// [CupertinoThemeData.primaryColor] with 20% opacity. For [TextField]s, the
  /// value is null on non-iOS platforms and the same color used in [CupertinoTextField]
  /// on iOS.
  ///
  /// Currently the autocorrection Rect only appears on iOS.
  ///
  /// Defaults to null, which disables autocorrection Rect painting.
  final Color? autocorrectionTextRectColor;

  /// The color to use when painting the background cursor aligned with the text
  /// while rendering the floating cursor.
  ///
  /// Cannot be null. By default it is the disabled grey color from
  /// CupertinoColors.
  final Color backgroundCursorColor;

  /// {@template flutter.widgets.editableText.maxLines}
  /// The maximum number of lines to show at one time, wrapping if necessary.
  ///
  /// This affects the height of the field itself and does not limit the number
  /// of lines that can be entered into the field.
  ///
  /// If this is 1 (the default), the text will not wrap, but will scroll
  /// horizontally instead.
  ///
  /// If this is null, there is no limit to the number of lines, and the text
  /// container will start with enough vertical space for one line and
  /// automatically grow to accommodate additional lines as they are entered, up
  /// to the height of its constraints.
  ///
  /// If this is not null, the value must be greater than zero, and it will lock
  /// the input to the given number of lines and take up enough horizontal space
  /// to accommodate that number of lines. Setting [minLines] as well allows the
  /// input to grow and shrink between the indicated range.
  ///
  /// The full set of behaviors possible with [minLines] and [maxLines] are as
  /// follows. These examples apply equally to [TextField], [TextFormField],
  /// [CupertinoTextField], and [EditableText].
  ///
  /// Input that occupies a single line and scrolls horizontally as needed.
  /// ```dart
  /// TextField()
  /// ```
  ///
  /// Input whose height grows from one line up to as many lines as needed for
  /// the text that was entered. If a height limit is imposed by its parent, it
  /// will scroll vertically when its height reaches that limit.
  /// ```dart
  /// TextField(maxLines: null)
  /// ```
  ///
  /// The input's height is large enough for the given number of lines. If
  /// additional lines are entered the input scrolls vertically.
  /// ```dart
  /// TextField(maxLines: 2)
  /// ```
  ///
  /// Input whose height grows with content between a min and max. An infinite
  /// max is possible with `maxLines: null`.
  /// ```dart
  /// TextField(minLines: 2, maxLines: 4)
  /// ```
  ///
  /// See also:
  ///
  ///  * [minLines], which sets the minimum number of lines visible.
  /// {@endtemplate}
  ///  * [expands], which determines whether the field should fill the height of
  ///    its parent.
  final int? maxLines;

  /// {@template flutter.widgets.editableText.minLines}
  /// The minimum number of lines to occupy when the content spans fewer lines.
  ///
  /// This affects the height of the field itself and does not limit the number
  /// of lines that can be entered into the field.
  ///
  /// If this is null (default), text container starts with enough vertical space
  /// for one line and grows to accommodate additional lines as they are entered.
  ///
  /// This can be used in combination with [maxLines] for a varying set of behaviors.
  ///
  /// If the value is set, it must be greater than zero. If the value is greater
  /// than 1, [maxLines] should also be set to either null or greater than
  /// this value.
  ///
  /// When [maxLines] is set as well, the height will grow between the indicated
  /// range of lines. When [maxLines] is null, it will grow as high as needed,
  /// starting from [minLines].
  ///
  /// A few examples of behaviors possible with [minLines] and [maxLines] are as follows.
  /// These apply equally to [TextField], [TextFormField], [CupertinoTextField],
  /// and [EditableText].
  ///
  /// Input that always occupies at least 2 lines and has an infinite max.
  /// Expands vertically as needed.
  /// ```dart
  /// TextField(minLines: 2)
  /// ```
  ///
  /// Input whose height starts from 2 lines and grows up to 4 lines at which
  /// point the height limit is reached. If additional lines are entered it will
  /// scroll vertically.
  /// ```dart
  /// TextField(minLines:2, maxLines: 4)
  /// ```
  ///
  /// Defaults to null.
  ///
  /// See also:
  ///
  ///  * [maxLines], which sets the maximum number of lines visible, and has
  ///    several examples of how minLines and maxLines interact to produce
  ///    various behaviors.
  /// {@endtemplate}
  ///  * [expands], which determines whether the field should fill the height of
  ///    its parent.
  final int? minLines;

  /// {@template flutter.widgets.editableText.expands}
  /// Whether this widget's height will be sized to fill its parent.
  ///
  /// If set to true and wrapped in a parent widget like [Expanded] or
  /// [SizedBox], the input will expand to fill the parent.
  ///
  /// [maxLines] and [minLines] must both be null when this is set to true,
  /// otherwise an error is thrown.
  ///
  /// Defaults to false.
  ///
  /// See the examples in [maxLines] for the complete picture of how [maxLines],
  /// [minLines], and [expands] interact to produce various behaviors.
  ///
  /// Input that matches the height of its parent:
  /// ```dart
  /// Expanded(
  ///   child: TextField(maxLines: null, expands: true),
  /// )
  /// ```
  /// {@endtemplate}
  final bool expands;

  /// {@template flutter.widgets.editableText.autofocus}
  /// Whether this text field should focus itself if nothing else is already
  /// focused.
  ///
  /// If true, the keyboard will open as soon as this text field obtains focus.
  /// Otherwise, the keyboard is only shown after the user taps the text field.
  ///
  /// Defaults to false. Cannot be null.
  /// {@endtemplate}
  // See https://github.com/flutter/flutter/issues/7035 for the rationale for this
  // keyboard behavior.
  final bool autofocus;

  /// The color to use when painting the selection.
  ///
  /// If this property is null, this widget gets the selection color from the
  /// [DefaultSelectionStyle].
  ///
  /// For [CupertinoTextField]s, the value is set to the ambient
  /// [CupertinoThemeData.primaryColor] with 20% opacity. For [TextField]s, the
  /// value is set to the ambient [TextSelectionThemeData.selectionColor].
  final Color? selectionColor;

  /// {@template flutter.widgets.editableText.selectionControls}
  /// Optional delegate for building the text selection handles and toolbar.
  ///
  /// The [EditableText] widget used on its own will not trigger the display
  /// of the selection toolbar by itself. The toolbar is shown by calling
  /// [EditableTextState.showToolbar] in response to an appropriate user event.
  ///
  /// See also:
  ///
  ///  * [CupertinoTextField], which wraps an [EditableText] and which shows the
  ///    selection toolbar upon user events that are appropriate on the iOS
  ///    platform.
  ///  * [TextField], a Material Design themed wrapper of [EditableText], which
  ///    shows the selection toolbar upon appropriate user events based on the
  ///    user's platform set in [ThemeData.platform].
  /// {@endtemplate}
  final TextSelectionControls? selectionControls;

  /// {@template flutter.widgets.editableText.keyboardType}
  /// The type of keyboard to use for editing the text.
  ///
  /// Defaults to [TextInputType.text] if [maxLines] is one and
  /// [TextInputType.multiline] otherwise.
  /// {@endtemplate}
  final TextInputType keyboardType;

  /// The type of action button to use with the soft keyboard.
  final TextInputAction? textInputAction;

  /// {@template flutter.widgets.editableText.onChanged}
  /// Called when the user initiates a change to the TextField's
  /// value: when they have inserted or deleted text.
  ///
  /// This callback doesn't run when the TextField's text is changed
  /// programmatically, via the TextField's [controller]. Typically it
  /// isn't necessary to be notified of such changes, since they're
  /// initiated by the app itself.
  ///
  /// To be notified of all changes to the TextField's text, cursor,
  /// and selection, one can add a listener to its [controller] with
  /// [TextEditingController.addListener].
  ///
  /// [onChanged] is called before [onSubmitted] when user indicates completion
  /// of editing, such as when pressing the "done" button on the keyboard. That default
  /// behavior can be overridden. See [onEditingComplete] for details.
  ///
  /// {@tool dartpad}
  /// This example shows how onChanged could be used to check the TextField's
  /// current value each time the user inserts or deletes a character.
  ///
  /// ** See code in examples/api/lib/widgets/editable_text/editable_text.on_changed.0.dart **
  /// {@end-tool}
  /// {@endtemplate}
  ///
  /// ## Handling emojis and other complex characters
  /// {@template flutter.widgets.EditableText.onChanged}
  /// It's important to always use
  /// [characters](https://pub.dev/packages/characters) when dealing with user
  /// input text that may contain complex characters. This will ensure that
  /// extended grapheme clusters and surrogate pairs are treated as single
  /// characters, as they appear to the user.
  ///
  /// For example, when finding the length of some user input, use
  /// `string.characters.length`. Do NOT use `string.length` or even
  /// `string.runes.length`. For the complex character "👨‍👩‍👦", this
  /// appears to the user as a single character, and `string.characters.length`
  /// intuitively returns 1. On the other hand, `string.length` returns 8, and
  /// `string.runes.length` returns 5!
  /// {@endtemplate}
  ///
  /// See also:
  ///
  ///  * [inputFormatters], which are called before [onChanged]
  ///    runs and can validate and change ("format") the input value.
  ///  * [onEditingComplete], [onSubmitted], [onSelectionChanged]:
  ///    which are more specialized input change notifications.
  final ValueChanged<String>? onChanged;

  /// {@template flutter.widgets.editableText.onEditingComplete}
  /// Called when the user submits editable content (e.g., user presses the "done"
  /// button on the keyboard).
  ///
  /// The default implementation of [onEditingComplete] executes 2 different
  /// behaviors based on the situation:
  ///
  ///  - When a completion action is pressed, such as "done", "go", "send", or
  ///    "search", the user's content is submitted to the [controller] and then
  ///    focus is given up.
  ///
  ///  - When a non-completion action is pressed, such as "next" or "previous",
  ///    the user's content is submitted to the [controller], but focus is not
  ///    given up because developers may want to immediately move focus to
  ///    another input widget within [onSubmitted].
  ///
  /// Providing [onEditingComplete] prevents the aforementioned default behavior.
  /// {@endtemplate}
  final VoidCallback? onEditingComplete;

  /// {@template flutter.widgets.editableText.onSubmitted}
  /// Called when the user indicates that they are done editing the text in the
  /// field.
  ///
  /// By default, [onSubmitted] is called after [onChanged] when the user
  /// has finalized editing; or, if the default behavior has been overridden,
  /// after [onEditingComplete]. See [onEditingComplete] for details.
  /// {@endtemplate}
  final ValueChanged<String>? onSubmitted;

  /// {@template flutter.widgets.editableText.onAppPrivateCommand}
  /// This is used to receive a private command from the input method.
  ///
  /// Called when the result of [TextInputClient.performPrivateCommand] is
  /// received.
  ///
  /// This can be used to provide domain-specific features that are only known
  /// between certain input methods and their clients.
  ///
  /// See also:
  ///   * [performPrivateCommand](https://developer.android.com/reference/android/view/inputmethod/InputConnection#performPrivateCommand\(java.lang.String,%20android.os.Bundle\)),
  ///     which is the Android documentation for performPrivateCommand, used to
  ///     send a command from the input method.
  ///   * [sendAppPrivateCommand](https://developer.android.com/reference/android/view/inputmethod/InputMethodManager#sendAppPrivateCommand),
  ///     which is the Android documentation for sendAppPrivateCommand, used to
  ///     send a command to the input method.
  /// {@endtemplate}
  final AppPrivateCommandCallback? onAppPrivateCommand;

