// Drives a real Chrome at the running server and checks two things that no
// assertion in cljs.test can: that the frozen take is a MOVING MOUTH on a canvas,
// and that a document which has been through the server comes back as the same
// picture.
//
// This exists because port-plan step 5 is the first step whose done-criterion is
// a picture, and a picture cannot be asserted from cljs.test. A take that
// resolves to the right numbers and draws nothing would pass every assertion in
// arthur.flow.freeze-test: a blank canvas under a perfectly correct transport is
// the bug class unit tests miss, and it has already happened once here.
//
// No dependencies, deliberately. Playwright is not installed and CDP needs
// nothing: `node --experimental-websocket` has a global WebSocket and
// `--headless=new --remote-debugging-port=N` is the whole of the other side.
//
// Since step 9 the page is Django's, so the suite needs the backend up rather than
// shadow-cljs's `:dev-http`, which is gone. ARTHUR_URL is unchanged because the
// port is unchanged — 8778 was never 8777, which is still the old JS tool's.
//
//   mise exec -- python manage.py runserver 8778   # from the REPO ROOT
//   cd frontend && mise exec -- npx shadow-cljs watch app
//   cd frontend && mise exec -- node --experimental-websocket test/browser/take.mjs
//
// Writes a PNG per sampled frame into test/browser/out/ so that "it drew
// something" can be checked by eye as well as by pixel count.

import { spawn, spawnSync } from 'node:child_process';
import { mkdirSync, writeFileSync, rmSync } from 'node:fs';
import { mkdtempSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';

const HERE = dirname(fileURLToPath(import.meta.url));
const OUT = join(HERE, 'out');
const URL_ = process.env.ARTHUR_URL ?? 'http://localhost:8778/index.html';
const PORT = 9333;
const CHROME = process.env.CHROME ??
  '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome';

// The palette's background, from domain/palette. A pixel of this colour is
// nothing drawn, and every check below is a count of pixels that are not it.
const BG = [0x12, 0x14, 0x1c];

// :mouth-dark, from domain/palette, packed the way PROBE packs a tone. It is the
// mouth INTERIOR's colour and nothing else on the stage carries it, so its
// presence is the whole of "the mouth is open" without needing to know where the
// mouth is. A whole-canvas tone COUNT cannot answer that any more: step 7 put
// eyes, brows, an iris, a pupil and teeth on the same stage, so every frame has
// several tones whatever the mouth is doing.
const MOUTH_DARK = (0x24 << 16) | (0x16 << 8) | 0x1a;

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

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

// ---------------------------------------------------------------------------
// the CDP connection

async function connect() {
  const profile = mkdtempSync(join(tmpdir(), 'arthur-chrome-'));
  const chrome = spawn(CHROME, [
    '--headless=new',
    `--remote-debugging-port=${PORT}`,
    `--user-data-dir=${profile}`,
    // The take plays against audio.wav, and the clock IS the audio element, so
    // without these the frame never advances and "plays back" cannot be checked
    // at all — the failure would look like a broken rAF loop.
    '--autoplay-policy=no-user-gesture-required',
    '--mute-audio',
    '--no-first-run',
    '--no-default-browser-check',
    '--disable-gpu',
    '--window-size=1200,900',
    URL_,
  ], { stdio: ['ignore', 'ignore', 'pipe'] });
  chrome.stderr.on('data', () => {});

  let wsUrl = null;
  for (let i = 0; i < 100 && !wsUrl; i++) {
    await sleep(100);
    try {
      const targets = await fetch(`http://127.0.0.1:${PORT}/json/list`).then((r) => r.json());
      wsUrl = targets.find((t) => t.type === 'page' && t.url.includes('index.html'))
        ?.webSocketDebuggerUrl;
    } catch { /* not up yet */ }
  }
  if (!wsUrl) throw new Error(`Chrome never offered a page target on ${PORT}`);

  const ws = new WebSocket(wsUrl);
  await new Promise((res, rej) => { ws.onopen = res; ws.onerror = rej; });

