/**
 * Podcast mode: notes → a spoken episode with a synced transcript.
 *
 * Runs against a stub Ollama (no model needed) and a stubbed speech engine, so
 * the word highlight can be driven deterministically: the stub records what
 * was spoken and fires boundary events on demand.
 */
import http from "node:http";
import { mkdirSync } from "node:fs";

import {
  launchBrowser,
  makeChecker,
  makePage,
  portInUse,
  seed,
  spawnApp,
  waitForHttp,
} from "./lib.mjs";

const { check, finish } = makeChecker();

const STUB_PORT = 3211;
const APP_PORT = 3212;
const STUB_BASE = `http://127.0.0.1:${STUB_PORT}`;
const APP = `http://127.0.0.1:${APP_PORT}`;

/** Two sections, a handful of words each — enough to watch the highlight walk. */
const EPISODE_REPLY = {
  title: "Why the sky is blue",
  language: "English",
  summary: "Rayleigh scattering, explained out loud.",
  sections: [
    { heading: "Daylight", text: "Look up on a clear day. The sky is blue." },
    { heading: "Why", text: "Tiny molecules scatter short wavelengths far more than long ones." },
  ],
};

/** An episode seeded straight into storage, for the voice/scroll sections. */
const EPISODE_RECORD = {
  id: "pod_local",
  title: "The sky, out loud",
  summary: "Rayleigh scattering.",
  language: "English",
  sourceText: "Rayleigh scattering.",
  createdAt: Date.now(),
  updatedAt: Date.now(),
  sections: [
    { heading: "Daylight", text: "Look up on a clear day. The sky is blue. Every direction you look, the same blue." },
    { heading: "Why", text: "Tiny molecules scatter short wavelengths far more than long ones, so blue reaches your eyes from everywhere at once." },
  ],
};

/** Long enough to scroll: eight paragraphs of a few lines each. */
const LONG_RECORD = {
  ...EPISODE_RECORD,
  id: "pod_long",
  title: "A long walk through the atmosphere",
  /* One long sentence per part on purpose: with the sentence clock a section
     is spoken in one utterance only while it has no sentence break, which is
     exactly the shape the scroll checks need (a boundary can land far away). */
  sections: Array.from({ length: 8 }, (_, index) => ({
    heading: `Part ${index + 1}`,
    text: `Part ${index + 1}, ${"the atmosphere scatters light in every direction, and the shorter wavelengths bounce far more often than the longer ones, ".repeat(3).trim()}`,
  })),
};

/** Three sentences: the fallback clock must re-anchor at every one. */
const SENTENCES_RECORD = {
  ...EPISODE_RECORD,
  id: "pod_sentences",
  sections: [
    {
      heading: "Daylight",
      text: "Look up on a clear day. The sky is blue. Molecules scatter short wavelengths far more than long ones. That is what reaches your eyes.",
    },
    { heading: "Why", text: "That scattering is what colours the sky." },
  ],
};

/** A speech engine that never reports boundaries: the timer clock drives it. */
const WORD_TIMER_SPEECH = `
window.__utterances = [];
class FakeUtterance {
  constructor(text) { this.text = String(text); this.rate = 1; this.lang = "en-US"; this.onstart = null; this.onend = null; this.onerror = null; this.onboundary = null; }
}
Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
Object.defineProperty(window, "speechSynthesis", {
  configurable: true,
  value: {
    speak(utterance) { window.__utterances.push(utterance); queueMicrotask(() => utterance.onstart && utterance.onstart({ name: "start", charIndex: 0 })); },
    cancel() {}, getVoices() { return [{ name: "Daniel", lang: "en-GB", voiceURI: "daniel", localService: true, default: true }]; },
    addEventListener() {}, removeEventListener() {}, speaking: false, paused: false,
  },
});
`;

