// Static file server + same-origin proxy to the fal.ai queue API.
// ponytail: keeping the proxy (rather than calling queue.fal.run directly
// from the browser) sidesteps having to verify fal's CORS behavior at all —
// same trick used for the MiniMax-native integration this replaced.
const http = require("http");
const https = require("https");
const fs = require("fs");
const path = require("path");
const crypto = require("crypto");

try {
  process.loadEnvFile(path.join(__dirname, ".env"));
} catch {
  // no .env file — fine, env vars may be set another way
}

const PORT = process.env.PORT || 8934;
const FAL_HOST = "queue.fal.run";
const H3_CONSOLE_BASE = process.env.H3_CONSOLE_BASE || "";
const H3_CONSOLE_TOKEN = process.env.H3_CONSOLE_TOKEN || "";
const H3_CONSOLE_URL = H3_CONSOLE_BASE ? new URL(H3_CONSOLE_BASE) : null;

// GLM Coding Plan — used only to expand a viewer's short chat prompt into a
// detailed shot-by-shot prompt before handing it to H3 (see optimizePrompt).
// Must hit the /api/coding/ path specifically — the plain /api/paas/ path
// bills against a different (pay-per-token) quota than the coding plan.
const GLM_API_KEY = process.env.GLM_API_KEY || "";
const GLM_HOST = "open.bigmodel.cn";
const GLM_PATH = "/api/coding/paas/v4/chat/completions";
const GLM_MODEL = "glm-5.3-flash";

// T24 credit topup. No test-mode key yet (2026-09-03: user said "先做一个
// mock，我明天再给你真实测试的 key") — see createCheckoutSession()'s doc
// comment for how the two paths split.
const STRIPE_SECRET_KEY = process.env.STRIPE_SECRET_KEY || "";
const STRIPE_WEBHOOK_SECRET = process.env.STRIPE_WEBHOOK_SECRET || "";
const APP_BASE_URL = process.env.APP_BASE_URL || `http://localhost:${process.env.PORT || 8934}`;

const MIME = {
  ".html": "text/html",
  ".js": "text/javascript",
  ".css": "text/css",
  ".json": "application/json",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".png": "image/png",
  ".webp": "image/webp",
  ".mp4": "video/mp4",
};

const { syncLibrary } = require("./ingest.js");
const {
  UPLOADS_DIR,
  readRawBody,
  parseMultipart,
  boundaryFromContentType,
  sniffImageType,
  sniffVideoType,
  stripMetadataAndSave,
  saveVideoUpload,
  forwardToH3Assets,
} = require("./uploads.js");
const { characters, garments, danceRefs, generationJobs, moderationLog } = require("./dressup-store.js");
const { buildStage2Prompt } = require("./prompt-template.js");
const { users: userStore, sessions: userSessions, creditLedger } = require("./db.js");
const { pricing } = require("./pricing.js");

const LIBRARY_PATH = path.join(__dirname, "library.json");
function getLibrary() {
  try {
    return JSON.parse(fs.readFileSync(LIBRARY_PATH, "utf8"));
  } catch {
    return [];
  }
}
function saveLibrary(lib) {
  fs.writeFileSync(LIBRARY_PATH, JSON.stringify(lib, null, 2));
}

const LIVE_STATE_PATH = path.join(__dirname, "live-state.json");
function loadLiveState() {
  try {
    const s = JSON.parse(fs.readFileSync(LIVE_STATE_PATH, "utf8"));
    return { schedule: s.schedule || [], promptQueue: s.promptQueue || [], chatMessages: s.chatMessages || [] };
  } catch {
    return { schedule: [], promptQueue: [], chatMessages: [] };
  }
}
function saveLiveState() {
  fs.writeFileSync(LIVE_STATE_PATH, JSON.stringify({ schedule, promptQueue, chatMessages }, null, 2));
}

