import { Readable } from 'stream';
import Gherkin from 'gherkin';
import { messages } from 'cucumber-messages';
import { UserProperties } from 'json-html-reporter-models';
import { StreamFunctions } from './functions/stream-functions';
import { FileSystemFunctions } from './functions/file-system-functions';

export class CollectFeatureFiles {
  private featuresDir: string;

  public constructor( userProperties?: UserProperties ) {
    this.featuresDir = userProperties.featuresFolder;
  }
  public async collectFeatures(): Promise<messages.IGherkinDocument[]> {
    await new FileSystemFunctions().checkFolder( this.featuresDir ).then( ( result ) => {
      if ( !result && typeof this.featuresDir !== 'undefined' ) {
        throw new Error( `ENOENT: no such file or directory, stat '${this.featuresDir}'` );
      }
    } );

    if ( typeof this.featuresDir === 'undefined' ) {
      return null;
    }

    const files = await new FileSystemFunctions().getFilesAsync( this.featuresDir );
    const featureFiles = files.filter( ( file ) => file.endsWith( '.feature' ) );

    let features = await Promise.all(
      featureFiles.map( async ( feature ) => {
        const stream = await ( <Readable>Gherkin.fromPaths( [feature] ) );
        const gherkinDocument = ( await new StreamFunctions().streamToArrayAsync( stream ) )[1].gherkinDocument;
        return gherkinDocument;
      } ),
    );

    features = features.filter( ( x ) => x );

    return features.length > 0 ? features : null;
  }
}