// 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.

/// @docImport 'package:flutter/widgets.dart';
library;

import 'package:flutter/foundation.dart';

import 'constants.dart';
import 'events.dart';
import 'gesture_details.dart';
import 'recognizer.dart';
import 'velocity_tracker.dart';

export 'dart:ui' show Offset, PointerDeviceKind;

export 'arena.dart' show GestureDisposition;
export 'events.dart' show PointerDownEvent, PointerEvent;
export 'velocity_tracker.dart' show Velocity;

/// Callback signature for [LongPressGestureRecognizer.onLongPressDown].
///
/// Called when a pointer that might cause a long-press has contacted the
/// screen. The position at which the pointer contacted the screen is available
/// in the `details`.
///
/// See also:
///
///  * [GestureDetector.onLongPressDown], which matches this signature.
///  * [GestureLongPressStartCallback], the signature that gets called when the
///    pointer has been in contact with the screen long enough to be considered
///    a long-press.
typedef GestureLongPressDownCallback = void Function(LongPressDownDetails details);

/// Callback signature for [LongPressGestureRecognizer.onLongPressCancel].
///
/// Called when the pointer that previously triggered a
/// [GestureLongPressDownCallback] will not end up causing a long-press.
///
/// See also:
///
///  * [GestureDetector.onLongPressCancel], which matches this signature.
typedef GestureLongPressCancelCallback = void Function();

/// Callback signature for [LongPressGestureRecognizer.onLongPress].
///
/// Called when a pointer has remained in contact with the screen at the
/// same location for a long period of time.
///
/// See also:
///
///  * [GestureDetector.onLongPress], which matches this signature.
///  * [GestureLongPressStartCallback], which is the same signature but with
///    details of where the long press occurred.
typedef GestureLongPressCallback = void Function();

/// Callback signature for [LongPressGestureRecognizer.onLongPressUp].
///
/// Called when a pointer stops contacting the screen after a long press
/// gesture was detected.
///
/// See also:
///
///  * [GestureDetector.onLongPressUp], which matches this signature.
typedef GestureLongPressUpCallback = void Function();

/// Callback signature for [LongPressGestureRecognizer.onLongPressStart].
///
/// Called when a pointer has remained in contact with the screen at the
/// same location for a long period of time. Also reports the long press down
/// position.
///
/// See also:
///
///  * [GestureDetector.onLongPressStart], which matches this signature.
///  * [GestureLongPressCallback], which is the same signature without the
///    details.
typedef GestureLongPressStartCallback = void Function(LongPressStartDetails details);

/// Callback signature for [LongPressGestureRecognizer.onLongPressMoveUpdate].
///
/// Called when a pointer is moving after being held in contact at the same
/// location for a long period of time. Reports the new position and its offset
/// from the original down position.
///
/// See also:
///
///  * [GestureDetector.onLongPressMoveUpdate], which matches this signature.
typedef GestureLongPressMoveUpdateCallback = void Function(LongPressMoveUpdateDetails details);

/// Callback signature for [LongPressGestureRecognizer.onLongPressEnd].
///
/// Called when a pointer stops contacting the screen after a long press
/// gesture was detected. Also reports the position where the pointer stopped
/// contacting the screen.
///
/// See also:
///
///  * [GestureDetector.onLongPressEnd], which matches this signature.
typedef GestureLongPressEndCallback = void Function(LongPressEndDetails details);

/// Details for callbacks that use [GestureLongPressDownCallback].
///
/// See also:
///
///  * [LongPressGestureRecognizer.onLongPressDown], whose callback passes
///    these details.
///  * [LongPressGestureRecognizer.onSecondaryLongPressDown], whose callback
///    passes these details.
///  * [LongPressGestureRecognizer.onTertiaryLongPressDown], whose callback
///    passes these details.
class LongPressDownDetails with Diagnosticable implements PositionedGestureDetails {
  /// Creates the details for a [GestureLongPressDownCallback].
  ///
  /// If the `localPosition` argument is not specified, it will default to the
  /// global position.
  const LongPressDownDetails({this.globalPosition = Offset.zero, Offset? localPosition, this.kind})
    : localPosition = localPosition ?? globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.globalPosition}
  @override
  final Offset globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.localPosition}
  @override
  final Offset localPosition;

  /// The kind of the device that initiated the event.
  final PointerDeviceKind? kind;