  let id = 0;
  const pending = new Map();
  const logs = [];
  ws.onmessage = (ev) => {
    const msg = JSON.parse(ev.data);
    if (msg.id && pending.has(msg.id)) {
      const { res, rej } = pending.get(msg.id);
      pending.delete(msg.id);
      msg.error ? rej(new Error(JSON.stringify(msg.error))) : res(msg.result);
    } else if (msg.method === 'Runtime.consoleAPICalled' && msg.params.type === 'error') {
      logs.push(msg.params.args.map((a) => a.value ?? a.description).join(' '));
    } else if (msg.method === 'Runtime.exceptionThrown') {
      logs.push(msg.params.exceptionDetails.text + ' ' +
                (msg.params.exceptionDetails.exception?.description ?? ''));
    }
  };
  const send = (method, params = {}) =>
    new Promise((res, rej) => {
      const n = ++id;
      pending.set(n, { res, rej });
      ws.send(JSON.stringify({ id: n, method, params }));
    });

  await send('Runtime.enable');
  await send('Page.enable');
  return {
    send, logs,
    async eval(expr) {
      const r = await this.send('Runtime.evaluate', {
        expression: expr, awaitPromise: true, returnByValue: true,
      });
      if (r.exceptionDetails) {
        throw new Error(r.exceptionDetails.exception?.description ??
                        r.exceptionDetails.text);
      }
      return r.result.value;
    },
    async shot(name) {
      const r = await this.send('Page.captureScreenshot', { format: 'png' });
      writeFileSync(join(OUT, `${name}.png`), Buffer.from(r.data, 'base64'));
    },
    // Teardown must not be able to fail the run. `chrome.kill()` returns as soon
    // as the signal is sent, so Chrome is often still writing its profile when
    // rmSync walks it, and macOS then throws ENOTEMPTY on a directory that
    // reappeared mid-delete. That throw used to propagate out of main's `finally`
    // and past the summary line, so the suite exited 2 and printed no verdict
    // whether it had passed or failed — which is how a stale assertion sat here
    // unnoticed. A leaked temp profile is worth less than a truthful exit code.
    close() {
      ws.close();
      chrome.kill();
      try {
        rmSync(profile, { recursive: true, force: true, maxRetries: 5, retryDelay: 50 });
      } catch (e) {
        console.log(`  note  could not remove the temp profile — ${e.code ?? e.message}`);
      }
    },
  };
}

// ---------------------------------------------------------------------------
// what we ask the page
//
// Every probe reads the canvas's own pixels rather than a screenshot: the CSS
// scales the stage up by 2 with image-rendering:pixelated, so a screenshot is
// four pixels per raster pixel and is for looking at, not for counting.

const PROBE = `(() => {
  const c = document.querySelector('canvas.stage');
  if (!c) return null;
  const d = c.getContext('2d').getImageData(0, 0, c.width, c.height).data;
  const bg = [${BG.join(',')}];
  let drawn = 0;
  const tones = new Set();
  let cx = 0, cy = 0;
  for (let i = 0; i < d.length; i += 4) {
    if (d[i] === bg[0] && d[i+1] === bg[1] && d[i+2] === bg[2]) continue;
    drawn++;
    tones.add((d[i] << 16) | (d[i+1] << 8) | d[i+2]);
    const p = i / 4;
    cx += p % c.width; cy += Math.floor(p / c.width);
  }
  // A cheap 32-bit hash of the whole buffer: two frames with the same drawn
  // count can still be different pictures, and "the mouth moved" is a question
  // about the picture.
  let h = 2166136261;
  for (let i = 0; i < d.length; i += 4) { h ^= d[i] + d[i+1] * 31 + d[i+2] * 131; h = Math.imul(h, 16777619); }
  return {
    w: c.width, h: c.height, drawn, tones: [...tones].length, toneSet: [...tones],
    cx: drawn ? cx / drawn : null, cy: drawn ? cy / drawn : null,
    hash: h >>> 0,
    frame: document.querySelector('.readout span')?.textContent ?? '',
    selectedClip: [...document.querySelectorAll('.transport .row button')]
      .filter((b) => b.classList.contains('on')).map((b) => b.textContent),
  };
})()`;

