#!/usr/bin/env node
/**
 * Render Prometheus to static files and upload to Sia as the DR fallback.
 *
 * The architecture decision (see
 * ../../../_coordination/sessions/prometheus-x-architecture.md §4):
 * prometheus.x's `ip`+`tls` records point at the live service, but a weekly
 * snapshot of the browseable surface is also published to `bns/prometheus/`
 * on Sia. Resolver clients that cannot reach the service can fall back to
 * the `s3` record and still read what's there — stale by up to a snapshot
 * interval, but readable.
 *
 * Scope — the browse surface, not the dynamic surface:
 *   /, /browse, /publish, /boundaries, /c/<slug> × 8, /app/<pub>/<slug> × N,
 *   plus /static/style.css + /static/favicon.svg + /sitemap.xml + /robots.txt.
 * NOT snapshotted: /submit (requires the live API), /admin/*, /api/*.
 *
 * Flags:
 *   --out <dir>         write files here (default: ./build)
 *   --upload            after writing, `aws s3 sync` to bns/prometheus/
 *   --bucket <name>     target bucket (default: bns/prometheus)
 *   --endpoint <url>    S3 endpoint URL for the aws CLI
 *   --dry-run           print the sync command instead of running it
 *
 * The sync uses the `sia-storage` AWS profile per
 * [[sia-storage-credentials-location]].
 */

import { mkdir, writeFile, rm, copyFile } from 'node:fs/promises';
import { createReadStream } from 'node:fs';
import { resolve, dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { spawn } from 'node:child_process';
import { layout } from '../service/layout.js';
import { home, publish, boundaries } from '../service/pages.js';
import { browse as browsePage } from '../service/pages.js';
import { CATEGORIES, categoryPage, appPage } from '../service/pages-browse.js';
import { allActiveListings } from '../service/db.js';
import { renderSitemap, renderRobots } from '../service/seo.js';

const SELF_DIR = dirname(fileURLToPath(import.meta.url));
const ROOT = resolve(SELF_DIR, '..');
const PUBLIC_DIR = resolve(ROOT, 'public');

const args = parseArgs(process.argv.slice(2));
const OUT = resolve(ROOT, args.out || 'build');
const BUCKET = args.bucket || 'bns/prometheus';
const ENDPOINT = args.endpoint || process.env.AWS_ENDPOINT_URL_S3 || process.env.AWS_ENDPOINT_URL;

const log = (...a) => console.log('[snapshot]', ...a);

async function main() {
  log(`output: ${OUT}`);
  await rm(OUT, { recursive: true, force: true });
  await mkdir(OUT, { recursive: true });

  const listings = allActiveListings();
  log(`rendering ${CATEGORIES.length} category pages + ${listings.length} listings …`);

  // Core pages — the "here" path doubles as the output URL.
  await writePage('/', home());
  await writePage('/browse', browsePage());
  await writePage('/publish', publish());
  await writePage('/boundaries', boundaries());

  // Category pages — fake a request object for the signature.
  for (const c of CATEGORIES) {
    await writePage(`/c/${c.slug}`, categoryPage({ url: `/c/${c.slug}` }, c.slug));
  }

  // App detail pages — one per active listing.
  for (const r of listings) {
    await writePage(`/app/${r.publisher}/${r.slug}`,
      appPage({ url: `/app/${r.publisher}/${r.slug}` }, r.publisher, r.slug));
  }

  // Static assets live next to the rendered HTML at the same /static/ URL.
  const staticOut = resolve(OUT, 'static');
  await mkdir(staticOut, { recursive: true });
  await copyFile(resolve(PUBLIC_DIR, 'style.css'), resolve(staticOut, 'style.css'));
  await copyFile(resolve(PUBLIC_DIR, 'favicon.svg'), resolve(staticOut, 'favicon.svg'));

  // SEO files at the root of the bucket.
  await writeFile(resolve(OUT, 'sitemap.xml'), renderSitemap({
    categories: CATEGORIES.map((c) => c.slug),
    listings: listings.map((r) => ({ publisher: r.publisher, slug: r.slug, lastmod: r.created_at })),
  }), 'utf8');
  await writeFile(resolve(OUT, 'robots.txt'), renderRobots(), 'utf8');

  log(`wrote ${listings.length + CATEGORIES.length + 6} HTML files + static assets`);

  if (args.upload) {
    await uploadToSia();
  } else {
    log(`skipping upload — rerun with --upload (or --dry-run to just print the aws command)`);
  }
  log('done.');
}

/**
 * Resolve the page's URL to the filesystem path the bucket serves at.
 *
 *   /                     → index.html
 *   /browse               → browse/index.html
 *   /c/privacy            → c/privacy/index.html
 *   /app/foo.x/bar        → app/foo.x/bar/index.html
 *
 * Directory-with-index-html lets `/browse` and `/browse/` both work on an
 * S3-style static host — the bucket's "serve index when the path is a prefix"
 * rule picks index.html for us.
 */
async function writePage(urlPath, page) {
  const html = layout(page);
  const rel = urlPath === '/' ? 'index.html' : urlPath.replace(/^\/+/, '').replace(/\/+$/, '') + '/index.html';
  const full = resolve(OUT, rel);
  await mkdir(dirname(full), { recursive: true });
  await writeFile(full, html, 'utf8');
}

async function uploadToSia() {
  const cmd = 'aws';
  const argv = [
    '--profile', 'sia-storage',
    ...(ENDPOINT ? ['--endpoint-url', ENDPOINT] : []),
    's3', 'sync', OUT + '/', `s3://${BUCKET}/`,
    '--delete',   // objects dropped from the snapshot vanish from the bucket too
  ];
  if (args['dry-run']) {
    log(`DRY RUN: ${cmd} ${argv.join(' ')}`);
    return;
  }
  log(`$ ${cmd} ${argv.join(' ')}`);
  await spawnOk(cmd, argv);
}

function spawnOk(cmd, argv) {
  return new Promise((resolveP, rejectP) => {
    const c = spawn(cmd, argv, { stdio: 'inherit' });
    c.on('error', rejectP);
    c.on('close', (code) => code === 0 ? resolveP() : rejectP(new Error(`${cmd} exited ${code}`)));
  });
}

function parseArgs(argv) {
  const out = {};
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (!a.startsWith('--')) continue;
    const k = a.slice(2);
    const next = argv[i + 1];
    if (next && !next.startsWith('--')) {
      out[k] = next; i++;
    } else {
      out[k] = true;
    }
  }
  return out;
}

main().catch((err) => {
  console.error('[snapshot] FAIL:', err?.stack || err);
  process.exit(1);
});