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<Offset>('globalPosition', globalPosition));
    properties.add(DiagnosticsProperty<Offset>('localPosition', localPosition));
    properties.add(EnumProperty<PointerDeviceKind?>('kind', kind));
  }
}

/// Details for callbacks that use [GestureLongPressStartCallback].
///
/// See also:
///
///  * [LongPressGestureRecognizer.onLongPressStart], which uses [GestureLongPressStartCallback].
///  * [LongPressMoveUpdateDetails], the details for [GestureLongPressMoveUpdateCallback]
///  * [LongPressEndDetails], the details for [GestureLongPressEndCallback].
class LongPressStartDetails with Diagnosticable implements PositionedGestureDetails {
  /// Creates the details for a [GestureLongPressStartCallback].
  const LongPressStartDetails({this.globalPosition = Offset.zero, Offset? localPosition})
    : localPosition = localPosition ?? globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.globalPosition}
  @override
  final Offset globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.localPosition}
  @override
  final Offset localPosition;

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<Offset>('globalPosition', globalPosition));
    properties.add(DiagnosticsProperty<Offset>('localPosition', localPosition));
  }
}

/// Details for callbacks that use [GestureLongPressMoveUpdateCallback].
///
/// See also:
///
///  * [LongPressGestureRecognizer.onLongPressMoveUpdate], which uses [GestureLongPressMoveUpdateCallback].
///  * [LongPressEndDetails], the details for [GestureLongPressEndCallback]
///  * [LongPressStartDetails], the details for [GestureLongPressStartCallback].
class LongPressMoveUpdateDetails with Diagnosticable implements PositionedGestureDetails {
  /// Creates the details for a [GestureLongPressMoveUpdateCallback].
  const LongPressMoveUpdateDetails({
    this.globalPosition = Offset.zero,
    Offset? localPosition,
    this.offsetFromOrigin = Offset.zero,
    Offset? localOffsetFromOrigin,
  }) : localPosition = localPosition ?? globalPosition,
       localOffsetFromOrigin = localOffsetFromOrigin ?? offsetFromOrigin;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.globalPosition}
  @override
  final Offset globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.localPosition}
  @override
  final Offset localPosition;

  /// A delta offset from the point where the long press drag initially contacted
  /// the screen to the point where the pointer is currently located (the
  /// present [globalPosition]) when this callback is triggered.
  final Offset offsetFromOrigin;

  /// A local delta offset from the point where the long press drag initially contacted
  /// the screen to the point where the pointer is currently located (the
  /// present [localPosition]) when this callback is triggered.
  final Offset localOffsetFromOrigin;

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<Offset>('globalPosition', globalPosition));
    properties.add(DiagnosticsProperty<Offset>('localPosition', localPosition));
    properties.add(DiagnosticsProperty<Offset>('offsetFromOrigin', offsetFromOrigin));
    properties.add(DiagnosticsProperty<Offset>('localOffsetFromOrigin', localOffsetFromOrigin));
  }
}

/// Details for callbacks that use [GestureLongPressEndCallback].
///
/// See also:
///
///  * [LongPressGestureRecognizer.onLongPressEnd], which uses [GestureLongPressEndCallback].
///  * [LongPressMoveUpdateDetails], the details for [GestureLongPressMoveUpdateCallback].
///  * [LongPressStartDetails], the details for [GestureLongPressStartCallback].
class LongPressEndDetails with Diagnosticable implements PositionedGestureDetails {
  /// Creates the details for a [GestureLongPressEndCallback].
  const LongPressEndDetails({
    this.globalPosition = Offset.zero,
    Offset? localPosition,
    this.velocity = Velocity.zero,
  }) : localPosition = localPosition ?? globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.globalPosition}
  @override
  final Offset globalPosition;

  /// {@macro flutter.gestures.gesturedetails.PositionedGestureDetails.localPosition}
  @override
  final Offset localPosition;

  /// The pointer's velocity when it stopped contacting the screen.
  ///
  /// Defaults to zero if not specified in the constructor.
  final Velocity velocity;

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties.add(DiagnosticsProperty<Offset>('globalPosition', globalPosition));
    properties.add(DiagnosticsProperty<Offset>('localPosition', localPosition));
    properties.add(DiagnosticsProperty<Velocity>('velocity', velocity));
  }
}

