// adaptive_menu.dart — 自适应方向的弹出菜单(通用组件)。
//
// 行为:点触发按钮后,根据按钮在屏幕的位置自动决定菜单**向下**还是**向上**弹
// (下方空间够就向下,不够就向上;都不够取较大一侧),且**始终留间隙、不遮挡触发
// 按钮本身**。水平方向菜单右缘对齐按钮右缘并夹在屏内。点菜单外区域关闭。
//
// 用 Overlay 自绘(而非 PopupMenuButton——后者不保证翻转、可能盖住按钮)。
import 'package:flutter/material.dart';

import '../pangolin_theme.dart';

/// 一个菜单项。danger=true 用危险色(如删除)。
class AdaptiveMenuItem {
  const AdaptiveMenuItem({
    required this.icon,
    required this.label,
    required this.onSelected,
    this.danger = false,
  });

  final IconData icon;
  final String label;
  final VoidCallback onSelected;
  final bool danger;
}

/// 触发按钮(图标)+ 自适应弹出菜单。
class AdaptiveMenuButton extends StatefulWidget {
  const AdaptiveMenuButton({
    super.key,
    required this.items,
    required this.icon,
    this.iconColor,
    this.iconSize = 18,
    this.menuWidth = 208,
    this.itemHeight = 44,
  });

  final List<AdaptiveMenuItem> items;
  final IconData icon;
  final Color? iconColor;
  final double iconSize;
  final double menuWidth;
  final double itemHeight;

  @override
  State<AdaptiveMenuButton> createState() => _AdaptiveMenuButtonState();
}

class _AdaptiveMenuButtonState extends State<AdaptiveMenuButton> {
  final _anchorKey = GlobalKey();
  OverlayEntry? _entry;

  @override
  void dispose() {
    _close();
    super.dispose();
  }

  void _close() {
    _entry?.remove();
    _entry = null;
  }

  void _open() {
    if (widget.items.isEmpty) return;
    final box = _anchorKey.currentContext?.findRenderObject() as RenderBox?;
    final overlay = Overlay.of(context);
    final overlayBox = overlay.context.findRenderObject() as RenderBox?;
    if (box == null || overlayBox == null) return;

    final topLeft = box.localToGlobal(Offset.zero, ancestor: overlayBox);
    final size = box.size;
    final screen = overlayBox.size;
    final safe = MediaQuery.of(context).padding;

    const gap = 6.0;
    final menuH = widget.items.length * widget.itemHeight + 10;
    final triggerTop = topLeft.dy;
    final triggerBottom = topLeft.dy + size.height;

    final spaceBelow = screen.height - safe.bottom - 8 - triggerBottom;
    final spaceAbove = triggerTop - safe.top - 8;
    // 下方放得下就向下;否则若下方比上方大也向下;否则向上。
    final openDown = spaceBelow >= menuH + gap || spaceBelow >= spaceAbove;

    // 水平:菜单右缘对齐按钮右缘,夹在屏内。
    final maxLeft = (screen.width - widget.menuWidth - 8).clamp(8.0, double.infinity);
    final left = (topLeft.dx + size.width - widget.menuWidth).clamp(8.0, maxLeft);

    // 垂直:向下→按钮底+gap(不遮挡);向上→按钮顶-gap-菜单高(不遮挡)。
    final top = openDown
        ? triggerBottom + gap
        : (triggerTop - gap - menuH).clamp(safe.top + 8, double.infinity);

    final c = context.pangolin;
    _entry = OverlayEntry(
      builder: (_) => Stack(children: [
        Positioned.fill(
          child: GestureDetector(behavior: HitTestBehavior.translucent, onTap: _close),
        ),
        Positioned(
          left: left,
          top: top,
          width: widget.menuWidth,
          child: _MenuCard(
            scheme: c,
            items: widget.items,
            itemHeight: widget.itemHeight,
            fromTop: openDown,
            onPick: (it) {
              _close();
              it.onSelected();
            },
          ),
        ),
      ]),
    );
    overlay.insert(_entry!);
  }

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    return InkResponse(
      key: _anchorKey,
      radius: 22,
      onTap: _open,
      child: Padding(
        padding: const EdgeInsets.all(6),
        child: Icon(widget.icon, size: widget.iconSize, color: widget.iconColor ?? c.fg3),
      ),
    );
  }
}

class _MenuCard extends StatelessWidget {
  const _MenuCard({
    required this.scheme,
    required this.items,
    required this.itemHeight,
    required this.fromTop,
    required this.onPick,
  });

  final PangolinScheme scheme;
  final List<AdaptiveMenuItem> items;
  final double itemHeight;
  final bool fromTop; // 向下弹时从顶部展开,向上弹时从底部展开
  final ValueChanged<AdaptiveMenuItem> onPick;

  @override
  Widget build(BuildContext context) {
    final c = scheme;
    return TweenAnimationBuilder<double>(
      duration: const Duration(milliseconds: 130),
      curve: Curves.easeOutCubic,
      tween: Tween(begin: 0, end: 1),
      builder: (_, v, child) => Opacity(
        opacity: v.clamp(0.0, 1.0),
        child: Transform.scale(
          scale: 0.96 + 0.04 * v,
          alignment: fromTop ? Alignment.topRight : Alignment.bottomRight,
          child: child,
        ),
      ),
      child: Material(
        color: c.surface,
        elevation: 6,
        shadowColor: PangolinColors.sand950.withValues(alpha: 0.24), // 暖近黑阴影(§5;非冷黑 Colors.black26)
        clipBehavior: Clip.antiAlias,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(PangolinRadius.md),
          side: BorderSide(color: c.border),
        ),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const SizedBox(height: 5),
            for (final it in items)
              InkWell(
                onTap: () => onPick(it),
                child: SizedBox(
                  height: itemHeight,
                  child: Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 14),
                    child: Row(children: [
                      Icon(it.icon, size: 16, color: it.danger ? c.danger : c.fg2),
                      const SizedBox(width: 11),
                      Text(it.label,
                          style: PangolinText.sm.copyWith(color: it.danger ? c.danger : c.fg1)),
                    ]),
                  ),
                ),
              ),
            const SizedBox(height: 5),
          ],
        ),
      ),
    );
  }
}