// Records short, narrated MKV screen-capture clips of RaceCore's UI for use as new-user
// video guides, driven against a real, isolated instance of the app (own temp SQLite dir,
// own headless Chrome profile) exactly like the tests/browser_*.js suite - nothing here
// ever touches a real installation's data.
//
// Each clip is a list of steps ({ text, action }). For every step, the narration line's
// audio is synthesized up front (espeak-ng) so its real duration is known, the on-screen
// action runs, and the recording pauses for exactly that duration before moving to the
// next line - the actual wall-clock time each action took is recorded too, so the final
// narration track is built from real measured offsets (via ffmpeg's adelay/amix), not an
// idealized schedule that would drift out of sync with page-load/network latency.
//
// Usage: node scripts/record-video-guides.mjs [clip-name ...]
//   With no arguments, records every clip below. Pass one or more names (e.g.
//   "settings-tabs") to record only those. Output lands in video-guides/<name>.mkv
//   (gitignored - these are sizeable binaries, not something to commit by default).
//
// Requires ffmpeg and espeak-ng on PATH.

import { spawn, execFileSync } from "node:child_process";
import { existsSync, mkdtempSync, rmSync, mkdirSync, writeFileSync } from "node:fs";
import { createServer } from "node:net";
import { tmpdir } from "node:os";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";

const projectDir = dirname(dirname(fileURLToPath(import.meta.url)));
const outputDir = join(projectDir, "video-guides");
const chrome = [process.env.CHROME_PATH, "/usr/bin/google-chrome", "/usr/bin/chromium", "/usr/bin/chromium-browser"].find((p) => p && existsSync(p));
if (!chrome) throw new Error("Chrome/Chromium not found. Set CHROME_PATH to the browser executable.");
try { execFileSync("espeak-ng", ["--version"], { stdio: "ignore" }); } catch { throw new Error("espeak-ng not found on PATH (used for narration audio)."); }

const NARRATION_VOICE = "en-us";
const NARRATION_RATE = 160;
const LEAD_MS = 600; // silence before the first line, so the opening frame settles first
const GAP_MS = 450; // silence between narration lines
const TAIL_MS = 1400; // hold on the final frame after the last line finishes

const pause = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function waitFor(check, label, timeout = 15000) {
  const until = Date.now() + timeout;
  while (Date.now() < until) {
    try { if (await check()) return; } catch {}
    await pause(100);
  }
  throw new Error("Timed out: " + label);
}

async function freePort() {
  const server = createServer();
  await new Promise((resolve, reject) => { server.once("error", reject); server.listen(0, "127.0.0.1", resolve); });
  const port = server.address().port;
  await new Promise((resolve) => server.close(resolve));
  return port;
}

function wavDurationMs(wavPath) {
  const out = execFileSync("ffprobe", ["-v", "error", "-show_entries", "format=duration", "-of", "csv=p=0", wavPath]).toString().trim();
  return Math.round(parseFloat(out) * 1000);
}

function synthesizeNarration(steps, narrationDir) {
  return steps.map((step, index) => {
    const wavPath = join(narrationDir, `line_${String(index).padStart(2, "0")}.wav`);
    execFileSync("espeak-ng", ["-v", NARRATION_VOICE, "-s", String(NARRATION_RATE), "-w", wavPath, step.text]);
    return { ...step, wavPath, durationMs: wavDurationMs(wavPath) };
  });
}

// Places each narration line at its own real measured start offset (via adelay) and mixes
// them onto one track (amix, normalize=0 since lines never overlap - normalizing would
// quietly halve/third the volume for no reason). `normalize=0` is an amix filter option
// available since ffmpeg 4.x.
function mixNarrationTrack(narrated, outputPath) {
  const inputs = narrated.flatMap((line) => ["-i", line.wavPath]);
  const delayed = narrated.map((line, i) => `[${i}]adelay=${Math.max(0, Math.round(line.startMs))}|${Math.max(0, Math.round(line.startMs))}[a${i}]`);
  const mixInputs = narrated.map((_, i) => `[a${i}]`).join("");
  const filter = `${delayed.join(";")};${mixInputs}amix=inputs=${narrated.length}:duration=longest:normalize=0[aout]`;
  execFileSync("ffmpeg", ["-y", ...inputs, "-filter_complex", filter, "-map", "[aout]", "-c:a", "pcm_s16le", outputPath], { stdio: "inherit" });
}