/// Recognizes when the user has pressed down at the same location for a long
/// period of time.
///
/// The gesture must not deviate in position from its touch down point for 500ms
/// until it's recognized. Once the gesture is accepted, the finger can be
/// moved, triggering [onLongPressMoveUpdate] callbacks, unless the
/// [postAcceptSlopTolerance] constructor argument is specified.
///
/// [LongPressGestureRecognizer] may compete on pointer events of
/// [kPrimaryButton], [kSecondaryButton], and/or [kTertiaryButton] if at least
/// one corresponding callback is non-null. If it has no callbacks, it is a no-op.
class LongPressGestureRecognizer extends PrimaryPointerGestureRecognizer {
  /// Creates a long-press gesture recognizer.
  ///
  /// Consider assigning the [onLongPressStart] callback after creating this
  /// object.
  ///
  /// The [postAcceptSlopTolerance] argument can be used to specify a maximum
  /// allowed distance for the gesture to deviate from the starting point once
  /// the long press has triggered. If the gesture deviates past that point,
  /// subsequent callbacks ([onLongPressMoveUpdate], [onLongPressUp],
  /// [onLongPressEnd]) will stop. Defaults to null, which means the gesture
  /// can be moved without limit once the long press is accepted.
  ///
  /// The [duration] argument can be used to overwrite the default duration
  /// after which the long press will be recognized.
  ///
  /// {@macro flutter.gestures.tap.TapGestureRecognizer.allowedButtonsFilter}
  ///
  /// {@macro flutter.gestures.GestureRecognizer.supportedDevices}
  LongPressGestureRecognizer({
    Duration? duration,
    super.postAcceptSlopTolerance = null,
    super.supportedDevices,
    super.debugOwner,
    AllowedButtonsFilter? allowedButtonsFilter,
  }) : super(
         deadline: duration ?? kLongPressTimeout,
         allowedButtonsFilter: allowedButtonsFilter ?? _defaultButtonAcceptBehavior,
       );

  bool _longPressAccepted = false;
  OffsetPair? _longPressOrigin;
  // The buttons sent by `PointerDownEvent`. If a `PointerMoveEvent` comes with a
  // different set of buttons, the gesture is canceled.
  int? _initialButtons;

  // Accept the input if, and only if, a single button is pressed.
  static bool _defaultButtonAcceptBehavior(int buttons) =>
      buttons == kPrimaryButton || buttons == kSecondaryButton || buttons == kTertiaryButton;

  /// Called when a pointer has contacted the screen at a particular location
  /// with a primary button, which might be the start of a long-press.
  ///
  /// This triggers after the pointer down event.
  ///
  /// If this recognizer doesn't win the arena, [onLongPressCancel] is called
  /// next. Otherwise, [onLongPressStart] is called next.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  ///  * [onSecondaryLongPressDown], a similar callback but for a secondary button.
  ///  * [onTertiaryLongPressDown], a similar callback but for a tertiary button.
  ///  * [LongPressDownDetails], which is passed as an argument to this callback.
  ///  * [GestureDetector.onLongPressDown], which exposes this callback in a widget.
  GestureLongPressDownCallback? onLongPressDown;

  /// Called when a pointer that previously triggered [onLongPressDown] will
  /// not end up causing a long-press.
  ///
  /// This triggers once the gesture loses the arena if [onLongPressDown] has
  /// previously been triggered.
  ///
  /// If this recognizer wins the arena, [onLongPressStart] and [onLongPress]
  /// are called instead.
  ///
  /// If the gesture is deactivated due to [postAcceptSlopTolerance] having
  /// been exceeded, this callback will not be called, since the gesture will
  /// have already won the arena at that point.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  GestureLongPressCancelCallback? onLongPressCancel;

  /// Called when a long press gesture by a primary button has been recognized.
  ///
  /// This is equivalent to (and is called immediately after) [onLongPressStart].
  /// The only difference between the two is that this callback does not
  /// contain details of the position at which the pointer initially contacted
  /// the screen.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  GestureLongPressCallback? onLongPress;

  /// Called when a long press gesture by a primary button has been recognized.
  ///
  /// This is equivalent to (and is called immediately before) [onLongPress].
  /// The only difference between the two is that this callback contains
  /// details of the position at which the pointer initially contacted the
  /// screen, whereas [onLongPress] does not.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  ///  * [LongPressStartDetails], which is passed as an argument to this callback.
  GestureLongPressStartCallback? onLongPressStart;

