import 'package:lucide_icons_flutter/lucide_icons.dart';
import 'package:flutter/material.dart';

import '../core/theme/context_tokens.dart';
import '../core/theme/app_dims.g.dart';
import 'searchable_option_field.dart' show OptionItem;
import '../core/theme/app_fonts.dart';

/// 搜索下拉框（对齐原型 .combo + .combo-pop）：
/// 触发器（带框 input 样式 + caret/清除）+ 锚定在下方的弹层
/// （顶部搜索框 + 名称/编码两列 + 选中蓝勾 + 底部「共 N 条结果」）。
///
/// 与 SearchableOptionField（居中 AlertDialog）不同——这是**锚定弹层**，
/// 用于列表工具栏「供应商/客户」等就地筛选。
class ComboSearchField extends StatefulWidget {
  final List<OptionItem> options;
  final int? selectedId;
  final String hint;
  final ValueChanged<int?> onChanged;

  /// 固定宽度；传 null 则填满父约束（用于弹窗内 Expanded 布局）。
  final double? width;

  /// 触发器高度（工具栏 34，表单/弹窗 38，对齐原型 .combo）。
  final double height;

  /// 触发器填充色；null=透明（工具栏用，透出底色）。弹窗内传 surface 保持不透明一致。
  final Color? fillColor;

  const ComboSearchField({
    super.key,
    required this.options,
    required this.selectedId,
    required this.hint,
    required this.onChanged,
    this.width,
    this.height = 34,
    this.fillColor,
  });

  @override
  State<ComboSearchField> createState() => _ComboSearchFieldState();
}

class _ComboSearchFieldState extends State<ComboSearchField> {
  final _link = LayerLink();
  OverlayEntry? _entry;

  OptionItem? get _selected {
    for (final o in widget.options) {
      if (o.id == widget.selectedId) return o;
    }
    return null;
  }

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

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

  void _open() {
    if (_entry != null) return;
    _entry = OverlayEntry(builder: (_) => _buildPopup());
    Overlay.of(context).insert(_entry!);
  }

  void _pick(int? id) {
    widget.onChanged(id);
    _remove();
  }

  Widget _buildPopup() {
    final t = context.tokens;
    return Stack(
      children: [
        // 外部点击关闭
        Positioned.fill(
          child: GestureDetector(
            behavior: HitTestBehavior.translucent,
            onTap: _remove,
          ),
        ),
        CompositedTransformFollower(
          link: _link,
          showWhenUnlinked: false,
          targetAnchor: Alignment.bottomLeft,
          followerAnchor: Alignment.topLeft,
          offset: const Offset(0, 6),
          child: Align(
            alignment: Alignment.topLeft,
            child: Material(
              elevation: 8,
              borderRadius: BorderRadius.circular(AppDims.rMd),
              color: t.surface,
              child: ConstrainedBox(
                constraints: BoxConstraints(
                    minWidth: (widget.width == null || widget.width! < 240)
                        ? 240
                        : widget.width!,
                    maxWidth: 320),
                child: _ComboPop(
                  options: widget.options,
                  selectedId: widget.selectedId,
                  hint: widget.hint,
                  onPick: _pick,
                ),
              ),
            ),
          ),
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    final sel = _selected;
    return CompositedTransformTarget(
      link: _link,
      child: SizedBox(
        width: widget.width, // null → 由父约束决定（Expanded 内填满）
        height: widget.height,
        child: InkWell(
          borderRadius: BorderRadius.circular(AppDims.rMd),
          onTap: _open,
          child: Container(
            padding: const EdgeInsets.symmetric(horizontal: 11),
            decoration: BoxDecoration(
              color: widget.fillColor,
              border: Border.all(color: t.border),
              borderRadius: BorderRadius.circular(AppDims.rMd),
            ),
            child: Row(
              children: [
                Expanded(
                  child: Text(
                    sel?.name ?? widget.hint,
                    overflow: TextOverflow.ellipsis,
                    style: TextStyle(
                      fontSize: AppDims.fsBody,
                      color: sel == null ? t.faint : t.text,
                    ),
                  ),
                ),
                if (sel != null)
                  GestureDetector(
                    onTap: () => _pick(null),
                    child: Icon(LucideIcons.x, size: 14, color: t.muted),
                  )
                else
                  Icon(LucideIcons.chevronDown, size: 16, color: t.faint),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