const SEEK = (f) => `(() => {
  const el = document.querySelector('input.scrub');
  // React installs its own value setter on the element, so assigning .value
  // directly updates the DOM and not React's idea of it, and onChange never
  // fires. The prototype-level setter plus a bubbling 'input' event is what
  // React's synthetic onChange actually listens for.
  const set = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value').set;
  set.call(el, '${f}');
  el.dispatchEvent(new Event('input', { bubbles: true }));
  return el.value;
})()`;

// Everything the page has to say about loading, saving and opening. Read off the
// page rather than out of app-db, for the same reason the playhead is: what the
// page SHOWS is what a person would check.
const STATUS = `[...document.querySelectorAll('.load-status')].map((d) => d.textContent).join(' | ')`;

const CLICK = (label) => `(() => {
  const b = [...document.querySelectorAll('.transport button')]
    .find((b) => b.textContent.trim() === ${JSON.stringify(label)});
  if (!b) return false;
  b.click();
  return true;
})()`;

// ---------------------------------------------------------------------------

async function main() {
  rmSync(OUT, { recursive: true, force: true });
  mkdirSync(OUT, { recursive: true });

  const page = await connect();
  try {
    // Mounted, and painting. Polled rather than waited on a fixed delay: the
    // canvas :ref fires after the loop starts, so there genuinely is a window in
    // which the page is up and the canvas is blank.
    let probe = null;
    for (let i = 0; i < 100; i++) {
      probe = await page.eval(PROBE);
      if (probe && probe.drawn > 0) break;
      await sleep(100);
    }
    if (!probe) throw new Error('no canvas.stage on the page — ' +
      (page.logs.slice(0, 3).join(' | ') || 'is `shadow-cljs watch app` running?'));

    console.log(`\ncanvas ${probe.w}x${probe.h}, clip ${JSON.stringify(probe.selectedClip)}`);

    check(probe.selectedClip.includes('take'), 'the take is the clip that opens');
    check(probe.w === 320 && probe.h === 200, 'the canvas is the stage size',
          `${probe.w}x${probe.h}`);
    check(probe.drawn > 200, 'the first frame is not blank', `${probe.drawn} px drawn`);

    // --- it is a mouth: two tones, one inside the other ---
    //
    // The three-layer structure is what makes a flat shape read as an opening
    // rather than a blob, so the interior being its OWN tone is the check that
    // this is a mouth and not one polygon. Asked of :mouth-dark specifically
    // rather than of the tone count: the count is now dominated by the eyes and
    // brows, which are on the stage whatever the mouth is doing.
    await page.eval(SEEK(10));           // beat 1: wide open
    await sleep(120);
    const open = await page.eval(PROBE);
    await page.shot('take-open');
    check(open.toneSet.includes(MOUTH_DARK),
          'an open mouth draws an outline and an interior',
          `${open.tones} tones, interior ${open.toneSet.includes(MOUTH_DARK) ? 'present' : 'MISSING'}`);

    await page.eval(SEEK(28));           // beat 3: shut
    await sleep(120);
    const shut = await page.eval(PROBE);
    await page.shot('take-shut');
    check(!shut.toneSet.includes(MOUTH_DARK), 'a shut mouth draws the outline alone',
          `${shut.tones} tones, interior ${shut.toneSet.includes(MOUTH_DARK) ? 'STILL DRAWN' : 'gone'}`);
    check(open.hash !== shut.hash, 'the open and the shut mouth are different pictures');
    check(open.drawn > shut.drawn, 'the open mouth covers more of the stage',
          `${open.drawn} vs ${shut.drawn} px`);