  /// Called when moving after the long press by a primary button is recognized.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  ///  * [LongPressMoveUpdateDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressMoveUpdateCallback? onLongPressMoveUpdate;

  /// Called when the pointer stops contacting the screen after a long-press
  /// by a primary button.
  ///
  /// This is equivalent to (and is called immediately after) [onLongPressEnd].
  /// The only difference between the two is that this callback does not
  /// contain details of the state of the pointer when it stopped contacting
  /// the screen.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  GestureLongPressUpCallback? onLongPressUp;

  /// Called when the pointer stops contacting the screen after a long-press
  /// by a primary button.
  ///
  /// This is equivalent to (and is called immediately before) [onLongPressUp].
  /// The only difference between the two is that this callback contains
  /// details of the state of the pointer when it stopped contacting the
  /// screen, whereas [onLongPressUp] does not.
  ///
  /// See also:
  ///
  ///  * [kPrimaryButton], the button this callback responds to.
  ///  * [LongPressEndDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressEndCallback? onLongPressEnd;

  /// Called when a pointer has contacted the screen at a particular location
  /// with a secondary button, which might be the start of a long-press.
  ///
  /// This triggers after the pointer down event.
  ///
  /// If this recognizer doesn't win the arena, [onSecondaryLongPressCancel] is
  /// called next. Otherwise, [onSecondaryLongPressStart] is called next.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  ///  * [onLongPressDown], a similar callback but for a primary button.
  ///  * [onTertiaryLongPressDown], a similar callback but for a tertiary button.
  ///  * [LongPressDownDetails], which is passed as an argument to this callback.
  ///  * [GestureDetector.onSecondaryLongPressDown], which exposes this callback
  ///    in a widget.
  GestureLongPressDownCallback? onSecondaryLongPressDown;

  /// Called when a pointer that previously triggered [onSecondaryLongPressDown]
  /// will not end up causing a long-press.
  ///
  /// This triggers once the gesture loses the arena if
  /// [onSecondaryLongPressDown] has previously been triggered.
  ///
  /// If this recognizer wins the arena, [onSecondaryLongPressStart] and
  /// [onSecondaryLongPress] are called instead.
  ///
  /// If the gesture is deactivated due to [postAcceptSlopTolerance] having
  /// been exceeded, this callback will not be called, since the gesture will
  /// have already won the arena at that point.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  GestureLongPressCancelCallback? onSecondaryLongPressCancel;

  /// Called when a long press gesture by a secondary button has been
  /// recognized.
  ///
  /// This is equivalent to (and is called immediately after)
  /// [onSecondaryLongPressStart]. The only difference between the two is that
  /// this callback does not contain details of the position at which the
  /// pointer initially contacted the screen.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  GestureLongPressCallback? onSecondaryLongPress;

  /// Called when a long press gesture by a secondary button has been recognized.
  ///
  /// This is equivalent to (and is called immediately before)
  /// [onSecondaryLongPress]. The only difference between the two is that this
  /// callback contains details of the position at which the pointer initially
  /// contacted the screen, whereas [onSecondaryLongPress] does not.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  ///  * [LongPressStartDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressStartCallback? onSecondaryLongPressStart;

  /// Called when moving after the long press by a secondary button is
  /// recognized.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  ///  * [LongPressMoveUpdateDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressMoveUpdateCallback? onSecondaryLongPressMoveUpdate;

  /// Called when the pointer stops contacting the screen after a long-press by
  /// a secondary button.
  ///
  /// This is equivalent to (and is called immediately after)
  /// [onSecondaryLongPressEnd]. The only difference between the two is that
  /// this callback does not contain details of the state of the pointer when
  /// it stopped contacting the screen.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  GestureLongPressUpCallback? onSecondaryLongPressUp;

  /// Called when the pointer stops contacting the screen after a long-press by
  /// a secondary button.
  ///
  /// This is equivalent to (and is called immediately before)
  /// [onSecondaryLongPressUp]. The only difference between the two is that
  /// this callback contains details of the state of the pointer when it
  /// stopped contacting the screen, whereas [onSecondaryLongPressUp] does not.
  ///
  /// See also:
  ///
  ///  * [kSecondaryButton], the button this callback responds to.
  ///  * [LongPressEndDetails], which is passed as an argument to this callback.
  GestureLongPressEndCallback? onSecondaryLongPressEnd;

