bookorbit/server/test/e2e/metadata-write/metadata-write-fixture-builder.ts

import { ZipArchive } from 'archiver';
import { execFile as execFileCallback } from 'child_process';
import { randomUUID } from 'crypto';
import { createWriteStream } from 'fs';
import { mkdir, mkdtemp, rm, writeFile } from 'fs/promises';
import { createRequire } from 'module';
import { tmpdir } from 'os';
import { dirname, isAbsolute, join, normalize } from 'path';
import { PDFDocument } from 'pdf-lib';
import { promisify } from 'util';

import { getSevenZip } from '../../../src/common/sevenzip';

export interface MetadataWriteFixtureRoot {
  rootPath: string;
  booksPath: string;
  cleanup: () => Promise<void>;
}

export interface ZipEntryInput {
  path: string;
  content: string | Buffer;
  store?: boolean;
}

interface EpubFixtureInput {
  title?: string;
  language?: string;
  uid?: string;
  /** Adds a stored entry of this many bytes, for a file genuinely over a size limit on disk. */
  paddingBytes?: number;
}

interface Fb2FixtureInput {
  title?: string;
  language?: string;
  bodyText?: string;
}

interface ComicFixtureInput {
  title?: string;
  author?: string;
  publisher?: string;
  year?: number;
  genre?: string;
  tags?: string;
}

const execFile = promisify(execFileCallback);
const requireInstaller = createRequire(__filename);

/**
 * The FFmpeg and FFprobe builds the test suite ships with, so audio scenarios do not depend on
 * whatever the machine running them has installed.
 */
export function bundledFfmpegPaths(): { ffmpeg: string; ffprobe: string } {
  const ffmpeg = requireInstaller('@ffmpeg-installer/ffmpeg') as { path: string };
  const ffprobe = requireInstaller('@ffprobe-installer/ffprobe') as { path: string };
  return { ffmpeg: ffmpeg.path, ffprobe: ffprobe.path };
}

export async function createM4bFixture(rootPath: string, relativePath: string, input: { title: string; durationSeconds?: number }): Promise<string> {
  assertRelativePath(relativePath);
  const absolutePath = join(rootPath, relativePath);
  await mkdir(dirname(absolutePath), { recursive: true });
  await execFile(bundledFfmpegPaths().ffmpeg, [
    '-hide_banner',
    '-loglevel',
    'error',
    '-f',
    'lavfi',
    '-i',
    `sine=frequency=440:sample_rate=8000:duration=${input.durationSeconds ?? 1}`,
    '-c:a',
    'aac',
    '-b:a',
    '16k',
    '-metadata',
    `title=${input.title}`,
    '-metadata',
    `album=${input.title}`,
    '-f',
    'ipod',
    absolutePath,
  ]);
  return absolutePath;
}

export async function readAudioTags(absolutePath: string): Promise<Record<string, string>> {
  const { stdout } = await execFile(bundledFfmpegPaths().ffprobe, ['-v', 'error', '-show_entries', 'format_tags', '-of', 'json', absolutePath]);
  const tags = (JSON.parse(String(stdout)) as { format?: { tags?: Record<string, string> } }).format?.tags ?? {};
  return Object.fromEntries(Object.entries(tags).map(([key, value]) => [key.toLowerCase(), value]));
}

function assertRelativePath(relativePath: string): void {
  const normalized = normalize(relativePath);
  if (isAbsolute(relativePath) || normalized === '..' || normalized.startsWith('../') || normalized.startsWith('..\\')) {
    throw new Error(`Fixture paths must be relative. Received "${relativePath}"`);
  }
}

export async function createMetadataWriteFixtureRoot(prefix = 'metadata-write-e2e-'): Promise<MetadataWriteFixtureRoot> {
  const rootPath = await mkdtemp(join(tmpdir(), prefix));
  const booksPath = join(rootPath, 'books');
  await mkdir(booksPath, { recursive: true });

  return {
    rootPath,
    booksPath,
    cleanup: async () => {
      await rm(rootPath, { recursive: true, force: true });
    },
  };
}

