import 'package:fis_common/event/event_type.dart';
import 'package:fis_measure/interfaces/process/items/item.dart';
import 'package:fis_measure/interfaces/process/items/item_metas.dart';
import 'package:fis_measure/interfaces/process/workspace/point_info.dart';
import 'package:flutter/foundation.dart';

import 'item.dart';
import 'item_feature.dart';

abstract class TopMeasureItem<T extends MeasureItemFeature>
    extends MeasureItem<T> implements ITopMeasureItem {
  final List<IMeasureItem> _childItems = [];
  int _childIndex = 0;

  TopMeasureItem(ItemMeta meta) : super(meta) {
    workingChildChanged = FEventHandler<int>();
  }

  @override
  List<IMeasureItem> get childItems => _childItems;

  @override
  IMeasureItem get workingChild => _childItems[_childIndex];

  /// 子项全部完成
  @protected
  bool get childrenAllDone =>
      _childItems.every((e) => e.measuredFeatures.isNotEmpty);

  @override
  late final FEventHandler<int> workingChildChanged;

  @override
  void switchChild(int index) {
    if (index == _childIndex) return;

    _childIndex = index;
    workingChildChanged.emit(this, index);
  }

  T buildFeature();

  @override
  bool onExecuteMouse(PointInfo args) {
    if (args.pointType == PointInfoType.mouseDown) {
      if (feature == null) {
        feature = buildFeature();
        listenChildrenUpdate();
      }
      if (childrenAllDone) {
        workingChild.clear();
      }
    }
    feature?.hostVisualArea = args.hostVisualArea;
    final result = workingChild.execute(args);
    if (result) {
      doCalculate();
    }
    return result;
  }

  @override
  bool onExecuteTouch(PointInfo args) {
    return workingChild.execute(args);
  }

  @protected
  void nextChild() {
    final count = _childItems.length;
    int nextIdx = -1;
    for (var i = 0; i < count; i++) {
      final child = _childItems[i];
      if (child.measuredFeatures.isEmpty) {
        nextIdx = i;
        break;
      }
    }
    if (nextIdx > -1) {
      switchChild(nextIdx);
    }
  }

  @protected
  void listenChildrenUpdate() {
    for (var item in childItems) {
      item.featureUpdated.addListener((sender, e) {
        _onChildFeatureUpdated();
      });
    }
  }

  void _onChildFeatureUpdated() {
    if (workingChild.measuredFeatures.isNotEmpty) {
      nextChild();
    }
    doFeatureUpdate();
  }
}