/**
 * Runs 7-Zip for johnmcm.com's Archive Toolkit. The page sends the archive
 * once; each request after that is a fresh run of 7zz on it.
 *
 * Messages in:  { id, type: 'open', file: File, others?: { paths: string[], file: File }[] }
 *               (others: a differencing disk's parents or a VMDK's extents, at the
 *               path the archive names them by)
 *               { id, type: 'list', op: { type?, inner? } }
 *               { id, type: 'extract', op: { type?, inner?, paths } }
 * Messages out: { id } after open; { id, entries, warning } after list;
 *               { id, files: { path, data, error }[] } after extract;
 *               or { id, error }.
 *
 * Written for johnmcm.com (2026); part of the module published at /source/7zip/.
 */

import create7z from './7zz.mjs';
import { extract, list } from './run.mjs';

let compiled = null;
let file = null;
let others = [];

function wasmModule() {
  // A failed fetch or compile is not kept, so the next request tries again.
  compiled ??= WebAssembly.compileStreaming(fetch(new URL('./7zz.wasm', import.meta.url))).catch((err) => {
    compiled = null;
    throw err;
  });
  return compiled;
}

async function options() {
  let module;
  try {
    module = await wasmModule();
  } catch {
    throw new Error('load');
  }
  return {
    instantiateWasm(imports, done) {
      WebAssembly.instantiate(module, imports).then((i) => done(i));
      return {};
    },
  };
}

self.onmessage = async (e) => {
  const msg = e.data;
  try {
    if (msg.type === 'open') {
      file = msg.file;
      others = (msg.others ?? []).map((o) => ({ paths: o.paths ?? [o.path], blob: o.file }));
      await options();
      self.postMessage({ id: msg.id });
      return;
    }
    if (!file) throw new Error('No archive was opened.');
    const input = { name: file.name, blob: file, others };
    if (msg.type === 'list') {
      const r = await list(create7z, input, msg.op, await options());
      self.postMessage({ id: msg.id, ...r });
    } else if (msg.type === 'extract') {
      const files = await extract(create7z, input, msg.op, await options());
      self.postMessage({ id: msg.id, files }, files.filter((f) => f.data).map((f) => f.data.buffer));
    }
  } catch (err) {
    self.postMessage({ id: msg.id, error: String(err?.message || err) });
  }
};