  /// {@template flutter.widgets.editableText.onSelectionChanged}
  /// Called when the user changes the selection of text (including the cursor
  /// location).
  /// {@endtemplate}
  final SelectionChangedCallback? onSelectionChanged;

  /// {@macro flutter.widgets.SelectionOverlay.onSelectionHandleTapped}
  final VoidCallback? onSelectionHandleTapped;

  /// {@template flutter.widgets.editableText.inputFormatters}
  /// Optional input validation and formatting overrides.
  ///
  /// Formatters are run in the provided order when the text input changes. When
  /// this parameter changes, the new formatters will not be applied until the
  /// next time the user inserts or deletes text.
  /// {@endtemplate}
  final List<TextInputFormatter>? inputFormatters;

  /// The cursor for a mouse pointer when it enters or is hovering over the
  /// widget.
  ///
  /// If this property is null, [SystemMouseCursors.text] will be used.
  ///
  /// The [mouseCursor] is the only property of [EditableText] that controls the
  /// appearance of the mouse pointer. All other properties related to "cursor"
  /// stands for the text cursor, which is usually a blinking vertical line at
  /// the editing position.
  final MouseCursor? mouseCursor;

  /// If true, the [RenderEditable] created by this widget will not handle
  /// pointer events, see [RenderEditable] and [RenderEditable.ignorePointer].
  ///
  /// This property is false by default.
  final bool rendererIgnoresPointer;

  /// {@template flutter.widgets.editableText.cursorWidth}
  /// How thick the cursor will be.
  ///
  /// Defaults to 2.0.
  ///
  /// The cursor will draw under the text. The cursor width will extend
  /// to the right of the boundary between characters for left-to-right text
  /// and to the left for right-to-left text. This corresponds to extending
  /// downstream relative to the selected position. Negative values may be used
  /// to reverse this behavior.
  /// {@endtemplate}
  final double cursorWidth;

  /// {@template flutter.widgets.editableText.cursorHeight}
  /// How tall the cursor will be.
  ///
  /// If this property is null, [RenderEditable.preferredLineHeight] will be used.
  /// {@endtemplate}
  final double? cursorHeight;

  /// {@template flutter.widgets.editableText.cursorRadius}
  /// How rounded the corners of the cursor should be.
  ///
  /// By default, the cursor has no radius.
  /// {@endtemplate}
  final Radius? cursorRadius;

  /// Whether the cursor will animate from fully transparent to fully opaque
  /// during each cursor blink.
  ///
  /// By default, the cursor opacity will animate on iOS platforms and will not
  /// animate on Android platforms.
  final bool cursorOpacityAnimates;

  ///{@macro flutter.rendering.RenderEditable.cursorOffset}
  final Offset? cursorOffset;

  ///{@macro flutter.rendering.RenderEditable.paintCursorAboveText}
  final bool paintCursorAboveText;

  /// Controls how tall the selection highlight boxes are computed to be.
  ///
  /// See [ui.BoxHeightStyle] for details on available styles.
  final ui.BoxHeightStyle selectionHeightStyle;

  /// Controls how wide the selection highlight boxes are computed to be.
  ///
  /// See [ui.BoxWidthStyle] for details on available styles.
  final ui.BoxWidthStyle selectionWidthStyle;

  /// The appearance of the keyboard.
  ///
  /// This setting is only honored on iOS devices.
  ///
  /// Defaults to [Brightness.light].
  final Brightness keyboardAppearance;

  /// {@template flutter.widgets.editableText.scrollPadding}
  /// Configures padding to edges surrounding a [Scrollable] when the Textfield scrolls into view.
  ///
  /// When this widget receives focus and is not completely visible (for example scrolled partially
  /// off the screen or overlapped by the keyboard)
  /// then it will attempt to make itself visible by scrolling a surrounding [Scrollable], if one is present.
  /// This value controls how far from the edges of a [Scrollable] the TextField will be positioned after the scroll.
  ///
  /// Defaults to EdgeInsets.all(20.0).
  /// {@endtemplate}
  final EdgeInsets scrollPadding;

  /// {@template flutter.widgets.editableText.enableInteractiveSelection}
  /// Whether to enable user interface affordances for changing the
  /// text selection.
  ///
  /// For example, setting this to true will enable features such as
  /// long-pressing the TextField to select text and show the
  /// cut/copy/paste menu, and tapping to move the text caret.
  ///
  /// When this is false, the text selection cannot be adjusted by
  /// the user, text cannot be copied, and the user cannot paste into
  /// the text field from the clipboard.
  ///
  /// Defaults to true.
  /// {@endtemplate}
  final bool enableInteractiveSelection;

  /// Setting this property to true makes the cursor stop blinking or fading
  /// on and off once the cursor appears on focus. This property is useful for
  /// testing purposes.
  ///
  /// It does not affect the necessity to focus the EditableText for the cursor
  /// to appear in the first place.
  ///
  /// Defaults to false, resulting in a typical blinking cursor.
  static bool debugDeterministicCursor = false;

  /// {@macro flutter.widgets.scrollable.dragStartBehavior}
  final DragStartBehavior dragStartBehavior;

  /// {@template flutter.widgets.editableText.scrollController}
  /// The [ScrollController] to use when vertically scrolling the input.
  ///
  /// If null, it will instantiate a new ScrollController.
  ///
  /// See [Scrollable.controller].
  /// {@endtemplate}
  final ScrollController? scrollController;

  /// {@template flutter.widgets.editableText.scrollPhysics}
  /// The [ScrollPhysics] to use when vertically scrolling the input.
  ///
  /// If not specified, it will behave according to the current platform.
  ///
  /// See [Scrollable.physics].
  /// {@endtemplate}
  ///
  /// If an explicit [ScrollBehavior] is provided to [scrollBehavior], the
  /// [ScrollPhysics] provided by that behavior will take precedence after
  /// [scrollPhysics].
  final ScrollPhysics? scrollPhysics;

  /// {@template flutter.widgets.editableText.scribbleEnabled}
  /// Whether iOS 14 Scribble features are enabled for this widget.
  ///
  /// Only available on iPads.
  ///
  /// Defaults to true.
  /// {@endtemplate}
  final bool scribbleEnabled;

  /// {@template flutter.widgets.editableText.selectionEnabled}
  /// Same as [enableInteractiveSelection].
  ///
  /// This getter exists primarily for consistency with
  /// [RenderEditable.selectionEnabled].
  /// {@endtemplate}
  bool get selectionEnabled => enableInteractiveSelection;

  /// {@template flutter.widgets.editableText.autofillHints}
  /// A list of strings that helps the autofill service identify the type of this
  /// text input.
  ///
  /// When set to null, this text input will not send its autofill information
  /// to the platform, preventing it from participating in autofills triggered
  /// by a different [AutofillClient], even if they're in the same
  /// [AutofillScope]. Additionally, on Android and web, setting this to null
  /// will disable autofill for this text field.
  ///
  /// The minimum platform SDK version that supports Autofill is API level 26
  /// for Android, and iOS 10.0 for iOS.
  ///
  /// Defaults to an empty list.
  ///
  /// ### Setting up iOS autofill:
  ///
  /// To provide the best user experience and ensure your app fully supports
  /// password autofill on iOS, follow these steps:
  ///
  /// * Set up your iOS app's
  ///   [associated domains](https://developer.apple.com/documentation/safariservices/supporting_associated_domains_in_your_app).
  /// * Some autofill hints only work with specific [keyboardType]s. For example,
  ///   [AutofillHints.name] requires [TextInputType.name] and [AutofillHints.email]
  ///   works only with [TextInputType.emailAddress]. Make sure the input field has a
  ///   compatible [keyboardType]. Empirically, [TextInputType.name] works well
  ///   with many autofill hints that are predefined on iOS.
  ///
  /// ### Troubleshooting Autofill
  ///
  /// Autofill service providers rely heavily on [autofillHints]. Make sure the
  /// entries in [autofillHints] are supported by the autofill service currently
  /// in use (the name of the service can typically be found in your mobile
  /// device's system settings).
  ///
  /// #### Autofill UI refuses to show up when I tap on the text field
  ///
  /// Check the device's system settings and make sure autofill is turned on,
  /// and there are available credentials stored in the autofill service.
  ///
  /// * iOS password autofill: Go to Settings -> Password, turn on "Autofill
  ///   Passwords", and add new passwords for testing by pressing the top right
  ///   "+" button. Use an arbitrary "website" if you don't have associated
  ///   domains set up for your app. As long as there's at least one password
  ///   stored, you should be able to see a key-shaped icon in the quick type
  ///   bar on the software keyboard, when a password related field is focused.
  ///
  /// * iOS contact information autofill: iOS seems to pull contact info from
  ///   the Apple ID currently associated with the device. Go to Settings ->
  ///   Apple ID (usually the first entry, or "Sign in to your iPhone" if you
  ///   haven't set up one on the device), and fill out the relevant fields. If
  ///   you wish to test more contact info types, try adding them in Contacts ->
  ///   My Card.
  ///
  /// * Android autofill: Go to Settings -> System -> Languages & input ->
  ///   Autofill service. Enable the autofill service of your choice, and make
  ///   sure there are available credentials associated with your app.
  ///
  /// #### I called `TextInput.finishAutofillContext` but the autofill save
  /// prompt isn't showing
  ///
  /// * iOS: iOS may not show a prompt or any other visual indication when it
  ///   saves user password. Go to Settings -> Password and check if your new
  ///   password is saved. Neither saving password nor auto-generating strong
  ///   password works without properly setting up associated domains in your
  ///   app. To set up associated domains, follow the instructions in
  ///   <https://developer.apple.com/documentation/safariservices/supporting_associated_domains_in_your_app>.
  ///
  /// {@endtemplate}
  /// {@macro flutter.services.AutofillConfiguration.autofillHints}
  final Iterable<String>? autofillHints;

  /// The [AutofillClient] that controls this input field's autofill behavior.
  ///
  /// When null, this widget's [EditableTextState] will be used as the
  /// [AutofillClient]. This property may override [autofillHints].
  final AutofillClient? autofillClient;

  /// {@macro flutter.material.Material.clipBehavior}
  ///
  /// Defaults to [Clip.hardEdge].
  final Clip clipBehavior;

  /// Restoration ID to save and restore the scroll offset of the
  /// [EditableText].
  ///
  /// If a restoration id is provided, the [EditableText] will persist its
  /// current scroll offset and restore it during state restoration.
  ///
  /// The scroll offset is persisted in a [RestorationBucket] claimed from
  /// the surrounding [RestorationScope] using the provided restoration ID.
  ///
  /// Persisting and restoring the content of the [EditableText] is the
  /// responsibility of the owner of the [controller], who may use a
  /// [RestorableTextEditingController] for that purpose.
  ///
  /// See also:
  ///
  ///  * [RestorationManager], which explains how state restoration works in
  ///    Flutter.
  final String? restorationId;

