// The catalogue's own copy, end to end: a roll of two frames is read, the
// catalogue is written into a folder the visitor picked, the browser's storage is
// taken away from under it, and the catalogue is read back out — with the frames
// never read a second time.
//
// The folder of frames is a stand-in served off a local server, because the check
// cannot hand a real directory to a page. The backup folder is not: the picker
// answers with a directory out of the origin's own file system (OPFS), which is a
// real `FileSystemDirectoryHandle` with a real `createWritable`, so what is
// written is written by the code under test through the API it will use on a
// visitor's disk — and what the check then reads back is the bytes on it.
//
// What the run claims, in order:
//   * the catalogue file holds the rows and neither of the two things a file
//     cannot hold — a handle and a tile;
//   * the tiles are written beside it, one per frame, under `thumbs/<frame id>`;
//   * a second run writes no tile at all;
//   * a catalogue with nothing in it gets every row back, tiles included, and the
//     frames themselves are never read from the disk again — not by the restore,
//     which takes the tiles off the backup folder, and not by the reading that
//     follows it, which matches each frame on its size and its write time.
//
//   npm run build && node scripts/backup-check.mjs
//   PLAYWRIGHT_CORE=<path to playwright-core/index.mjs> node scripts/backup-check.mjs
//
// Playwright is not a dependency of this package, so a run without it says SKIP
// and exits 0. APP_PORT says where the preview goes, CHROME says which browser.
import { spawn } from 'node:child_process';
import { createServer } from 'node:http';
import { readFile } from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const FRONTEND = fileURLToPath(new URL('..', import.meta.url));
const SAMPLES = process.env.SAMPLE_DIR ?? path.resolve(FRONTEND, '..');
const APP_PORT = Number(process.env.APP_PORT ?? 4198);
const SAMPLE_PORT = Number(process.env.SAMPLE_PORT ?? 4321);
// Two frames of one folder, both read off the sample roll.
const FILES = ['P1010256.JPG', 'DSCF1701.JPG'];
const FOLDER = 'TestRoll';
const BACKUP = 'BackupRoll';

let failures = 0;
function step(name, ok, detail = '') {
  if (!ok) failures++;
  console.log(`${ok ? 'ok  ' : 'FAIL'} ${name}${detail ? ` — ${detail}` : ''}`);
  return ok;
}

const playwright = await import(process.env.PLAYWRIGHT_CORE ?? 'playwright-core').catch(() => null);
if (!playwright) {
  console.log('SKIP playwright-core is not installed — pass PLAYWRIGHT_CORE=<path to its index.mjs>');
  process.exit(0);
}

// --- the frames, off a local server (the page fetches them by CORS) ----------
const sampleServer = createServer(async (req, res) => {
  const name = path.basename(decodeURIComponent((req.url ?? '/').split('?')[0]));
  if (!FILES.includes(name)) {
    res.writeHead(404).end();
    return;
  }
  const bytes = await readFile(path.join(SAMPLES, name));
  res.writeHead(200, {
    'Content-Type': 'image/jpeg',
    'Content-Length': bytes.length,
    'Access-Control-Allow-Origin': '*',
  });
  res.end(bytes);
});
await new Promise((resolve) => sampleServer.listen(SAMPLE_PORT, '127.0.0.1', resolve));

// `--host 127.0.0.1`: without it vite's preview binds the name `localhost`, which
// on a dual-stack box can be ::1 alone and every 127.0.0.1 fetch below fails.
const app = spawn('npx', ['vite', 'preview', '--port', String(APP_PORT), '--strictPort', '--host', '127.0.0.1'], {
  cwd: FRONTEND,
  stdio: 'ignore',
});
const base = `http://127.0.0.1:${APP_PORT}`;
let up = false;
for (let i = 0; i < 60 && !up; i++) {
  up = await fetch(`${base}/library`).then((r) => r.ok).catch(() => false);
  if (!up) await new Promise((r) => setTimeout(r, 500));
}
if (!up) {
  app.kill('SIGTERM');
  sampleServer.close();
  console.log(`FAIL no preview on ${base} — run \`npm run build\` first (vite preview serves dist/)`);
  process.exit(1);
}

