import 'package:lucide_icons_flutter/lucide_icons.dart';
import 'dart:async';

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

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

/// 内联可键盘操作的下拉选择格（对齐原型 `.combo` / `.combo.cell` + `.combo-pop`）。
///
/// - 聚焦即打开浮层；输入即过滤（名称 / 全拼 / 首字母 / 编码）。
/// - ↑↓ 移动高亮，Enter 选中并回调 [onPickedByKeyboard]（供上层推进到下一格），
///   Esc 关闭，Tab 交由上层 [onTab] 决定前进/后退。
/// - [allowCreate] 时，输入无匹配可「新增到基础数据」，走 [onCreate]。
/// - [commonIds] 命中的选项在无关键字时置顶为「常用」组（对齐系列/规格默认）。
class GridComboCell extends StatefulWidget {
  final FocusNode focusNode;
  final List<OptionItem> options;
  final int? selectedId;
  final String hint;

  /// true=网格单元格样式（透明、32 高）；false=独立表单 combo（描边、38 高）。
  final bool cell;

  /// 浮层是否置顶持久搜索框（对齐原型 .combo-pop > .cp-search，触发框只读展示）。
  /// null=沿用默认（单据头 combo 用弹层搜索、网格 combo 用单元格内联输入）；
  /// 传 true 可让网格单元格也走弹层搜索（如入库明细的商品名/系列/规格）。
  final bool? popupSearch;
  final bool hasError;
  final bool enabled;
  final bool allowCreate;

  /// 无关键字时置顶显示的「常用」选项 id（如按商品名带出的默认系列/规格）。
  final Set<int> commonIds;

  /// 选项数、供应商/客户等大字典时置底显示计数（对齐原型单据头 combo 的 cp-foot）。
  final bool showCount;

  /// 单据头 combo（cell=false）浮层顶部 .cp-search 的占位文案；空则回退到 [hint]。
  final String? searchHint;

  /// 服务端搜索（供供应商/客户/库存商品等）；提供时输入 debounce 调它取结果。
  final Future<List<OptionItem>> Function(String keyword)? onSearch;

  /// 新增到基础数据；返回新选项 id（自动选中）。
  final Future<int?> Function(String keyword)? onCreate;

  final void Function(int? id) onChanged;

  /// 通过键盘 Enter 选中后触发（上层据此推进到下一格 / 加行）。
  final VoidCallback? onPickedByKeyboard;

  /// Tab（shift=后退）；返回 true 表示已处理。
  final bool Function({required bool backward})? onTab;

  const GridComboCell({
    super.key,
    required this.focusNode,
    required this.options,
    required this.selectedId,
    required this.hint,
    required this.onChanged,
    this.cell = false,
    this.popupSearch,
    this.hasError = false,
    this.enabled = true,
    this.allowCreate = false,
    this.commonIds = const {},
    this.showCount = false,
    this.searchHint,
    this.onSearch,
    this.onCreate,
    this.onPickedByKeyboard,
    this.onTab,
  });

  @override
  State<GridComboCell> createState() => _GridComboCellState();
}

/// 浮层里可高亮/选中的一项：既有选项，或「新增」行。
class _PopEntry {
  final OptionItem? opt; // null → 新增行
  final String? createKw;
  const _PopEntry.opt(this.opt) : createKw = null;
  const _PopEntry.create(this.createKw) : opt = null;
  bool get isCreate => opt == null;
}

class _GridComboCellState extends State<GridComboCell> {
  final _ctrl = TextEditingController();
  final _link = LayerLink();
  final _listScroll = ScrollController();
  // 单据头 combo：浮层顶部持久搜索框的焦点（网格 combo 不用，走单元格内联输入）。
  final _searchFocus = FocusNode();
  OverlayEntry? _entry;
  Timer? _debounce;

  /// 弹层搜索模式：浮层置顶显式搜索框，触发框保持只读展示（对齐原型 scope==='doc'）；
  /// 反之走网格单元格内联输入过滤。默认单据头(cell=false)开、网格(cell=true)关，
  /// 可由 [GridComboCell.popupSearch] 显式覆盖。
  bool get _docHead => widget.popupSearch ?? !widget.cell;

  bool _open = false;
  String _kw = '';
  int _cursor = -1;
  List<_PopEntry> _entries = const [];
  List<OptionItem>? _remote; // onSearch 结果；null=用本地 options

  @override
  void initState() {
    super.initState();
    widget.focusNode.addListener(_onFocusChange);
  }