    // --- it moves under the head, and the head is a channel ---
    const filmed = [];
    for (const f of [0, 40, 80, 120, 160, 200]) {
      await page.eval(SEEK(f));
      await sleep(120);
      filmed.push(await page.eval(PROBE));
    }
    check(new Set(filmed.map((p) => p.hash)).size === filmed.length,
          'every sampled frame is a different picture');
    const xs = filmed.map((p) => p.cx);
    check(Math.max(...xs) - Math.min(...xs) > 8,
          'as filmed, the head carries the mouth across the stage',
          `centroid x spans ${(Math.max(...xs) - Math.min(...xs)).toFixed(1)} px`);

    check(await page.eval(CLICK('locked')), 'the locked take is selectable');
    await sleep(200);
    const locked = [];
    for (const f of [0, 40, 80, 120, 160, 200]) {
      await page.eval(SEEK(f));
      await sleep(120);
      locked.push(await page.eval(PROBE));
    }
    await page.shot('take-locked');
    const lxs = locked.map((p) => p.cx);
    check(locked.every((p) => p.drawn > 200), 'the locked take draws too');
    // The same blocks with one node's channels written differently: the mouth
    // still articulates, and the head no longer wanders. That is the claim
    // "stabilisation is a channel, not a mode", by eye.
    check(Math.max(...lxs) - Math.min(...lxs) < (Math.max(...xs) - Math.min(...xs)) / 2,
          'locked, the head holds still while the mouth still articulates',
          `centroid x spans ${(Math.max(...lxs) - Math.min(...lxs)).toFixed(1)} px`);
    check(new Set(locked.map((p) => p.hash)).size > 3,
          'and it is still a performance, not a still frame');

    // --- it PLAYS, against the audio clock ---
    check(await page.eval(CLICK('take')), 'back to the take');
    await sleep(150);
    await page.eval(SEEK(0));
    await sleep(150);
    check(await page.eval(CLICK('play')), 'play is clickable');
    const during = [];
    for (let i = 0; i < 8; i++) { await sleep(180); during.push(await page.eval(PROBE)); }
    await page.eval(CLICK('pause'));
    // The readout is "frame 12 / 229", so the first run of digits is the
    // playhead. Parsed rather than reached for in app-db on purpose: what the
    // page SHOWS is what a person would check, and the readout agreeing with the
    // picture is half of what the transport is for.
    const nums = during.map((p) => parseInt((p.frame.match(/\d+/) ?? [NaN])[0], 10));
    check(nums[nums.length - 1] > nums[0] + 5, 'the playhead advances under the clock',
          `frame ${nums[0]} -> ${nums[nums.length - 1]}`);
    check(new Set(during.map((p) => p.hash)).size > 4,
          'and the picture changes while it runs',
          `${new Set(during.map((p) => p.hash)).size} distinct of ${during.length}`);
    await page.shot('take-playing');

    // --- it round-trips through the server ---
    //
    // THE DONE CRITERION of port-plan step 9, end to end: tier 1 over HTTP, tier 2
    // as content-addressed blocks, and the same frames on the far side. The ops are
    // compared frame for frame in arthur.domain.project-test, which is the strict
    // version of this; what only a browser can check is that the whole path — the
    // CSRF header, the block upload, the leaf write, the reload, the typed arrays
    // rebuilt out of base64 — draws the same pixels at the end of it.
    async function statusMatching(pattern, tries = 120) {
      for (let i = 0; i < tries; i++) {
        const text = await page.eval(STATUS);
        if (pattern.test(text)) return text;
        await sleep(250);
      }
      return null;
    }
    async function sample(frames) {
      const out = [];
      for (const f of frames) {
        await page.eval(SEEK(f));
        await sleep(120);
        out.push(await page.eval(PROBE));
      }
      return out;
    }

    const FRAMES = [0, 10, 28, 80, 160];
    check(await page.eval(CLICK('take')), 'back to the take, for the round trip');
    await sleep(150);
    const sent = await sample(FRAMES);