export async function writeFixtureFile(rootPath: string, relativePath: string, content: string | Buffer): Promise<string> {
  assertRelativePath(relativePath);

  const absolutePath = join(rootPath, relativePath);
  await mkdir(dirname(absolutePath), { recursive: true });
  await writeFile(absolutePath, content);
  return absolutePath;
}

export async function createPdfFixture(rootPath: string, relativePath: string, title = 'Fixture PDF Title'): Promise<string> {
  const pdf = await PDFDocument.create();
  const page = pdf.addPage([360, 240]);
  page.drawText('metadata write fixture');
  pdf.setTitle(title);
  const bytes = await pdf.save();
  return writeFixtureFile(rootPath, relativePath, Buffer.from(bytes));
}

export async function createEpubFixture(rootPath: string, relativePath: string, input: EpubFixtureInput = {}): Promise<string> {
  assertRelativePath(relativePath);
  const absolutePath = join(rootPath, relativePath);
  await mkdir(dirname(absolutePath), { recursive: true });

  const uid = input.uid ?? `urn:uuid:${randomUUID()}`;
  const title = input.title ?? 'Fixture EPUB Title';
  const language = input.language ?? 'en';

  const containerXml = `<?xml version="1.0" encoding="UTF-8"?>
<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
  <rootfiles>
    <rootfile full-path="OPS/content.opf" media-type="application/oebps-package+xml" />
  </rootfiles>
</container>`;

  const opfXml = `<?xml version="1.0" encoding="UTF-8"?>
<package version="3.0" unique-identifier="uid" xmlns="http://www.idpf.org/2007/opf">
  <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
    <dc:identifier id="uid">${escapeXml(uid)}</dc:identifier>
    <dc:title>${escapeXml(title)}</dc:title>
    <dc:language>${escapeXml(language)}</dc:language>
    <meta property="dcterms:modified">2026-01-01T00:00:00Z</meta>
  </metadata>
  <manifest>
    <item id="chapter" href="chapter.xhtml" media-type="application/xhtml+xml" />
  </manifest>
  <spine>
    <itemref idref="chapter" />
  </spine>
</package>`;

  const chapterXml = `<html xmlns="http://www.w3.org/1999/xhtml"><head><title>${escapeXml(title)}</title></head><body><p>fixture</p></body></html>`;

  await writeZipArchive(absolutePath, [
    { path: 'mimetype', content: 'application/epub+zip', store: true },
    { path: 'META-INF/container.xml', content: containerXml },
    { path: 'OPS/content.opf', content: opfXml },
    { path: 'OPS/chapter.xhtml', content: chapterXml },
    ...(input.paddingBytes ? [{ path: 'OPS/padding.bin', content: Buffer.alloc(input.paddingBytes), store: true }] : []),
  ]);

  return absolutePath;
}

export async function createFb2Fixture(rootPath: string, relativePath: string, input: Fb2FixtureInput = {}): Promise<string> {
  const title = input.title ?? 'Fixture FB2 Title';
  const language = input.language ?? 'en';
  const bodyText = input.bodyText ?? 'fixture body text';

  const xml = [
    '<?xml version="1.0" encoding="UTF-8"?>',
    '<FictionBook xmlns="http://www.gribuser.ru/xml/fictionbook/2.0" xmlns:l="http://www.w3.org/1999/xlink">',
    '<description>',
    '  <title-info>',
    '    <genre>antique</genre>',
    '    <author><first-name>Fixture</first-name><last-name>Author</last-name></author>',
    `    <book-title>${escapeXml(title)}</book-title>`,
    `    <lang>${escapeXml(language)}</lang>`,
    '  </title-info>',
    '  <document-info><id>fixture-doc</id></document-info>',
    '</description>',
    `<body><section><p>${escapeXml(bodyText)}</p></section></body>`,
    '</FictionBook>',
    '',
  ].join('\n');

