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

/// 左滑露出操作按钮的列表项包装（如「我的关注」左滑取消关注）。
///
/// 不用 Dismissible：那个滑到底即执行，取关这种不可撤销的操作误触代价太大，
/// 这里做成「左滑露出按钮、点按钮才执行」。
class SwipeActionItem extends StatefulWidget {
  final Widget child;
  final String actionText;
  final VoidCallback onAction;
  final Color actionColor;
  final double actionWidth;

  /// 滑动层的底色。列表项自身多半是透明的，不垫一层实色，底下的按钮会直接透上来
  final Color? backgroundColor;

  const SwipeActionItem({
    super.key,
    required this.child,
    required this.actionText,
    required this.onAction,
    this.actionColor = const Color(0xffE03017),
    this.actionWidth = 88,
    this.backgroundColor,
  });

  /// 关掉当前展开的那一项（列表滚动时调，避免滑走了还留着一个张开的）
  static void closeOpened() => _opened?._close();

  @override
  State<SwipeActionItem> createState() => _SwipeActionItemState();
}

/// 全局只允许一项展开：展开新的会自动收起旧的
_SwipeActionItemState? _opened;

class _SwipeActionItemState extends State<SwipeActionItem> with SingleTickerProviderStateMixin {
  late final AnimationController _ctr = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 200),
  );

  bool get _isOpen => _ctr.value > 0;

  @override
  void dispose() {
    if (_opened == this) _opened = null;
    _ctr.dispose();
    super.dispose();
  }

  void _open() {
    if (_opened != null && _opened != this) _opened!._close();
    _opened = this;
    _ctr.forward();
  }

  void _close() {
    if (_opened == this) _opened = null;
    if (mounted) _ctr.reverse();
  }

  void _onDragUpdate(DragUpdateDetails d) {
    // 手指往左走 primaryDelta 为负，换算成 0~1 的展开进度
    _ctr.value -= (d.primaryDelta ?? 0) / widget.actionWidth;
  }

  void _onDragEnd(DragEndDetails d) {
    final v = d.primaryVelocity ?? 0;
    if (v < -300) return _open(); // 甩一下就展开，不看位置
    if (v > 300) return _close();
    _ctr.value > 0.5 ? _open() : _close();
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onHorizontalDragUpdate: _onDragUpdate,
      onHorizontalDragEnd: _onDragEnd,
      child: AnimatedBuilder(
        animation: _ctr,
        builder: (_, child) {
          return Stack(
            children: [
              // 按钮垫在底下，靠内容左移露出来；跟着内容一起裁，避免收起时露边
              Positioned.fill(child: _actionButton()),
              Transform.translate(
                offset: Offset(-widget.actionWidth * _ctr.value, 0),
                child: ColoredBox(
                  color: widget.backgroundColor ?? Get.theme.scaffoldBackgroundColor,
                  // 展开状态下先吞掉一次点击用于收起，别直接把用户点进详情页
                  child: _isOpen
                      ? GestureDetector(
                          onTap: _close,
                          child: AbsorbPointer(child: child),
                        )
                      : child,
                ),
              ),
            ],
          );
        },
        child: widget.child,
      ),
    );
  }

  Widget _actionButton() {
    return Align(
      alignment: Alignment.centerRight,
      child: GestureDetector(
        onTap: () {
          _close();
          widget.onAction();
        },
        child: Container(
          width: widget.actionWidth,
          alignment: Alignment.center,
          color: widget.actionColor,
          child: Text(
            widget.actionText,
            style: const TextStyle(color: Colors.white, fontSize: 14, fontWeight: FontWeight.w500),
          ),
        ),
      ),
    );
  }
}