// dance.html's own playout state (T11) — separate file/schedule/queue from
// live.html's (architecture.md 2.1: two independent channels, not shared).
// Per MVCP M.8, `schedule` here stores `videoId` references, not inlined
// clip snapshots like live's `schedule` does — dance clips join back to
// library.json at read time so an admin edit/takedown isn't stuck showing a
// stale copy.
const DANCE_STATE_PATH = path.join(__dirname, "dance-state.json");
function loadDanceState() {
  try {
    const s = JSON.parse(fs.readFileSync(DANCE_STATE_PATH, "utf8"));
    return { danceSchedule: s.schedule || [], danceQueue: s.freeQueue || [] };
  } catch {
    return { danceSchedule: [], danceQueue: [] };
  }
}
function saveDanceState() {
  fs.writeFileSync(DANCE_STATE_PATH, JSON.stringify({ schedule: danceSchedule, freeQueue: danceQueue }, null, 2));
}

function readJsonBody(req) {
  return new Promise((resolve, reject) => {
    let data = "";
    req.on("data", (chunk) => (data += chunk));
    req.on("end", () => {
      try {
        resolve(data ? JSON.parse(data) : {});
      } catch (err) {
        reject(err);
      }
    });
    req.on("error", reject);
  });
}

// Stripe's webhook signature is computed over the exact raw request bytes
// (T24) — JSON.parse-then-restringify would not reproduce the same bytes,
// so this can't reuse readJsonBody for that one route.
function readRawTextBody(req) {
  return new Promise((resolve, reject) => {
    let data = "";
    req.on("data", (chunk) => (data += chunk));
    req.on("end", () => resolve(data));
    req.on("error", reject);
  });
}

// Minimal admin auth (dev-plan.md T6): one shared password from .env, an
// HttpOnly session cookie, no accounts/roles/DB — the account system in
// MVCP M.1/M.10 supersedes this in period 3. Sessions are in-memory only,
// so a process restart logs everyone out (acceptable for this stopgap).
const ADMIN_PASSWORD = process.env.ADMIN_PASSWORD || "";
const ADMIN_SESSION_COOKIE = "admin_session";
const ADMIN_SESSION_TTL_MS = 30 * 24 * 60 * 60 * 1000; // 30 days, matches MVCP M.10's session TTL
const adminSessions = new Map(); // token -> expiresAt

function parseCookies(req) {
  const header = req.headers.cookie || "";
  const cookies = {};
  for (const pair of header.split(";")) {
    const idx = pair.indexOf("=");
    if (idx === -1) continue;
    cookies[pair.slice(0, idx).trim()] = decodeURIComponent(pair.slice(idx + 1).trim());
  }
  return cookies;
}

// T30: two accepted paths, either is enough — the ADMIN_PASSWORD cookie
// (T6, unchanged) stays as a fallback channel so nobody's locked out of the
// backend before any users.role='admin' account has been created by hand;
// requireUserSession + role='admin' (below, hoisted — same module scope) is
// the real per-admin identity path, MVCP M.10's stated rule for
// /api/admin/*. Calls requireUserSession before it's declared further down
// this file — fine, `function` declarations are fully hoisted.
function isAdminAuthed(req) {
  const token = parseCookies(req)[ADMIN_SESSION_COOKIE];
  if (token) {
    const expiresAt = adminSessions.get(token);
    if (expiresAt && expiresAt >= Date.now()) return true;
    adminSessions.delete(token);
  }
  const user = requireUserSession(req);
  return !!(user && user.role === "admin");
}

// Who to attribute an admin action to (T30's "credit_ledger 里能查到是哪个
//管理员做的") — null when the request came in over the legacy shared
// ADMIN_PASSWORD channel, which has no per-admin identity to attribute to.
function adminActorUserId(req) {
  const user = requireUserSession(req);
  return user && user.role === "admin" ? user.id : null;
}

// User account login (dev-plan-3.md T19; dressup-dance-room-mvcp.md
// M.1/M.10) — a separate cookie/session table from admin_session above, on
// purpose: this is for viewers, not the single shared admin credential, and
// the two must never be confused for one another.
const USER_SESSION_COOKIE = "user_session";
const USER_SESSION_TTL_MS = 30 * 24 * 60 * 60 * 1000; // 30 days, MVCP M.10
const EMAIL_VERIFY_TTL_MS = 24 * 60 * 60 * 1000; // 24 hours, MVCP M.10