const stub = http.createServer((request, response) => {
  if (request.url?.startsWith("/api/tags")) {
    response.writeHead(200, { "Content-Type": "application/json" });
    response.end(JSON.stringify({ models: [{ name: "stub", model: "stub" }] }));
    return;
  }
  let raw = "";
  request.on("data", (chunk) => (raw += chunk));
  request.on("end", () => {
    let content = "{}";
    try {
      const body = JSON.parse(raw);
      const system = String(body.messages?.[0]?.content ?? "");
      /* The podcast writer answers slowly on purpose: a real script takes a
         model a while, and the loading screen must be observable. */
      if (system.includes("podcast writer")) {
        content = JSON.stringify(EPISODE_REPLY);
        setTimeout(() => {
          response.writeHead(200, { "Content-Type": "application/json" });
          response.end(JSON.stringify({ message: { content } }));
        }, 900);
        return;
      }
      if (system.includes("study-note transcriber")) {
        content = JSON.stringify({
          title: "Sky notes",
          language: "English",
          notes: "Rayleigh scattering makes the sky blue.",
          keyConcepts: ["scattering"],
        });
      }
    } catch {
      /* keep the default */
    }
    response.writeHead(200, { "Content-Type": "application/json" });
    response.end(JSON.stringify({ message: { content } }));
  });
});
await new Promise((resolve) => stub.listen(STUB_PORT, "127.0.0.1", resolve));

check("podcast app port is free", !(await portInUse(APP_PORT)));
const syncDir = new URL("./.tmp/sync-podcast", import.meta.url).pathname;
mkdirSync(syncDir, { recursive: true });
const app = spawnApp(APP_PORT, {
  OLLAMA_BASE_URL: STUB_BASE,
  OLLAMA_AUTH: "local",
  OLLAMA_VERIFY_KEY: "false",
  SYNC_DIR: syncDir,
});

const browser = await launchBrowser();

/** Records utterances and lets the test fire boundaries/ends by hand. */
const SPEECH_STUB = `
window.__spoken = [];
window.__cancelCount = 0;
window.__droppedWhilePaused = 0;
window.__utterances = [];
class FakeUtterance {
  constructor(text) { this.text = String(text); this.rate = 1; this.lang = "en-US"; this.onstart = null; this.onend = null; this.onerror = null; this.onboundary = null; }
}
Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
Object.defineProperty(window, "speechSynthesis", {
  configurable: true,
  value: {
    _speaking: false,
    _paused: false,
    get speaking() { return this._speaking; },
    get pending() { return false; },
    get paused() { return this._paused; },
    speak(utterance) {
      /* WebKit's quirk, on purpose: a cancel leaves the synthesis paused and
         a speak() while paused is dropped on the floor. The app must resume
         before it speaks again. */
      if (this._paused) { window.__droppedWhilePaused += 1; return; }
      window.__spoken.push(utterance.text);
      window.__utterances.push(utterance);
      this._speaking = true;
      queueMicrotask(() => utterance.onstart && utterance.onstart({ name: "start", charIndex: 0 }));
    },
    cancel() { window.__cancelCount += 1; this._speaking = false; this._paused = true; },
    resume() { this._paused = false; },
    /* One installed voice: a working engine, which is what this stub is. */
    getVoices() { return [{ name: "Daniel", lang: "en-GB", voiceURI: "daniel", localService: true, default: true }]; },
  },
});
`;

try {
  const up = await waitForHttp(`${APP}/api/health`);
  check("podcast app instance is up", up);

  if (up) {
    /* 1. the wizard: mode switch, intake, generation ---------------- */
    const { context, page } = await makePage(browser, { width: 1280, height: 900, deviceScaleFactor: 1 });
    await page.addInitScript(SPEECH_STUB);
    await seed(page, { decks: [], theme: "dark" });

    await page.goto(`${APP}/create`, { waitUntil: "networkidle" });
    await page.waitForTimeout(1000);
    const switchLink = page.getByRole("link", { name: "Podcast" });
    check("wizard: the mode switch carries a podcast segment", (await switchLink.count()) === 1);
    await switchLink.click();
    await page.waitForTimeout(1200);
    check("wizard: the podcast intake opens", page.url().endsWith("/podcast"));
    check("wizard: the length options are offered", (await page.getByRole("button", { name: "4 minutes" }).count()) === 1);

    await page.fill("#podcast-text", "Rayleigh scattering makes the sky blue: molecules scatter short wavelengths far more than long ones.");
    await page.waitForTimeout(200);
    await page.getByRole("button", { name: "Create the episode" }).first().click();
    /* Loading screen while the stub answers. */
    await page.waitForTimeout(600);
    const loading = (await page.getByText(/Writing the script|Reading your notes/).count()) >= 1;
    await page.waitForURL(/\/podcast\/pod_/, { timeout: 30_000 }).catch(() => {});
    await page.waitForTimeout(1200);
    check("wizard: it lands on the player", /\/podcast\/pod_/.test(page.url()), page.url());
    check("wizard: the loading screen showed a script stage", loading);

    const stored = await page.evaluate(() => JSON.parse(localStorage.getItem("freezmo.podcasts.v1") ?? "[]"));
    check("wizard: the episode is saved with both sections", stored.length === 1 && stored[0].sections.length === 2, JSON.stringify(stored[0]?.sections?.length));
    check("wizard: the notes ride along for a rewrite", (stored[0]?.sourceText ?? "").includes("Rayleigh"));