    check(await page.eval(CLICK('save')), 'save is clickable');
    const saved = await statusMatching(/saved r\d+/);
    check(saved !== null, 'the document saves', saved ?? (await page.eval(STATUS)));
    // Upload count may be zero when the content-addressed blocks already exist
    // on this server. The saved clip must still reference them.
    const savedBlocks = await page.eval(`(async () => {
      const listed = await fetch('/api/projects').then(r => r.json());
      const project = await fetch('/api/projects/' + listed.projects[0].id).then(r => r.json());
      return project.clips[0].blocks.length;
    })()`);
    check(savedBlocks > 0, 'the saved clip references its tier 2 blocks',
          `${savedBlocks} blocks`);

    // Again, unchanged. Content addressing means the second save uploads nothing
    // and rewrites nothing: this is the assertion that the keys are stable across
    // two independent freezes of the same take, and that an unchanged leaf keeps
    // its version rather than being rewritten.
    check(await page.eval(CLICK('save')), 'save is clickable again');
    const resaved = await statusMatching(/saved r\d+ · 0 leaves · 0 blocks/);
    check(resaved !== null, 'saving an unchanged document writes nothing',
          resaved ?? (await page.eval(STATUS)));

    check(await page.eval(CLICK('open')), 'open is clickable');
    const opened = await statusMatching(/opened /);
    check(opened !== null, 'the project opens', opened ?? (await page.eval(STATUS)));

    const back = await sample(FRAMES);
    await page.shot('take-round-trip');
    check(back.every((p) => p.drawn > 200), 'the reopened take draws',
          back.map((p) => p.drawn).join(','));
    check(FRAMES.every((f, i) => sent[i].hash === back[i].hash),
          'every sampled frame is the same picture after the round trip',
          FRAMES.filter((f, i) => sent[i].hash !== back[i].hash).join(',') || 'all identical');
    check(back[1].toneSet.includes(MOUTH_DARK),
          'and the open mouth still has an interior on the far side');
    // The reopened clip is not one of the built-ins: this is the document that came
    // back from the server, not the one that was in the page all along.
    check(!back[0].selectedClip.includes('take'), 'the picture is the reopened document',
          JSON.stringify(back[0].selectedClip));