  /// {@template flutter.widgets.shadow.scrollBehavior}
  /// A [ScrollBehavior] that will be applied to this widget individually.
  ///
  /// Defaults to null, wherein the inherited [ScrollBehavior] is copied and
  /// modified to alter the viewport decoration, like [Scrollbar]s.
  /// {@endtemplate}
  ///
  /// [ScrollBehavior]s also provide [ScrollPhysics]. If an explicit
  /// [ScrollPhysics] is provided in [scrollPhysics], it will take precedence,
  /// followed by [scrollBehavior], and then the inherited ancestor
  /// [ScrollBehavior].
  ///
  /// The [ScrollBehavior] of the inherited [ScrollConfiguration] will be
  /// modified by default to only apply a [Scrollbar] if [maxLines] is greater
  /// than 1.
  final ScrollBehavior? scrollBehavior;

  /// {@macro flutter.services.TextInputConfiguration.enableIMEPersonalizedLearning}
  final bool enableIMEPersonalizedLearning;

  bool get _userSelectionEnabled => enableInteractiveSelection && (!readOnly || !obscureText);

  // Infer the keyboard type of an `EditableText` if it's not specified.
  static TextInputType _inferKeyboardType({
    required Iterable<String>? autofillHints,
    required int? maxLines,
  }) {
    if (autofillHints == null || autofillHints.isEmpty) {
      return maxLines == 1 ? TextInputType.text : TextInputType.multiline;
    }

    final String effectiveHint = autofillHints.first;

    // On iOS oftentimes specifying a text content type is not enough to qualify
    // the input field for autofill. The keyboard type also needs to be compatible
    // with the content type. To get autofill to work by default on EditableText,
    // the keyboard type inference on iOS is done differently from other platforms.
    //
    // The entries with "autofill not working" comments are the iOS text content
    // types that should work with the specified keyboard type but won't trigger
    // (even within a native app). Tested on iOS 13.5.
    if (!kIsWeb) {
      switch (defaultTargetPlatform) {
        case TargetPlatform.iOS:
        case TargetPlatform.macOS:
          const Map<String, TextInputType> iOSKeyboardType = <String, TextInputType> {
            AutofillHints.addressCity : TextInputType.name,
            AutofillHints.addressCityAndState : TextInputType.name, // Autofill not working.
            AutofillHints.addressState : TextInputType.name,
            AutofillHints.countryName : TextInputType.name,
            AutofillHints.creditCardNumber : TextInputType.number,  // Couldn't test.
            AutofillHints.email : TextInputType.emailAddress,
            AutofillHints.familyName : TextInputType.name,
            AutofillHints.fullStreetAddress : TextInputType.name,
            AutofillHints.givenName : TextInputType.name,
            AutofillHints.jobTitle : TextInputType.name,            // Autofill not working.
            AutofillHints.location : TextInputType.name,            // Autofill not working.
            AutofillHints.middleName : TextInputType.name,          // Autofill not working.
            AutofillHints.name : TextInputType.name,
            AutofillHints.namePrefix : TextInputType.name,          // Autofill not working.
            AutofillHints.nameSuffix : TextInputType.name,          // Autofill not working.
            AutofillHints.newPassword : TextInputType.text,
            AutofillHints.newUsername : TextInputType.text,
            AutofillHints.nickname : TextInputType.name,            // Autofill not working.
            AutofillHints.oneTimeCode : TextInputType.number,
            AutofillHints.organizationName : TextInputType.text,    // Autofill not working.
            AutofillHints.password : TextInputType.text,
            AutofillHints.postalCode : TextInputType.name,
            AutofillHints.streetAddressLine1 : TextInputType.name,
            AutofillHints.streetAddressLine2 : TextInputType.name,  // Autofill not working.
            AutofillHints.sublocality : TextInputType.name,         // Autofill not working.
            AutofillHints.telephoneNumber : TextInputType.name,
            AutofillHints.url : TextInputType.url,                  // Autofill not working.
            AutofillHints.username : TextInputType.text,
          };

          final TextInputType? keyboardType = iOSKeyboardType[effectiveHint];
          if (keyboardType != null) {
            return keyboardType;
          }
          break;
        case TargetPlatform.android:
        case TargetPlatform.fuchsia:
        case TargetPlatform.linux:
        case TargetPlatform.windows:
          break;
      }
    }

    if (maxLines != 1) {
      return TextInputType.multiline;
    }

    const Map<String, TextInputType> inferKeyboardType = <String, TextInputType> {
      AutofillHints.addressCity : TextInputType.streetAddress,
      AutofillHints.addressCityAndState : TextInputType.streetAddress,
      AutofillHints.addressState : TextInputType.streetAddress,
      AutofillHints.birthday : TextInputType.datetime,
      AutofillHints.birthdayDay : TextInputType.datetime,
      AutofillHints.birthdayMonth : TextInputType.datetime,
      AutofillHints.birthdayYear : TextInputType.datetime,
      AutofillHints.countryCode : TextInputType.number,
      AutofillHints.countryName : TextInputType.text,
      AutofillHints.creditCardExpirationDate : TextInputType.datetime,
      AutofillHints.creditCardExpirationDay : TextInputType.datetime,
      AutofillHints.creditCardExpirationMonth : TextInputType.datetime,
      AutofillHints.creditCardExpirationYear : TextInputType.datetime,
      AutofillHints.creditCardFamilyName : TextInputType.name,
      AutofillHints.creditCardGivenName : TextInputType.name,
      AutofillHints.creditCardMiddleName : TextInputType.name,
      AutofillHints.creditCardName : TextInputType.name,
      AutofillHints.creditCardNumber : TextInputType.number,
      AutofillHints.creditCardSecurityCode : TextInputType.number,
      AutofillHints.creditCardType : TextInputType.text,
      AutofillHints.email : TextInputType.emailAddress,
      AutofillHints.familyName : TextInputType.name,
      AutofillHints.fullStreetAddress : TextInputType.streetAddress,
      AutofillHints.gender : TextInputType.text,
      AutofillHints.givenName : TextInputType.name,
      AutofillHints.impp : TextInputType.url,
      AutofillHints.jobTitle : TextInputType.text,
      AutofillHints.language : TextInputType.text,
      AutofillHints.location : TextInputType.streetAddress,
      AutofillHints.middleInitial : TextInputType.name,
      AutofillHints.middleName : TextInputType.name,
      AutofillHints.name : TextInputType.name,
      AutofillHints.namePrefix : TextInputType.name,
      AutofillHints.nameSuffix : TextInputType.name,
      AutofillHints.newPassword : TextInputType.text,
      AutofillHints.newUsername : TextInputType.text,
      AutofillHints.nickname : TextInputType.text,
      AutofillHints.oneTimeCode : TextInputType.text,
      AutofillHints.organizationName : TextInputType.text,
      AutofillHints.password : TextInputType.text,
      AutofillHints.photo : TextInputType.text,
      AutofillHints.postalAddress : TextInputType.streetAddress,
      AutofillHints.postalAddressExtended : TextInputType.streetAddress,
      AutofillHints.postalAddressExtendedPostalCode : TextInputType.number,
      AutofillHints.postalCode : TextInputType.number,
      AutofillHints.streetAddressLevel1 : TextInputType.streetAddress,
      AutofillHints.streetAddressLevel2 : TextInputType.streetAddress,
      AutofillHints.streetAddressLevel3 : TextInputType.streetAddress,
      AutofillHints.streetAddressLevel4 : TextInputType.streetAddress,
      AutofillHints.streetAddressLine1 : TextInputType.streetAddress,
      AutofillHints.streetAddressLine2 : TextInputType.streetAddress,
      AutofillHints.streetAddressLine3 : TextInputType.streetAddress,
      AutofillHints.sublocality : TextInputType.streetAddress,
      AutofillHints.telephoneNumber : TextInputType.phone,
      AutofillHints.telephoneNumberAreaCode : TextInputType.phone,
      AutofillHints.telephoneNumberCountryCode : TextInputType.phone,
      AutofillHints.telephoneNumberDevice : TextInputType.phone,
      AutofillHints.telephoneNumberExtension : TextInputType.phone,
      AutofillHints.telephoneNumberLocal : TextInputType.phone,
      AutofillHints.telephoneNumberLocalPrefix : TextInputType.phone,
      AutofillHints.telephoneNumberLocalSuffix : TextInputType.phone,
      AutofillHints.telephoneNumberNational : TextInputType.phone,
      AutofillHints.transactionAmount : TextInputType.numberWithOptions(decimal: true),
      AutofillHints.transactionCurrency : TextInputType.text,
      AutofillHints.url : TextInputType.url,
      AutofillHints.username : TextInputType.text,
    };

    return inferKeyboardType[effectiveHint] ?? TextInputType.text;
  }

  @override
  EditableTextState createState() => EditableTextState();

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<TextEditingController>('controller', controller));
    properties.add(DiagnosticsProperty<FocusNode>('focusNode', focusNode));
    properties.add(DiagnosticsProperty<bool>('obscureText', obscureText, defaultValue: false));
    properties.add(DiagnosticsProperty<bool>('readOnly', readOnly, defaultValue: false));
    properties.add(DiagnosticsProperty<bool>('autocorrect', autocorrect, defaultValue: true));
    properties.add(EnumProperty<SmartDashesType>('smartDashesType', smartDashesType, defaultValue: obscureText ? SmartDashesType.disabled : SmartDashesType.enabled));
    properties.add(EnumProperty<SmartQuotesType>('smartQuotesType', smartQuotesType, defaultValue: obscureText ? SmartQuotesType.disabled : SmartQuotesType.enabled));
    properties.add(DiagnosticsProperty<bool>('enableSuggestions', enableSuggestions, defaultValue: true));
    style.debugFillProperties(properties);
    properties.add(EnumProperty<TextAlign>('textAlign', textAlign, defaultValue: null));
    properties.add(EnumProperty<TextDirection>('textDirection', textDirection, defaultValue: null));
    properties.add(DiagnosticsProperty<Locale>('locale', locale, defaultValue: null));
    properties.add(DoubleProperty('textScaleFactor', textScaleFactor, defaultValue: null));
    properties.add(IntProperty('maxLines', maxLines, defaultValue: 1));
    properties.add(IntProperty('minLines', minLines, defaultValue: null));
    properties.add(DiagnosticsProperty<bool>('expands', expands, defaultValue: false));
    properties.add(DiagnosticsProperty<bool>('autofocus', autofocus, defaultValue: false));
    properties.add(DiagnosticsProperty<TextInputType>('keyboardType', keyboardType, defaultValue: null));
    properties.add(DiagnosticsProperty<ScrollController>('scrollController', scrollController, defaultValue: null));
    properties.add(DiagnosticsProperty<ScrollPhysics>('scrollPhysics', scrollPhysics, defaultValue: null));
    properties.add(DiagnosticsProperty<Iterable<String>>('autofillHints', autofillHints, defaultValue: null));
    properties.add(DiagnosticsProperty<TextHeightBehavior>('textHeightBehavior', textHeightBehavior, defaultValue: null));
    properties.add(DiagnosticsProperty<bool>('scribbleEnabled', scribbleEnabled, defaultValue: true));
    properties.add(DiagnosticsProperty<bool>('enableIMEPersonalizedLearning', enableIMEPersonalizedLearning, defaultValue: true));
    properties.add(DiagnosticsProperty<bool>('enableInteractiveSelection', enableInteractiveSelection, defaultValue: true));
  }
}

