import {IGeoTransformStrategy} from './geo-transform-strategy.interface';
import {OwsKmlTransformStrategy} from './ows-kml-transform-strategy';
import {
  GeoJsonTransformStrategy
}
  from './geojson-transform-strategy';

export class ResolveGeoTransformStrategy {
  static strategyMap: {[name: string]: IGeoTransformStrategy} = {
    owsKml: new OwsKmlTransformStrategy(),
    getOwnReference: new GeoJsonTransformStrategy()
  };

  /**
   * Resolve a transform strategy from its string representation.
   * @param type
   * @returns {IGeoTransformStrategy}
   */
  static resolveStrategy(type: string): IGeoTransformStrategy {
    const strategy = ResolveGeoTransformStrategy.strategyMap[type];

    if (!strategy) {
      throw `Error: No geo transformation strategy for type ${type}`;
    }

    return strategy;
  }

  /**
   * Exports strategy as a string for persistence.
   * @param type
   * @returns {string}
   */
  static exportStrategy(strategy: any): string {
    const exported = _.findKey(
      ResolveGeoTransformStrategy.strategyMap,
      strat => strat === strategy
    );

    if (!exported) {
      throw `Unable to export geo transform strategy`;
    }

    return exported;
  }
}