    // The local 8625 study is optional in a fresh test database. When present,
    // tune its shared symbol while its stage is playing.
    const stageSource = await page.eval(`fetch('/api/projects/4379f900-bdd2-409b-acf6-32081f8ce01f')
      .then(r => r.ok)`);
    if (stageSource) {
      check(await page.eval(CLICK('stage 8625')), 'the 8625 stage loads');
      const stageLoaded = await statusMatching(/loaded 8625 stage study/, 160);
      check(stageLoaded !== null, 'the 8625 stage is ready', stageLoaded ?? (await page.eval(STATUS)));
      const eyeSelected = await page.eval(`(() => {
        const select = document.querySelector('.controls select');
        // The instance prefix is the placement's NAME ("8625 left"), not its id:
        // a placement is keyed by a uuid now, and a uuid is not something to show
        // anyone. So this matches the feature and requires SOME instance prefix,
        // rather than pinning the label a rename is free to change.
        const option = [...select.options]
          .find(o => o.textContent.trim().endsWith('/ feature · eye-r')
                  && o.textContent.includes(' / '));
        if (!option) return false;
        select.value = option.value;
        select.dispatchEvent(new Event('change', { bubbles: true }));
        return true;
      })()`);
      check(eyeSelected, 'a stage instance exposes its tracked right eye');
      await sleep(100);
      const irisSlider = await page.eval(`(() => {
        const row = [...document.querySelectorAll('.control-row')]
          .find(row => row.querySelector('span')?.textContent === 'iris-size');
        if (!row) return null;
        // Scrolled into view FIRST, because the click below is dispatched at
        // viewport coordinates: a control panel that has grown past the fold
        // otherwise reports a y outside the window, the click lands on nothing,
        // and the failure reads as "regeneration is broken" rather than "the
        // slider was off-screen". Which is exactly what it read as once.
        row.scrollIntoView({ block: 'center' });
        const r = row.querySelector('input').getBoundingClientRect();
        return { x: r.x + r.width * 0.9, y: r.y + r.height / 2 };
      })()`);
      check(irisSlider !== null, 'the stage eye has an iris-size slider');
      if (irisSlider) {
        check(await page.eval(CLICK('play')), 'the stage starts playing');
        const startFrame = await page.eval(`Number(document.querySelector('.readout span').textContent.match(/\\d+/)[0])`);
        await page.send('Input.dispatchMouseEvent', {
          type: 'mousePressed', x: irisSlider.x, y: irisSlider.y, button: 'left', clickCount: 1,
        });
        await page.send('Input.dispatchMouseEvent', {
          type: 'mouseReleased', x: irisSlider.x, y: irisSlider.y, button: 'left', clickCount: 1,
        });
        const preview = await statusMatching(/preview · unsaved/, 160);
        const debug = await page.eval(`document.querySelector('.regeneration-debug')?.textContent ?? ''`);
        check(preview !== null, 'the slider updates the stage preview', preview ?? debug);
        check(debug.includes(':eye-r') && debug.includes('tier 1 only'),
              'the panel reports the affected feature and tier', debug);
        const endFrame = await page.eval(`Number(document.querySelector('.readout span').textContent.match(/\\d+/)[0])`);
        check(endFrame > startFrame, 'playback continues during tuning', `${startFrame} -> ${endFrame}`);
        await page.eval(CLICK('pause'));
      }
      const subjectSelected = await page.eval(`(() => {
        const select = document.querySelector('.controls select');
        const option = [...select.options]
          .find(o => o.textContent.includes('subject · face-1'));
        if (!option) return false;
        select.value = option.value;
        select.dispatchEvent(new Event('change', { bubbles: true }));
        return true;
      })()`);
      check(subjectSelected, 'the stage exposes its tracked subject');
      if (subjectSelected) {
        await sleep(100);
        const anchorSlider = await page.eval(`(() => {
          const row = [...document.querySelectorAll('.control-row')]
            .find(row => row.querySelector('span')?.textContent === 'anchor-avg');
          if (!row) return null;
          // Scrolled into view FIRST, because the click below is dispatched at
          // viewport coordinates: a control panel that has grown past the fold
          // otherwise reports a y outside the window, the click lands on nothing,
          // and the failure reads as "regeneration is broken" rather than "the
          // slider was off-screen". Which is exactly what it read as once.
          row.scrollIntoView({ block: 'center' });
          const r = row.querySelector('input').getBoundingClientRect();
          return { x: r.x + r.width * 0.9, y: r.y + r.height / 2 };
        })()`);
        check(anchorSlider !== null, 'the subject has an anchor slider');
        if (anchorSlider) {
          const anchorStart = Date.now();
          await page.send('Input.dispatchMouseEvent', {
            type: 'mousePressed', x: anchorSlider.x, y: anchorSlider.y,
            button: 'left', clickCount: 1,
          });
          await page.send('Input.dispatchMouseEvent', {
            type: 'mouseReleased', x: anchorSlider.x, y: anchorSlider.y,
            button: 'left', clickCount: 1,
          });
          let debug = '';
          for (let i = 0; i < 160; i++) {
            debug = await page.eval(`document.querySelector('.regeneration-debug')?.textContent ?? ''`);
            if (debug.includes('head-pos')) break;
            await sleep(250);
          }
          check(debug.includes('head-pos') && debug.includes(':teeth'),
                'anchor invalidates the head and teeth', debug);
          const preview = await statusMatching(/preview · unsaved/, 160);
          check(preview !== null, 'the anchor edit finishes previewing',
                preview ? `${Date.now() - anchorStart}ms` : (await page.eval(STATUS)));
        }
      }
      const teethSelected = await page.eval(`(() => {
        const select = document.querySelector('.controls select');
        const option = [...select.options]
          .find(o => o.textContent.trim().endsWith('/ feature · teeth')
                  && o.textContent.includes(' / '));
        if (!option) return false;
        select.value = option.value;
        select.dispatchEvent(new Event('change', { bubbles: true }));
        return true;
      })()`);
      check(teethSelected, 'the stage exposes its tracked teeth');
      if (teethSelected) {
        await sleep(100);
        const slider = await page.eval(`(() => {
          const row = [...document.querySelectorAll('.control-row')]
            .find(row => row.querySelector('span')?.textContent === 'cavity-erode');
          if (!row) return null;
          // Scrolled into view FIRST, because the click below is dispatched at
          // viewport coordinates: a control panel that has grown past the fold
          // otherwise reports a y outside the window, the click lands on nothing,
          // and the failure reads as "regeneration is broken" rather than "the
          // slider was off-screen". Which is exactly what it read as once.
          row.scrollIntoView({ block: 'center' });
          const r = row.querySelector('input').getBoundingClientRect();
          return { x: r.x + r.width * 0.9, y: r.y + r.height / 2 };
        })()`);
        check(slider !== null, 'the teeth have a pixel-setting slider');
        if (slider) {
          await page.send('Input.dispatchMouseEvent', {
            type: 'mousePressed', x: slider.x, y: slider.y,
            button: 'left', clickCount: 1,
          });
          await page.send('Input.dispatchMouseEvent', {
            type: 'mouseReleased', x: slider.x, y: slider.y,
            button: 'left', clickCount: 1,
          });
          let debug = '';
          for (let i = 0; i < 160; i++) {
            debug = await page.eval(`document.querySelector('.regeneration-debug')?.textContent ?? ''`);
            if (debug.includes('dirty features: [:teeth]')) break;
            await sleep(250);
          }
          check(debug.includes('dirty features: [:teeth]'),
                'the pixel setting invalidates only teeth', debug);
          const preview = await statusMatching(/preview · unsaved/, 160);
          check(preview !== null, 'the teeth edit finishes previewing',
                preview ?? (await page.eval(STATUS)));
        }
      }
    }

