import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

/// 远端触摸控制层（对应 Android 端 RemoteTouchView）。
///
/// 捕获指针（触摸/鼠标）事件，将其转换为相对于控件区域的百分比坐标
/// （0.0 ~ 1.0），以便在不同分辨率的设备间换算。
///
/// - 短时间内位移很小的抬起 -> 单击（TOUCH）
/// - 否则 -> 滑动（SWIPE）
/// 同时捕获物理按键事件（KEY），用于外接键盘 / 遥控器场景。
///
/// 该控件完全基于 Flutter 框架实现，无需任何原生代码，可运行于
/// Android、iOS 等平台。
class RemoteTouchView extends StatefulWidget {
  final void Function(double x, double y) onTouch;
  final void Function(
    double x1,
    double y1,
    double x2,
    double y2,
    int durationMs,
  ) onSwipe;
  final void Function(int keyCode, int action) onKey;

  const RemoteTouchView({
    super.key,
    required this.onTouch,
    required this.onSwipe,
    required this.onKey,
  });

  @override
  State<RemoteTouchView> createState() => _RemoteTouchViewState();
}

class _RemoteTouchViewState extends State<RemoteTouchView> {
  Offset? _startPosition;
  DateTime? _startTime;

  double _toRelativeX(Offset local, Size size) =>
      (local.dx / size.width).clamp(0.0, 1.0);

  double _toRelativeY(Offset local, Size size) =>
      (local.dy / size.height).clamp(0.0, 1.0);

  @override
  Widget build(BuildContext context) {
    return Focus(
      autofocus: true,
      // 捕获物理按键（外接键盘 / 遥控器等）。
      onKeyEvent: (node, event) {
        if (event is KeyDownEvent) {
          widget.onKey(event.logicalKey.keyId, 0);
          return KeyEventResult.handled;
        } else if (event is KeyUpEvent) {
          widget.onKey(event.logicalKey.keyId, 1);
          return KeyEventResult.handled;
        }
        return KeyEventResult.ignored;
      },
      child: Listener(
        behavior: HitTestBehavior.opaque,
        onPointerDown: (event) {
          _startPosition = event.localPosition;
          _startTime = DateTime.now();
        },
        onPointerUp: (event) {
          final size = context.size;
          if (_startPosition == null || size == null || _startTime == null) {
            return;
          }
          final startX = _toRelativeX(_startPosition!, size);
          final startY = _toRelativeY(_startPosition!, size);
          final endX = _toRelativeX(event.localPosition, size);
          final endY = _toRelativeY(event.localPosition, size);
          final duration = DateTime.now().difference(_startTime!).inMilliseconds;

          final dx = (endX - startX).abs();
          final dy = (endY - startY).abs();

          if (duration < 200 && dx < 0.02 && dy < 0.02) {
            widget.onTouch(startX, startY);
          } else {
            widget.onSwipe(startX, startY, endX, endY, max(duration, 1));
          }
          _startPosition = null;
          _startTime = null;
        },
        child: const ColoredBox(
          color: Colors.transparent,
          child: SizedBox.expand(),
        ),
      ),
    );
  }
}