import { stat, readdir, writeFile } from 'node:fs/promises';
import { join } from 'node:path';
import { db } from 'officerdb/db';
import { fofosAdminSettings } from '../db/schema';
import { readDatabases } from './databases';

/**
 * Production: a directory of files behind nginx, not a running server.
 *
 * ── Why production is not a process ──
 *
 * The site's own build script says it plainly: *"The public site is not served by Bun in production —
 * it is a directory of files behind nginx."* `bun run build:site` walks every route, renders it through
 * the same Hono app that serves development, and writes `dist/`. So production has no port, nothing to
 * restart, and nothing that can crash at three in the morning — it is a build that either succeeded or
 * did not, and a web server with no application in it.
 *
 * Development stays a pm2 process, because that is what `bun --hot` is for.
 *
 * ── The container exists because nginx could not see the files ──
 *
 * Nginx Proxy Manager mounts only its own `/data` and `/etc/letsencrypt`. It cannot read `dist`, and
 * there is no other nginx on the machine. The alternatives were putting site files inside NPM's own
 * volume, or editing NPM's compose and restarting it — which takes every site on the box down for a
 * moment.
 *
 * So: one `nginx:alpine`, `dist` mounted READ-ONLY, on the same docker network as NPM and with **no
 * published port**. NPM reaches it by container name. Nothing about the site is exposed except through
 * the proxy, which is the same property every other part of this plugin depends on.
 *
 * ── This plugin owns exactly one container name ──
 *
 * `fofos-web`. Every command here is built from that constant and from nothing a caller supplies, so no
 * request can stop or remove another container on this machine — the same rule the pm2 side follows,
 * and it matters for the same reason: Officer's own services share this daemon.
 */

const CONTAINER = 'fofos-web';
const IMAGE = 'nginx:alpine';

/** The network NPM is on, so it can reach the container by name without a published port. */
const NETWORK = 'fofos';

const DOCKER = '/usr/bin/docker';

export type StaticStatus = {
  /** `<root>/website/dist`. */
  path: string;
  /** The build has produced something. */
  built: boolean;
  /** Pages written — top-level entries, which is close enough to be useful and cheap to count. */
  entries: number | null;
  /** When the build last wrote. */
  builtAt: string | null;
  container: {
    name: string;
    /** docker's own word: `running`, `exited`, or null when it does not exist. */
    state: string | null;
    /** What NPM should forward to. Only meaningful while it is running. */
    forward: string;
  };
};

const readRow = async () => (await db.select().from(fofosAdminSettings).limit(1))[0] ?? null;

export const distPath = (root: string): string => join(root, 'website', 'dist');

const run = async (
  argv: string[],
  timeoutMs = 60_000,
  options: { env?: Record<string, string>; cwd?: string } = {},
) => {
  /*
    `cwd` matters and its absence was silent.

    `bun run build:site` resolves the script from the package.json in the CURRENT directory. Without a
    cwd it ran in the platform's own, which has no such script, and the error — "Script not found" —
    reads like the site is missing one rather than like it was asked in the wrong place.
  */
  const proc = Bun.spawn(argv, {
    stdout: 'pipe',
    stderr: 'pipe',
    stdin: 'ignore',
    ...(options.cwd ? { cwd: options.cwd } : {}),
    ...(options.env ? { env: { ...process.env, ...options.env } } : {}),
  });
  const timer = setTimeout(() => proc.kill(), timeoutMs);
  try {
    const [stdout, stderr, code] = await Promise.all([
      new Response(proc.stdout).text(),
      new Response(proc.stderr).text(),
      proc.exited,
    ]);
    return { ok: code === 0, output: `${stdout}${stderr}`.trim() };
  } finally {
    clearTimeout(timer);
  }
};

export async function readStatic(): Promise<StaticStatus> {
  const row = await readRow();
  const path = row?.rootPath ? distPath(row.rootPath) : '';

  const info = path ? await stat(path).catch(() => null) : null;
  const entries = info?.isDirectory() ? await readdir(path).catch(() => null) : null;

  const inspected = await run([DOCKER, 'inspect', '-f', '{{.State.Status}}', CONTAINER], 20_000);

  return {
    path,
    built: Boolean(info?.isDirectory() && entries?.length),
    entries: entries?.length ?? null,
    builtAt: info?.mtime.toISOString() ?? null,
    container: {
      name: CONTAINER,
      // `docker inspect` fails when there is no such container, which is "not created" rather than an
      // error — a state to report, not a fault to raise.
      state: inspected.ok ? inspected.output.trim() : null,
      forward: `${CONTAINER}:80`,
    },
  };
}