const browser = await playwright.chromium.launch({
  // Playwright's own Chromium when it has one; CHROME points at any other.
  executablePath: process.env.CHROME || undefined,
  args: ['--no-sandbox', '--enable-unsafe-swiftshader', '--use-gl=angle', '--use-angle=swiftshader'],
});
const context = await browser.newContext();
// The words this screen says are read below, so the run is pinned to one of the
// two dictionaries rather than to whatever the browser's own language is.
await context.addInitScript(() => localStorage.setItem('rc.lang', 'en'));
// The picker, twice over: the roll of frames is a stand-in — a page cannot be
// handed a real directory by a test — and the backup folder is the origin's own
// file system, which is a real one. Which of the two a call is for is the `id`
// the code passes, the same one it passes to a visitor's browser.
await context.addInitScript(
  ({ origin, files, folder, backup }) => {
    const bytes = new Map();
    const load = async (name) => {
      if (!bytes.has(name)) bytes.set(name, fetch(`${origin}/${name}`).then((r) => r.arrayBuffer()));
      return bytes.get(name);
    };
    // What a frame costs is its bytes, and the bytes of a frame are read through
    // `arrayBuffer` — on the file, or on a slice of it, which is how a scan reads
    // the head of a JPEG. Only the stand-in's own files are counted: the tiles
    // that come back out of the backup folder are read the same way, and they are
    // named after the frames.
    window.__frameReads = 0;
    const off = new WeakMap();
    const part = Blob.prototype.slice;
    Blob.prototype.slice = function (...args) {
      const cut = part.apply(this, args);
      off.set(cut, off.get(this) ?? this);
      return cut;
    };
    const pull = Blob.prototype.arrayBuffer;
    Blob.prototype.arrayBuffer = function () {
      if ((off.get(this) ?? this).__fake) window.__frameReads++;
      return pull.apply(this);
    };
    const fileHandle = (name) => {
      const handle = { kind: 'file', name };
      Object.defineProperty(handle, 'getFile', {
        value: async () => {
          const file = new File([await load(name)], name, {
            type: 'image/jpeg',
            // One write time per frame, and the same one on every read: a fresh
            // `Date.now()` would make every frame look touched and hide what is
            // being checked — the reading after the restore has to match.
            lastModified: Date.UTC(2016, 1, 15, 9, 30),
          });
          Object.defineProperty(file, '__fake', { value: true });
          return file;
        },
      });
      return handle;
    };
    const dirHandle = (label, node) => {
      const handle = { kind: 'directory', name: label };
      Object.defineProperties(handle, {
        values: { value: () => [...(node.files ?? []).map(fileHandle)][Symbol.iterator]() },
        queryPermission: { value: async () => 'granted' },
        requestPermission: { value: async () => 'granted' },
        getDirectoryHandle: { value: async (name) => {
          throw new Error(`no folder named ${name}`);
        } },
        getFileHandle: {
          value: async (name) => {
            if (!(node.files ?? []).includes(name)) throw new Error(`no frame named ${name}`);
            return fileHandle(name);
          },
        },
      });
      return handle;
    };
    const root = (label) => dirHandle(label, { files });
    window.showDirectoryPicker = async (opts) => {
      if (opts?.id !== 'recipescam-backup') return root(folder);
      const opfs = await navigator.storage.getDirectory();
      // A folder of the origin's own, emptied at the start of the run and named
      // as the picker would name it.
      await opfs.removeEntry(backup, { recursive: true }).catch(() => {});
      const dir = await opfs.getDirectoryHandle(backup, { create: true });
      // OPFS handles are always writable and say so only through the API the
      // picker's handles carry: the two methods are stood in where the real
      // handle leaves them out, so the code under test takes the same road it
      // would with a folder off a disk.
      for (const mode of ['queryPermission', 'requestPermission']) {
        if (typeof dir[mode] !== 'function') Object.defineProperty(dir, mode, { value: async () => 'granted' });
      }
      return dir;
    };
  },
  { origin: `http://127.0.0.1:${SAMPLE_PORT}`, files: FILES, folder: FOLDER, backup: BACKUP }
);

const page = await context.newPage();
// The restore asks before it replaces anything, and a dismissed dialog is a
// cancel — the run says yes the way a reader would.
page.on('dialog', (dialog) => void dialog.accept());
const note = () => page.$eval('.adm-note', (el) => el.textContent ?? '').catch(() => '');
const waitNote = (re) =>
  page.waitForFunction(
    (src) => new RegExp(src).test(document.querySelector('.adm-note')?.textContent ?? ''),
    re.source,
    { timeout: 120_000 }
  );
const count = () => page.$eval('[data-key="lib-count"]', (el) => el.textContent ?? '');
// The bytes of a frame actually read off the disk, counted inside the page: the
// whole claim of the catalogued size and write time is this number staying put.
const framesRead = () => page.evaluate(() => window.__frameReads ?? 0);
// The catalogue the page itself keeps, read straight out of the browser: what the
// restore puts back is a row in there, not a picture on the screen.
const rows = () =>
  page.evaluate(
    () =>
      new Promise((resolve) => {
        const open = indexedDB.open('recipescam-library');
        open.onsuccess = () => {
          const req = open.result.transaction('photos', 'readonly').objectStore('photos').getAll();
          req.onsuccess = () =>
            resolve(
              req.result.map((r) => ({
                id: r.id,
                tile: r.thumb ? r.thumb.size : 0,
                handle: !!r.handle,
                star: r.star ?? null,
              }))
            );
          req.onerror = () => resolve([]);
        };
        open.onerror = () => resolve([]);
      })
  );
// Everything the backup folder holds, walked the way a person looking at it in a
// file manager would.
const backupTree = () =>
  page.evaluate(async (name) => {
    const opfs = await navigator.storage.getDirectory();
    const root = await opfs.getDirectoryHandle(name);
    const out = [];
    const walk = async (dir, at) => {
      for await (const [child, handle] of dir.entries()) {
        const rel = at ? `${at}/${child}` : child;
        if (handle.kind === 'directory') await walk(handle, rel);
        else out.push({ rel, size: (await handle.getFile()).size });
      }
    };
    await walk(root, '');
    return out;
  }, BACKUP);

