part of "./side_nav.dart";

class _SideBar extends StatefulWidget {
  /// 导航Id
  final int? navId;

  /// 菜单项集合
  final List<VSideNavMenuItem> items;

  final VSideNavViewController controller;

  const _SideBar({
    required this.controller,
    this.navId,
    required this.items,
  });

  @override
  State<StatefulWidget> createState() => _SideBarState();
}

class _SideBarState extends State<_SideBar> {
  static const double _cellHegiht = 68.0;

  @override
  void initState() {
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      if (mounted) {
        widget.controller.titleChangedEvent.addListener(_onTitleChanged);
      }
    });
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return Scrollbar(
      thumbVisibility: true,
      child: ListView(
        padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 12),
        children: _buildChildren(context),
      ),
    );
  }

  List<Widget> _buildChildren(BuildContext context) {
    final children = <Widget>[];

    final hasAnyIcon = widget.items.any((e) => e.icon != null);

    final divider = Divider(
      height: 1,
      color: Colors.grey.shade400,
      indent: hasAnyIcon ? 36 : 0,
      endIndent: 12,
    );

    final count = widget.items.length;
    for (var i = 0; i < count; i++) {
      final item = widget.items[i];

      if (item.shouldRearrage) {
        children.add(const SizedBox(height: 32));
      } else if (i > 0) {
        children.add(divider);
      }

      final cell = _buildMenuCell(item);
      children.add(cell);
    }

    return children;
  }

  Widget _buildMenuCell(VSideNavMenuItem item) {
    final hasSection = item.title == widget.controller.currentTitle;

    final cell = Padding(
      padding: const EdgeInsets.symmetric(horizontal: 12),
      child: VListFormCell(
        height: _cellHegiht,
        leadingIcon: Container(
          alignment: Alignment.center,
          child: item.icon,
        ),
        leadingIconWidth: 36,
        label: item.title,
        onTap: () {
          _onItemTap(item, hasSection);
        },
      ),
    );
    if (hasSection) {
      return _buildSectionItem(cell);
    } else {
      return cell;
    }
  }

  Widget _buildSectionItem(Widget itemWidget) {
    return SizedBox(
      height: _cellHegiht,
      child: Stack(
        children: [
          itemWidget,
          Positioned.fill(
            child: Container(
              decoration: BoxDecoration(
                borderRadius: GlobalStyles.borderRadius,
                color: Theme.of(context).primaryColor.withOpacity(.2),
              ),
            ),
          ),
        ],
      ),
    );
  }

  void _onTitleChanged(_, String? e) {
    setState(() {});
  }

  void _onItemTap(VSideNavMenuItem item, bool hasSection) {
    if (item.onTap != null) {
      item.onTap!.call();
      return;
    }

    if (hasSection) {
      // 不可重复路由
      return;
    }
    if (item.pageBuilder != null) {
      widget.controller.pageChangedEvent.emit(this, item.pageBuilder!);
      widget.controller.titleChangedEvent.emit(this, item.title);
    }
    if (item.route != null) {
      Get.offAllNamed(item.route!.name, id: widget.navId);
    }
  }
}