    /* 2. the player: transcript, highlight, controls ----------------- */
    const words = await page.locator("[data-word]").count();
    /* "Look up on a clear day. The sky is blue." (10) + "Tiny molecules
       scatter short wavelengths far more than long ones." (10). */
    check("player: the transcript is word-wrapped", words === 20, String(words));
    check("player: nothing is highlighted before playing", (await page.locator("[data-word-active]").count()) === 0);

    await page.getByRole("button", { name: "Play the episode" }).click();
    await page.waitForTimeout(400);
    const firstSpoken = await page.evaluate(() => window.__spoken[0]);
    check("player: the first section is what gets spoken", String(firstSpoken).startsWith("Look up on a clear day."), String(firstSpoken).slice(0, 40));
    check("player: the first word is highlighted", (await page.locator("[data-word-active]").count()) === 1);

    /* The boundary events are the exact clock: jump to a later word. */
    await page.evaluate(() => {
      const utterance = window.__utterances.at(-1);
      utterance.onboundary({ name: "word", charIndex: 12 });
    });
    await page.waitForTimeout(300);
    const active = await page.locator("[data-word-active]").first();
    check("player: a boundary event moves the highlight", (await active.textContent()) === "clear", String(await active.textContent()));

    /* Pausing stops the voice and keeps the place. */
    await page.getByRole("button", { name: "Pause the episode" }).click();
    await page.waitForTimeout(300);
    const cancelled = await page.evaluate(() => window.__cancelCount);
    check("player: pause cancels the voice", cancelled >= 1, String(cancelled));

    /* Resuming speaks from the highlighted word, not from the top. */
    await page.getByRole("button", { name: "Play the episode" }).click();
    await page.waitForTimeout(400);
    const resumed = await page.evaluate(() => window.__spoken.at(-1));
    check("player: resume starts at the current word", String(resumed).startsWith("clear day."), String(resumed).slice(0, 30));
    check(
      "player: nothing was spoken into a paused engine (the WebKit quirk)",
      (await page.evaluate(() => window.__droppedWhilePaused)) === 0,
      String(await page.evaluate(() => window.__droppedWhilePaused)),
    );

    /* 3. chapters, speed, progress save ------------------------------ */
    await page.getByRole("button", { name: "Why", exact: true }).click();
    await page.waitForTimeout(500);
    const chapterSpoken = await page.evaluate(() => window.__spoken.at(-1));
    check("player: a chapter jump speaks that section", String(chapterSpoken).startsWith("Tiny molecules"), String(chapterSpoken).slice(0, 30));
    check(
      "player: the header names the part",
      (await page.getByText("Part 2 of 2").count()) === 1,
    );

    await page.getByRole("button", { name: "Playback speed" }).click();
    await page.waitForTimeout(500);
    const rate = await page.evaluate(() => {
      const utterance = window.__utterances.at(-1);
      return utterance?.rate;
    });
    check("player: the speed applies to the voice", rate === 1.15, String(rate));

    /* Speed changes rebuild the engine mid-play; it keeps speaking. */
    const spokenCount = await page.evaluate(() => window.__spoken.length);
    check("player: changing speed keeps playing", spokenCount >= 4, String(spokenCount));

    /* Leaving saves the position for the next visit. */
    await page.goto(`${APP}/?tab=podcasts`, { waitUntil: "networkidle" });
    await page.waitForTimeout(900);
    const saved = await page.evaluate(() => JSON.parse(localStorage.getItem("freezmo.podcasts.v1") ?? "[]")[0]?.progress);
    check("player: the position is saved on leave", Boolean(saved) && saved.section === 1, JSON.stringify(saved));

    /* 4. the library tab -------------------------------------------- */
    check("library: the podcasts tab lists the episode", (await page.getByText("Why the sky is blue").count()) === 1);
    await page.getByRole("link", { name: "Listen" }).click();
    await page.waitForTimeout(1200);
    check("library: Listen opens the player", /\/podcast\/pod_/.test(page.url()), page.url());
    check(
      "player: reopening resumes at the saved part",
      (await page.getByText("Part 2 of 2").count()) === 1,
    );
    await context.close();

