/**
 * One decompile of a WinHelp file: helpdeco in a fresh instance with the .hlp
 * in its in-memory file system, returning every file it wrote (the RTF
 * topics, the project file, pictures, phrases, icon, baggage). Used by
 * worker.mjs in the browser and by the site's tests in Node.
 *
 * helpdeco stops to ask "Press CR to continue at your own risk" when part of
 * a help file is damaged; stdin always answers with a carriage return, so it
 * carries on and the page reports what it said.
 *
 * Written for johnmcm.com (2026); part of the module published at /source/helpdeco/.
 */

const CR = 13;

/**
 * Decompiles `bytes` (a .hlp called `name`). `createHelpdeco` is the module
 * factory; `options` is passed to it (locateFile, instantiateWasm...).
 * Resolves { code, files: { name, data }[], log: string[] }.
 */
export async function decompile(createHelpdeco, name, bytes, options = {}) {
  const log = [];
  const m = await createHelpdeco({
    print: (line) => log.push(line),
    printErr: (line) => log.push(line),
    stdin: () => CR,
    ...options,
  });
  m.FS.mkdir('/w');
  m.FS.chdir('/w');
  m.FS.writeFile(`/w/${name}`, bytes);
  let code = 0;
  try {
    code = m.callMain([name, '-y']) ?? 0;
  } catch (err) {
    if (typeof err?.status === 'number') code = err.status;
    else throw err;
  }
  const files = [];
  for (const f of m.FS.readdir('/w')) {
    if (f === '.' || f === '..' || f === name) continue;
    const path = `/w/${f}`;
    if (m.FS.isFile(m.FS.stat(path).mode)) files.push({ name: f, data: m.FS.readFile(path) });
  }
  return { code, files, log };
}