/**
 * Build the site.
 *
 * `FOFOS_ENV=production`, so the site's own guard reads the production database and refuses if the
 * name disagrees — the same check the schema push goes through, and for the same reason. The build
 * reads content, so pointing it at the wrong database would publish the wrong site rather than fail.
 *
 * It renders every route through the real app, so it needs everything the server needs: the database,
 * the media directory, and the secrets. Assembled here for the same reason the dev server's are.
 */
export async function buildSite(secrets: {
  apiToken: string;
  sessionSecret: string;
}): Promise<{ ok: boolean; output: string }> {
  const row = await readRow();
  if (!row?.rootPath) throw new Error('No root location is set.');

  const websiteDir = join(row.rootPath, 'website');
  const databases = await readDatabases();
  if (!databases.production.name || !databases.production.exists) {
    throw new Error('The production database does not exist yet.');
  }

  const raw = process.env.OFFICERDEV_POSTGRES_URL ?? process.env.POSTGRES_URL;
  if (!raw) throw new Error('The platform has no Postgres connection configured.');
  const url = new URL(raw);
  url.pathname = `/${databases.production.name}`;

  const result = await run(['bun', 'run', 'build:site'], 15 * 60 * 1000, {
    cwd: websiteDir,
    env: {
      NODE_ENV: 'production',
      FOFOS_ENV: 'production',
      POSTGRES_URL: url.toString(),
      ...(databases.production.name ? { FOFOS_DB_PRODUCTION: databases.production.name } : {}),
      ...(databases.development.name ? { FOFOS_DB_DEVELOPMENT: databases.development.name } : {}),
      FOFOS_API_TOKEN: secrets.apiToken,
      ADMIN_SESSION_SECRET: secrets.sessionSecret,
      FOFOS_MEDIA_DIR: join(row.rootPath, 'media'),
      // TEMPORARY — passed through so a bisect can rebuild one page instead of all 48. The site's
      // build script leaves every other page alone when this is set. Unset, nothing changes.
      ...(process.env.FOFOS_BUILD_ONLY ? { FOFOS_BUILD_ONLY: process.env.FOFOS_BUILD_ONLY } : {}),
      // Only used to build absolute URLs in the output — og:image, canonical links. The real domain
      // belongs in the checkout's own env, where it is a deployment fact rather than one this invented.
      PUBLIC_URL: process.env.FOFOS_PUBLIC_URL ?? 'http://127.0.0.1',
      API_URL: process.env.FOFOS_PUBLIC_URL ?? 'http://127.0.0.1',
    },
  });

  return { ok: result.ok, output: `$ bun run build:site  (FOFOS_ENV=production)\n${result.output}` };
}