    /* 4b. voices: the best installed one, and a picker that sticks ------ */
{
  const { context, page } = await makePage(browser, { width: 390, height: 844, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  /* A catalogue that looks like a bare Linux box next to Chrome: the robot
     must lose to the natural male voice. */
  await page.addInitScript(() => {
    window.__spoken = [];
    const voices = [
      { name: "eSpeak English", lang: "en-US", voiceURI: "espeak", localService: true, default: true },
      { name: "Google US English", lang: "en-US", voiceURI: "g-us", localService: false, default: false },
      { name: "Google UK English Male", lang: "en-GB", voiceURI: "g-uk-male", localService: false, default: false },
      { name: "Czech (Czech Republic)", lang: "cs-CZ", voiceURI: "cs-cz", localService: true, default: false },
    ];
    class FakeUtterance {
      constructor(text) {
        this.text = String(text);
        this.rate = 1;
        this.lang = "en-US";
        this.voice = null;
        this.onstart = null;
        this.onend = null;
        this.onerror = null;
        this.onboundary = null;
      }
    }
    Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
    Object.defineProperty(window, "speechSynthesis", {
      configurable: true,
      value: {
        speak(utterance) {
          window.__spoken.push({ text: utterance.text, voice: utterance.voice?.voiceURI ?? null });
          queueMicrotask(() => utterance.onstart && utterance.onstart({ name: "start", charIndex: 0 }));
        },
        cancel() {},
        getVoices: () => voices,
        addEventListener() {},
        removeEventListener() {},
        speaking: false,
        paused: false,
      },
    });
  });
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([EPISODE_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_local`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);
  await page.getByRole("button", { name: "Play the episode" }).click();
  await page.waitForTimeout(400);
  const firstVoice = await page.evaluate(() => window.__spoken.at(-1)?.voice);
  check("voice: the natural male voice beats the robot", firstVoice === "g-uk-male", String(firstVoice));

  await page.getByRole("button", { name: "Voice" }).click();
  await page.waitForTimeout(300);
  const listed = await page.evaluate(() =>
    [...document.querySelectorAll("[aria-pressed]")].map((el) => el.textContent?.trim() ?? ""),
  );
  check("voice: the picker lists the voices for the language", listed.some((entry) => entry.includes("Google UK English Male")), JSON.stringify(listed.slice(0, 4)));
  check("voice: other languages are filtered out", !listed.some((entry) => entry.includes("Czech")), JSON.stringify(listed));

  await page.getByRole("button", { name: /Google US English/ }).click();
  await page.waitForTimeout(500);
  const chosen = await page.evaluate(() => window.__spoken.at(-1)?.voice);
  check("voice: choosing one speaks with it", chosen === "g-us", String(chosen));
  const stored = await page.evaluate(() => localStorage.getItem("freezmo.podcast-voice.v1"));
  check("voice: the choice is remembered", String(stored).includes("g-us"), String(stored));
  await context.close();
}

/* 4b2. an iPhone gets told where the other voices live -------------- */
{
  const { context, page } = await makePage(browser, { width: 390, height: 844, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  /* Safari's shape: one voice for the language, whatever is installed. */
  await page.addInitScript(() => {
    Object.defineProperty(navigator, "userAgent", {
      configurable: true,
      get: () => "Mozilla/5.0 (iPhone; CPU iPhone OS 18_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Mobile/15E148 Safari/604.1",
    });
    window.__spoken = [];
    const voices = [{ name: "Daniel", lang: "en-GB", voiceURI: "daniel", localService: true, default: true }];
    class FakeUtterance {
      constructor(text) { this.text = String(text); this.rate = 1; this.lang = "en-US"; this.voice = null; }
    }
    Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
    Object.defineProperty(window, "speechSynthesis", {
      configurable: true,
      value: { speak(u) { queueMicrotask(() => u.onstart?.({ name: "start", charIndex: 0 })); }, cancel() {}, getVoices: () => voices, addEventListener() {}, removeEventListener() {}, speaking: false, paused: false },
    });
  });
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([EPISODE_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_local`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);