  return writeFixtureFile(rootPath, relativePath, Buffer.from(xml, 'utf8'));
}

export async function createCbzFixture(rootPath: string, relativePath: string, input: ComicFixtureInput = {}): Promise<string> {
  assertRelativePath(relativePath);
  const absolutePath = join(rootPath, relativePath);
  await mkdir(dirname(absolutePath), { recursive: true });

  const xml = buildComicInfoXml(input);
  await writeZipArchive(absolutePath, [
    { path: 'ComicInfo.xml', content: xml },
    { path: 'page-001.txt', content: 'fixture page' },
  ]);

  return absolutePath;
}

export async function createCb7Fixture(rootPath: string, relativePath: string, input: ComicFixtureInput = {}): Promise<string> {
  const xml = buildComicInfoXml(input);
  const archiveBytes = await buildCb7Archive(xml);
  return writeFixtureFile(rootPath, relativePath, archiveBytes);
}

export async function createZipArchiveFixture(rootPath: string, relativePath: string, entries: ZipEntryInput[]): Promise<string> {
  assertRelativePath(relativePath);
  const absolutePath = join(rootPath, relativePath);
  await mkdir(dirname(absolutePath), { recursive: true });
  await writeZipArchive(absolutePath, entries);
  return absolutePath;
}

async function writeZipArchive(absolutePath: string, entries: ZipEntryInput[]): Promise<void> {
  const output = createWriteStream(absolutePath);
  const archive = new ZipArchive({ zlib: { level: 6 } });

  await new Promise<void>((resolve, reject) => {
    output.on('close', resolve);
    output.on('error', reject);
    archive.on('error', reject);
    archive.pipe(output);

    for (const entry of entries) {
      archive.append(typeof entry.content === 'string' ? Buffer.from(entry.content, 'utf8') : entry.content, {
        name: entry.path,
        store: entry.store ?? false,
      });
    }

    void archive.finalize();
  });
}

async function buildCb7Archive(comicInfoXml: string): Promise<Buffer> {
  const sevenZip = await getSevenZip();
  const archivePath = `/metadata-write-${randomUUID().replaceAll('-', '')}.cb7`;
  const xmlPath = '/ComicInfo.xml';
  const xmlBytes = Buffer.from(comicInfoXml, 'utf8');

  try {
    safeVfsUnlink(sevenZip.FS, xmlPath);
    safeVfsUnlink(sevenZip.FS, archivePath);

    const fd = sevenZip.FS.open(xmlPath, 'w+');
    sevenZip.FS.write(fd, xmlBytes, 0, xmlBytes.length);
    sevenZip.FS.close(fd);

    sevenZip.callMain(['a', archivePath, xmlPath]);
    return Buffer.from(sevenZip.FS.readFile(archivePath));
  } finally {
    safeVfsUnlink(sevenZip.FS, xmlPath);
    safeVfsUnlink(sevenZip.FS, archivePath);
  }
}

function safeVfsUnlink(vfs: { unlink: (path: string) => void }, path: string): void {
  try {
    vfs.unlink(path);
  } catch {
    // no-op: path may not exist
  }
}

function buildComicInfoXml(input: ComicFixtureInput): string {
  const title = escapeXml(input.title ?? 'Fixture Comic Title');
  const author = escapeXml(input.author ?? 'Fixture Author');
  const publisher = escapeXml(input.publisher ?? 'Fixture Publisher');
  const year = input.year ?? 2024;

  return `<?xml version="1.0" encoding="UTF-8"?>
<ComicInfo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Title>${title}</Title>
  <Writer>${author}</Writer>
  <Publisher>${publisher}</Publisher>${optionalXmlElement('Genre', input.genre)}${optionalXmlElement('Tags', input.tags)}
  <Year>${year}</Year>
</ComicInfo>`;
}

function optionalXmlElement(name: string, value: string | undefined): string {
  return value === undefined ? '' : `\n  <${name}>${escapeXml(value)}</${name}>`;
}

function escapeXml(value: string): string {
  return value.replaceAll('&', '&amp;').replaceAll('<', '&lt;').replaceAll('>', '&gt;').replaceAll('"', '&quot;').replaceAll("'", '&apos;');
}