  /// Called when a pointer has contacted the screen at a particular location
  /// with a tertiary button, which might be the start of a long-press.
  ///
  /// This triggers after the pointer down event.
  ///
  /// If this recognizer doesn't win the arena, [onTertiaryLongPressCancel] is
  /// called next. Otherwise, [onTertiaryLongPressStart] is called next.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  ///  * [onLongPressDown], a similar callback but for a primary button.
  ///  * [onSecondaryLongPressDown], a similar callback but for a secondary button.
  ///  * [LongPressDownDetails], which is passed as an argument to this callback.
  ///  * [GestureDetector.onTertiaryLongPressDown], which exposes this callback
  ///    in a widget.
  GestureLongPressDownCallback? onTertiaryLongPressDown;

  /// Called when a pointer that previously triggered [onTertiaryLongPressDown]
  /// will not end up causing a long-press.
  ///
  /// This triggers once the gesture loses the arena if
  /// [onTertiaryLongPressDown] has previously been triggered.
  ///
  /// If this recognizer wins the arena, [onTertiaryLongPressStart] and
  /// [onTertiaryLongPress] are called instead.
  ///
  /// If the gesture is deactivated due to [postAcceptSlopTolerance] having
  /// been exceeded, this callback will not be called, since the gesture will
  /// have already won the arena at that point.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  GestureLongPressCancelCallback? onTertiaryLongPressCancel;

  /// Called when a long press gesture by a tertiary button has been
  /// recognized.
  ///
  /// This is equivalent to (and is called immediately after)
  /// [onTertiaryLongPressStart]. The only difference between the two is that
  /// this callback does not contain details of the position at which the
  /// pointer initially contacted the screen.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  GestureLongPressCallback? onTertiaryLongPress;

  /// Called when a long press gesture by a tertiary button has been recognized.
  ///
  /// This is equivalent to (and is called immediately before)
  /// [onTertiaryLongPress]. The only difference between the two is that this
  /// callback contains details of the position at which the pointer initially
  /// contacted the screen, whereas [onTertiaryLongPress] does not.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  ///  * [LongPressStartDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressStartCallback? onTertiaryLongPressStart;

  /// Called when moving after the long press by a tertiary button is
  /// recognized.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  ///  * [LongPressMoveUpdateDetails], which is passed as an argument to this
  ///    callback.
  GestureLongPressMoveUpdateCallback? onTertiaryLongPressMoveUpdate;

  /// Called when the pointer stops contacting the screen after a long-press by
  /// a tertiary button.
  ///
  /// This is equivalent to (and is called immediately after)
  /// [onTertiaryLongPressEnd]. The only difference between the two is that
  /// this callback does not contain details of the state of the pointer when
  /// it stopped contacting the screen.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  GestureLongPressUpCallback? onTertiaryLongPressUp;

  /// Called when the pointer stops contacting the screen after a long-press by
  /// a tertiary button.
  ///
  /// This is equivalent to (and is called immediately before)
  /// [onTertiaryLongPressUp]. The only difference between the two is that
  /// this callback contains details of the state of the pointer when it
  /// stopped contacting the screen, whereas [onTertiaryLongPressUp] does not.
  ///
  /// See also:
  ///
  ///  * [kTertiaryButton], the button this callback responds to.
  ///  * [LongPressEndDetails], which is passed as an argument to this callback.
  GestureLongPressEndCallback? onTertiaryLongPressEnd;

  VelocityTracker? _velocityTracker;

  @override
  bool isPointerAllowed(PointerDownEvent event) {
    switch (event.buttons) {
      case kPrimaryButton:
        if (onLongPressDown == null &&
            onLongPressCancel == null &&
            onLongPressStart == null &&
            onLongPress == null &&
            onLongPressMoveUpdate == null &&
            onLongPressEnd == null &&
            onLongPressUp == null) {
          return false;
        }
      case kSecondaryButton:
        if (onSecondaryLongPressDown == null &&
            onSecondaryLongPressCancel == null &&
            onSecondaryLongPressStart == null &&
            onSecondaryLongPress == null &&
            onSecondaryLongPressMoveUpdate == null &&
            onSecondaryLongPressEnd == null &&
            onSecondaryLongPressUp == null) {
          return false;
        }
      case kTertiaryButton:
        if (onTertiaryLongPressDown == null &&
            onTertiaryLongPressCancel == null &&
            onTertiaryLongPressStart == null &&
            onTertiaryLongPress == null &&
            onTertiaryLongPressMoveUpdate == null &&
            onTertiaryLongPressEnd == null &&
            onTertiaryLongPressUp == null) {
          return false;
        }
      default:
        return false;
    }
    return super.isPointerAllowed(event);
  }