  const voiceButton = page.getByRole("button", { name: "Voice" });
  const badge = await voiceButton.evaluate((element) => Boolean(element.querySelector("span[aria-hidden]")));
  check("ios: the voice button carries a hint dot", badge);
  await voiceButton.click();
  await page.waitForTimeout(300);
  const note = await page.getByText(/Spoken Content/).count();
  check("ios: the picker explains where to add voices", note === 1, String(note));
  const steps = await page.evaluate(() => {
    const text = [...document.querySelectorAll("p")].map((el) => el.textContent ?? "").find((entry) => entry.includes("Spoken Content")) ?? "";
    return { settings: text.includes("Settings"), accessibility: text.includes("Accessibility"), premium: text.includes("Enhanced") || text.includes("Premium") };
  });
  check("ios: the note names the actual settings path", steps.settings && steps.accessibility && steps.premium, JSON.stringify(steps));
  await context.close();
}

/* 4b2b. no speech engine behind the browser (Firefox on Linux) ------- */
{
  const { context, page } = await makePage(browser, { width: 390, height: 844, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  /* speechSynthesis exists but is empty and silent — exactly what Firefox
     does on a Linux box without speech-dispatcher. */
  await page.addInitScript(() => {
    class FakeUtterance {
      constructor(text) { this.text = String(text); this.rate = 1; this.lang = "en-US"; }
    }
    Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
    Object.defineProperty(window, "speechSynthesis", {
      configurable: true,
      value: {
        speak() { /* nothing at all: no engine, no events */ },
        cancel() {},
        getVoices: () => [],
        addEventListener() {},
        removeEventListener() {},
        speaking: false,
        paused: false,
      },
    });
    localStorage.setItem(
      "freezmo.providers.v1",
      JSON.stringify({ keys: { openai: "sk-test" }, models: {}, customBaseUrl: "", generation: null }),
    );
  });
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([EPISODE_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_local`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);

  await page.getByRole("button", { name: "Play the episode" }).click();
  await page.waitForTimeout(400);
  const banner = await page.getByText(/speech engine behind it/).count();
  check("no engine: the banner explains what is missing", banner === 1, String(banner));
  check(
    "no engine: it names the Linux fix",
    (await page.getByText(/speech-dispatcher/).count()) === 1,
  );
  const toNatural = page.getByRole("button", { name: "Use the natural voice" });
  check("no engine: the one-tap way out is offered", (await toNatural.count()) === 1);
  await toNatural.click();
  await page.waitForTimeout(400);
  check(
    "no engine: the switch sticks",
    (await page.evaluate(() => localStorage.getItem("freezmo.podcast-natural.v1")))?.includes("natural"),
    String(await page.evaluate(() => localStorage.getItem("freezmo.podcast-natural.v1"))),
  );
  await context.close();
}

/* 4b3. natural voices: the provider TTS behind the same player ------- */
{
  const { context, page } = await makePage(browser, { width: 390, height: 844, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  /* One second of silence as a real WAV — the player measures the clip and
     times its words against it, so the header alone is not enough. */
  const wav = (() => {
    const sampleRate = 8000;
    const samples = sampleRate;
    const buffer = Buffer.alloc(44 + samples * 2);
    buffer.write("RIFF", 0);
    buffer.writeUInt32LE(36 + samples * 2, 4);
    buffer.write("WAVE", 8);
    buffer.write("fmt ", 12);
    buffer.writeUInt32LE(16, 16);
    buffer.writeUInt16LE(1, 20);
    buffer.writeUInt16LE(1, 22);
    buffer.writeUInt32LE(sampleRate, 24);
    buffer.writeUInt32LE(sampleRate * 2, 28);
    buffer.writeUInt16LE(2, 32);
    buffer.writeUInt16LE(16, 34);
    buffer.write("data", 36);
    buffer.writeUInt32LE(samples * 2, 40);
    return buffer;
  })();
  const bodies = [];
  await page.route("**/api/tts", async (route) => {
    bodies.push(route.request().postDataJSON());
    await route.fulfill({ status: 200, contentType: "audio/wav", body: wav });
  });
  await page.addInitScript(() => {
    localStorage.setItem(
      "freezmo.providers.v1",
      JSON.stringify({ keys: { openai: "sk-test" }, models: {}, customBaseUrl: "", generation: null }),
    );
  });
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([EPISODE_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_local`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);