/**
 * Create or replace the web server.
 *
 * Removed and recreated rather than restarted, for the same reason the pm2 side does it: a container
 * keeps the mounts and the network it was created with, so a root location changed here would be saved,
 * shown, and still serving the old directory.
 *
 * `--restart unless-stopped`, so it comes back with the machine. No published port: NPM reaches it on
 * the shared network by name, and a port on the host would be the site available unauthenticated beside
 * the proxy that exists to gate it.
 */
/**
 * The nginx configuration the container runs.
 *
 * Written out on every start rather than kept as a file somebody edits, so what nginx does is decided
 * here and cannot drift. The stock `nginx:alpine` config serves the directory and nothing else: no
 * compression, and no cache headers at all, so every asset carried a TTL of zero and a returning
 * visitor re-downloaded the whole site.
 *
 * ── Three lifetimes, because there are three kinds of file ──
 *
 * `derived/` renditions are rebuilt IN PLACE — av-club replaces the contents of `1280.webp` rather
 * than writing a new name. So they cannot be `immutable`, however much they look like they could be:
 * a re-crop would be invisible to everyone who had seen the old one, for as long as the header said.
 * Thirty days is the compromise, and it is the reason this is spelled out rather than copied from the
 * usual recipe.
 *
 * Bundled assets — the stylesheet, the scripts, the fonts — change only when a build runs, and a build
 * is also the only thing that changes the HTML that references them. A week, revalidated after.
 *
 * HTML is `no-cache`: revalidate every time. Not `no-store` — the file is still cached, it is just
 * never used without asking. Anything longer and a publish is invisible to whoever already visited,
 * which is the one failure that makes the whole panel look broken.
 *
 * ── Why `^~` on the prefixes ──
 *
 * A regex location beats a prefix location in nginx, so the extension rule below would otherwise
 * capture `/derived/…/1280.webp` and hand it the wrong lifetime. `^~` stops the regex from being
 * considered at all. This is the kind of thing that is correct or silently wrong with no middle.
 */
const NGINX_CONF = `server {
  listen 80;
  listen [::]:80;
  server_name _;

  root /usr/share/nginx/html;
  index index.html;

  # Text compresses; the images and video here are already compressed formats and would only burn CPU.
  gzip on;
  gzip_vary on;
  gzip_min_length 1024;
  gzip_types text/css text/plain application/javascript application/json image/svg+xml;

  # Rebuilt in place by av-club, so a long life would pin a stale crop. See the note above.
  location ^~ /derived/ {
    expires 30d;
    add_header Cache-Control "public";
  }

  location ^~ /media/ {
    expires 30d;
    add_header Cache-Control "public";
  }

  # The typefaces. A year, because a face is not edited — it is replaced, and a replacement is a new
  # name. This is the one directory here where a long life carries no risk of pinning something stale.
  location ^~ /fonts/ {
    expires 1y;
    add_header Cache-Control "public, immutable";
  }

  # Everything a build produces. Seven days and no more: these names are stable across builds and the
  # HTML that references them is revalidated every time, so a longer life means a visitor running last
  # week's stylesheet against this week's markup. Fingerprinted filenames are what would earn a year
  # here, and the build does not write them.
  location ~* \\.(css|js|webp|png|jpg|jpeg|gif|svg|ico|mp4)$ {
    expires 7d;
    add_header Cache-Control "public";
  }

  location / {
    # The build writes about/index.html, so a directory match is what serves /about.
    try_files $uri $uri/ =404;
    add_header Cache-Control "no-cache";
  }
}
`;

export async function startStatic(): Promise<{ ok: boolean; output: string }> {
  const row = await readRow();
  if (!row?.rootPath) throw new Error('No root location is set.');

  const dist = distPath(row.rootPath);
  if (!(await stat(dist).catch(() => null))) throw new Error('There is no dist directory yet — build first.');

  // Beside the site rather than inside dist/, which the build empties and replaces.
  const conf = join(row.rootPath, 'nginx.conf');
  await writeFile(conf, NGINX_CONF);

  // Expected to fail the first time; the usual case is that it was never there.
  await run([DOCKER, 'rm', '-f', CONTAINER], 30_000);

  const created = await run(
    [
      DOCKER, 'run', '-d',
      '--name', CONTAINER,
      '--restart', 'unless-stopped',
      '--network', NETWORK,
      // Read-only: nginx serves this and has no business writing to somebody's build output.
      '-v', `${dist}:/usr/share/nginx/html:ro`,
      '-v', `${conf}:/etc/nginx/conf.d/default.conf:ro`,
      IMAGE,
    ],
    120_000,
  );

  return { ok: created.ok, output: `$ docker run ${CONTAINER} (${dist} -> /usr/share/nginx/html, network ${NETWORK})\n${created.output}` };
}

export async function stopStatic(): Promise<{ ok: boolean; output: string }> {
  const result = await run([DOCKER, 'rm', '-f', CONTAINER], 60_000);
  return { ok: result.ok, output: `$ docker rm -f ${CONTAINER}\n${result.output}` };
}