  @override
  void didUpdateWidget(GridComboCell old) {
    super.didUpdateWidget(old);
    if (old.focusNode != widget.focusNode) {
      old.focusNode.removeListener(_onFocusChange);
      widget.focusNode.addListener(_onFocusChange);
    }
    if (_open) _rebuildEntries();
  }

  @override
  void dispose() {
    _debounce?.cancel();
    widget.focusNode.removeListener(_onFocusChange);
    _removeOverlay();
    _ctrl.dispose();
    _searchFocus.dispose();
    _listScroll.dispose();
    super.dispose();
  }

  String get _selectedName =>
      widget.options
          .where((o) => o.id == widget.selectedId)
          .firstOrNull
          ?.name ??
      '';

  void _onFocusChange() {
    if (widget.focusNode.hasFocus) {
      _openPop();
      if (_docHead) {
        // 触发框获焦即打开浮层，随后把输入焦点移进浮层顶部搜索框。
        WidgetsBinding.instance.addPostFrameCallback((_) {
          if (_open && mounted) _searchFocus.requestFocus();
        });
      }
    } else if (!_docHead) {
      // 网格 combo：单元格失焦即收起。弹层搜索 combo 的收起改由 选中 / Esc / Tab /
      // 点浮层外（TapRegion.onTapOutside）显式驱动——不再监听搜索框失焦，
      // 避免点选项时「按下即失焦→微任务提前拆浮层→onTap 落空」的竞态（选中不填充）。
      _closePop();
    }
  }

  void _dismiss() {
    _searchFocus.unfocus();
    widget.focusNode.unfocus();
    _closePop();
  }

  // ── 浮层开合 ────────────────────────────────────────────────────────────
  void _openPop() {
    if (_open || !widget.enabled) return;
    _open = true;
    _kw = '';
    _remote = null;
    _ctrl.text = '';
    _rebuildEntries();
    _entry = OverlayEntry(builder: _buildPop);
    Overlay.of(context).insert(_entry!);
  }

  void _closePop() {
    if (!_open) return;
    _open = false;
    _debounce?.cancel();
    _ctrl.text = '';
    _removeOverlay();
    if (mounted) setState(() {});
  }

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

  List<OptionItem> get _sourceOptions => _remote ?? widget.options;

  void _rebuildEntries() {
    final kw = _kw.trim();
    final matched = kw.isEmpty
        ? _sourceOptions
        : _sourceOptions.where((o) => o.matches(kw)).toList();
    final list = <_PopEntry>[];
    for (final o in matched) {
      list.add(_PopEntry.opt(o));
    }
    final canCreate = widget.allowCreate &&
        widget.onCreate != null &&
        kw.isNotEmpty &&
        !_sourceOptions.any((o) => o.name == kw);
    if (canCreate) list.add(_PopEntry.create(kw));
    _entries = list;
    // 当前高亮：选中项优先，否则首项
    _cursor =
        list.indexWhere((e) => !e.isCreate && e.opt!.id == widget.selectedId);
    if (_cursor < 0) _cursor = list.isEmpty ? -1 : 0;
    _entry?.markNeedsBuild();
  }

  void _onInput(String v) {
    _kw = v;
    if (widget.onSearch != null) {
      _debounce?.cancel();
      _debounce = Timer(const Duration(milliseconds: 250), () async {
        final res = await widget.onSearch!(v.trim());
        if (!mounted || !_open) return;
        _remote = res;
        _rebuildEntries();
      });
      // 本地即时反馈（用已有 options 过滤）
      _rebuildEntries();
    } else {
      _rebuildEntries();
    }
  }

  void _move(int d) {
    if (_entries.isEmpty) return;
    _cursor = (_cursor + d + _entries.length) % _entries.length;
    _entry?.markNeedsBuild();
    _scrollToCursor();
  }

  void _scrollToCursor() {
    if (!_listScroll.hasClients || _cursor < 0) return;
    const itemH = 36.0;
    final target = _cursor * itemH;
    final vp = _listScroll.position.viewportDimension;
    final off = _listScroll.offset;
    if (target < off) {
      _listScroll.jumpTo(target);
    } else if (target + itemH > off + vp) {
      _listScroll.jumpTo(
          (target + itemH - vp).clamp(0, _listScroll.position.maxScrollExtent));
    }
  }

  Future<void> _pickCursor({required bool byKeyboard}) async {
    if (_cursor < 0 || _cursor >= _entries.length) return;
    final e = _entries[_cursor];
    if (e.isCreate) {
      final id = await widget.onCreate!(e.createKw!);
      if (id != null) {
        widget.onChanged(id);
        if (byKeyboard) widget.onPickedByKeyboard?.call();
      }
      _dismiss();
      return;
    }
    widget.onChanged(e.opt!.id);
    _dismiss();
    if (byKeyboard) widget.onPickedByKeyboard?.call();
  }