/// 弹层内容：搜索框 + 列表（名称 + 编码 + 选中勾）+ 底部计数。
class _ComboPop extends StatefulWidget {
  final List<OptionItem> options;
  final int? selectedId;
  final String hint;
  final ValueChanged<int?> onPick;
  const _ComboPop({
    required this.options,
    required this.selectedId,
    required this.hint,
    required this.onPick,
  });

  @override
  State<_ComboPop> createState() => _ComboPopState();
}

class _ComboPopState extends State<_ComboPop> {
  String _kw = '';

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    final q = _kw.trim().toLowerCase();
    final hits = q.isEmpty
        ? widget.options
        : widget.options.where((o) => o.matches(_kw)).toList();
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        // 顶部搜索框
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 11, vertical: 9),
          decoration: BoxDecoration(
            border: Border(bottom: BorderSide(color: t.borderSubtle)),
          ),
          child: Row(
            children: [
              Icon(LucideIcons.search, size: 14, color: t.faint),
              const SizedBox(width: 8),
              Expanded(
                child: TextField(
                  autofocus: true,
                  style: TextStyle(fontSize: AppDims.fsBody, color: t.text),
                  decoration: InputDecoration(
                    isCollapsed: true,
                    contentPadding: EdgeInsets.zero,
                    border: InputBorder.none,
                    filled: false,
                    enabledBorder: InputBorder.none,
                    focusedBorder: InputBorder.none,
                    hintText: '搜索${widget.hint}…',
                    hintStyle:
                        TextStyle(fontSize: AppDims.fsBody, color: t.faint),
                  ),
                  onChanged: (v) => setState(() => _kw = v),
                ),
              ),
            ],
          ),
        ),
        // 列表
        ConstrainedBox(
          constraints: const BoxConstraints(maxHeight: 264),
          child: hits.isEmpty
              ? Padding(
                  padding: const EdgeInsets.all(20),
                  child: Text('无匹配结果',
                      style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)))
              : ListView.builder(
                  padding: const EdgeInsets.all(5),
                  shrinkWrap: true,
                  itemCount: hits.length,
                  itemBuilder: (_, i) {
                    final o = hits[i];
                    final sel = o.id == widget.selectedId;
                    return InkWell(
                      borderRadius: BorderRadius.circular(AppDims.rSm),
                      onTap: () => widget.onPick(o.id),
                      child: Container(
                        padding: const EdgeInsets.symmetric(
                            horizontal: 10, vertical: 8),
                        child: Row(
                          children: [
                            Expanded(
                              child: Text(o.name,
                                  overflow: TextOverflow.ellipsis,
                                  style: TextStyle(
                                      fontSize: AppDims.fsBody,
                                      color: sel ? t.primary : t.text,
                                      fontWeight: sel
                                          ? FontWeight.w600
                                          : FontWeight.w400)),
                            ),
                            if (o.code != null && o.code!.isNotEmpty) ...[
                              const SizedBox(width: 12),
                              Text(o.code!,
                                  style: TextStyle(
                                      fontSize: AppDims.fsXs,
                                      fontFamily: AppFonts.mono,
                                      fontFamilyFallback: AppFonts.monoFallback,
                                      color: t.faint)),
                            ],
                            if (sel) ...[
                              const SizedBox(width: 8),
                              Icon(LucideIcons.check,
                                  size: 15, color: t.primary),
                            ],
                          ],
                        ),
                      ),
                    );
                  },
                ),
        ),
        // 底部计数
        Container(
          width: double.infinity,
          padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 7),
          decoration: BoxDecoration(
            color: t.bg,
            border: Border(top: BorderSide(color: t.borderSubtle)),
          ),
          child: Text(
            q.isEmpty
                ? '共 ${widget.options.length} 条结果'
                : '匹配 ${hits.length} 条 · 共 ${widget.options.length} 条',
            style: TextStyle(fontSize: AppDims.fsXs, color: t.muted),
          ),
        ),
      ],
    );
  }
}