/// State for a [EditableText].
class EditableTextState extends State<EditableText> with AutomaticKeepAliveClientMixin<EditableText>, WidgetsBindingObserver, TickerProviderStateMixin<EditableText>, TextSelectionDelegate implements TextInputClient, AutofillClient {
  Timer? _cursorTimer;
  bool _targetCursorVisibility = false;
  final ValueNotifier<bool> _cursorVisibilityNotifier = ValueNotifier<bool>(true);
  final GlobalKey _editableKey = GlobalKey();
  final ClipboardStatusNotifier? _clipboardStatus = kIsWeb ? null : ClipboardStatusNotifier();

  TextInputConnection? _textInputConnection;
  TextSelectionOverlay? _selectionOverlay;

  ScrollController? _internalScrollController;
  ScrollController get _scrollController => widget.scrollController ?? (_internalScrollController ??= ScrollController());

  AnimationController? _cursorBlinkOpacityController;

  final LayerLink _toolbarLayerLink = LayerLink();
  final LayerLink _startHandleLayerLink = LayerLink();
  final LayerLink _endHandleLayerLink = LayerLink();

  bool _didAutoFocus = false;

  AutofillGroupState? _currentAutofillScope;
  @override
  AutofillScope? get currentAutofillScope => _currentAutofillScope;

  AutofillClient get _effectiveAutofillClient => widget.autofillClient ?? this;

  /// Whether to create an input connection with the platform for text editing
  /// or not.
  ///
  /// Read-only input fields do not need a connection with the platform since
  /// there's no need for text editing capabilities (e.g. virtual keyboard).
  ///
  /// On the web, we always need a connection because we want some browser
  /// functionalities to continue to work on read-only input fields like:
  ///
  /// - Relevant context menu.
  /// - cmd/ctrl+c shortcut to copy.
  /// - cmd/ctrl+a to select all.
  /// - Changing the selection using a physical keyboard.
  bool get _shouldCreateInputConnection => kIsWeb || !widget.readOnly;

  // This value is an eyeball estimation of the time it takes for the iOS cursor
  // to ease in and out.
  static const Duration _fadeDuration = Duration(milliseconds: 250);

  // The time it takes for the floating cursor to snap to the text aligned
  // cursor position after the user has finished placing it.
  static const Duration _floatingCursorResetTime = Duration(milliseconds: 125);

  AnimationController? _floatingCursorResetController;

  @override
  bool get wantKeepAlive => widget.focusNode.hasFocus;

  Color get _cursorColor => widget.cursorColor.withOpacity(_cursorBlinkOpacityController!.value);

  @override
  bool get cutEnabled => widget.toolbarOptions.cut && !widget.readOnly && !widget.obscureText;

  @override
  bool get copyEnabled => widget.toolbarOptions.copy && !widget.obscureText;

  @override
  bool get pasteEnabled => widget.toolbarOptions.paste && !widget.readOnly;

  @override
  bool get selectAllEnabled => widget.toolbarOptions.selectAll && (!widget.readOnly || !widget.obscureText) && widget.enableInteractiveSelection;

  void _onChangedClipboardStatus() {
    setState(() {
      // Inform the widget that the value of clipboardStatus has changed.
    });
  }

  TextEditingValue get _textEditingValueforTextLayoutMetrics {
    final Widget? editableWidget =_editableKey.currentContext?.widget;
    if (editableWidget is! _Editable) {
      throw StateError('_Editable must be mounted.');
    }
    return editableWidget.value;
  }

  /// Copy current selection to [Clipboard].
  @override
  void copySelection(SelectionChangedCause cause) {
    final TextSelection selection = textEditingValue.selection;
    assert(selection != null);
    if (selection.isCollapsed || widget.obscureText) {
      return;
    }
    final String text = textEditingValue.text;
    Clipboard.setData(ClipboardData(text: selection.textInside(text)));
    if (cause == SelectionChangedCause.toolbar) {
      bringIntoView(textEditingValue.selection.extent);
      hideToolbar(false);

      switch (defaultTargetPlatform) {
        case TargetPlatform.iOS:
          break;
        case TargetPlatform.macOS:
        case TargetPlatform.android:
        case TargetPlatform.fuchsia:
        case TargetPlatform.linux:
        case TargetPlatform.windows:
          // Collapse the selection and hide the toolbar and handles.
          userUpdateTextEditingValue(
            TextEditingValue(
              text: textEditingValue.text,
              selection: TextSelection.collapsed(offset: textEditingValue.selection.end),
            ),
            SelectionChangedCause.toolbar,
          );
          break;
      }
    }
    _clipboardStatus?.update();
  }

  /// Cut current selection to [Clipboard].
  @override
  void cutSelection(SelectionChangedCause cause) {
    if (widget.readOnly || widget.obscureText) {
      return;
    }
    final TextSelection selection = textEditingValue.selection;
    final String text = textEditingValue.text;
    assert(selection != null);
    if (selection.isCollapsed) {
      return;
    }
    Clipboard.setData(ClipboardData(text: selection.textInside(text)));
    _replaceText(ReplaceTextIntent(textEditingValue, '', selection, cause));
    if (cause == SelectionChangedCause.toolbar) {
      // Schedule a call to bringIntoView() after renderEditable updates.
      SchedulerBinding.instance.addPostFrameCallback((_) {
        if (mounted) {
          bringIntoView(textEditingValue.selection.extent);
        }
      });
      hideToolbar();
    }
    _clipboardStatus?.update();
  }

  /// Paste text from [Clipboard].
  @override
  Future<void> pasteText(SelectionChangedCause cause) async {
    if (widget.readOnly) {
      return;
    }
    final TextSelection selection = textEditingValue.selection;
    assert(selection != null);
    if (!selection.isValid) {
      return;
    }
    // Snapshot the input before using `await`.
    // See https://github.com/flutter/flutter/issues/11427
    final ClipboardData? data = await Clipboard.getData(Clipboard.kTextPlain);
    if (data == null) {
      return;
    }

    // After the paste, the cursor should be collapsed and located after the
    // pasted content.
    final int lastSelectionIndex = math.max(selection.baseOffset, selection.extentOffset);
    final TextEditingValue collapsedTextEditingValue = textEditingValue.copyWith(
      selection: TextSelection.collapsed(offset: lastSelectionIndex),
    );

    userUpdateTextEditingValue(
      collapsedTextEditingValue.replaced(selection, data.text!),
      cause,
    );
    if (cause == SelectionChangedCause.toolbar) {
      // Schedule a call to bringIntoView() after renderEditable updates.
      SchedulerBinding.instance.addPostFrameCallback((_) {
        if (mounted) {
          bringIntoView(textEditingValue.selection.extent);
        }
      });
      hideToolbar();
    }
  }

  /// Select the entire text value.
  @override
  void selectAll(SelectionChangedCause cause) {
    if (widget.readOnly && widget.obscureText) {
      // If we can't modify it, and we can't copy it, there's no point in
      // selecting it.
      return;
    }
    userUpdateTextEditingValue(
      textEditingValue.copyWith(
        selection: TextSelection(baseOffset: 0, extentOffset: textEditingValue.text.length),
      ),
      cause,
    );
    if (cause == SelectionChangedCause.toolbar) {
      bringIntoView(textEditingValue.selection.extent);
    }
  }

  // State lifecycle:

  @override
  void initState() {
    super.initState();
    _cursorBlinkOpacityController = AnimationController(
      vsync: this,
      duration: _fadeDuration,
    )..addListener(_onCursorColorTick);
    _clipboardStatus?.addListener(_onChangedClipboardStatus);
    widget.controller.addListener(_didChangeTextEditingValue);
    widget.focusNode.addListener(_handleFocusChanged);
    _scrollController.addListener(_updateSelectionOverlayForScroll);
    _cursorVisibilityNotifier.value = widget.showCursor;
  }

  // Whether `TickerMode.of(context)` is true and animations (like blinking the
  // cursor) are supposed to run.
  bool _tickersEnabled = true;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();

    final AutofillGroupState? newAutofillGroup = AutofillGroup.of(context);
    if (currentAutofillScope != newAutofillGroup) {
      _currentAutofillScope?.unregister(autofillId);
      _currentAutofillScope = newAutofillGroup;
      _currentAutofillScope?.register(_effectiveAutofillClient);
    }

    if (!_didAutoFocus && widget.autofocus) {
      _didAutoFocus = true;
      SchedulerBinding.instance.addPostFrameCallback((_) {
        if (mounted && renderEditable.hasSize) {
          FocusScope.of(context).autofocus(widget.focusNode);
        }
      });
    }

    // Restart or stop the blinking cursor when TickerMode changes.
    final bool newTickerEnabled = TickerMode.of(context);
    if (_tickersEnabled != newTickerEnabled) {
      _tickersEnabled = newTickerEnabled;
      if (_tickersEnabled && _cursorActive) {
        _startCursorTimer();
      } else if (!_tickersEnabled && _cursorTimer != null) {
        // Cannot use _stopCursorTimer because it would reset _cursorActive.
        _cursorTimer!.cancel();
        _cursorTimer = null;
      }
    }
  }

  @override
  void didUpdateWidget(EditableText oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.controller != oldWidget.controller) {
      oldWidget.controller.removeListener(_didChangeTextEditingValue);
      widget.controller.addListener(_didChangeTextEditingValue);
      _updateRemoteEditingValueIfNeeded();
    }
    if (widget.controller.selection != oldWidget.controller.selection) {
      _selectionOverlay?.update(_value);
    }
    _selectionOverlay?.handlesVisible = widget.showSelectionHandles;

    if (widget.autofillClient != oldWidget.autofillClient) {
      _currentAutofillScope?.unregister(oldWidget.autofillClient?.autofillId ?? autofillId);
      _currentAutofillScope?.register(_effectiveAutofillClient);
    }

    if (widget.focusNode != oldWidget.focusNode) {
      oldWidget.focusNode.removeListener(_handleFocusChanged);
      widget.focusNode.addListener(_handleFocusChanged);
      updateKeepAlive();
    }

    if (widget.scrollController != oldWidget.scrollController) {
      (oldWidget.scrollController ?? _internalScrollController)?.removeListener(_updateSelectionOverlayForScroll);
      _scrollController.addListener(_updateSelectionOverlayForScroll);
    }

    if (!_shouldCreateInputConnection) {
      _closeInputConnectionIfNeeded();
    } else if (oldWidget.readOnly && _hasFocus) {
      _openInputConnection();
    }

    if (kIsWeb && _hasInputConnection) {
      if (oldWidget.readOnly != widget.readOnly) {
        _textInputConnection!.updateConfig(_effectiveAutofillClient.textInputConfiguration);
      }
    }

    if (widget.style != oldWidget.style) {
      final TextStyle style = widget.style;
      // The _textInputConnection will pick up the new style when it attaches in
      // _openInputConnection.
      if (_hasInputConnection) {
        _textInputConnection!.setStyle(
          fontFamily: style.fontFamily,
          fontSize: style.fontSize,
          fontWeight: style.fontWeight,
          textDirection: _textDirection,
          textAlign: widget.textAlign,
        );
      }
    }
    if (widget.selectionEnabled && pasteEnabled && (widget.selectionControls?.canPaste(this) ?? false)) {
      _clipboardStatus?.update();
    }
  }

  @override
  void dispose() {
    _internalScrollController?.dispose();
    _currentAutofillScope?.unregister(autofillId);
    widget.controller.removeListener(_didChangeTextEditingValue);
    _floatingCursorResetController?.dispose();
    _floatingCursorResetController = null;
    _closeInputConnectionIfNeeded();
    assert(!_hasInputConnection);
    _cursorTimer?.cancel();
    _cursorTimer = null;
    _cursorBlinkOpacityController?.dispose();
    _cursorBlinkOpacityController = null;
    _selectionOverlay?.dispose();
    _selectionOverlay = null;
    widget.focusNode.removeListener(_handleFocusChanged);
    WidgetsBinding.instance.removeObserver(this);
    _clipboardStatus?.removeListener(_onChangedClipboardStatus);
    _clipboardStatus?.dispose();
    super.dispose();
    assert(_batchEditDepth <= 0, 'unfinished batch edits: $_batchEditDepth');
  }

  // TextInputClient implementation:

  /// The last known [TextEditingValue] of the platform text input plugin.
  ///
  /// This value is updated when the platform text input plugin sends a new
  /// update via [updateEditingValue], or when [EditableText] calls
  /// [TextInputConnection.setEditingState] to overwrite the platform text input
  /// plugin's [TextEditingValue].
  ///
  /// Used in [_updateRemoteEditingValueIfNeeded] to determine whether the
  /// remote value is outdated and needs updating.
  TextEditingValue? _lastKnownRemoteTextEditingValue;

  @override
  TextEditingValue get currentTextEditingValue => _value;

  @override
  void updateEditingValue(TextEditingValue value) {
    // This method handles text editing state updates from the platform text
    // input plugin. The [EditableText] may not have the focus or an open input
    // connection, as autofill can update a disconnected [EditableText].

