import {IGeoTransformStrategy} from './geo-transform-strategy.interface';
import {IRecord, RecordCollection} from '../record-collection';
import {
  IGeoJSONFeature,
  IFeatureCollection
} from '../../utility/feature-collection.interface';
import {FeatureIdService} from '../../utility/feature-id.service';
import * as turf from 'turf';

export class OwsKmlTransformStrategy implements IGeoTransformStrategy {
  private coordinateRegex: RegExp = /<coordinates>(.*?)<\/coordinates>/;
  private idService: FeatureIdService = new FeatureIdService();

  transform(record: IRecord, collection: RecordCollection): IFeatureCollection {
    const pointFeature =
      this.hasPointFeature(record) ? this.getPointFeature(record) : null;
    const polygonFeature =
      this.hasPolygonFeature(record) ? this.getPolygonFeature(record) : null;

    return _([pointFeature, polygonFeature])
      .filter(_.isObject)
      .map(this.idService.addFeatureId)
      .thru(features => <IFeatureCollection>turf.featurecollection(features))
      .value();
  }

  private getPointFeature(record: IRecord): IGeoJSONFeature {
    const kml = this.findPointKml(record);
    const coords = this.parseCoordinates(kml);

    return turf.point(coords[0], record);
  }

  private getPolygonFeature(record: IRecord): IGeoJSONFeature {
    const kml = this.findPolygonKml(record);
    const coords = this.parseCoordinates(kml);

    return turf.polygon([coords], record);
  }

  hasPointFeature(record: IRecord): boolean {
    return !!(this.findPointKml(record));
  }

  hasPolygonFeature(record: IRecord): boolean {
    return !!(this.findPolygonKml(record));
  }

  private findPointKml(record: IRecord): string {
    return record['kml_centroid']
      || record['kml_centroid_tract']
      || record['kml_tract_centroid'];
  }

  private findPolygonKml(record: IRecord): string {
    return record['kml_polygon']
      || record['kml_polygon_tract']
      || record['kml_tract_polygon'];
  }

  private parseCoordinates(kml: string): number[][] {
    const coordString = this.coordinateRegex.exec(kml)[1];

    return _.map(
      coordString.split(' '),
      coords => _.map(coords.split(','), parseFloat)
    );
  }
}