  @override
  void didExceedDeadline() {
    // Exceeding the deadline puts the gesture in the accepted state.
    resolve(GestureDisposition.accepted);
    _longPressAccepted = true;
    super.acceptGesture(primaryPointer!);
    _checkLongPressStart();
  }

  @override
  void handlePrimaryPointer(PointerEvent event) {
    if (!event.synthesized) {
      if (event is PointerDownEvent) {
        _velocityTracker = VelocityTracker.withKind(event.kind);
        _velocityTracker!.addPosition(event.timeStamp, event.localPosition);
      }
      if (event is PointerMoveEvent) {
        assert(_velocityTracker != null);
        _velocityTracker!.addPosition(event.timeStamp, event.localPosition);
      }
    }

    if (event is PointerUpEvent) {
      if (_longPressAccepted) {
        _checkLongPressEnd(event);
      } else {
        // Pointer is lifted before timeout.
        resolve(GestureDisposition.rejected);
      }
      _reset();
    } else if (event is PointerCancelEvent) {
      _checkLongPressCancel();
      _reset();
    } else if (event is PointerDownEvent) {
      // The first touch.
      _longPressOrigin = OffsetPair.fromEventPosition(event);
      _initialButtons = event.buttons;
      _checkLongPressDown(event);
    } else if (event is PointerMoveEvent) {
      if (event.buttons != _initialButtons && !_longPressAccepted) {
        resolve(GestureDisposition.rejected);
        stopTrackingPointer(primaryPointer!);
      } else if (_longPressAccepted) {
        _checkLongPressMoveUpdate(event);
      }
    }
  }

  void _checkLongPressDown(PointerDownEvent event) {
    assert(_longPressOrigin != null);
    final details = LongPressDownDetails(
      globalPosition: _longPressOrigin!.global,
      localPosition: _longPressOrigin!.local,
      kind: getKindForPointer(event.pointer),
    );
    switch (_initialButtons) {
      case kPrimaryButton:
        if (onLongPressDown != null) {
          invokeCallback<void>('onLongPressDown', () => onLongPressDown!(details));
        }
      case kSecondaryButton:
        if (onSecondaryLongPressDown != null) {
          invokeCallback<void>(
            'onSecondaryLongPressDown',
            () => onSecondaryLongPressDown!(details),
          );
        }
      case kTertiaryButton:
        if (onTertiaryLongPressDown != null) {
          invokeCallback<void>('onTertiaryLongPressDown', () => onTertiaryLongPressDown!(details));
        }
      default:
        assert(false, 'Unhandled button $_initialButtons');
    }
  }

  void _checkLongPressCancel() {
    if (state == GestureRecognizerState.possible) {
      switch (_initialButtons) {
        case kPrimaryButton:
          if (onLongPressCancel != null) {
            invokeCallback<void>('onLongPressCancel', onLongPressCancel!);
          }
        case kSecondaryButton:
          if (onSecondaryLongPressCancel != null) {
            invokeCallback<void>('onSecondaryLongPressCancel', onSecondaryLongPressCancel!);
          }
        case kTertiaryButton:
          if (onTertiaryLongPressCancel != null) {
            invokeCallback<void>('onTertiaryLongPressCancel', onTertiaryLongPressCancel!);
          }
        default:
          assert(false, 'Unhandled button $_initialButtons');
      }
    }
  }