    // Since we still have to support keyboard select, this is the best place
    // to disable text updating.
    if (!_shouldCreateInputConnection) {
      return;
    }

    if (widget.readOnly) {
      // In the read-only case, we only care about selection changes, and reject
      // everything else.
      value = _value.copyWith(selection: value.selection);
    }
    _lastKnownRemoteTextEditingValue = value;

    if (value == _value) {
      // This is possible, for example, when the numeric keyboard is input,
      // the engine will notify twice for the same value.
      // Track at https://github.com/flutter/flutter/issues/65811
      return;
    }

    if (value.text == _value.text && value.composing == _value.composing) {
      // `selection` is the only change.
      _handleSelectionChanged(value.selection, (_textInputConnection?.scribbleInProgress ?? false) ? SelectionChangedCause.scribble : SelectionChangedCause.keyboard);
    } else {
      hideToolbar();
      _currentPromptRectRange = null;

      final bool revealObscuredInput = _hasInputConnection
                                    && widget.obscureText
                                    && WidgetsBinding.instance.platformDispatcher.brieflyShowPassword
                                    && value.text.length == _value.text.length + 1;

      _obscureShowCharTicksPending = revealObscuredInput ? _kObscureShowLatestCharCursorTicks : 0;
      _obscureLatestCharIndex = revealObscuredInput ? _value.selection.baseOffset : null;
      _formatAndSetValue(value, SelectionChangedCause.keyboard);
    }

    // Wherever the value is changed by the user, schedule a showCaretOnScreen
    // to make sure the user can see the changes they just made. Programmatical
    // changes to `textEditingValue` do not trigger the behavior even if the
    // text field is focused.
    _scheduleShowCaretOnScreen(withAnimation: true);
    if (_hasInputConnection) {
      // To keep the cursor from blinking while typing, we want to restart the
      // cursor timer every time a new character is typed.
      _stopCursorTimer(resetCharTicks: false);
      _startCursorTimer();
    }
  }

  @override
  void performAction(TextInputAction action) {
    switch (action) {
      case TextInputAction.newline:
        // If this is a multiline EditableText, do nothing for a "newline"
        // action; The newline is already inserted. Otherwise, finalize
        // editing.
        if (!_isMultiline)
          _finalizeEditing(action, shouldUnfocus: true);
        break;
      case TextInputAction.done:
      case TextInputAction.go:
      case TextInputAction.next:
      case TextInputAction.previous:
      case TextInputAction.search:
      case TextInputAction.send:
        _finalizeEditing(action, shouldUnfocus: true);
        break;
      case TextInputAction.continueAction:
      case TextInputAction.emergencyCall:
      case TextInputAction.join:
      case TextInputAction.none:
      case TextInputAction.route:
      case TextInputAction.unspecified:
        // Finalize editing, but don't give up focus because this keyboard
        // action does not imply the user is done inputting information.
        _finalizeEditing(action, shouldUnfocus: false);
        break;
    }
  }

  @override
  void performPrivateCommand(String action, Map<String, dynamic> data) {
    widget.onAppPrivateCommand!(action, data);
  }

  // The original position of the caret on FloatingCursorDragState.start.
  Rect? _startCaretRect;

  // The most recent text position as determined by the location of the floating
  // cursor.
  TextPosition? _lastTextPosition;

  // The offset of the floating cursor as determined from the start call.
  Offset? _pointOffsetOrigin;

  // The most recent position of the floating cursor.
  Offset? _lastBoundedOffset;

  // Because the center of the cursor is preferredLineHeight / 2 below the touch
  // origin, but the touch origin is used to determine which line the cursor is
  // on, we need this offset to correctly render and move the cursor.
  Offset get _floatingCursorOffset => Offset(0, renderEditable.preferredLineHeight / 2);

  @override
  void updateFloatingCursor(RawFloatingCursorPoint point) {
    _floatingCursorResetController ??= AnimationController(
      vsync: this,
    )..addListener(_onFloatingCursorResetTick);
    switch(point.state) {
      case FloatingCursorDragState.Start:
        if (_floatingCursorResetController!.isAnimating) {
          _floatingCursorResetController!.stop();
          _onFloatingCursorResetTick();
        }
        // We want to send in points that are centered around a (0,0) origin, so
        // we cache the position.
        _pointOffsetOrigin = point.offset;

        final TextPosition currentTextPosition = TextPosition(offset: renderEditable.selection!.baseOffset);
        _startCaretRect = renderEditable.getLocalRectForCaret(currentTextPosition);

        _lastBoundedOffset = _startCaretRect!.center - _floatingCursorOffset;
        _lastTextPosition = currentTextPosition;
        renderEditable.setFloatingCursor(point.state, _lastBoundedOffset!, _lastTextPosition!);
        break;
      case FloatingCursorDragState.Update:
        final Offset centeredPoint = point.offset! - _pointOffsetOrigin!;
        final Offset rawCursorOffset = _startCaretRect!.center + centeredPoint - _floatingCursorOffset;

        _lastBoundedOffset = renderEditable.calculateBoundedFloatingCursorOffset(rawCursorOffset);
        _lastTextPosition = renderEditable.getPositionForPoint(renderEditable.localToGlobal(_lastBoundedOffset! + _floatingCursorOffset));
        renderEditable.setFloatingCursor(point.state, _lastBoundedOffset!, _lastTextPosition!);
        break;
      case FloatingCursorDragState.End:
        // We skip animation if no update has happened.
        if (_lastTextPosition != null && _lastBoundedOffset != null) {
          _floatingCursorResetController!.value = 0.0;
          _floatingCursorResetController!.animateTo(1.0, duration: _floatingCursorResetTime, curve: Curves.decelerate);
        }
        break;
    }
  }

  void _onFloatingCursorResetTick() {
    final Offset finalPosition = renderEditable.getLocalRectForCaret(_lastTextPosition!).centerLeft - _floatingCursorOffset;
    if (_floatingCursorResetController!.isCompleted) {
      renderEditable.setFloatingCursor(FloatingCursorDragState.End, finalPosition, _lastTextPosition!);
      if (_lastTextPosition!.offset != renderEditable.selection!.baseOffset)
        // The cause is technically the force cursor, but the cause is listed as tap as the desired functionality is the same.
        _handleSelectionChanged(TextSelection.collapsed(offset: _lastTextPosition!.offset), SelectionChangedCause.forcePress);
      _startCaretRect = null;
      _lastTextPosition = null;
      _pointOffsetOrigin = null;
      _lastBoundedOffset = null;
    } else {
      final double lerpValue = _floatingCursorResetController!.value;
      final double lerpX = ui.lerpDouble(_lastBoundedOffset!.dx, finalPosition.dx, lerpValue)!;
      final double lerpY = ui.lerpDouble(_lastBoundedOffset!.dy, finalPosition.dy, lerpValue)!;

      renderEditable.setFloatingCursor(FloatingCursorDragState.Update, Offset(lerpX, lerpY), _lastTextPosition!, resetLerpValue: lerpValue);
    }
  }

  @pragma('vm:notify-debugger-on-exception')
  void _finalizeEditing(TextInputAction action, {required bool shouldUnfocus}) {
    // Take any actions necessary now that the user has completed editing.
    if (widget.onEditingComplete != null) {
      try {
        widget.onEditingComplete!();
      } catch (exception, stack) {
        FlutterError.reportError(FlutterErrorDetails(
          exception: exception,
          stack: stack,
          library: 'widgets',
          context: ErrorDescription('while calling onEditingComplete for $action'),
        ));
      }
    } else {
      // Default behavior if the developer did not provide an
      // onEditingComplete callback: Finalize editing and remove focus, or move
      // it to the next/previous field, depending on the action.
      widget.controller.clearComposing();
      if (shouldUnfocus) {
        switch (action) {
          case TextInputAction.none:
          case TextInputAction.unspecified:
          case TextInputAction.done:
          case TextInputAction.go:
          case TextInputAction.search:
          case TextInputAction.send:
          case TextInputAction.continueAction:
          case TextInputAction.join:
          case TextInputAction.route:
          case TextInputAction.emergencyCall:
          case TextInputAction.newline:
            widget.focusNode.unfocus();
            break;
          case TextInputAction.next:
            widget.focusNode.nextFocus();
            break;
          case TextInputAction.previous:
            widget.focusNode.previousFocus();
            break;
        }
      }
    }

    final ValueChanged<String>? onSubmitted = widget.onSubmitted;
    if (onSubmitted == null) {
      return;
    }

    // Invoke optional callback with the user's submitted content.
    try {
      onSubmitted(_value.text);
    } catch (exception, stack) {
      FlutterError.reportError(FlutterErrorDetails(
        exception: exception,
        stack: stack,
        library: 'widgets',
        context: ErrorDescription('while calling onSubmitted for $action'),
      ));
    }

    // If `shouldUnfocus` is true, the text field should no longer be focused
    // after the microtask queue is drained. But in case the developer cancelled
    // the focus change in the `onSubmitted` callback by focusing this input
    // field again, reset the soft keyboard.
    // See https://github.com/flutter/flutter/issues/84240.
    //
    // `_restartConnectionIfNeeded` creates a new TextInputConnection to replace
    // the current one. This on iOS switches to a new input view and on Android
    // restarts the input method, and in both cases the soft keyboard will be
    // reset.
    if (shouldUnfocus) {
      _scheduleRestartConnection();
    }
  }

  int _batchEditDepth = 0;

  /// Begins a new batch edit, within which new updates made to the text editing
  /// value will not be sent to the platform text input plugin.
  ///
  /// Batch edits nest. When the outermost batch edit finishes, [endBatchEdit]
  /// will attempt to send [currentTextEditingValue] to the text input plugin if
  /// it detected a change.
  void beginBatchEdit() {
    _batchEditDepth += 1;
  }

