import Feature from 'ol/Feature';
import Point from 'ol/geom/Point';
import OlMap from 'ol/Map';
import VectorLayer from 'ol/layer/Vector';
import VectorSource from 'ol/source/Vector';
import { fromLonLat } from 'ol/proj';
import { getIconPath } from '@/utils/index';

type PointLayerStyleFactory = (feature: Feature) => any;

type PointLayerManagerOptions = {
  map: OlMap | null;
  createStyle: PointLayerStyleFactory;
};

export class PointLayerManager {
  private map: OlMap | null;
  private createStyle: PointLayerStyleFactory;
  private layerRegistry: Map<string, VectorLayer<VectorSource>> = new Map();
  private layerFeatureIndexes: Map<
    string,
    Map<string, Map<string, Feature[]>>
  > = new Map();

  constructor(options: PointLayerManagerOptions) {
    this.map = options.map;
    this.createStyle = options.createStyle;
  }

  // 备注：同步更新地图实例，供地图初始化后把真实 map 注入点图层管理器。
  setMap(map: OlMap | null) {
    this.map = map;
  }

  // 备注：获取当前屏幕可视区域内的所有点要素（仅包含图层可见且图例可见的要素）。
  getFeaturesInViewport(): Feature[] {
    if (!this.map) return [];

    const extent = this.map.getView().calculateExtent(this.map.getSize());
    if (!extent) return [];

    const [minX, minY, maxX, maxY] = extent;
    const result: Feature[] = [];

    this.forEachFeature((feature, layer) => {
      // 跳过图层本身不可见的要素
      if (!layer.getVisible()) return;

      const geom = feature.getGeometry();
      if (!geom || geom.getType() !== 'Point') return;

      const coords = (geom as Point).getCoordinates();
      const [x, y] = coords;

      if (x >= minX && x <= maxX && y >= minY && y <= maxY) {
        result.push(feature);
      }
    });

    return result;
  }

  // 备注：统一返回当前点图层注册表，供外层做遍历或清理。
  getRegistry() {
    return this.layerRegistry;
  }

  // 备注：按图层 key 获取已注册的点图层实例。
  getLayer(layerKey: string) {
    return this.layerRegistry.get(layerKey);
  }

  // 备注：返回当前所有点图层实例，供命中检测和批量刷新使用。
  getLayers(): VectorLayer<VectorSource>[] {
    return Array.from(this.layerRegistry.values());
  }

  // 备注：判断指定图层 key 的点图层是否已存在。
  hasLayer(layerKey: string): boolean {
    return this.layerRegistry.has(layerKey);
  }

  // 备注：按需获取或创建点图层实例，并自动完成注册与挂载。
  ensureLayer(layerKey: string, layerType?: string) {
    if (!this.map || !layerKey) return null;

    let vectorLayer = this.layerRegistry.get(layerKey);
    if (vectorLayer) {
      return vectorLayer;
    }

    const vectorSource = new VectorSource();
    vectorLayer = new VectorLayer({
      source: vectorSource,
      zIndex: 100,
      declutter: true,
      style: feature => this.createStyle(feature as Feature)
    });
    (vectorLayer as any).type = layerType || layerKey;
    this.layerRegistry.set(layerKey, vectorLayer);
    this.map.addLayer(vectorLayer);
    return vectorLayer;
  }

  // 备注：把后端点位数组转换为 OpenLayers Feature，并写入指定点图层。
  addDataLayer(pointData: any, layerType: string): void {
    if (!this.map) return;

    let dataArray: any[] = [];
    let targetLayerKey = layerType;

    if (Array.isArray(pointData)) {
      dataArray = pointData;
    } else {
      dataArray = pointData?.data || [];
      targetLayerKey = pointData?.key || layerType;
    }

    if (!targetLayerKey) {
      console.warn('缺少图层 Key，无法加载描点');
      return;
    }

    const vectorLayer = this.ensureLayer(targetLayerKey, layerType);
    if (!vectorLayer) return;

    const vectorSource = vectorLayer.getSource();
    if (!vectorSource) {
      return;
    }

    vectorSource.clear();
    this.resetLayerFeatureIndexes(targetLayerKey);

    if (dataArray.length === 0) {
      return;
    }

    const features: Feature[] = [];

    dataArray.forEach((item: any) => {
      const feature = this.createFeature(item, targetLayerKey);
      if (feature) {
        this.indexFeature(targetLayerKey, feature);
        features.push(feature);
      }
    });

    if (features.length > 0) {
      vectorSource.addFeatures(features);
    }
  }

  // 备注：统一控制整个点图层显隐，供图层树勾选联动使用。
  setLayerVisible(layerKey: string, visible?: boolean): void {
    const vectorLayer = this.layerRegistry.get(layerKey);
    if (vectorLayer && vectorLayer.getVisible() !== visible) {
      vectorLayer.setVisible(visible);
      vectorLayer.changed();
    }
  }

  // 备注：按图层 key 删除点图层并清空其 source 数据。
  removeLayer(layerKey: string): void {
    if (!this.map || !layerKey) {
      console.warn('removePointLayer: 无效的图层 key 或地图未初始化');
      return;
    }

    const vectorLayer = this.layerRegistry.get(layerKey);
    if (!vectorLayer) {
      console.warn(`未找到标识为 [${layerKey}] 的描点图层实例`);
      return;
    }

    const source = vectorLayer.getSource();
    if (source) {
      source.clear();
    }
    this.map.removeLayer(vectorLayer);
    this.layerRegistry.delete(layerKey);
    this.layerFeatureIndexes.delete(layerKey);
  }

