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

import { hashArtifact } from '../release-gate/artifact.mjs';
import {
  diffTouchesRuntimePaths,
  isReleaseOnlyPath,
} from '../release-gate/incremental.mjs';

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="$2"',
  'stable_manifest="/Users/john/Project/Memind/.release-manifest.txt"',
  'matched=""',
  'latest=""',
  'for dir in "${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"',
  'if [[ -f "${stable_manifest}" ]]; then',
  '  printf \'\\n---STABLE---\\n\'',
  '  cat "${stable_manifest}"',
  'fi',
  'printf \'\\n---HEALTH---\\n\'',
  'curl -s -D - -o /dev/null http://127.0.0.1:18081/api/status 2>/dev/null | tr -d \'\\r\' || true',
  'printf \'\\n---STABLE-HEALTH---\\n\'',
  'curl -s -D - -o /dev/null http://127.0.0.1:8081/api/status 2>/dev/null | tr -d \'\\r\' || true',
  '',
].join('\n');

function parseArgs(argv) {
  const options = {
    host: process.env.STUDIO_HOST ?? '58.38.22.103',
    commit: null,
    artifact: path.join(ROOT, '.runtime', 'portal'),
  };
  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 if (arg === '--artifact') options.artifact = path.resolve(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;
}

function listReleaseOnlyDiff(baseCommit, headCommit) {
  const result = spawnSync(
    'git',
    ['diff', '--name-only', `${baseCommit}..${headCommit}`],
    { cwd: ROOT, encoding: 'utf8' },
  );
  if (result.status !== 0) {
    throw new Error(`git diff failed: ${result.stderr || result.stdout}`);
  }
  return result.stdout
    .split('\n')
    .map((line) => line.trim())
    .filter(Boolean);
}

function assertArtifactIdenticalPromotion({
  candidateCommit,
  expectedCommit,
}) {
  const changedPaths = listReleaseOnlyDiff(candidateCommit, expectedCommit);
  if (changedPaths.length === 0) {
    return { changedPaths, promotion: 'artifact_identical_no_diff' };
  }
  if (diffTouchesRuntimePaths(changedPaths)) {
    throw new Error(
      `Canary candidate commit mismatch and diff is not release-only: candidate=${candidateCommit} expected=${expectedCommit} changed=${changedPaths.join(',')}`,
    );
  }
  if (!changedPaths.every(isReleaseOnlyPath)) {
    throw new Error(
      `Canary promotion diff contains non-release paths: ${changedPaths.join(',')}`,
    );
  }
  return { changedPaths, promotion: 'artifact_identical_release_only_diff' };
}

function parseRemoteSections(remoteOutput) {
  const sections = {
    manifestText: remoteOutput,
    stableText: '',
    healthText: '',
    stableHealthText: '',
  };
  const stableMarker = '\n---STABLE---\n';
  const healthMarker = '\n---HEALTH---\n';
  const stableHealthMarker = '\n---STABLE-HEALTH---\n';

  const stableIndex = remoteOutput.indexOf('---STABLE---');
  const healthIndex = remoteOutput.indexOf('---HEALTH---');
  const stableHealthIndex = remoteOutput.indexOf('---STABLE-HEALTH---');

  if (healthIndex < 0) {
    throw new Error('Canary promotion evidence response missing health probe');
  }

  sections.manifestText = remoteOutput.slice(
    0,
    stableIndex >= 0 ? stableIndex : healthIndex,
  );
  if (stableIndex >= 0 && healthIndex > stableIndex) {
    sections.stableText = remoteOutput.slice(
      stableIndex + stableMarker.trim().length,
      healthIndex,
    );
  }
  sections.healthText = remoteOutput.slice(
    healthIndex + healthMarker.trim().length,
    stableHealthIndex >= 0 ? stableHealthIndex : remoteOutput.length,
  );
  if (stableHealthIndex >= 0) {
    sections.stableHealthText = remoteOutput.slice(
      stableHealthIndex + stableHealthMarker.trim().length,
    );
  }
  return sections;
}

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 localArtifact = await hashArtifact(options.artifact);

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

  const sections = parseRemoteSections(remoteOutput);
  const manifestText = sections.manifestText;
  const healthText = sections.healthText;
  const stableHealthText = sections.stableHealthText;
  const stableManifest = parseManifest(sections.stableText);

  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');
  }

  let promotionMode = 'commit_match';
  if (manifest.git_head !== commit) {
    const promotion = assertArtifactIdenticalPromotion({
      candidateCommit: manifest.git_head,
      expectedCommit: commit,
    });
    promotionMode = promotion.promotion;
  }

  const candidateHealthy = /^HTTP\/1\.1 200/m.test(healthText)
    && /^x-memind-runtime-role: candidate/im.test(healthText);
  const stableHealthy = /^HTTP\/1\.1 200/m.test(stableHealthText);

  if (candidateHealthy) {
    promotionMode = `${promotionMode}_candidate_healthy`;
  } else if (
    promotionMode.startsWith('artifact_identical')
    && stableHealthy
    && stableManifest.git_head === manifest.git_head
  ) {
    promotionMode = `${promotionMode}_stable_fallback`;
  } else if (!candidateHealthy) {
    throw new Error('Canary candidate /api/status is not healthy on 18081');
  }

  if (candidateHealthy && !/^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=${manifest.git_head}`);
  console.log(`promotion_mode=${promotionMode}`);
  console.log(`artifact_sha256=${localArtifact.sha256}`);
} catch (error) {
  console.error(error.message);
  process.exit(1);
}