const crypto = require('crypto');
const fs = require('fs');
const os = require('os');
const path = require('path');
const {execFileSync} = require('child_process');
const esbuild = require('esbuild');
const {version: packageVersion} = require('../package.json');

function normalizeBuildVersion(value) {
  const version = (value || packageVersion || '0.0.0').toString().trim();
  return version.startsWith('v') ? version : `v${version}`;
}

async function download(url) {
  const response = await fetch(url);
  if (!response.ok) {
    throw new Error(`Failed to download ${url}: ${response.status} ${response.statusText}`);
  }
  return Buffer.from(await response.arrayBuffer());
}

// SEA blobs must be injected into a node binary of the same version, and non-Windows hosts need a Windows base binary.
async function getWindowsNodeBinary(tempDir) {
  if (process.platform === 'win32') {
    return process.execPath;
  }

  const baseUrl = `https://nodejs.org/dist/${process.version}`;
  const [binary, shasums] = await Promise.all([
    download(`${baseUrl}/win-x64/node.exe`),
    download(`${baseUrl}/SHASUMS256.txt`),
  ]);

  const expected = shasums.toString('utf8').split('\n')
    .map(line => line.trim().split(/\s+/))
    .find(([, file]) => file === 'win-x64/node.exe');
  const actual = crypto.createHash('sha256').update(binary).digest('hex');
  if (!expected || expected[0] !== actual) {
    throw new Error('Checksum verification failed for downloaded win-x64/node.exe');
  }

  const binaryPath = path.join(tempDir, 'node.exe');
  fs.writeFileSync(binaryPath, binary);
  return binaryPath;
}

async function main() {
  const distDir = path.resolve(__dirname, '..', 'dist');
  if (!fs.existsSync(distDir)) {
    fs.mkdirSync(distDir, {recursive: true});
  }

  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsa-sea-'));
  const bundlePath = path.join(tempDir, 'index.cjs');
  const seaBlobPath = path.join(tempDir, 'sea-prep.blob');
  const seaConfigPath = path.join(tempDir, 'sea-config.json');
  const buildVersion = normalizeBuildVersion(process.env.BUILD_VERSION);
  const outputFile = path.join(distDir, `gSheets-Rate-Assistant-${buildVersion}.exe`);

  await esbuild.build({
    entryPoints: [path.resolve(__dirname, '..', 'index.js')],
    bundle: true,
    platform: 'node',
    format: 'cjs',
    target: 'node26',
    outfile: bundlePath,
    logLevel: 'info',
  });

  const executable = await getWindowsNodeBinary(tempDir);

  fs.writeFileSync(seaConfigPath, JSON.stringify({
    main: bundlePath,
    executable,
    output: outputFile,
    mainFormat: 'commonjs',
    disableExperimentalSEAWarning: true,
    useCodeCache: false,
    useSnapshot: false,
  }, null, 2));

  execFileSync(process.execPath, ['--build-sea', seaConfigPath], {stdio: 'inherit'});

  const header = Buffer.alloc(2);
  const fd = fs.openSync(outputFile, 'r');
  fs.readSync(fd, header, 0, 2, 0);
  fs.closeSync(fd);
  if (header.toString('latin1') !== 'MZ') {
    throw new Error(`${outputFile} is not a Windows PE executable`);
  }
}

main().catch(error => {
  console.error(error && error.stack ? error.stack : error);
  process.exit(1);
});