import {IRecordTransformer} from './record-transformer.interface';
import {
  RecordCollection,
  ISerializedRecordCollection
} from '../record-collection';
import _ from 'lodash';

export class EsSearchRecordTransformService
  implements IRecordTransformer<IEsSearchHit[]> {

  transform(
    rawData: IEsSearchHit[],
    opts: ISerializedRecordCollection = {}): RecordCollection {
    const data = this.extractNestedAttributes(rawData);
    const columns = this.parseColumns(data);
    const records = this.parseRecords(data, opts);
    return new RecordCollection(
      _.defaults(
        {
          fields: columns,
          records: records,
          geoTransformStrategy: 'getOwnReference'
        },
        opts
      )
    );
  }

  private parseColumns(data: IEsSearchHit[]) {
    const firstHit = data[0] ? data[0]._source : undefined;
    return firstHit ?
      _.reduce(firstHit, this.reduceHitToColumns.bind(this), []) :
      [];
  }

  private reduceHitToColumns(acc: IEsSearchResultColumn[], value, key)
  : IEsSearchResultColumn[] {
    return !_.isArray(value) ? this.addColTo(acc, key) : acc;
  }

  private addColTo(acc: IEsSearchResultColumn[], key: any) {
    const label = this.resolveLabel(key);
    return acc.concat({
      name: key,
      label: label,
      visible: key === 'geoJson' ? false : true
    });
  }

  private resolveLabel(key): string {
    const cumRegex = /([Cc])um/;
    return _.startCase(key).replace(cumRegex, '$1umulative');
  }

  private parseRecords(
    data: IEsSearchHit[],
    opts: ISerializedRecordCollection)
  : any {
    return _(data)
      .map('_source')
      .map(source => this.filterFlatRecords(source))
      .map(record => this.addMapMetadata(record, opts))
      .value();
  }

  private filterFlatRecords(source: any): any {
    return _.pick(source, value => !_.isArray(value));
  }

  private extractNestedAttributes(rawData: IEsSearchHit[]): any {
    return _.map(rawData, (data: IEsSearchHit) => {
      const source = data._source;
      if (source.qualifyTaxRates[0]) {
        source.leaseName = source.qualifyTaxRates[0].leaseName;
        source.leaseNumber = source.leaseName;
      }
      const operators = source.operators;
      if (operators[0]) {
        source['operator_names'] = operators[0].companyName;
      }
      return data;
    });
  }

  private addMapMetadata(record: any, opts: ISerializedRecordCollection): any {
    // all of this is a pretty ugly bandaid over having to bridge between
    // data from es & ows and what attributes the map expects to be present in
    // order to map the data. Ideally, once we rely fully on elastic search
    // we can just alter the DocRenderSettings class in atla-map to change
    // what the map expects when applying styles. 
    const date = new Date(record.firstReportedMonth).toISOString().slice(0, 10);
    record['timespan'] = {begin: date};
    record['record-type'] = opts.name;
    record['cumulative_oil'] = record.oilCum;
    record['cumulative_gas'] = record.gasCum;
    return record;
  }
}

export interface IEsSearchHit {
  _id: string;
  _index: string;
  _score: number;
  _source: any;
  _type: string;
}

export interface IEsSearchResultColumn {
  name: string;
  label: string;
  visible: boolean;
}