  KeyEventResult _onKey(FocusNode node, KeyEvent event) {
    if (event is! KeyDownEvent && event is! KeyRepeatEvent) {
      return KeyEventResult.ignored;
    }
    final key = event.logicalKey;
    if (!_open) {
      if (key == LogicalKeyboardKey.enter ||
          key == LogicalKeyboardKey.arrowDown) {
        _openPop();
        return KeyEventResult.handled;
      }
      return KeyEventResult.ignored;
    }
    if (key == LogicalKeyboardKey.arrowDown) {
      _move(1);
      return KeyEventResult.handled;
    }
    if (key == LogicalKeyboardKey.arrowUp) {
      _move(-1);
      return KeyEventResult.handled;
    }
    if (key == LogicalKeyboardKey.enter ||
        key == LogicalKeyboardKey.numpadEnter) {
      _pickCursor(byKeyboard: true);
      return KeyEventResult.handled;
    }
    if (key == LogicalKeyboardKey.escape) {
      _dismiss();
      return KeyEventResult.handled;
    }
    if (key == LogicalKeyboardKey.tab) {
      final backward = HardwareKeyboard.instance.isShiftPressed;
      // 先按当前高亮选中（若有），再收起本浮层并交给上层移动焦点。
      // 收起必须显式做：已移除搜索框失焦监听，Tab 走后不再自动关闭。
      if (_cursor >= 0 && !_entries[_cursor].isCreate) {
        widget.onChanged(_entries[_cursor].opt!.id);
      }
      _closePop();
      final handled = widget.onTab?.call(backward: backward) ?? false;
      return handled ? KeyEventResult.handled : KeyEventResult.ignored;
    }
    return KeyEventResult.ignored;
  }

  void _clear() {
    widget.onChanged(null);
  }

  // ── 浮层内容 ───────────────────────────────────────────────────────────
  Widget _buildPop(BuildContext ctx) {
    final t = context.tokens;
    final field = context.findRenderObject() as RenderBox?;
    final width = (field?.size.width ?? 200).clamp(200.0, 420.0);
    return Positioned(
      width: width,
      child: CompositedTransformFollower(
        link: _link,
        showWhenUnlinked: false,
        targetAnchor: Alignment.bottomLeft,
        followerAnchor: Alignment.topLeft,
        offset: const Offset(0, 4),
        child: TapRegion(
          onTapOutside: (_) => _dismiss(),
          child: Material(
            elevation: 6,
            borderRadius: BorderRadius.circular(AppDims.rMd),
            color: t.surface,
            child: Container(
              decoration: BoxDecoration(
                border: Border.all(color: t.border),
                borderRadius: BorderRadius.circular(AppDims.rMd),
              ),
              clipBehavior: Clip.antiAlias,
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  if (_docHead) _buildSearch(t),
                  Flexible(child: _buildList(t)),
                  if (widget.showCount) _buildCount(t),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  // 浮层顶部持久搜索框（对齐原型 .combo-pop > .cp-search，仅单据头 combo）。
  Widget _buildSearch(AppTokens t) {
    final hint = widget.searchHint ?? widget.hint;
    return Container(
      padding: const EdgeInsets.fromLTRB(11, 9, 11, 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: Focus(
              canRequestFocus: false,
              onKeyEvent: _onKey,
              child: TextField(
                controller: _ctrl,
                focusNode: _searchFocus,
                autofocus: true,
                style: TextStyle(fontSize: AppDims.fsBody, color: t.text),
                cursorColor: t.primary,
                onChanged: _onInput,
                onSubmitted: (_) => _pickCursor(byKeyboard: true),
                decoration: InputDecoration(
                  isCollapsed: true,
                  contentPadding: EdgeInsets.zero,
                  border: InputBorder.none,
                  filled: false,
                  enabledBorder: InputBorder.none,
                  focusedBorder: InputBorder.none,
                  hintText: hint,
                  hintStyle:
                      TextStyle(fontSize: AppDims.fsBody, color: t.faint),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildList(AppTokens t) {
    if (_entries.isEmpty) {
      return Padding(
        padding: const EdgeInsets.all(20),
        child: Text('无匹配结果',
            textAlign: TextAlign.center,
            style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
      );
    }
    final kw = _kw.trim();
    final commonMode = kw.isEmpty && widget.commonIds.isNotEmpty;
    return ConstrainedBox(
      constraints: const BoxConstraints(maxHeight: 264),
      child: ListView.builder(
        controller: _listScroll,
        padding: const EdgeInsets.all(5),
        shrinkWrap: true,
        itemCount: _entries.length + (commonMode ? _groupHeaderCount() : 0),
        itemBuilder: (c, i) => _rowAt(t, i, commonMode, kw),
      ),
    );
  }