  /// Ends the current batch edit started by the last call to [beginBatchEdit],
  /// and send [currentTextEditingValue] to the text input plugin if needed.
  ///
  /// Throws an error in debug mode if this [EditableText] is not in a batch
  /// edit.
  void endBatchEdit() {
    _batchEditDepth -= 1;
    assert(
      _batchEditDepth >= 0,
      'Unbalanced call to endBatchEdit: beginBatchEdit must be called first.',
    );
    _updateRemoteEditingValueIfNeeded();
  }

  void _updateRemoteEditingValueIfNeeded() {
    if (_batchEditDepth > 0 || !_hasInputConnection)
      return;
    final TextEditingValue localValue = _value;
    if (localValue == _lastKnownRemoteTextEditingValue)
      return;
    _textInputConnection!.setEditingState(localValue);
    _lastKnownRemoteTextEditingValue = localValue;
  }

  TextEditingValue get _value => widget.controller.value;
  set _value(TextEditingValue value) {
    widget.controller.value = value;
  }

  bool get _hasFocus => widget.focusNode.hasFocus;
  bool get _isMultiline => widget.maxLines != 1;

  // Finds the closest scroll offset to the current scroll offset that fully
  // reveals the given caret rect. If the given rect's main axis extent is too
  // large to be fully revealed in `renderEditable`, it will be centered along
  // the main axis.
  //
  // If this is a multiline EditableText (which means the Editable can only
  // scroll vertically), the given rect's height will first be extended to match
  // `renderEditable.preferredLineHeight`, before the target scroll offset is
  // calculated.
  RevealedOffset _getOffsetToRevealCaret(Rect rect) {
    if (!_scrollController.position.allowImplicitScrolling)
      return RevealedOffset(offset: _scrollController.offset, rect: rect);

    final Size editableSize = renderEditable.size;
    final double additionalOffset;
    final Offset unitOffset;

    if (!_isMultiline) {
      additionalOffset = rect.width >= editableSize.width
        // Center `rect` if it's oversized.
        ? editableSize.width / 2 - rect.center.dx
        // Valid additional offsets range from (rect.right - size.width)
        // to (rect.left). Pick the closest one if out of range.
        : 0.0.clamp(rect.right - editableSize.width, rect.left);
      unitOffset = const Offset(1, 0);
    } else {
      // The caret is vertically centered within the line. Expand the caret's
      // height so that it spans the line because we're going to ensure that the
      // entire expanded caret is scrolled into view.
      final Rect expandedRect = Rect.fromCenter(
        center: rect.center,
        width: rect.width,
        height: math.max(rect.height, renderEditable.preferredLineHeight),
      );

      additionalOffset = expandedRect.height >= editableSize.height
        ? editableSize.height / 2 - expandedRect.center.dy
        : 0.0.clamp(expandedRect.bottom - editableSize.height, expandedRect.top);
      unitOffset = const Offset(0, 1);
    }

    // No overscrolling when encountering tall fonts/scripts that extend past
    // the ascent.
    final double targetOffset = (additionalOffset + _scrollController.offset)
      .clamp(
        _scrollController.position.minScrollExtent,
        _scrollController.position.maxScrollExtent,
      );

    final double offsetDelta = _scrollController.offset - targetOffset;
    return RevealedOffset(rect: rect.shift(unitOffset * offsetDelta), offset: targetOffset);
  }

  bool get _hasInputConnection => _textInputConnection?.attached ?? false;
  /// Whether to send the autofill information to the autofill service. True by
  /// default.
  bool get _needsAutofill => _effectiveAutofillClient.textInputConfiguration.autofillConfiguration.enabled;

  void _openInputConnection() {
    if (!_shouldCreateInputConnection) {
      return;
    }
    if (!_hasInputConnection) {
      final TextEditingValue localValue = _value;

      // When _needsAutofill == true && currentAutofillScope == null, autofill
      // is allowed but saving the user input from the text field is
      // discouraged.
      //
      // In case the autofillScope changes from a non-null value to null, or
      // _needsAutofill changes to false from true, the platform needs to be
      // notified to exclude this field from the autofill context. So we need to
      // provide the autofillId.
      _textInputConnection = _needsAutofill && currentAutofillScope != null
        ? currentAutofillScope!.attach(this, _effectiveAutofillClient.textInputConfiguration)
        : TextInput.attach(this, _effectiveAutofillClient.textInputConfiguration);
      _updateSizeAndTransform();
      _updateComposingRectIfNeeded();
      _updateCaretRectIfNeeded();
      final TextStyle style = widget.style;
      _textInputConnection!
        ..setStyle(
          fontFamily: style.fontFamily,
          fontSize: style.fontSize,
          fontWeight: style.fontWeight,
          textDirection: _textDirection,
          textAlign: widget.textAlign,
        )
        ..setEditingState(localValue)
        ..show();
      if (_needsAutofill) {
        // Request autofill AFTER the size and the transform have been sent to
        // the platform text input plugin.
        _textInputConnection!.requestAutofill();
      }
      _lastKnownRemoteTextEditingValue = localValue;
    } else {
      _textInputConnection!.show();
    }
  }

  void _closeInputConnectionIfNeeded() {
    if (_hasInputConnection) {
      _textInputConnection!.close();
      _textInputConnection = null;
      _lastKnownRemoteTextEditingValue = null;
    }
  }

  void _openOrCloseInputConnectionIfNeeded() {
    if (_hasFocus && widget.focusNode.consumeKeyboardToken()) {
      _openInputConnection();
    } else if (!_hasFocus) {
      _closeInputConnectionIfNeeded();
      widget.controller.clearComposing();
    }
  }

  bool _restartConnectionScheduled = false;
  void _scheduleRestartConnection() {
    if (_restartConnectionScheduled) {
      return;
    }
    _restartConnectionScheduled = true;
    scheduleMicrotask(_restartConnectionIfNeeded);
  }
  // Discards the current [TextInputConnection] and establishes a new one.
  //
  // This method is rarely needed. This is currently used to reset the input
  // type when the "submit" text input action is triggered and the developer
  // puts the focus back to this input field..
  void _restartConnectionIfNeeded() {
    _restartConnectionScheduled = false;
    if (!_hasInputConnection || !_shouldCreateInputConnection) {
      return;
    }
    _textInputConnection!.close();
    _textInputConnection = null;
    _lastKnownRemoteTextEditingValue = null;

    final AutofillScope? currentAutofillScope = _needsAutofill ? this.currentAutofillScope : null;
    final TextInputConnection newConnection = currentAutofillScope?.attach(this, textInputConfiguration)
      ?? TextInput.attach(this, _effectiveAutofillClient.textInputConfiguration);
    _textInputConnection = newConnection;

    final TextStyle style = widget.style;
    newConnection
      ..show()
      ..setStyle(
        fontFamily: style.fontFamily,
        fontSize: style.fontSize,
        fontWeight: style.fontWeight,
        textDirection: _textDirection,
        textAlign: widget.textAlign,
      )
      ..setEditingState(_value);
    _lastKnownRemoteTextEditingValue = _value;
  }


  @override
  void connectionClosed() {
    if (_hasInputConnection) {
      _textInputConnection!.connectionClosedReceived();
      _textInputConnection = null;
      _lastKnownRemoteTextEditingValue = null;
      _finalizeEditing(TextInputAction.done, shouldUnfocus: true);
    }
  }

  /// Express interest in interacting with the keyboard.
  ///
  /// If this control is already attached to the keyboard, this function will
  /// request that the keyboard become visible. Otherwise, this function will
  /// ask the focus system that it become focused. If successful in acquiring
  /// focus, the control will then attach to the keyboard and request that the
  /// keyboard become visible.
  void requestKeyboard() {
    if (_hasFocus) {
      _openInputConnection();
    } else {
      widget.focusNode.requestFocus(); // This eventually calls _openInputConnection also, see _handleFocusChanged.
    }
  }

  void _updateOrDisposeSelectionOverlayIfNeeded() {
    if (_selectionOverlay != null) {
      if (_hasFocus) {
        _selectionOverlay!.update(_value);
      } else {
        _selectionOverlay!.dispose();
        _selectionOverlay = null;
      }
    }
  }

  void _updateSelectionOverlayForScroll() {
    _selectionOverlay?.updateForScroll();
  }

  @pragma('vm:notify-debugger-on-exception')
  void _handleSelectionChanged(TextSelection selection, SelectionChangedCause? cause) {
    // We return early if the selection is not valid. This can happen when the
    // text of [EditableText] is updated at the same time as the selection is
    // changed by a gesture event.
    if (!widget.controller.isSelectionWithinTextBounds(selection))
      return;

    widget.controller.selection = selection;

    // This will show the keyboard for all selection changes on the
    // EditableText except for those triggered by a keyboard input.
    // Typically EditableText shouldn't take user keyboard input if
    // it's not focused already. If the EditableText is being
    // autofilled it shouldn't request focus.
    switch (cause) {
      case null:
      case SelectionChangedCause.doubleTap:
      case SelectionChangedCause.drag:
      case SelectionChangedCause.forcePress:
      case SelectionChangedCause.longPress:
      case SelectionChangedCause.scribble:
      case SelectionChangedCause.tap:
      case SelectionChangedCause.toolbar:
        requestKeyboard();
        break;
      case SelectionChangedCause.keyboard:
        if (_hasFocus) {
          requestKeyboard();
        }
        break;
    }
    if (widget.selectionControls == null) {
      _selectionOverlay?.dispose();
      _selectionOverlay = null;
    } else {
      if (_selectionOverlay == null) {
        _selectionOverlay = TextSelectionOverlay(
          clipboardStatus: _clipboardStatus,
          context: context,
          value: _value,
          debugRequiredFor: widget,
          toolbarLayerLink: _toolbarLayerLink,
          startHandleLayerLink: _startHandleLayerLink,
          endHandleLayerLink: _endHandleLayerLink,
          renderObject: renderEditable,
          selectionControls: widget.selectionControls,
          selectionDelegate: this,
          dragStartBehavior: widget.dragStartBehavior,
          onSelectionHandleTapped: widget.onSelectionHandleTapped,
        );
      } else {
        _selectionOverlay!.update(_value);
      }
      _selectionOverlay!.handlesVisible = widget.showSelectionHandles;
      _selectionOverlay!.showHandles();
    }
    // TODO(chunhtai): we should make sure selection actually changed before
    // we call the onSelectionChanged.
    // https://github.com/flutter/flutter/issues/76349.
    try {
      widget.onSelectionChanged?.call(selection, cause);
    } catch (exception, stack) {
      FlutterError.reportError(FlutterErrorDetails(
        exception: exception,
        stack: stack,
        library: 'widgets',
        context: ErrorDescription('while calling onSelectionChanged for $cause'),
      ));
    }

    // To keep the cursor from blinking while it moves, restart the timer here.
    if (_cursorTimer != null) {
      _stopCursorTimer(resetCharTicks: false);
      _startCursorTimer();
    }
  }

  Rect? _currentCaretRect;
  // ignore: use_setters_to_change_properties, (this is used as a callback, can't be a setter)
  void _handleCaretChanged(Rect caretRect) {
    _currentCaretRect = caretRect;
  }