// A single recording session: isolated server + headless Chrome + CDP screencast capture,
// narrated by stepping through `steps` in order.
async function recordClip(name, { seedState, setup, steps }) {
  const temporary = mkdtempSync(join(tmpdir(), "racecore-recguide-"));
  const framesDir = join(temporary, "frames");
  const narrationDir = join(temporary, "narration");
  mkdirSync(framesDir, { recursive: true });
  mkdirSync(narrationDir, { recursive: true });
  const children = [];
  let socket;
  const launch = (command, args, options = {}) => {
    const child = spawn(command, args, { cwd: projectDir, stdio: "ignore", ...options });
    children.push(child);
    child.on("error", (e) => console.error(e.message));
    return child;
  };
  try {
    console.log(`[${name}] synthesizing narration (${steps.length} lines)...`);
    const narrationSteps = synthesizeNarration(steps, narrationDir);

    const port = await freePort();
    const debugPort = await freePort();
    const base = `http://127.0.0.1:${port}`;
    launch(process.execPath, ["server.js"], { env: { ...process.env, HOST: "127.0.0.1", PORT: String(port), RC_TIMING_DATA_DIR: join(temporary, "data"), RC_TIMING_PID_FILE: "" } });
    await waitFor(async () => (await fetch(base + "/api/health")).ok, "isolated server");

    const initial = {
      classes: [], drivers: [], cars: [], events: [], sessions: [], resultsBySession: {},
      settings: { language: "en", autoReconnect: false, backendUrl: base, raceAudio: { enabled: false } },
      training: {},
    };
    seedState?.(initial);
    await fetch(base + "/api/state", { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify(initial) });

    launch(chrome, [
      "--headless", "--disable-gpu", "--no-first-run", "--no-default-browser-check", "--disable-background-networking",
      ...(process.env.RC_BROWSER_NO_SANDBOX === "1" ? ["--no-sandbox"] : []),
      "--window-size=1600,900", `--user-data-dir=${join(temporary, "browser")}`, `--remote-debugging-port=${debugPort}`, "about:blank",
    ]);
    let target;
    await waitFor(async () => {
      target = (await (await fetch(`http://127.0.0.1:${debugPort}/json/list`)).json()).find((p) => p.type === "page");
      return target;
    }, "headless browser");

    socket = new WebSocket(target.webSocketDebuggerUrl);
    await new Promise((resolve, reject) => { socket.addEventListener("open", resolve, { once: true }); socket.addEventListener("error", reject, { once: true }); });

    let nextId = 0;
    const requests = new Map();
    let frameCount = 0;
    socket.addEventListener("message", (event) => {
      const message = JSON.parse(event.data);
      if (message.id) {
        const request = requests.get(message.id);
        requests.delete(message.id);
        if (message.error) request?.reject(new Error(message.error.message)); else request?.resolve(message.result);
      } else if (message.method === "Page.screencastFrame") {
        const { data, sessionId } = message.params;
        frameCount += 1;
        writeFileSync(join(framesDir, `frame_${String(frameCount).padStart(6, "0")}.jpg`), Buffer.from(data, "base64"));
        send("Page.screencastFrameAck", { sessionId });
      }
    });
    function send(method, params = {}) {
      return new Promise((resolve, reject) => { const id = ++nextId; requests.set(id, { resolve, reject }); socket.send(JSON.stringify({ id, method, params })); });
    }
    async function evaluate(expression) {
      const result = await send("Runtime.evaluate", { expression, returnByValue: true, awaitPromise: true });
      if (result.exceptionDetails) throw new Error(result.exceptionDetails.exception?.description || JSON.stringify(result.exceptionDetails));
      return result.result.value;
    }
    async function navigate(view, form) {
      await send("Page.navigate", { url: base + "/?view=" + view });
      await waitFor(async () =>
        Boolean(await evaluate(`document.getElementById(${JSON.stringify(form)})`)) &&
        (await evaluate(`document.getElementById("syncStatusDetail")?.textContent`) || "").includes("Data loaded"),
        view + " hydrated");
    }
    async function fill(form, fields) {
      await evaluate(`(() => { const form = document.getElementById(${JSON.stringify(form)}); for (const [name,value] of Object.entries(${JSON.stringify(fields)})) { const field=form.elements.namedItem(name); if (!field) throw new Error("Missing field "+name); field.value=value; field.dispatchEvent(new Event("input", {bubbles:true})); } })()`);
    }
    const click = (selector) => evaluate(`document.querySelector(${JSON.stringify(selector)}).click()`);
    const scrollTo = (selector, block = "start") => evaluate(`document.querySelector(${JSON.stringify(selector)})?.scrollIntoView({block: ${JSON.stringify(block)}})`);

    await send("Runtime.enable");
    await send("Page.enable");
    await send("Emulation.setDeviceMetricsOverride", { width: 1600, height: 900, deviceScaleFactor: 1, mobile: false });