  await page.getByRole("button", { name: "Voice" }).click();
  await page.waitForTimeout(300);
  await page.getByRole("button", { name: "Natural voice" }).click();
  await page.waitForTimeout(400);
  const voicesShown = await page.evaluate(() =>
    [...document.querySelectorAll("button[aria-pressed]")].map((el) => el.textContent?.trim() ?? ""),
  );
  check(
    "natural: the provider's voices are offered (male first)",
    voicesShown.some((entry) => entry.includes("Onyx")) && voicesShown.some((entry) => entry.includes("male")),
    JSON.stringify(voicesShown.slice(0, 5)),
  );
  await page.getByRole("button", { name: /Onyx/ }).click();
  await page.waitForTimeout(300);
  await page.getByRole("button", { name: "Close" }).click();
  await page.waitForTimeout(200);

  await page.getByRole("button", { name: "Play the episode" }).click();
  /* The stub clip is half a second of silence: check while it is playing. */
  await page.waitForTimeout(320);
  const first = bodies[0];
  check("natural: the voice is generated through the API", bodies.length >= 1, String(bodies.length));
  check(
    "natural: the request carries the section text and the picked voice",
    Boolean(first) && String(first.text).startsWith("Daylight.") && first.voice === "onyx",
    JSON.stringify({ voice: first?.voice, head: String(first?.text).slice(0, 24) }),
  );
  const audioState = await page.evaluate(() => {
    const elements = [...document.querySelectorAll("[data-podcast-audio]")];
    const audio = elements.at(-1);
    return audio ? { count: elements.length, paused: audio.paused, blob: audio.src.startsWith("blob:") } : "no-audio-element";
  });
  check(
    "natural: one audio element plays the clip",
    typeof audioState === "object" && audioState.blob && audioState.paused === false && audioState.count === 1,
    JSON.stringify(audioState),
  );
  check("natural: the position is remembered for later", (await page.evaluate(() => localStorage.getItem("freezmo.podcast-natural.v1")))?.includes("onyx"), "");
  /* The word highlight rides the clip's real clock. */
  const before = await page.evaluate(() => document.querySelector("[data-word-active]")?.textContent ?? "");
  await page.waitForTimeout(1200);
  const after = await page.evaluate(() => document.querySelector("[data-word-active]")?.textContent ?? "");
  check("natural: the highlight follows the audio", before !== "" && after !== "", JSON.stringify({ before, after }));
  await context.close();
}

/* 4c. the transcript follows by line, and yields to a manual scroll --- */
{
  const { context, page } = await makePage(browser, { width: 390, height: 700, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  await page.addInitScript(WORD_TIMER_SPEECH);
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([LONG_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_long`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);
  await page.getByRole("button", { name: "Play the episode" }).click();
  await page.waitForTimeout(400);

  const scrollTop = () => page.evaluate(() => document.querySelector("[data-testid=podcast-transcript]")?.scrollTop ?? -1);
  const boundary = (charIndex) =>
    page.evaluate((index) => {
      const utterance = window.__utterances.at(-1);
      utterance.onboundary({ name: "word", charIndex: index });
    }, charIndex);

  /* Three words into the same line: the page must not move. */
  const start = await scrollTop();
  await boundary(3);
  await boundary(6);
  await boundary(9);
  await page.waitForTimeout(400);
  check("scroll: words on the same line do not move the page", (await scrollTop()) === start, `${start} -> ${await scrollTop()}`);

  /* A word far into the script: the page follows it. */
  await boundary(900);
  await page.waitForTimeout(700);
  const followed = await scrollTop();
  check("scroll: a new line is followed", followed > start, `${start} -> ${followed}`);

  /* The reader scrolls on purpose: following pauses instead of fighting. */
  await page.evaluate(() => {
    const container = document.querySelector("[data-testid=podcast-transcript]");
    container.scrollTop = 0;
    container.dispatchEvent(new WheelEvent("wheel", { bubbles: true }));
  });
  await page.waitForTimeout(200);
  const manual = await scrollTop();
  await boundary(1400);
  await page.waitForTimeout(500);
  check("scroll: a manual scroll is left alone", (await scrollTop()) === manual, `${manual} -> ${await scrollTop()}`);
  await context.close();
}

