export class GeneIDTypeDetector {
  /**
   * Detect items from a data array starting `ENS` or `LRG`.
   * Returns a number between 0 and 1 defining the fraction of matching genes in the array.
   *
   * @param data Data array with objects or strings
   * @param accessor Accessor function to retrieve a certain field from a data item
   * @param sampleSize Number of samples to test; can be used to limit iterations for large arrays
   */
  static detectIDType(data: any[], accessor: (row: any) => string, sampleSize: number): number {
    const testSize = Math.min(data.length, sampleSize);
    if (testSize <= 0) {
      return 0;
    }

    let foundIDTypes = 0;
    let validSize = 0;

    for (let i = 0; i < testSize; ++i) {
      const v = accessor(data[i]);

      if (v == null || typeof v !== 'string' || v.trim().length === 0) {
        continue; // skip empty samples
      }

      if (v.indexOf('ENS') === 0 || v.indexOf('LRG') === 0) {
        ++foundIDTypes;
      }
      ++validSize;
    }

    return foundIDTypes / validSize;
  }

  static geneIDTypeDetector() {
    return {
      detectIDType: GeneIDTypeDetector.detectIDType,
    };
  }
}