    // Setup (navigation, opening the right event, scrolling to the starting point) happens
    // before the screencast starts, so the recording opens already on the right view
    // instead of capturing the page load itself.
    await setup?.({ evaluate, navigate, fill, click, scrollTo, pause });

    console.log(`[${name}] recording...`);
    const captureStart = Date.now();
    await send("Page.startScreencast", { format: "jpeg", quality: 80, maxWidth: 1600, maxHeight: 900, everyNthFrame: 1 });

    await pause(LEAD_MS);
    const narrated = [];
    for (const step of narrationSteps) {
      const actionStart = Date.now();
      await step.action?.({ evaluate, navigate, fill, click, scrollTo, pause });
      narrated.push({ ...step, startMs: Date.now() - captureStart });
      await pause(step.durationMs);
      await pause(GAP_MS);
    }
    await pause(TAIL_MS);

    await send("Page.stopScreencast");
    await pause(300);
    const elapsedSec = (Date.now() - captureStart) / 1000;
    console.log(`[${name}] captured ${frameCount} frames over ${elapsedSec.toFixed(1)}s`);

    mkdirSync(outputDir, { recursive: true });
    const silentVideoPath = join(temporary, "silent.mkv");
    const inputFps = Math.max(1, frameCount / elapsedSec);
    execFileSync("ffmpeg", [
      "-y", "-framerate", inputFps.toFixed(2), "-i", join(framesDir, "frame_%06d.jpg"),
      "-c:v", "libx264", "-pix_fmt", "yuv420p", "-r", "30", silentVideoPath,
    ], { stdio: "inherit" });

    const audioPath = join(temporary, "narration.wav");
    mixNarrationTrack(narrated, audioPath);

    const outputPath = join(outputDir, `${name}.mkv`);
    execFileSync("ffmpeg", [
      "-y", "-i", silentVideoPath, "-i", audioPath,
      "-map", "0:v:0", "-map", "1:a:0", "-c:v", "copy", "-c:a", "aac", "-b:a", "96k",
      outputPath,
    ], { stdio: "inherit" });
    console.log(`[${name}] wrote ${outputPath}`);
  } finally {
    try { socket?.close(); } catch {}
    for (const child of children.reverse()) { try { child.kill(); } catch {} }
    await pause(300);
    rmSync(temporary, { recursive: true, force: true, maxRetries: 5, retryDelay: 200 });
  }
}

const clips = {
  "settings-tabs": {
    async setup({ navigate }) {
      await navigate("settings", "settingsForm");
    },
    steps: [
      { text: "This is the Settings page, split into four tabs: Connection, Audio, Appearance, and System." },
      { text: "Audio controls race sound announcements, volume, and which events get a spoken callout.", async action({ click }) { await click('[data-settings-tab="audio"]'); } },
      { text: "Appearance and Overlay covers club branding, track layouts, and the OBS overlay setup.", async action({ click }) { await click('[data-settings-tab="appearance"]'); } },
      { text: "System and Backup handles software updates, backups, and race presets.", async action({ click }) { await click('[data-settings-tab="system"]'); } },
      { text: "And Connection, where we started, is where you link up the decoder.", async action({ click }) { await click('[data-settings-tab="connection"]'); } },
    ],
  },