/* 4d. no boundary events: sentences carry the clock ---------------- */
{
  const { context, page } = await makePage(browser, { width: 390, height: 844, deviceScaleFactor: 1, isMobile: true, hasTouch: true });
  /* An engine that never reports boundaries (Firefox + speech-dispatcher,
     iOS) and *finishes* every utterance, so the sentence clock can be watched
     sentence by sentence. */
  await page.addInitScript(() => {
    window.__utterances = [];
    const SENTENCE_MS = 700;
    class FakeUtterance {
      constructor(text) { this.text = String(text); this.rate = 1; this.lang = "en-US"; this.voice = null; this.onstart = null; this.onend = null; this.onerror = null; this.onboundary = null; }
    }
    Object.defineProperty(window, "SpeechSynthesisUtterance", { configurable: true, value: FakeUtterance });
    Object.defineProperty(window, "speechSynthesis", {
      configurable: true,
      value: {
        _speaking: false,
        get speaking() { return this._speaking; },
        pending: false,
        paused: false,
        speak(utterance) {
          window.__utterances.push(utterance);
          window.speechSynthesis._speaking = true;
          queueMicrotask(() => utterance.onstart && utterance.onstart({ name: "start", charIndex: 0 }));
          setTimeout(() => {
            window.speechSynthesis._speaking = false;
            if (utterance.onend) utterance.onend();
          }, SENTENCE_MS);
        },
        cancel() { this._speaking = false; },
        resume() {},
        getVoices: () => [{ name: "Daniel", lang: "en-GB", voiceURI: "daniel", localService: true, default: true }],
        addEventListener() {},
        removeEventListener() {},
      },
    });
  });
  await seed(page, { decks: [], theme: "dark", extra: { "freezmo.podcasts.v1": JSON.stringify([SENTENCES_RECORD]) } });
  await page.goto(`${APP}/podcast/pod_sentences`, { waitUntil: "networkidle" });
  await page.waitForTimeout(1000);
  await page.getByRole("button", { name: "Play the episode" }).click();
  await page.waitForTimeout(500);

  const texts = () => page.evaluate(() => window.__utterances.map((u) => u.text));
  /** Poll until at least `n` utterances have been spoken. */
  const waitFor = async (n, timeout = 4000) => {
    const started = Date.now();
    while (Date.now() - started < timeout) {
      if ((await page.evaluate(() => window.__utterances.length)) >= n) return true;
      await page.waitForTimeout(80);
    }
    return false;
  };

  check("clock: without boundaries the first utterance is one sentence", (await waitFor(1)) && (await texts())[0] === "Look up on a clear day.", JSON.stringify(await texts()));
  check("clock: the next sentence follows on its own", (await waitFor(2)) && (await texts())[1] === "The sky is blue.", JSON.stringify(await texts()));
  const active = await page.evaluate(() => document.querySelector("[data-word-active]")?.textContent ?? "");
  check("clock: the highlight is inside the spoken text", (await texts()).some((text) => text.includes(active)), JSON.stringify({ active }));

  /* A boundary event on the sentence that is playing hands the rest of the
     section to the exact clock: the next utterance is no longer one sentence. */
  await page.evaluate(() => {
    const utterance = window.__utterances[1];
    if (utterance && utterance.onboundary) utterance.onboundary({ name: "word", charIndex: 0 });
  });
  await waitFor(3);
  const spoken = await texts();
  check(
    "clock: a boundary switches the rest of the section to one utterance",
    spoken.length >= 3 && (spoken[2].match(/\./g) ?? []).length >= 2,
    JSON.stringify(spoken),
  );

  /* The highlight keeps moving with the voice instead of drifting away. */
  const marks = [];
  for (let i = 0; i < 5; i += 1) {
    marks.push(await page.evaluate(() => document.querySelector("[data-word-active]")?.textContent ?? ""));
    await page.waitForTimeout(350);
  }
  check("clock: the highlight advances over time", new Set(marks.filter(Boolean)).size >= 2, JSON.stringify(marks));
  await context.close();}

/* 5. server guards ---------------------------------------------- */
    const bad = await fetch(`${APP}/api/podcast`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ text: "" }),
    });
    check("api: empty notes are refused", bad.status === 400, String(bad.status));

    const streamed = await fetch(`${APP}/api/podcast`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ text: "Some notes about the sky.", minutes: 3 }),
    });
    const body = await streamed.text();
    check("api: a script streams back with a podcast event", body.includes('"type":"podcast"') && body.includes('"sections"'), body.slice(0, 120));
  }
} finally {
  app.stop();
  stub.close();
  await browser.close();
}

finish();