PiliPlus/lib/pages/common/slide/common_slide_page.dart

import 'dart:math' show max;

import 'package:PiliPlus/utils/storage_pref.dart';
import 'package:flutter/gestures.dart' show HorizontalDragGestureRecognizer;
import 'package:flutter/material.dart';
import 'package:get/get.dart';

abstract class CommonSlidePage extends StatefulWidget {
  const CommonSlidePage({super.key, this.enableSlide = true});

  final bool enableSlide;
}

mixin CommonSlideMixin<T extends CommonSlidePage> on State<T>, TickerProvider {
  double? _downDx;
  late double _maxWidth;
  late bool _isRTL = false;
  late final bool enableSlide;
  late final AnimationController _animController;
  SlideDragGestureRecognizer? _slideDragGestureRecognizer;

  static bool slideDismissReplyPage = Pref.slideDismissReplyPage;

  @override
  void initState() {
    super.initState();
    enableSlide = widget.enableSlide && slideDismissReplyPage;
    if (enableSlide) {
      _animController = AnimationController(
        vsync: this,
        reverseDuration: const Duration(milliseconds: 500),
      );
      _slideDragGestureRecognizer =
          SlideDragGestureRecognizer(
              isDxAllowed: (double dx) {
                const offset = 30;
                final isLTR = dx <= offset;
                final isRTL = dx >= _maxWidth - offset;
                if (isLTR || isRTL) {
                  _isRTL = isRTL;
                  _downDx = dx;
                  return true;
                }
                return false;
              },
            )
            ..onUpdate = _onDragUpdate
            ..onEnd = _onDragEnd
            ..onCancel = _onDragEnd;
    }
  }

  @override
  void dispose() {
    if (enableSlide) {
      _animController.dispose();
      _slideDragGestureRecognizer?.dispose();
      _slideDragGestureRecognizer = null;
    }
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    if (enableSlide) {
      return LayoutBuilder(
        builder: (context, constraints) {
          _maxWidth = constraints.maxWidth;
          return AnimatedBuilder(
            animation: _animController,
            builder: (context, child) {
              return Align(
                alignment: AlignmentDirectional.topStart,
                heightFactor: 1 - _animController.value,
                child: child,
              );
            },
            child: buildPage(theme),
          );
        },
      );
    }
    return buildPage(theme);
  }

  Widget buildPage(ThemeData theme);

  Widget buildList(ThemeData theme) => throw UnimplementedError();

  void _onDragEnd([_]) {
    final dx = _downDx!;
    if (_animController.value * _maxWidth + (_isRTL ? (_maxWidth - dx) : dx) >=
        100) {
      Get.back();
    } else {
      _animController.reverse();
    }
    _downDx = null;
  }

  void _onDragUpdate(DragUpdateDetails details) {
    final from = _downDx!;
    final to = details.localPosition.dx;
    _animController.value = max(0, _isRTL ? from - to : to - from) / _maxWidth;
  }

  Widget slideList(ThemeData theme) => Listener(
    onPointerDown: (event) => _slideDragGestureRecognizer?.addPointer(event),
    child: buildList(theme),
  );
}

class SlideDragGestureRecognizer extends HorizontalDragGestureRecognizer {
  SlideDragGestureRecognizer({
    super.debugOwner,
    super.supportedDevices,
    super.allowedButtonsFilter,
    required this.isDxAllowed,
  });

  final bool Function(double dx) isDxAllowed;

  @override
  bool isPointerAllowed(PointerEvent event) {
    return isDxAllowed(event.localPosition.dx) && super.isPointerAllowed(event);
  }
}