  // Animation configuration for scrolling the caret back on screen.
  static const Duration _caretAnimationDuration = Duration(milliseconds: 100);
  static const Curve _caretAnimationCurve = Curves.fastOutSlowIn;

  bool _showCaretOnScreenScheduled = false;

  void _scheduleShowCaretOnScreen({required bool withAnimation}) {
    if (_showCaretOnScreenScheduled) {
      return;
    }
    _showCaretOnScreenScheduled = true;
    SchedulerBinding.instance.addPostFrameCallback((Duration _) {
      _showCaretOnScreenScheduled = false;
      if (_currentCaretRect == null || !_scrollController.hasClients) {
        return;
      }

      final double lineHeight = renderEditable.preferredLineHeight;

      // Enlarge the target rect by scrollPadding to ensure that caret is not
      // positioned directly at the edge after scrolling.
      double bottomSpacing = widget.scrollPadding.bottom;
      if (_selectionOverlay?.selectionControls != null) {
        final double handleHeight = _selectionOverlay!.selectionControls!
          .getHandleSize(lineHeight).height;
        final double interactiveHandleHeight = math.max(
          handleHeight,
          kMinInteractiveDimension,
        );
        final Offset anchor = _selectionOverlay!.selectionControls!
          .getHandleAnchor(
            TextSelectionHandleType.collapsed,
            lineHeight,
          );
        final double handleCenter = handleHeight / 2 - anchor.dy;
        bottomSpacing = math.max(
          handleCenter + interactiveHandleHeight / 2,
          bottomSpacing,
        );
      }

      final EdgeInsets caretPadding = widget.scrollPadding
        .copyWith(bottom: bottomSpacing);

      final RevealedOffset targetOffset = _getOffsetToRevealCaret(_currentCaretRect!);

      if (withAnimation) {
        _scrollController.animateTo(
          targetOffset.offset,
          duration: _caretAnimationDuration,
          curve: _caretAnimationCurve,
        );
        renderEditable.showOnScreen(
          rect: caretPadding.inflateRect(targetOffset.rect),
          duration: _caretAnimationDuration,
          curve: _caretAnimationCurve,
        );
      } else {
        _scrollController.jumpTo(targetOffset.offset);
        renderEditable.showOnScreen(
          rect: caretPadding.inflateRect(targetOffset.rect),
        );
      }
    });
  }

  late double _lastBottomViewInset;

  @override
  void didChangeMetrics() {
    if (_lastBottomViewInset != WidgetsBinding.instance.window.viewInsets.bottom) {
      SchedulerBinding.instance.addPostFrameCallback((Duration _) {
        _selectionOverlay?.updateForScroll();
      });
      if (_lastBottomViewInset < WidgetsBinding.instance.window.viewInsets.bottom) {
        // Because the metrics change signal from engine will come here every frame
        // (on both iOS and Android). So we don't need to show caret with animation.
        _scheduleShowCaretOnScreen(withAnimation: false);
      }
    }
    _lastBottomViewInset = WidgetsBinding.instance.window.viewInsets.bottom;
  }

  @pragma('vm:notify-debugger-on-exception')
  void _formatAndSetValue(TextEditingValue value, SelectionChangedCause? cause, {bool userInteraction = false}) {
    // Only apply input formatters if the text has changed (including uncommitted
    // text in the composing region), or when the user committed the composing
    // text.
    // Gboard is very persistent in restoring the composing region. Applying
    // input formatters on composing-region-only changes (except clearing the
    // current composing region) is very infinite-loop-prone: the formatters
    // will keep trying to modify the composing region while Gboard will keep
    // trying to restore the original composing region.
    final bool textChanged = _value.text != value.text
                          || (!_value.composing.isCollapsed && value.composing.isCollapsed);
    final bool selectionChanged = _value.selection != value.selection;

    if (textChanged) {
      try {
        value = widget.inputFormatters?.fold<TextEditingValue>(
          value,
          (TextEditingValue newValue, TextInputFormatter formatter) => formatter.formatEditUpdate(_value, newValue),
        ) ?? value;
      } catch (exception, stack) {
        FlutterError.reportError(FlutterErrorDetails(
          exception: exception,
          stack: stack,
          library: 'widgets',
          context: ErrorDescription('while applying input formatters'),
        ));
      }
    }

    // Put all optional user callback invocations in a batch edit to prevent
    // sending multiple `TextInput.updateEditingValue` messages.
    beginBatchEdit();
    _value = value;
    // Changes made by the keyboard can sometimes be "out of band" for listening
    // components, so always send those events, even if we didn't think it
    // changed. Also, the user long pressing should always send a selection change
    // as well.
    if (selectionChanged ||
        (userInteraction &&
        (cause == SelectionChangedCause.longPress ||
         cause == SelectionChangedCause.keyboard))) {
      _handleSelectionChanged(_value.selection, cause);
    }
    if (textChanged) {
      try {
        widget.onChanged?.call(_value.text);
      } catch (exception, stack) {
        FlutterError.reportError(FlutterErrorDetails(
          exception: exception,
          stack: stack,
          library: 'widgets',
          context: ErrorDescription('while calling onChanged'),
        ));
      }
    }

    endBatchEdit();
  }

  void _onCursorColorTick() {
    renderEditable.cursorColor = widget.cursorColor.withOpacity(_cursorBlinkOpacityController!.value);
    _cursorVisibilityNotifier.value = widget.showCursor && _cursorBlinkOpacityController!.value > 0;
  }

  /// Whether the blinking cursor is actually visible at this precise moment
  /// (it's hidden half the time, since it blinks).
  @visibleForTesting
  bool get cursorCurrentlyVisible => _cursorBlinkOpacityController!.value > 0;

  /// The cursor blink interval (the amount of time the cursor is in the "on"
  /// state or the "off" state). A complete cursor blink period is twice this
  /// value (half on, half off).
  @visibleForTesting
  Duration get cursorBlinkInterval => _kCursorBlinkHalfPeriod;

  /// The current status of the text selection handles.
  @visibleForTesting
  TextSelectionOverlay? get selectionOverlay => _selectionOverlay;

  int _obscureShowCharTicksPending = 0;
  int? _obscureLatestCharIndex;

  void _cursorTick(Timer timer) {
    _targetCursorVisibility = !_targetCursorVisibility;
    final double targetOpacity = _targetCursorVisibility ? 1.0 : 0.0;
    if (widget.cursorOpacityAnimates) {
      // If we want to show the cursor, we will animate the opacity to the value
      // of 1.0, and likewise if we want to make it disappear, to 0.0. An easing
      // curve is used for the animation to mimic the aesthetics of the native
      // iOS cursor.
      //
      // These values and curves have been obtained through eyeballing, so are
      // likely not exactly the same as the values for native iOS.
      _cursorBlinkOpacityController!.animateTo(targetOpacity, curve: Curves.easeOut);
    } else {
      _cursorBlinkOpacityController!.value = targetOpacity;
    }

    if (_obscureShowCharTicksPending > 0) {
      setState(() {
        _obscureShowCharTicksPending = WidgetsBinding.instance.platformDispatcher.brieflyShowPassword
          ? _obscureShowCharTicksPending - 1
          : 0;
      });
    }
  }

  void _cursorWaitForStart(Timer timer) {
    assert(_kCursorBlinkHalfPeriod > _fadeDuration);
    assert(!EditableText.debugDeterministicCursor);
    _cursorTimer?.cancel();
    _cursorTimer = Timer.periodic(_kCursorBlinkHalfPeriod, _cursorTick);
  }

  // Indicates whether the cursor should be blinking right now (but it may
  // actually not blink because it's disabled via TickerMode.of(context)).
  bool _cursorActive = false;

  void _startCursorTimer() {
    assert(_cursorTimer == null);
    _cursorActive = true;
    if (!_tickersEnabled) {
      return;
    }
    _targetCursorVisibility = true;
    _cursorBlinkOpacityController!.value = 1.0;
    if (EditableText.debugDeterministicCursor)
      return;
    if (widget.cursorOpacityAnimates) {
      _cursorTimer = Timer.periodic(_kCursorBlinkWaitForStart, _cursorWaitForStart);
    } else {
      _cursorTimer = Timer.periodic(_kCursorBlinkHalfPeriod, _cursorTick);
    }
  }

  void _stopCursorTimer({ bool resetCharTicks = true }) {
    _cursorActive = false;
    _cursorTimer?.cancel();
    _cursorTimer = null;
    _targetCursorVisibility = false;
    _cursorBlinkOpacityController!.value = 0.0;
    if (EditableText.debugDeterministicCursor)
      return;
    if (resetCharTicks)
      _obscureShowCharTicksPending = 0;
    if (widget.cursorOpacityAnimates) {
      _cursorBlinkOpacityController!.stop();
      _cursorBlinkOpacityController!.value = 0.0;
    }
  }

  void _startOrStopCursorTimerIfNeeded() {
    if (_cursorTimer == null && _hasFocus && _value.selection.isCollapsed)
      _startCursorTimer();
    else if (_cursorActive && (!_hasFocus || !_value.selection.isCollapsed))
      _stopCursorTimer();
  }

  void _didChangeTextEditingValue() {
    _updateRemoteEditingValueIfNeeded();
    _startOrStopCursorTimerIfNeeded();
    _updateOrDisposeSelectionOverlayIfNeeded();
    // TODO(abarth): Teach RenderEditable about ValueNotifier<TextEditingValue>
    // to avoid this setState().
    setState(() { /* We use widget.controller.value in build(). */ });
    _adjacentLineAction.stopCurrentVerticalRunIfSelectionChanges();
  }

  void _handleFocusChanged() {
    _openOrCloseInputConnectionIfNeeded();
    _startOrStopCursorTimerIfNeeded();
    _updateOrDisposeSelectionOverlayIfNeeded();
    if (_hasFocus) {
      // Listen for changing viewInsets, which indicates keyboard showing up.
      WidgetsBinding.instance.addObserver(this);
      _lastBottomViewInset = WidgetsBinding.instance.window.viewInsets.bottom;
      if (!widget.readOnly) {
        _scheduleShowCaretOnScreen(withAnimation: true);
      }
      if (!_value.selection.isValid) {
        // Place cursor at the end if the selection is invalid when we receive focus.
        _handleSelectionChanged(TextSelection.collapsed(offset: _value.text.length), null);
      }

      _cachedText = '';
      _cachedFirstRect = null;
      _cachedSize = Size.zero;
      _cachedPlaceholder = -1;
    } else {
      WidgetsBinding.instance.removeObserver(this);
      setState(() { _currentPromptRectRange = null; });
    }
    updateKeepAlive();
  }