  // 「常用 / 全部」分组时插入两个 header，索引需换算。
  int _commonCount() => _entries
      .where((e) => !e.isCreate && widget.commonIds.contains(e.opt!.id))
      .length;
  int _groupHeaderCount() {
    final c = _commonCount();
    final r = _entries.where((e) => !e.isCreate).length - c;
    return (c > 0 ? 1 : 0) + (r > 0 ? 1 : 0);
  }

  Widget _rowAt(AppTokens t, int i, bool commonMode, String kw) {
    if (!commonMode) return _entryRow(t, i, kw);
    // 分组渲染：常用组 header + 常用项，全部组 header + 其余项
    final common = <int>[];
    final rest = <int>[];
    for (var k = 0; k < _entries.length; k++) {
      final e = _entries[k];
      if (e.isCreate) {
        rest.add(k);
      } else if (widget.commonIds.contains(e.opt!.id)) {
        common.add(k);
      } else {
        rest.add(k);
      }
    }
    final seq = <Widget Function()>[];
    if (common.isNotEmpty) {
      seq.add(() => _groupHeader(t, '常用'));
      for (final k in common) {
        seq.add(() => _entryRow(t, k, kw));
      }
    }
    if (rest.isNotEmpty) {
      seq.add(() => _groupHeader(t, '全部'));
      for (final k in rest) {
        seq.add(() => _entryRow(t, k, kw));
      }
    }
    return seq[i]();
  }

  Widget _groupHeader(AppTokens t, String label) => Padding(
        padding: const EdgeInsets.fromLTRB(9, 8, 9, 4),
        child: Text(label,
            style: TextStyle(
                fontSize: AppDims.fsXs,
                color: t.faint,
                fontWeight: FontWeight.w600,
                letterSpacing: 0.5)),
      );

  Widget _entryRow(AppTokens t, int idx, String kw) {
    final e = _entries[idx];
    final cur = idx == _cursor;
    if (e.isCreate) {
      return _PopRow(
        cur: cur,
        onTap: () => _pickCursor(byKeyboard: false),
        onHover: () => _setCursor(idx),
        topBorder: t.borderSubtle,
        child: Row(children: [
          Icon(LucideIcons.plus, size: 14, color: t.primary),
          const SizedBox(width: 8),
          Expanded(
            child: Text('新增「${e.createKw}」到基础数据',
                overflow: TextOverflow.ellipsis,
                style: TextStyle(
                    fontSize: AppDims.fsSm,
                    color: t.primary,
                    fontWeight: FontWeight.w600)),
          ),
        ]),
      );
    }
    final o = e.opt!;
    final sel = o.id == widget.selectedId;
    return _PopRow(
      cur: cur,
      onTap: () {
        _setCursor(idx);
        _pickCursor(byKeyboard: false);
      },
      onHover: () => _setCursor(idx),
      child: Row(children: [
        Expanded(
          child: _highlight(o.name, kw, t, sel ? t.primary : t.text,
              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),
        ],
      ]),
    );
  }

  void _setCursor(int i) {
    if (_cursor == i) return;
    _cursor = i;
    _entry?.markNeedsBuild();
  }

  Widget _highlight(
      String name, String kw, AppTokens t, Color base, FontWeight w) {
    if (kw.isEmpty) {
      return Text(name,
          overflow: TextOverflow.ellipsis,
          style:
              TextStyle(fontSize: AppDims.fsBody, color: base, fontWeight: w));
    }
    final lower = name.toLowerCase();
    final i = lower.indexOf(kw.toLowerCase());
    if (i < 0) {
      return Text(name,
          overflow: TextOverflow.ellipsis,
          style:
              TextStyle(fontSize: AppDims.fsBody, color: base, fontWeight: w));
    }
    return RichText(
      overflow: TextOverflow.ellipsis,
      text: TextSpan(
        style: TextStyle(fontSize: AppDims.fsBody, color: base, fontWeight: w),
        children: [
          TextSpan(text: name.substring(0, i)),
          TextSpan(
              text: name.substring(i, i + kw.length),
              style: TextStyle(color: t.primary, fontWeight: FontWeight.w700)),
          TextSpan(text: name.substring(i + kw.length)),
        ],
      ),
    );
  }

