import VectorLayer from 'ol/layer/Vector';
import GeoJSON from 'ol/format/GeoJSON';
import {Vector as VectorSource} from 'ol/source';
import {EPSG} from "../enums/EPSG";
import Style from 'ol/style/Style';
import Stroke from 'ol/style/Stroke';
import Fill from 'ol/style/Fill';
import {Config} from "../misc/Config";
import {Feature} from 'ol/Feature';
/**
 * Represents a raw (not processed) map layer
 */
export class RawLayer {
  constructor(
    /**
     * Name of layer
     */
    public name: string,
    /**
     * Data of Layer (normally in geojson format)
     */
    public data: string
  ) {
  }

  /**
   * Creates a RawLayer instance from a VectorLayer and saves the style properties in geojson. Consider that the
   * layer color information are applied to each feature!
   * @param layer
   */
  public static fromVectorLayer(layer: VectorLayer): RawLayer {
    const source = layer.getSource();
    const features = source.getFeatures();
    const geoJSONString = RawLayer.featuresToGeoJSON(features);
    return new RawLayer(layer.get('name'), geoJSONString);
  }

  /**
   * Creates a VectorLayer instance from a RawLayer and applies the layer color to all features
   * @param rawLayer
   */
  public static toVectorLayer(rawLayer: RawLayer): VectorLayer {
    const vectorSource = new VectorSource();
    const features = RawLayer.geoJSONToFeatures(rawLayer.data);
    // apply style to all features
    features.forEach(feature => {
      // TODO
      //  determine if this feature has a own color! If so, do not apply default color and use own color.
      const featureProperties = feature.getProperties();
      const strokeColor = featureProperties[Config.GEO_JSON_PREFIX]['default-style-stroke'];
      const fillColor = featureProperties[Config.GEO_JSON_PREFIX]['default-style-fill'];

      feature.setStyle(new Style({
        stroke: new Stroke({
          color: strokeColor,
          width: 1
        }),
        fill: new Fill({
          color: fillColor
        })
      }));
    })

    // add features to source
    vectorSource.addFeatures(features);

    return new VectorLayer({
      name: rawLayer.name,
      renderMode: 'image',
      source: vectorSource
    });
  }

  /**
   * Saves a default color property to geoJSON
   */
  public saveDefaultColor(color: number[]) {
    const features = RawLayer.geoJSONToFeatures(this.data);
    features.forEach(feature => {
      // save default color in feature properties
      const stylesToSave = {};
      stylesToSave[Config.GEO_JSON_PREFIX] = {};
      stylesToSave[Config.GEO_JSON_PREFIX]['default-style-stroke'] = color;
      stylesToSave[Config.GEO_JSON_PREFIX]['default-style-fill'] = [...color.slice(0, 3), 0.1];
      feature.setProperties(stylesToSave);
    })
    this.data = RawLayer.featuresToGeoJSON(features);
  }

  /**
   * Reads the default color property from geoJSON
   */
  public getDefaultColor(): number[]{
    const features = RawLayer.geoJSONToFeatures(this.data);
    const featureProperties = features[0].getProperties();
    return featureProperties[Config.GEO_JSON_PREFIX]['default-style-stroke'];
  }

  /**
   * Creates the features from geoJSON
   */
  private static geoJSONToFeatures(geoJSON: string): Feature[] {
    return new GeoJSON().readFeatures(geoJSON, {featureProjection: EPSG.openLayersDefault});
  }

  /**
   * Creates geoJSON string from features
   * @param features
   */
  private static featuresToGeoJSON(features: Feature[]): string {
    return new GeoJSON().writeFeatures(features, {featureProjection: EPSG.openLayersDefault});
  }
}