#!/usr/bin/env node

/**
 * Installs and verifies Trivy binary against checksums lockfile.
 */

const fs = require('node:fs');
const path = require('node:path');
const os = require('node:os');
const cp = require('node:child_process');
const { mapArch, parseChecksums, verifyFileSha256 } = require('./verifier.js');

function main() {
  const version = process.env.TRIVY_VERSION || '0.74.0';
  const homeDir = os.homedir();
  const binDir = path.join(homeDir, '.local', 'bin');
  const cacheDir = path.join(homeDir, '.cache', 'trivy-bin');

  fs.mkdirSync(binDir, { recursive: true });
  fs.mkdirSync(cacheDir, { recursive: true });

  // Expose bin directory to GITHUB_PATH if running in Actions runner
  if (process.env.GITHUB_PATH) {
    fs.appendFileSync(process.env.GITHUB_PATH, `${binDir}\n`);
  }

  const unameArch = os.arch() === 'x64' ? 'x86_64' : (os.arch() === 'arm64' ? 'ARM64' : os.arch());
  const tArch = mapArch(unameArch);
  const tarball = `trivy_${version}_Linux-${tArch}.tar.gz`;
  const tarballPath = path.join(cacheDir, tarball);

  const checksumsFile = path.resolve(__dirname, '..', 'checksums.txt');
  if (!fs.existsSync(checksumsFile)) {
    console.error(`::error::Checksums lockfile not found at ${checksumsFile}`);
    process.exit(1);
  }

  const checksums = parseChecksums(fs.readFileSync(checksumsFile, 'utf8'));
  const expectedHash = checksums.get(tarball);
  if (!expectedHash) {
    console.error(`::error::Tarball ${tarball} not found in checksums.txt`);
    process.exit(1);
  }

  if (fs.existsSync(tarballPath) && verifyFileSha256(tarballPath, expectedHash)) {
    console.log('Cached Trivy archive verified against lockfile.');
  } else {
    console.log('Archive missing or checksum mismatch; downloading...');
    const downloadUrl = `https://github.com/aquasecurity/trivy/releases/download/v${version}/${tarball}`;
    cp.execFileSync('curl', ['-sfLO', downloadUrl, '--output-dir', cacheDir], { stdio: 'inherit' });

    if (!verifyFileSha256(tarballPath, expectedHash)) {
      console.error(`::error::Downloaded archive ${tarball} failed SHA256 checksum verification!`);
      process.exit(1);
    }
    console.log('Downloaded Trivy archive verified successfully.');
  }

  // Extract binary
  cp.execFileSync('tar', ['-xzf', tarballPath, '-C', binDir, 'trivy'], { stdio: 'inherit' });
  const trivyBin = path.join(binDir, 'trivy');
  if (fs.existsSync(trivyBin)) {
    fs.chmodSync(trivyBin, 0o755);
    console.log(`Trivy ${version} installed and verified successfully at ${trivyBin}`);
  } else {
    console.error('::error::Failed to extract trivy binary from tarball.');
    process.exit(1);
  }
}

if (require.main === module) {
  main();
}

module.exports = { main };