import 'dart:async';

import 'package:flutter/material.dart';

///计时按钮
class CountingButton extends StatefulWidget {
  final CountingButtonController controller;
  final VoidCallback? onPressed;
  final Widget Function(int count, bool isCounting) onGetChild;
  final ButtonStyle? buttonStyle;

  const CountingButton(
      {super.key,
      required this.controller,
      required this.onGetChild,
      this.onPressed,
      this.buttonStyle});

  @override
  State<CountingButton> createState() => _CountingButtonState();
}

class _CountingButtonState extends State<CountingButton> {
  @override
  void initState() {
    super.initState();

    widget.controller.counter.addListener(() {
      setState(() {});
    });
  }

  @override
  void dispose() {
    super.dispose();
    widget.controller.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
        onPressed: _onPressed,
        style: widget.buttonStyle ??
            ButtonStyle(
                backgroundColor:
                    WidgetStatePropertyAll(Theme.of(context).primaryColor),
                elevation: const WidgetStatePropertyAll(0.0)),
        child: widget.onGetChild(
            widget.controller.counter.value, widget.controller.isCounting));
  }

  void _onPressed() {
    if (widget.controller.counter.value > 0) {
      return;
    }
    widget.onPressed?.call();
  }
}

class CountingButtonController {
  Timer? _timer;
  ValueNotifier<int>? _counter;

  ValueNotifier<int> get counter => _counter ??= ValueNotifier(-1);

  bool get isCounting => _timer != null;

  void start(int count) {
    _timer?.cancel();
    _timer = Timer.periodic(Duration(seconds: 1), (t) {
      counter.value = t.tick;
      if (t.tick >= count) {
        stop();
      }
    });
    counter.value = 0;
  }

  void stop() {
    _timer?.cancel();
    _timer = null;
    counter.value = -1;
  }

  void dispose() {
    _counter?.dispose();
    _counter = null;
  }
}