const AWS = require('aws-sdk');
const { parse, generate } = require('csv');

class CsvData {

  constructor() {
    this.s3 = new AWS.S3();

    // defaults for bucket and main CSV name
    this.bucketName = process.env.OB_SCRAPE_BUCKET || 'obregstoretest';
    this.keyName = process.env.OB_SCRAPE_KEYNAME || 'artefacts/UK/FCA/latest/Firms with PSD Permissions (CSV).csv';
  }

  async _getCsvDataFromS3() {
    return this.s3.getObject({
      'Bucket': this.bucketName,
      'Key': this.keyName
    }).promise();
  }

  async _parseCsvBufferData(csvBufferData) {
    return new Promise((resolve, reject) => {
      parse(
        csvBufferData.Body.toString('utf-8'),
        {
          'columns': true, // required to create objects (instead of array of strings), auto-discovery works fine
          'relax_column_count': true // needs to set to false as header have info when file was generated as extra column
        },
        (err, data) => {
          if (err) return reject(err);
          resolve(data);
        }
      );
    });
  }

  async _getFrnAndName(data) {
    return data.map(el => ({
      'frn': el.FRN,
      'firm': el.Firm
    }));
  }

  async getOrgIds() {
    const rawCsv = await this._getCsvDataFromS3();
    const parsedCsv = await this._parseCsvBufferData(rawCsv);
    const frnIds = this._getFrnAndName(parsedCsv);

    return frnIds;
  }
}

module.exports = CsvData;