  // 备注：按图层遍历所有点图层实例，供 hover 刷新和区域裁切复用。
  forEachLayer(
    callback: (layer: VectorLayer<VectorSource>, layerKey: string) => void
  ): void {
    this.layerRegistry.forEach((layer, layerKey) => {
      callback(layer, layerKey);
    });
  }

  // 备注：遍历所有点要素，供区域裁切或批量状态更新使用。
  forEachFeature(
    callback: (
      feature: Feature,
      layer: VectorLayer<VectorSource>,
      layerKey: string
    ) => void
  ): void {
    this.forEachLayer((layer, layerKey) => {
      const source = layer.getSource();
      if (!source) return;
      source.getFeatures().forEach(feature => {
        callback(feature as Feature, layer, layerKey);
      });
    });
  }

  // 备注：按图例字段值统一控制要素显隐，供图例和容量筛选联动复用。
  setLegendVisibleByField(
    layerKey: string,
    matchValue: string,
    checked: boolean,
    fieldKey: string = 'anchoPointState'
  ): void {
    const vectorLayer = this.layerRegistry.get(layerKey);
    if (!vectorLayer) return;

    const source = vectorLayer.getSource();
    if (!source) return;

    if (!matchValue) {
      source.getFeatures().forEach(feature => {
        if (feature.get('_legendVisible') !== false) {
          feature.set('_legendVisible', false);
          feature.changed();
        }
      });
      vectorLayer.changed();
      return;
    }

    const targetFeatures = this.getIndexedFeatures(
      layerKey,
      fieldKey,
      matchValue
    );
    if (targetFeatures.length === 0) return;

    targetFeatures.forEach(feature => {
      if (feature.get('_legendVisible') !== checked) {
        feature.set('_legendVisible', checked);
        feature.changed();
      }
    });
    vectorLayer.changed();
  }

  // 备注：统一销毁所有点图层并清空注册表，供地图销毁阶段复用。
  destroy(): void {
    this.forEachLayer(layer => {
      const source = layer.getSource();
      if (source) {
        source.clear();
      }
      if (this.map && this.map.getLayers().getArray().includes(layer)) {
        this.map.removeLayer(layer);
      }
      if ((layer as any).setMap) {
        (layer as any).setMap(null);
      }
    });
    this.layerRegistry.clear();
    this.layerFeatureIndexes.clear();
  }

  // 备注：统一把业务点位数据转换为 Feature，并补齐样式依赖字段。
  private createFeature(item: any, targetLayerKey: string): Feature | null {
    const { lgtd, lttd, stnm, iconCode, titleName, ennm } = item;

    if (lgtd == null || lttd == null) {
      return null;
    }

    const lon = Number(lgtd);
    const lat = Number(lttd);
    if (isNaN(lon) || isNaN(lat) || !isFinite(lon) || !isFinite(lat)) {
      return null;
    }
    if (Math.abs(lon) > 180 || Math.abs(lat) > 90) {
      return null;
    }

    const coord = fromLonLat([lon, lat]);
    if (!isFinite(coord[0]) || !isFinite(coord[1])) {
      return null;
    }

    let iconUrl = iconCode ? getIconPath(iconCode) : '';
    if (!iconUrl) {
      iconUrl = getIconPath('default') || '';
    }

    const feature = new Feature({
      geometry: new Point(coord),
      ...item,
      _layerKey: targetLayerKey
    });
    feature.setId(item.stcd || item._id);
    feature.set('_iconUrl', iconUrl);
    feature.set(
      '_labelText',
      item.sttpMap === 'ylfb' ? item.ftp || '' : titleName || stnm || ennm || ''
    );
    feature.set('_legendVisible', true);
    feature.set('_sttpMap', item.sttpMap);
    if (item.popupHtml) {
      feature.set('popupHtml', item.popupHtml);
    }

    return feature;
  }

  // 备注：重置单个图层的字段索引，供重新灌入数据或删除图层时复用。
  private resetLayerFeatureIndexes(layerKey: string): void {
    this.layerFeatureIndexes.set(layerKey, new Map());
  }

  // 备注：按字段值给要素建立索引，供图例切换时快速命中目标锚点集合。
  private indexFeature(layerKey: string, feature: Feature): void {
    const fieldIndexMap =
      this.layerFeatureIndexes.get(layerKey) ||
      new Map<string, Map<string, Feature[]>>();

    const legendFieldKey = 'anchoPointState';
    const legendFieldValue = feature.get(legendFieldKey);
    if (legendFieldValue != null) {
      const valueMap =
        fieldIndexMap.get(legendFieldKey) || new Map<string, Feature[]>();
      const normalizedValue = String(legendFieldValue);
      const targetFeatures = valueMap.get(normalizedValue) || [];
      targetFeatures.push(feature);
      valueMap.set(normalizedValue, targetFeatures);
      fieldIndexMap.set(legendFieldKey, valueMap);
    }

    this.layerFeatureIndexes.set(layerKey, fieldIndexMap);
  }

  // 备注：根据图层 key、字段名和值快速返回目标要素集合，避免图例切换时整层遍历。
  private getIndexedFeatures(
    layerKey: string,
    fieldKey: string,
    matchValue: string
  ): Feature[] {
    const fieldIndexMap = this.layerFeatureIndexes.get(layerKey);
    if (!fieldIndexMap) return [];

    const valueMap = fieldIndexMap.get(fieldKey);
    if (!valueMap) return [];

    return valueMap.get(String(matchValue)) || [];
  }
}