#!/usr/bin/env node
import { spawnSync } from 'node:child_process';
import path from 'node:path';

const ROOT = path.resolve(new URL('..', import.meta.url).pathname);
const REMOTE_ROOT = process.env.STUDIO_REMOTE_ROOT ?? '/Users/john/Project';
const CANDIDATE_BASE = `${REMOTE_ROOT}/Memind-candidates`;

const REMOTE_SCRIPT = [
  'set -euo pipefail',
  'expected_commit="$1"',
  'candidate_base="$2"',
  'matched=""',
  'latest=""',
  'for dir in "${candidate_base}"/*; do',
  '  [[ -d "${dir}" ]] || continue',
  '  [[ -f "${dir}/.release-manifest.txt" ]] || continue',
  '  if [[ -z "${latest}" || "$(basename "${dir}")" > "$(basename "${latest}")" ]]; then',
  '    latest="${dir}"',
  '  fi',
  '  if grep -q "^git_head=${expected_commit}$" "${dir}/.release-manifest.txt"; then',
  '    matched="${dir}"',
  '  fi',
  'done',
  'if [[ -n "${matched}" ]]; then candidate="${matched}"; else candidate="${latest}"; fi',
  '[[ -n "${candidate}" ]] || { echo "NO_CANDIDATE"; exit 1; }',
  'printf \'candidate_dir=%s\\n\' "${candidate}"',
  'cat "${candidate}/.release-manifest.txt"',
  'printf \'\\n---HEALTH---\\n\'',
  'curl -s -D - -o /dev/null http://127.0.0.1:18081/api/status | tr -d \'\\r\'',
  '',
].join('\n');

function parseArgs(argv) {
  const options = {
    host: process.env.STUDIO_HOST ?? '58.38.22.103',
    commit: null,
  };
  for (let index = 2; index < argv.length; index += 1) {
    const arg = argv[index];
    if (arg === '--host') options.host = argv[++index] ?? '';
    else if (arg === '--commit') options.commit = argv[++index] ?? '';
    else throw new Error(`Unknown argument: ${arg}`);
  }
  return options;
}

function git(...args) {
  const result = spawnSync('git', args, { cwd: ROOT, encoding: 'utf8' });
  if (result.status !== 0) {
    throw new Error(`git ${args.join(' ')} failed: ${result.stderr || result.stdout}`);
  }
  return result.stdout.trim();
}

function ssh(host, args, input = '') {
  const result = spawnSync('ssh', ['-o', 'BatchMode=yes', '-o', 'ConnectTimeout=15', host, ...args], {
    encoding: 'utf8',
    input,
  });
  if (result.status !== 0) {
    throw new Error(`SSH to ${host} failed:\n${result.stderr || result.stdout}`);
  }
  return result.stdout.trim();
}

function parseManifest(content) {
  const fields = {};
  for (const line of content.split('\n')) {
    const separator = line.indexOf('=');
    if (separator <= 0) continue;
    fields[line.slice(0, separator)] = line.slice(separator + 1);
  }
  return fields;
}

try {
  const options = parseArgs(process.argv);
  const commit = options.commit ?? git('rev-parse', 'HEAD');
  const remoteUserHost = options.host.includes('@') ? options.host : `john@${options.host}`;

  const remoteOutput = ssh(
    remoteUserHost,
    ['/bin/bash', '-s', '--', commit, CANDIDATE_BASE],
    REMOTE_SCRIPT,
  );

  const healthMarker = '\n---HEALTH---\n';
  const markerIndex = remoteOutput.indexOf('---HEALTH---');
  if (markerIndex < 0) {
    throw new Error('Canary promotion evidence response missing health probe');
  }
  const manifestText = remoteOutput.slice(0, markerIndex);
  const healthText = remoteOutput.slice(markerIndex + healthMarker.trim().length);

  const candidateDir = manifestText
    .split('\n')
    .find((line) => line.startsWith('candidate_dir='))
    ?.slice('candidate_dir='.length);
  const manifest = parseManifest(
    manifestText
      .split('\n')
      .filter((line) => !line.startsWith('candidate_dir='))
      .join('\n'),
  );

  if (!candidateDir) {
    throw new Error('103 has no canary candidate directory');
  }
  if (manifest.git_head !== commit) {
    throw new Error(
      `Canary candidate commit mismatch: candidate=${manifest.git_head ?? 'missing'} expected=${commit}`,
    );
  }
  if (!/^HTTP\/1\.1 200/m.test(healthText)) {
    throw new Error('Canary candidate /api/status is not healthy on 18081');
  }
  if (!/^x-memind-runtime-role: candidate/im.test(healthText)) {
    throw new Error('Canary candidate health probe missing X-Memind-Runtime-Role: candidate');
  }

  console.log('Canary promotion evidence verified');
  console.log(`candidate_dir=${candidateDir}`);
  console.log(`release_id=${manifest.release_id ?? 'unknown'}`);
  console.log(`git_head=${manifest.git_head}`);
} catch (error) {
  console.error(error.message);
  process.exit(1);
}