  void _checkLongPressStart() {
    switch (_initialButtons) {
      case kPrimaryButton:
        if (onLongPressStart != null) {
          final details = LongPressStartDetails(
            globalPosition: _longPressOrigin!.global,
            localPosition: _longPressOrigin!.local,
          );
          invokeCallback<void>('onLongPressStart', () => onLongPressStart!(details));
        }
        if (onLongPress != null) {
          invokeCallback<void>('onLongPress', onLongPress!);
        }
      case kSecondaryButton:
        if (onSecondaryLongPressStart != null) {
          final details = LongPressStartDetails(
            globalPosition: _longPressOrigin!.global,
            localPosition: _longPressOrigin!.local,
          );
          invokeCallback<void>(
            'onSecondaryLongPressStart',
            () => onSecondaryLongPressStart!(details),
          );
        }
        if (onSecondaryLongPress != null) {
          invokeCallback<void>('onSecondaryLongPress', onSecondaryLongPress!);
        }
      case kTertiaryButton:
        if (onTertiaryLongPressStart != null) {
          final details = LongPressStartDetails(
            globalPosition: _longPressOrigin!.global,
            localPosition: _longPressOrigin!.local,
          );
          invokeCallback<void>(
            'onTertiaryLongPressStart',
            () => onTertiaryLongPressStart!(details),
          );
        }
        if (onTertiaryLongPress != null) {
          invokeCallback<void>('onTertiaryLongPress', onTertiaryLongPress!);
        }
      default:
        assert(false, 'Unhandled button $_initialButtons');
    }
  }

  void _checkLongPressMoveUpdate(PointerEvent event) {
    final details = LongPressMoveUpdateDetails(
      globalPosition: event.position,
      localPosition: event.localPosition,
      offsetFromOrigin: event.position - _longPressOrigin!.global,
      localOffsetFromOrigin: event.localPosition - _longPressOrigin!.local,
    );
    switch (_initialButtons) {
      case kPrimaryButton:
        if (onLongPressMoveUpdate != null) {
          invokeCallback<void>('onLongPressMoveUpdate', () => onLongPressMoveUpdate!(details));
        }
      case kSecondaryButton:
        if (onSecondaryLongPressMoveUpdate != null) {
          invokeCallback<void>(
            'onSecondaryLongPressMoveUpdate',
            () => onSecondaryLongPressMoveUpdate!(details),
          );
        }
      case kTertiaryButton:
        if (onTertiaryLongPressMoveUpdate != null) {
          invokeCallback<void>(
            'onTertiaryLongPressMoveUpdate',
            () => onTertiaryLongPressMoveUpdate!(details),
          );
        }
      default:
        assert(false, 'Unhandled button $_initialButtons');
    }
  }

  void _checkLongPressEnd(PointerEvent event) {
    final VelocityEstimate? estimate = _velocityTracker!.getVelocityEstimate();
    final Velocity velocity = estimate == null
        ? Velocity.zero
        : Velocity(pixelsPerSecond: estimate.pixelsPerSecond);
    final details = LongPressEndDetails(
      globalPosition: event.position,
      localPosition: event.localPosition,
      velocity: velocity,
    );

    _velocityTracker = null;
    switch (_initialButtons) {
      case kPrimaryButton:
        if (onLongPressEnd != null) {
          invokeCallback<void>('onLongPressEnd', () => onLongPressEnd!(details));
        }
        if (onLongPressUp != null) {
          invokeCallback<void>('onLongPressUp', onLongPressUp!);
        }
      case kSecondaryButton:
        if (onSecondaryLongPressEnd != null) {
          invokeCallback<void>('onSecondaryLongPressEnd', () => onSecondaryLongPressEnd!(details));
        }
        if (onSecondaryLongPressUp != null) {
          invokeCallback<void>('onSecondaryLongPressUp', onSecondaryLongPressUp!);
        }
      case kTertiaryButton:
        if (onTertiaryLongPressEnd != null) {
          invokeCallback<void>('onTertiaryLongPressEnd', () => onTertiaryLongPressEnd!(details));
        }
        if (onTertiaryLongPressUp != null) {
          invokeCallback<void>('onTertiaryLongPressUp', onTertiaryLongPressUp!);
        }
      default:
        assert(false, 'Unhandled button $_initialButtons');
    }
  }

  void _reset() {
    _longPressAccepted = false;
    _longPressOrigin = null;
    _initialButtons = null;
    _velocityTracker = null;
  }

  @override
  void resolve(GestureDisposition disposition) {
    if (disposition == GestureDisposition.rejected) {
      if (_longPressAccepted) {
        // This can happen if the gesture has been canceled. For example when
        // the buttons have changed.
        _reset();
      } else {
        _checkLongPressCancel();
      }
    }
    super.resolve(disposition);
  }

  @override
  void acceptGesture(int pointer) {
    // Winning the arena isn't important here since it may happen from a sweep.
    // Explicitly exceeding the deadline puts the gesture in accepted state.
  }

  @override
  String get debugDescription => 'long press';
}