  "event-manager-tabs": {
    seedState(state) {
      const classId = "vid_class";
      const driverA = { id: "vid_driver_a", name: "Alex Karlsson", classId, transponder: "7910001" };
      const driverB = { id: "vid_driver_b", name: "Sam Nilsson", classId, transponder: "7910002" };
      const raceEvent = {
        id: "vid_event", name: "Club Race Night", classId, mode: "race",
        raceConfig: { participantsConfigured: true, driverIds: [driverA.id, driverB.id], teams: [] },
      };
      const practice = { id: "vid_practice", eventId: raceEvent.id, name: "Practice 1", type: "practice", durationMin: 10, status: "ready" };
      const qualifying = { id: "vid_quali", eventId: raceEvent.id, name: "Qualifying 1", type: "qualification", startMode: "position", durationMin: 5, status: "ready" };
      state.classes.push({ id: classId, name: "2WD Buggy" });
      state.drivers.push(driverA, driverB);
      state.events.push(raceEvent);
      state.sessions.push(practice, qualifying);
    },
    async setup({ navigate, click, evaluate, scrollTo }) {
      await navigate("race_setup", "raceWizardStepForm");
      await click("#event-manage-vid_event");
      await waitFor(async () => Boolean(await evaluate(`document.querySelector(".manage-tabs")`)), "manage tabs rendered");
      await scrollTo(".manage-tabs");
    },
    steps: [
      { text: "Opening Manage on a race event splits the page into four tabs: Setup, Format, Live, and Schedule." },
      {
        text: "Format is where you configure practice, qualifying, and finals, and generate the session plan.",
        async action({ click, scrollTo }) { await click('[data-manage-tab="format"]'); await scrollTo('[data-manage-panel="format"]'); },
      },
      {
        text: "Live shows the grid editor and every standings table while the race is running.",
        async action({ click, scrollTo }) { await click('[data-manage-tab="live"]'); await scrollTo('[data-manage-panel="live"]'); },
      },
      {
        text: "Schedule lets you set a start time and see the whole day's running order.",
        async action({ click, scrollTo }) { await click('[data-manage-tab="schedule"]'); await scrollTo('[data-manage-panel="schedule"]'); },
      },
      {
        text: "And Setup, where we started, is for managing participants and teams.",
        async action({ click, scrollTo }) { await click('[data-manage-tab="setup"]'); await scrollTo('[data-manage-panel="setup"]'); },
      },
      {
        text: "The Open Grid button on any session jumps straight to its grid editor on the Live tab.",
        async action({ click, scrollTo, pause: pauseFn }) {
          await scrollTo("#session-grid-vid_quali", "center");
          await pauseFn(500);
          await click("#session-grid-vid_quali");
          await pauseFn(300);
          await scrollTo('[data-manage-panel="live"]');
        },
      },
    ],
  },

  "event-schedule": {
    seedState(state) {
      const classId = "vid_sched_class";
      const driverA = { id: "vid_sched_driver_a", name: "Alex Karlsson", classId, transponder: "7920001" };
      const raceEvent = {
        id: "vid_sched_event", name: "Club Race Night", classId, mode: "race",
        raceConfig: { participantsConfigured: true, driverIds: [driverA.id], teams: [] },
      };
      const practice = { id: "vid_sched_practice", eventId: raceEvent.id, name: "Practice 1", type: "practice", durationMin: 10, status: "ready" };
      const qualifying = { id: "vid_sched_quali", eventId: raceEvent.id, name: "Qualifying 1", type: "qualification", durationMin: 5, status: "ready" };
      state.classes.push({ id: classId, name: "2WD Buggy" });
      state.drivers.push(driverA);
      state.events.push(raceEvent);
      state.sessions.push(practice, qualifying);
    },
    async setup({ navigate, click, evaluate, scrollTo }) {
      await navigate("race_setup", "raceWizardStepForm");
      await click("#event-manage-vid_sched_event");
      await waitFor(async () => Boolean(await evaluate(`document.querySelector(".manage-tabs")`)), "manage tabs rendered");
      await scrollTo(".manage-tabs");
    },
    steps: [
      {
        text: "Let's set up a time-based schedule for race day.",
        async action({ click, scrollTo }) { await click('[data-manage-tab="schedule"]'); await scrollTo("#scheduleForm"); },
      },
      {
        text: "Enter a start time, and the gap you want between sessions, in minutes.",
        async action({ fill }) { await fill("scheduleForm", { scheduleStartAt: "2026-09-12T12:30", scheduleGapMin: "3" }); },
      },
      {
        text: "Save it, and RaceCore works out every session's planned clock time automatically.",
        async action({ evaluate, scrollTo, pause: pauseFn }) {
          await evaluate(`document.getElementById("scheduleForm").requestSubmit()`);
          await pauseFn(500);
          await scrollTo('[data-manage-panel="schedule"] table');
        },
      },
      { text: "If a session starts late or runs long, everything after it shifts forward on its own." },
    ],
  },
};

const requested = process.argv.slice(2);
const names = requested.length ? requested : Object.keys(clips);
for (const name of names) {
  const clip = clips[name];
  if (!clip) { console.error(`Unknown clip "${name}". Available: ${Object.keys(clips).join(", ")}`); process.exitCode = 1; continue; }
  await recordClip(name, clip);
}