#!/usr/bin/env node
/**
 * Audit gate: fail the build on any advisory that is not a tracked exception.
 *
 * `npm audit --audit-level=<x>` is all-or-nothing, and this tree cannot pass a
 * flat gate: the Gatsby 5 build toolchain carries ~100 advisories at
 * low/moderate/high with no non-breaking fix, because gatsby is a runtime
 * dependency of the build. Blocking on any of those stops publishing
 * permanently; ignoring the tree lets a genuinely new advisory through. So the
 * known set is committed to audit-baseline.json with an owner and a reason,
 * and this script fails only when something NEW appears at or above the
 * threshold.
 *
 * Usage: node scripts/audit-gate.mjs [--write-baseline]
 */
import { execFileSync } from 'node:child_process';
import { readFileSync, writeFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';

const HERE = dirname(fileURLToPath(import.meta.url));
const BASELINE = join(HERE, 'audit-baseline.json');
const BLOCKING = new Set(['critical', 'high']);

/** npm audit exits non-zero when it finds anything, so ignore the status. */
function auditReport() {
  let out;
  try {
    out = execFileSync('npm', ['audit', '--json', '--omit=optional'], {
      encoding: 'utf8',
      stdio: ['ignore', 'pipe', 'ignore'],
      maxBuffer: 32 * 1024 * 1024
    });
  } catch (err) {
    out = err.stdout;
    if (!out) throw err;
  }
  return JSON.parse(out);
}

/** Flatten the report to one key per package/severity/advisory triple. */
function currentFindings(report) {
  const findings = new Map();
  for (const [pkg, v] of Object.entries(report.vulnerabilities ?? {})) {
    if (!BLOCKING.has(v.severity)) continue;
    const advisories = (v.via ?? []).filter((x) => typeof x === 'object');
    if (advisories.length === 0) {
      // via is a chain of parent package names - attribute to the package.
      findings.set(`${pkg}|${v.severity}|transitive`, { pkg, severity: v.severity, advisory: 'transitive' });
      continue;
    }
    for (const a of advisories) {
      const id = (a.url ?? '').split('/').pop() || a.title || 'unknown';
      findings.set(`${pkg}|${v.severity}|${id}`, { pkg, severity: v.severity, advisory: id, title: a.title, range: a.range });
    }
  }
  return findings;
}

const report = auditReport();
const current = currentFindings(report);

if (process.argv.includes('--write-baseline')) {
  const accepted = [...current.values()].sort((a, b) => `${a.pkg}${a.advisory}`.localeCompare(`${b.pkg}${b.advisory}`));
  writeFileSync(
    BASELINE,
    JSON.stringify(
      {
        $comment:
          'Advisories at critical/high accepted for this tree. scripts/audit-gate.mjs fails the build on anything not listed here, so removing an entry re-arms the gate for that advisory. Regenerate with: node scripts/audit-gate.mjs --write-baseline',
        owner: 'Site maintainers (allan@4gl.io)',
        reason:
          'Gatsby 5 build toolchain: no non-breaking fix available upstream, and these are build-time dependencies of a statically generated site. Re-check on each Gatsby major bump.',
        accepted
      },
      null,
      2
    ) + '\n'
  );
  console.log(`wrote ${accepted.length} accepted advisories to ${BASELINE}`);
  process.exit(0);
}

const baseline = JSON.parse(readFileSync(BASELINE, 'utf8'));
const accepted = new Set((baseline.accepted ?? []).map((a) => `${a.pkg}|${a.severity}|${a.advisory}`));

const fresh = [...current.entries()].filter(([key]) => !accepted.has(key));
const resolved = [...accepted].filter((key) => !current.has(key));

for (const [, f] of fresh) {
  console.error(`NEW ${f.severity.toUpperCase()}: ${f.pkg} - ${f.title ?? f.advisory} (${f.advisory})`);
}

if (resolved.length > 0) {
  // Not a failure: a bumped or removed dependency closes advisories, and the
  // baseline should be trimmed in the same change that closes them.
  console.log(`${resolved.length} baseline entries no longer present - consider re-running with --write-baseline:`);
  for (const key of resolved) console.log(`  stale: ${key}`);
}

if (fresh.length > 0) {
  console.error(`\n${fresh.length} untracked advisory/ies at critical or high.`);
  console.error('Fix it, or add it to scripts/audit-baseline.json with a reason and an owner.');
  process.exit(1);
}

console.log(`audit gate: no new critical/high advisories (${current.size} tracked in baseline)`);