  String _cachedText = '';
  Rect? _cachedFirstRect;
  Size _cachedSize = Size.zero;
  int _cachedPlaceholder = -1;
  TextStyle? _cachedTextStyle;

  void _updateSelectionRects({bool force = false}) {
    if (!widget.scribbleEnabled)
      return;
    if (defaultTargetPlatform != TargetPlatform.iOS)
      return;
    // This is to avoid sending selection rects on non-iPad devices.
    if (WidgetsBinding.instance.window.physicalSize.shortestSide < _kIPadWidth)
      return;

    final String text = renderEditable.text?.toPlainText(includeSemanticsLabels: false) ?? '';
    final List<Rect> firstSelectionBoxes = renderEditable.getBoxesForSelection(const TextSelection(baseOffset: 0, extentOffset: 1));
    final Rect? firstRect = firstSelectionBoxes.isNotEmpty ? firstSelectionBoxes.first : null;
    final ScrollDirection scrollDirection = _scrollController.position.userScrollDirection;
    final Size size = renderEditable.size;
    final bool textChanged = text != _cachedText;
    final bool textStyleChanged = _cachedTextStyle != widget.style;
    final bool firstRectChanged = _cachedFirstRect != firstRect;
    final bool sizeChanged = _cachedSize != size;
    final bool placeholderChanged = _cachedPlaceholder != _placeholderLocation;
    if (scrollDirection == ScrollDirection.idle && (force || textChanged || textStyleChanged || firstRectChanged || sizeChanged || placeholderChanged)) {
      _cachedText = text;
      _cachedFirstRect = firstRect;
      _cachedTextStyle = widget.style;
      _cachedSize = size;
      _cachedPlaceholder = _placeholderLocation;
      bool belowRenderEditableBottom = false;
      final List<SelectionRect> rects = List<SelectionRect?>.generate(
        _cachedText.characters.length,
        (int i) {
          if (belowRenderEditableBottom)
            return null;

          final int offset = _cachedText.characters.getRange(0, i).string.length;
          final List<Rect> boxes = renderEditable.getBoxesForSelection(TextSelection(baseOffset: offset, extentOffset: offset + _cachedText.characters.characterAt(i).string.length));
          if (boxes.isEmpty)
            return null;

          final SelectionRect selectionRect = SelectionRect(
            bounds: boxes.first,
            position: offset,
          );
          if (renderEditable.paintBounds.bottom < selectionRect.bounds.top) {
            belowRenderEditableBottom = true;
            return null;
          }
          return selectionRect;
        },
      ).where((SelectionRect? selectionRect) {
        if (selectionRect == null)
          return false;
        if (renderEditable.paintBounds.right < selectionRect.bounds.left || selectionRect.bounds.right < renderEditable.paintBounds.left)
          return false;
        if (renderEditable.paintBounds.bottom < selectionRect.bounds.top || selectionRect.bounds.bottom < renderEditable.paintBounds.top)
          return false;
        return true;
      }).map<SelectionRect>((SelectionRect? selectionRect) => selectionRect!).toList();
      _textInputConnection!.setSelectionRects(rects);
    }
  }

  void _updateSizeAndTransform() {
    if (_hasInputConnection) {
      final Size size = renderEditable.size;
      final Matrix4 transform = renderEditable.getTransformTo(null);
      _textInputConnection!.setEditableSizeAndTransform(size, transform);
      _updateSelectionRects();
      SchedulerBinding.instance.addPostFrameCallback((Duration _) => _updateSizeAndTransform());
    } else if (_placeholderLocation != -1) {
      removeTextPlaceholder();
    }
  }

  // Sends the current composing rect to the iOS text input plugin via the text
  // input channel. We need to keep sending the information even if no text is
  // currently marked, as the information usually lags behind. The text input
  // plugin needs to estimate the composing rect based on the latest caret rect,
  // when the composing rect info didn't arrive in time.
  void _updateComposingRectIfNeeded() {
    final TextRange composingRange = _value.composing;
    if (_hasInputConnection) {
      assert(mounted);
      Rect? composingRect = renderEditable.getRectForComposingRange(composingRange);
      // Send the caret location instead if there's no marked text yet.
      if (composingRect == null) {
        assert(!composingRange.isValid || composingRange.isCollapsed);
        final int offset = composingRange.isValid ? composingRange.start : 0;
        composingRect = renderEditable.getLocalRectForCaret(TextPosition(offset: offset));
      }
      assert(composingRect != null);
      _textInputConnection!.setComposingRect(composingRect);
      SchedulerBinding.instance.addPostFrameCallback((Duration _) => _updateComposingRectIfNeeded());
    }
  }

  void _updateCaretRectIfNeeded() {
    if (_hasInputConnection) {
      if (renderEditable.selection != null && renderEditable.selection!.isValid &&
          renderEditable.selection!.isCollapsed) {
        final TextPosition currentTextPosition = TextPosition(offset: renderEditable.selection!.baseOffset);
        final Rect caretRect = renderEditable.getLocalRectForCaret(currentTextPosition);
        _textInputConnection!.setCaretRect(caretRect);
      }
      SchedulerBinding.instance.addPostFrameCallback((Duration _) => _updateCaretRectIfNeeded());
    }
  }

  TextDirection get _textDirection {
    final TextDirection result = widget.textDirection ?? Directionality.of(context);
    assert(result != null, '$runtimeType created without a textDirection and with no ambient Directionality.');
    return result;
  }

  /// The renderer for this widget's descendant.
  ///
  /// This property is typically used to notify the renderer of input gestures
  /// when [RenderEditable.ignorePointer] is true.
  RenderEditable get renderEditable => _editableKey.currentContext!.findRenderObject()! as RenderEditable;

  @override
  TextEditingValue get textEditingValue => _value;

  double get _devicePixelRatio => MediaQuery.of(context).devicePixelRatio;

  @override
  void userUpdateTextEditingValue(TextEditingValue value, SelectionChangedCause? cause) {
    // Compare the current TextEditingValue with the pre-format new
    // TextEditingValue value, in case the formatter would reject the change.
    final bool shouldShowCaret = widget.readOnly
      ? _value.selection != value.selection
      : _value != value;
    if (shouldShowCaret) {
      _scheduleShowCaretOnScreen(withAnimation: true);
    }
    _formatAndSetValue(value, cause, userInteraction: true);
  }

  @override
  void bringIntoView(TextPosition position) {
    final Rect localRect = renderEditable.getLocalRectForCaret(position);
    final RevealedOffset targetOffset = _getOffsetToRevealCaret(localRect);

    _scrollController.jumpTo(targetOffset.offset);
    renderEditable.showOnScreen(rect: targetOffset.rect);
  }

  /// Shows the selection toolbar at the location of the current cursor.
  ///
  /// Returns `false` if a toolbar couldn't be shown, such as when the toolbar
  /// is already shown, or when no text selection currently exists.
  @override
  bool showToolbar() {
    // Web is using native dom elements to enable clipboard functionality of the
    // toolbar: copy, paste, select, cut. It might also provide additional
    // functionality depending on the browser (such as translate). Due to this
    // we should not show a Flutter toolbar for the editable text elements.
    if (kIsWeb) {
      return false;
    }

    if (_selectionOverlay == null || _selectionOverlay!.toolbarIsVisible) {
      return false;
    }
    _clipboardStatus?.update();
    _selectionOverlay!.showToolbar();
    return true;
  }

  @override
  void hideToolbar([bool hideHandles = true]) {
    if (hideHandles) {
      // Hide the handles and the toolbar.
      _selectionOverlay?.hide();
    } else if (_selectionOverlay?.toolbarIsVisible ?? false) {
      // Hide only the toolbar but not the handles.
      _selectionOverlay?.hideToolbar();
    }
  }

  /// Toggles the visibility of the toolbar.
  void toggleToolbar() {
    assert(_selectionOverlay != null);
    if (_selectionOverlay!.toolbarIsVisible) {
      hideToolbar();
    } else {
      showToolbar();
    }
  }

  // Tracks the location a [_ScribblePlaceholder] should be rendered in the
  // text.
  //
  // A value of -1 indicates there should be no placeholder, otherwise the
  // value should be between 0 and the length of the text, inclusive.
  int _placeholderLocation = -1;

  @override
  void insertTextPlaceholder(Size size) {
    if (!widget.scribbleEnabled)
      return;

    if (!widget.controller.selection.isValid)
      return;

    setState(() {
      _placeholderLocation = _value.text.length - widget.controller.selection.end;
    });
  }

  @override
  void removeTextPlaceholder() {
    if (!widget.scribbleEnabled)
      return;

    setState(() {
      _placeholderLocation = -1;
    });
  }

  @override
  String get autofillId => 'EditableText-$hashCode';

  @override
  TextInputConfiguration get textInputConfiguration {
    final List<String>? autofillHints = widget.autofillHints?.toList(growable: false);
    final AutofillConfiguration autofillConfiguration = autofillHints != null
      ? AutofillConfiguration(
          uniqueIdentifier: autofillId,
          autofillHints: autofillHints,
          currentEditingValue: currentTextEditingValue,
        )
      : AutofillConfiguration.disabled;

    return TextInputConfiguration(
      inputType: widget.keyboardType,
      readOnly: widget.readOnly,
      obscureText: widget.obscureText,
      autocorrect: widget.autocorrect,
      smartDashesType: widget.smartDashesType,
      smartQuotesType: widget.smartQuotesType,
      enableSuggestions: widget.enableSuggestions,
      enableInteractiveSelection: widget._userSelectionEnabled,
      inputAction: widget.textInputAction ?? (widget.keyboardType == TextInputType.multiline
        ? TextInputAction.newline
        : TextInputAction.done
      ),
      textCapitalization: widget.textCapitalization,
      keyboardAppearance: widget.keyboardAppearance,
      autofillConfiguration: autofillConfiguration,
      enableIMEPersonalizedLearning: widget.enableIMEPersonalizedLearning,
    );
  }

  @override
  void autofill(TextEditingValue value) => updateEditingValue(value);

  // null if no promptRect should be shown.
  TextRange? _currentPromptRectRange;

  @override
  void showAutocorrectionPromptRect(int start, int end) {
    setState(() {
      _currentPromptRectRange = TextRange(start: start, end: end);
    });
  }

  VoidCallback? _semanticsOnCopy(TextSelectionControls? controls) {
    return widget.selectionEnabled
        && copyEnabled
        && _hasFocus
        && (controls?.canCopy(this) ?? false)
      ? () => controls!.handleCopy(this)
      : null;
  }

  VoidCallback? _semanticsOnCut(TextSelectionControls? controls) {
    return widget.selectionEnabled
        && cutEnabled
        && _hasFocus
        && (controls?.canCut(this) ?? false)
      ? () => controls!.handleCut(this)
      : null;
  }

  VoidCallback? _semanticsOnPaste(TextSelectionControls? controls) {
    return widget.selectionEnabled
        && pasteEnabled
        && _hasFocus
        && (controls?.canPaste(this) ?? false)
        && (_clipboardStatus == null || _clipboardStatus!.value == ClipboardStatus.pasteable)
      ? () => controls!.handlePaste(this)
      : null;
  }


  // --------------------------- Text Editing Actions ---------------------------

  _TextBoundary _characterBoundary(DirectionalTextEditingIntent intent) {
    final _TextBoundary atomicTextBoundary = widget.obscureText ? _CodeUnitBoundary(_value) : _CharacterBoundary(_value);
    return _CollapsedSelectionBoundary(atomicTextBoundary, intent.forward);
  }

  _TextBoundary _nextWordBoundary(DirectionalTextEditingIntent intent) {
    final _TextBoundary atomicTextBoundary;
    final _TextBoundary boundary;

    if (widget.obscureText) {
      atomicTextBoundary = _CodeUnitBoundary(_value);
      boundary = _DocumentBoundary(_value);
    } else {
      final TextEditingValue textEditingValue = _textEditingValueforTextLayoutMetrics;
      atomicTextBoundary = _CharacterBoundary(textEditingValue);
      // This isn't enough. Newline characters.
      boundary = _ExpandedTextBoundary(_WhitespaceBoundary(textEditingValue), _WordBoundary(renderEditable, textEditingValue));
    }

    final _MixedBoundary mixedBoundary = intent.forward
      ? _MixedBoundary(atomicTextBoundary, boundary)
      : _MixedBoundary(boundary, atomicTextBoundary);
    // Use a _MixedBoundary to make sure we don't leave invalid c