import { createHash } from 'node:crypto';
import { cp, mkdir, readFile, rm, writeFile } from 'node:fs/promises';
import { dirname, join, relative } from 'node:path';
import { fileURLToPath } from 'node:url';

const repositoryRoot = join(dirname(fileURLToPath(import.meta.url)), '..');
const expectedVersion = '0.12.10';
const outputRoot = join(
  repositoryRoot,
  'public',
  'vendor',
  'ffmpeg',
  expectedVersion
);

const packages = [
  {
    packageName: '@ffmpeg/core',
    mode: 'st',
    files: ['ffmpeg-core.js', 'ffmpeg-core.wasm'],
  },
  {
    packageName: '@ffmpeg/core-mt',
    mode: 'mt',
    files: ['ffmpeg-core.js', 'ffmpeg-core.wasm', 'ffmpeg-core.worker.js'],
  },
];

const expectedHashes = new Map([
  [
    '@ffmpeg/core:ffmpeg-core.js',
    '67a48f11645f85439f3fde4f2119042c16b374b910206b7a7a24f342e28dcae3',
  ],
  [
    '@ffmpeg/core:ffmpeg-core.wasm',
    '9f57947a5bd530d8f00c5b3f2cb2a3492faa7e5d823315342d6a8656d0a6b7b7',
  ],
  [
    '@ffmpeg/core-mt:ffmpeg-core.js',
    '270a2e6ff945e173238610669a3f7132df5f9c52698a9bf708cf5c2ab6bda0de',
  ],
  [
    '@ffmpeg/core-mt:ffmpeg-core.wasm',
    'be2c97605366b78f3f13e21b52e81a55a79e1f29c133b03a68ec187b1a2ec41a',
  ],
  [
    '@ffmpeg/core-mt:ffmpeg-core.worker.js',
    'f77898d631dc010b45c29c23cb4379c611a7d7b131bf591d08a656bb729a4ca3',
  ],
]);

async function loadPackageVersion(packageName) {
  const packagePath = join(
    repositoryRoot,
    'node_modules',
    ...packageName.split('/'),
    'package.json'
  );
  const parsed = JSON.parse(await readFile(packagePath, 'utf8'));
  if (parsed.version !== expectedVersion) {
    throw new Error(
      `${packageName} ${parsed.version ?? '<unknown>'} is installed; expected exactly ${expectedVersion}`
    );
  }
}

async function copyAsset(packageName, mode, fileName) {
  const source = join(
    repositoryRoot,
    'node_modules',
    ...packageName.split('/'),
    'dist',
    'esm',
    fileName
  );
  const destination = join(outputRoot, mode, fileName);
  const sourceBytes = await readFile(source).catch((error) => {
    throw new Error(`Required FFmpeg asset is missing: ${source}`, {
      cause: error,
    });
  });
  const sourceDigest = createHash('sha256').update(sourceBytes).digest('hex');
  const expectedDigest = expectedHashes.get(`${packageName}:${fileName}`);
  if (!expectedDigest || sourceDigest !== expectedDigest) {
    throw new Error(
      `Pinned FFmpeg asset checksum mismatch for ${packageName}/${fileName}`
    );
  }

  await mkdir(dirname(destination), { recursive: true });
  await cp(source, destination, {
    dereference: true,
    errorOnExist: false,
    force: true,
    preserveTimestamps: false,
  });

  const destinationBytes = await readFile(destination);
  if (!sourceBytes.equals(destinationBytes)) {
    throw new Error(`Copied FFmpeg asset differs from its source: ${fileName}`);
  }

  return {
    path: relative(outputRoot, destination).replaceAll('\\', '/'),
    bytes: destinationBytes.byteLength,
    sha256: sourceDigest,
  };
}

await rm(outputRoot, { force: true, recursive: true });

const assets = [];
for (const entry of packages) {
  await loadPackageVersion(entry.packageName);
  for (const fileName of entry.files) {
    assets.push(await copyAsset(entry.packageName, entry.mode, fileName));
  }
}

assets.sort((left, right) => left.path.localeCompare(right.path, 'en'));
const versionManifest = {
  schemaVersion: 1,
  coreVersion: expectedVersion,
  packages: {
    '@ffmpeg/core': expectedVersion,
    '@ffmpeg/core-mt': expectedVersion,
  },
  assets,
};

await writeFile(
  join(outputRoot, 'version.json'),
  `${JSON.stringify(versionManifest, null, 2)}\n`
);

console.log(
  `Copied ${assets.length} pinned FFmpeg assets to ${relative(repositoryRoot, outputRoot)}`
);