import 'dart:async';

import 'package:flutter/foundation.dart';

typedef GuardedTapCallback = FutureOr<void> Function();

/// 通用防连点工具。
///
/// 适用于 `TextButton`、`IconButton`、`GestureDetector`、`InkWell` 等
/// 任意需要点击防抖的场景。
class ClickUtil {
  ClickUtil._();

  static const int defaultDelayMs = 800;

  static final Map<Object, DateTime> _lastTriggerTimes = <Object, DateTime>{};
  static final Set<Object> _runningKeys = <Object>{};
  static final Object _globalKey = Object();

  /// 运行一个带防连点保护的点击事件。
  ///
  /// `key` 相同的点击事件会共用一把锁；
  /// `delayMs` 内重复点击会被忽略；
  /// `lockDuringExecution` 为 true 时，异步执行期间也会被锁住。
  static Future<void> run(
    GuardedTapCallback action, {
    Object? key,
    int delayMs = defaultDelayMs,
    bool lockDuringExecution = true,
  }) async {
    final Object guardKey = key ?? action;
    final DateTime now = DateTime.now();
    final DateTime? lastTriggerTime = _lastTriggerTimes[guardKey];

    if (lastTriggerTime != null &&
        now.difference(lastTriggerTime).inMilliseconds < delayMs) {
      debugPrint('请稍后点击');
      return;
    }

    if (lockDuringExecution && _runningKeys.contains(guardKey)) {
      debugPrint('操作进行中，请稍后');
      return;
    }

    _lastTriggerTimes[guardKey] = now;
    if (lockDuringExecution) {
      _runningKeys.add(guardKey);
    }

    try {
      await action();
    } finally {
      if (lockDuringExecution) {
        final int elapsedMs = DateTime.now().difference(now).inMilliseconds;
        final int remainingMs = delayMs - elapsedMs;
        if (remainingMs > 0) {
          await Future.delayed(Duration(milliseconds: remainingMs));
        }
        _runningKeys.remove(guardKey);
      }
    }
  }

  /// 直接包装成可绑定给按钮的回调。
  ///
  /// 对于会在 `build` 中频繁新建的匿名函数，推荐显式传入 `key`。
  static VoidCallback? wrap(
    GuardedTapCallback? action, {
    Object? key,
    int delayMs = defaultDelayMs,
    bool lockDuringExecution = true,
  }) {
    if (action == null) return null;

    return () {
      unawaited(
        run(
          action,
          key: key,
          delayMs: delayMs,
          lockDuringExecution: lockDuringExecution,
        ),
      );
    };
  }

  /// 兼容旧调用方式：全局共用一把锁。
  static Future<void> noMultipleClicks(
    GuardedTapCallback action, {
    int delayMs = 2000,
  }) {
    return run(action, key: _globalKey, delayMs: delayMs);
  }

  static void reset([Object? key]) {
    if (key == null) {
      _lastTriggerTimes.clear();
      _runningKeys.clear();
      return;
    }

    _lastTriggerTimes.remove(key);
    _runningKeys.remove(key);
  }
}