// Copies the pdf.js runtime assets out of node_modules into public/pdfjs/ so the
// standalone viewer (public/viewer/) can load them as plain, unbundled ES modules.
// Runs via predev/prebuild, i.e. also inside the Docker web build stage.
//
// The target layout is dictated by the URLs the ported viewer uses:
//   /pdfjs/legacy/pdf.min.mjs         (import + GlobalWorkerOptions.workerSrc)
//   /pdfjs/wasm/                      (wasmUrl  — CCITT-G4/JBIG2, JPEG2000, ICC decoders)
//   /pdfjs/standard_fonts/            (standardFontDataUrl)
//   /pdfjs/iccs/                      (iccUrl)
import { cp, mkdir, rm, stat } from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const webRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const src = path.join(webRoot, 'node_modules', 'pdfjs-dist');
const dest = path.join(webRoot, 'public', 'pdfjs');

try {
  await stat(src);
} catch {
  console.error(`[copy-pdfjs] ${src} not found — run npm install first.`);
  process.exit(1);
}

// Full rebuild, so a pdfjs-dist upgrade never leaves stale files behind.
await rm(dest, { recursive: true, force: true });
await mkdir(path.join(dest, 'legacy'), { recursive: true });

const files = ['pdf.min.mjs', 'pdf.worker.min.mjs'];
for (const file of files) {
  await cp(path.join(src, 'legacy', 'build', file), path.join(dest, 'legacy', file));
}

const dirs = ['wasm', 'standard_fonts', 'iccs'];
for (const dir of dirs) {
  await cp(path.join(src, dir), path.join(dest, dir), { recursive: true });
}

console.log(`[copy-pdfjs] ${files.join(', ')} + ${dirs.join('/, ')}/ -> public/pdfjs/`);