    // Exercise the actual file input and FormData path, then wait for the
    // extraction job's footage to appear in the server list.
    const uploadDir = mkdtempSync(join(tmpdir(), 'arthur-upload-'));
    try {
      const video = join(uploadDir, 'browser-upload.mp4');
      const encoded = spawnSync('ffmpeg', [
        '-hide_banner', '-loglevel', 'error', '-y', '-f', 'lavfi',
        '-i', 'color=c=blue:s=64x48:r=4:d=1', '-c:v', 'mpeg4', video,
      ]);
      if (encoded.status !== 0) throw new Error(`ffmpeg failed: ${encoded.stderr}`);
      const { root } = await page.send('DOM.getDocument');
      const { nodeId } = await page.send('DOM.querySelector', {
        nodeId: root.nodeId, selector: 'input[type=file]',
      });
      await page.send('DOM.setFileInputFiles', { files: [video], nodeId });
      const extracted = await statusMatching(/video extracted/, 160);
      check(extracted !== null, 'the page uploads and extracts a video',
            extracted ?? (await page.eval(STATUS)));
      const uploadedFootage = await page.eval(`(async () => {
        const listed = await fetch('/api/footage').then(r => r.json());
        return listed.footage.some(f => f.label === 'browser-upload.mp4' && f.frames === 4);
      })()`);
      check(uploadedFootage, 'the uploaded footage is selectable');
    } finally {
      rmSync(uploadDir, { recursive: true, force: true });
    }

    check(page.logs.length === 0, 'no errors on the console',
          page.logs.slice(0, 3).join(' | '));
  } finally {
    page.close();
  }

  console.log(`\n${failures ? `${failures} FAILED` : 'all checks passed'}` +
              ` — screenshots in test/browser/out/\n`);
  process.exit(failures ? 1 : 0);
}

main().catch((e) => { console.error(e); process.exit(2); });