  Widget _buildCount(AppTokens t) {
    final total = _sourceOptions.length;
    final kw = _kw.trim();
    final matched = _entries.where((e) => !e.isCreate).length;
    return 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(
        kw.isEmpty ? '共 $total 条结果' : '匹配 $matched 条 · 共 $total 条',
        style: TextStyle(fontSize: AppDims.fsXs, color: t.muted),
      ),
    );
  }

  // ── 输入框本体 ─────────────────────────────────────────────────────────
  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    final has = widget.selectedId != null;
    final height = widget.cell ? 32.0 : 38.0;
    final borderColor = widget.hasError
        ? t.danger
        : (_open ? t.primary : (widget.cell ? Colors.transparent : t.border));
    return CompositedTransformTarget(
      link: _link,
      child: Container(
        height: height,
        decoration: BoxDecoration(
          color: widget.cell
              ? (_open ? t.surface : Colors.transparent)
              : t.surface,
          border: Border.all(color: borderColor),
          borderRadius: BorderRadius.circular(widget.cell ? 5 : AppDims.rMd),
          boxShadow: _open
              ? [
                  BoxShadow(
                      color: t.brand50,
                      blurRadius: 0,
                      spreadRadius: widget.cell ? 2 : 3)
                ]
              : null,
        ),
        child: Row(
          children: [
            Expanded(
              child: Focus(
                focusNode: widget.focusNode,
                onKeyEvent: _onKey,
                child: Builder(builder: (context) {
                  // 单据头 combo：触发框始终只读展示（输入在浮层顶部搜索框）；
                  // 网格 combo：聚焦时就地变为可输入过滤框。
                  if (!_open || _docHead) {
                    return GestureDetector(
                      behavior: HitTestBehavior.opaque,
                      onTap: widget.enabled
                          ? () => widget.focusNode.requestFocus()
                          : null,
                      child: Padding(
                        padding: EdgeInsets.only(
                            left: widget.cell ? 8 : 11, right: 4),
                        child: Align(
                          alignment: Alignment.centerLeft,
                          child: Text(
                            has ? _selectedName : widget.hint,
                            overflow: TextOverflow.ellipsis,
                            style: TextStyle(
                                fontSize: AppDims.fsBody,
                                color: has ? t.text : t.faint),
                          ),
                        ),
                      ),
                    );
                  }
                  return TextField(
                    controller: _ctrl,
                    autofocus: true,
                    style: TextStyle(fontSize: AppDims.fsBody, color: t.text),
                    cursorColor: t.primary,
                    decoration: InputDecoration(
                      isCollapsed: true,
                      contentPadding:
                          EdgeInsets.only(left: widget.cell ? 8 : 11, right: 4),
                      border: InputBorder.none,
                      filled: false,
                      enabledBorder: InputBorder.none,
                      focusedBorder: InputBorder.none,
                      hintText: has ? _selectedName : widget.hint,
                      hintStyle:
                          TextStyle(fontSize: AppDims.fsBody, color: t.faint),
                    ),
                    onChanged: _onInput,
                  );
                }),
              ),
            ),
            // caf：有值→X 清除；无值→chevron
            GestureDetector(
              behavior: HitTestBehavior.opaque,
              onTap: widget.enabled
                  ? () {
                      if (has) {
                        _clear();
                      } else {
                        widget.focusNode.requestFocus();
                      }
                    }
                  : null,
              child: Padding(
                padding: EdgeInsets.only(right: widget.cell ? 6 : 8, left: 2),
                child: Icon(
                  has ? LucideIcons.x : LucideIcons.chevronDown,
                  size: 14,
                  color: t.faint,
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _PopRow extends StatelessWidget {
  final bool cur;
  final Widget child;
  final VoidCallback onTap;
  final VoidCallback onHover;
  final Color? topBorder;
  const _PopRow({
    required this.cur,
    required this.child,
    required this.onTap,
    required this.onHover,
    this.topBorder,
  });

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    return MouseRegion(
      onEnter: (_) => onHover(),
      child: GestureDetector(
        onTap: onTap,
        behavior: HitTestBehavior.opaque,
        child: Container(
          height: 36,
          padding: const EdgeInsets.symmetric(horizontal: 10),
          alignment: Alignment.centerLeft,
          decoration: BoxDecoration(
            color: cur ? t.rowHover : Colors.transparent,
            borderRadius: BorderRadius.circular(AppDims.rSm),
            border: topBorder != null
                ? Border(top: BorderSide(color: topBorder!))
                : null,
          ),
          child: child,
        ),
      ),
    );
  }
}