let code = 0;
try {
  // --- the roll is read ------------------------------------------------------
  await page.goto(`${base}/library`);
  await page.click('[data-key="lib-add"]');
  await waitNote(/Scanned TestRoll/);
  const read = await rows();
  step('the roll was read and both frames are in the catalogue', read.length === 2, `${read.length} rows`);
  step('every frame has its tile', read.every((r) => r.tile > 0));
  step('the count on the bar says two', /2/.test(await count()), await count());
  const firstRead = await framesRead();
  step('reading a roll of two frames costs two frames', firstRead === 2, `${firstRead} reads`);

  // --- the catalogue is written ---------------------------------------------
  await page.click('[data-key="lib-backup"]');
  await waitNote(/Backed up 2 frames, 2 tiles written/);
  const tree = await backupTree();
  const cat = await page.evaluate(async (name) => {
    const opfs = await navigator.storage.getDirectory();
    const dir = await opfs.getDirectoryHandle(name);
    return JSON.parse(await (await (await dir.getFileHandle('recipescam-catalogue.json')).getFile()).text());
  }, BACKUP);
  step('the catalogue file holds both rows', cat.photos.length === 2, `${cat.photos.length}`);
  step(
    'a row carries no handle and no tile',
    cat.photos.every((r) => !('handle' in r) && !('thumb' in r)),
    Object.keys(cat.photos[0]).join(',')
  );
  step(
    'a row carries the size and the write time of its frame',
    cat.photos.every((r) => r.size > 0 && r.mtime === Date.UTC(2016, 1, 15, 9, 30))
  );
  const tiles = tree.filter((f) => f.rel.startsWith('thumbs/'));
  step(
    'the tiles are beside it, one file per frame',
    tiles.length === 2 && tiles.every((f) => f.size > 0) && tiles.every((f) => /^thumbs\/TestRoll\/[^/]+$/.test(f.rel)),
    tiles.map((f) => f.rel).join(' ')
  );

  // --- a second run writes no tile ------------------------------------------
  await page.click('[data-key="lib-backup"]');
  await waitNote(/Backed up 2 frames, 0 tiles written/);

  // --- the browser's storage is taken away ----------------------------------
  await page.goto('about:blank');
  await page.goto(`${base}/`);
  const gone = await page.evaluate(
    () =>
      new Promise((resolve) => {
        const req = indexedDB.deleteDatabase('recipescam-library');
        req.onsuccess = () => resolve(true);
        req.onerror = req.onblocked = () => resolve(false);
      })
  );
  step('the catalogue is gone from the browser', gone === true);
  await page.goto(`${base}/library`);
  step('the library comes up empty', /^0\b/.test((await count()).trim()), await count());
  step('and has read nothing', (await framesRead()) === 0);

  // --- and it is put back ----------------------------------------------------
  await page.click('[data-key="lib-restore"]');
  await waitNote(/Restored 2 frames/);
  const back = await rows();
  step('both rows are back', back.length === 2, `${back.length} rows`);
  step('each row came back with its tile', back.every((r) => r.tile > 0));
  step('no row came back with a handle — a handle is not a file', back.every((r) => !r.handle));
  step('the restore read no frame from the disk', (await framesRead()) === 0, `${await framesRead()} reads`);
  step('the count on the bar says two again', /2/.test(await count()), await count());

  // --- the folder is picked again, and no frame is read for it ---------------
  await page.click('[data-key="lib-add"]');
  await waitNote(/Scanned TestRoll/);
  const joined = await rows();
  step('the reading gave every row its handle back', joined.length === 2 && joined.every((r) => r.handle));
  step('and read no frame to do it', (await framesRead()) === 0, `${await framesRead()} reads`);
} catch (err) {
  step(`the run finished`, false, String(err).split('\n')[0]);
  code = 1;
}

console.log(failures ? `FAIL ${failures} step(s)` : 'ok  the catalogue survives its browser');
await browser.close();
app.kill('SIGTERM');
sampleServer.close();
process.exit(failures || code ? 1 : 0);