smartarchive/ts/classes.archiveanalyzer.ts

import type { SmartArchive } from './classes.smartarchive.js';
import * as plugins from './plugins.js';

export interface IAnalyzedResult {
  fileType: plugins.fileType.FileTypeResult;
  isArchive: boolean;
  resultStream: plugins.smartstream.SmartDuplex;
  decompressionStream:
    | plugins.stream.Transform
    | plugins.stream.Duplex
    | plugins.tarStream.Extract;
}

export class ArchiveAnalyzer {
  smartArchiveRef: SmartArchive;

  constructor(smartArchiveRefArg: SmartArchive) {
    this.smartArchiveRef = smartArchiveRefArg;
  }

  private async mimeTypeIsArchive(mimeType: string): Promise<boolean> {
    const archiveMimeTypes: Set<string> = new Set([
      'application/zip',
      'application/x-rar-compressed',
      'application/x-tar',
      'application/gzip',
      'application/x-7z-compressed',
      'application/x-bzip2',
      // Add other archive mime types here
    ]);

    return archiveMimeTypes.has(mimeType);
  }

  private async getDecompressionStream(
    mimeTypeArg: plugins.fileType.FileTypeResult['mime'],
  ): Promise<
    plugins.stream.Transform | plugins.stream.Duplex | plugins.tarStream.Extract
  > {
    switch (mimeTypeArg) {
      case 'application/gzip':
        return this.smartArchiveRef.gzipTools.getDecompressionStream();
      case 'application/zip':
        return this.smartArchiveRef.zipTools.getDecompressionStream();
      case 'application/x-bzip2':
        return await this.smartArchiveRef.bzip2Tools.getDecompressionStream(); // replace with your own bzip2 decompression stream
      case 'application/x-tar':
        return this.smartArchiveRef.tarTools.getDecompressionStream(); // replace with your own tar decompression stream
      default:
        // Handle unsupported formats or no decompression needed
        return plugins.smartstream.createPassThrough();
    }
  }

  public getAnalyzedStream() {
    let firstRun = true;
    const resultStream = plugins.smartstream.createPassThrough();
    const analyzerstream = new plugins.smartstream.SmartDuplex<
      Buffer,
      IAnalyzedResult
    >({
      readableObjectMode: true,
      writeFunction: async (chunkArg: Buffer, streamtools) => {
        if (firstRun) {
          firstRun = false;
          const fileType = await plugins.fileType.fileTypeFromBuffer(chunkArg);
          const decompressionStream = await this.getDecompressionStream(
            fileType?.mime as any,
          );
          /**
           * analyzed stream emits once with this object
           */
          const result: IAnalyzedResult = {
            fileType,
            isArchive: await this.mimeTypeIsArchive(fileType?.mime),
            resultStream,
            decompressionStream,
          };
          await streamtools.push(result);
        }
        await resultStream.backpressuredPush(chunkArg);
        return null;
      },
      finalFunction: async (tools) => {
        resultStream.push(null);
        return null;
      },
    });
    return analyzerstream;
  }
}