// T20: no email-delivery vendor has been picked yet (dev-plan-3.md §1's
// open question — SMTP vs. an HTTP-API provider like Resend/SendGrid).
// This is the one seam a real integration plugs into later; nothing else
// needs to change. For now it logs, and outside production also returns
// the link directly so registering can be tested end to end without a
// real inbox.
function sendVerificationEmail(email, token) {
  const verifyUrl = `/api/auth/verify?token=${token}`;
  console.log(`[email_verify] would send to ${email}: ${verifyUrl}`);
  return verifyUrl;
}

// T25: no vision-model vendor has been picked yet (dev-plan-4.md §1.2 item
// 2 — needed because mode 2's uploader has no admin around to hand-write
// garments.appearanceDescriptor the way admin_seed garments do). Same seam
// pattern as sendVerificationEmail above: today it's a fixed placeholder,
// swapping in a real vendor later is a one-function change, callers (T27)
// don't need to know the difference.
const VISION_API_KEY = process.env.VISION_API_KEY || "";
async function describeGarmentImage(absImagePath) {
  if (!VISION_API_KEY) return "用户上传的服装";
  throw new Error("vision vendor not implemented — set VISION_API_KEY only once a provider is wired up");
}

// T26: same seam pattern, for image-content moderation (dev-plan-4.md §1.2
// item 1 — the requirements doc names a vendor as "TBD" and never actually
// lists it as its own task, so this is that gap filled in). Every call logs
// to moderation_log (M.9) regardless of which branch runs, so the audit
// trail exists before a real vendor does. `assetId` is the caller's own
// stable id for the upload (T27 passes the just-saved file's relPath, since
// at moderation time there's no garments.id yet — moderation runs before
// the garment record is created, per dev-plan-4.md T27's ordering).
const MODERATION_API_KEY = process.env.MODERATION_API_KEY || "";
async function moderateGarmentImage(absImagePath, assetId) {
  let verdict, reason;
  if (!MODERATION_API_KEY) {
    // No vendor configured: default-permissive placeholder pass (T2's
    // upload endpoint already enforces the real trust-boundary checks —
    // file type by magic bytes, 8MB cap, EXIF-stripped re-encode — this is
    // only the *content* check, which nothing here can actually perform
    // without a vendor).
    verdict = "auto_pass";
    reason = null;
  } else {
    throw new Error("moderation vendor not implemented — set MODERATION_API_KEY only once a provider is wired up");
  }
  moderationLog.create({ assetType: "garment_upload", assetId, verdict, reason, reviewedBy: "system" });
  return { approved: verdict === "auto_pass", verdict, reason };
}

// T21: mirrors live.html/dance.html's own setCookie() exactly (path=/,
// samesite=lax, no httponly, max-age in seconds, 365-day TTL) — these are
// the same viewer_uid/viewer_nickname cookies those pages already read
// with plain client-side JS, not a new cookie scheme.
function viewerIdentityCookie(name, value) {
  return `${name}=${encodeURIComponent(value)}; Max-Age=${365 * 86400}; Path=/; SameSite=Lax`;
}

function hashPassword(password) {
  const salt = crypto.randomBytes(16).toString("hex");
  const hash = crypto.scryptSync(password, salt, 64).toString("hex");
  return `${salt}:${hash}`;
}

function verifyPassword(password, stored) {
  const [salt, hash] = (stored || "").split(":");
  if (!salt || !hash) return false;
  const candidate = crypto.scryptSync(password, salt, 64);
  const expected = Buffer.from(hash, "hex");
  // scryptSync's output length is fixed by the third argument above, so
  // both buffers are always the same length — timingSafeEqual would throw
  // otherwise, but that can't happen here.
  return crypto.timingSafeEqual(candidate, expected);
}

// Returns the logged-in user (plain object, MVCP M.1 shape) or null. Free
// endpoints (/api/dance/*) don't call this at all — only routes that
// actually need an account (T20's email verify, T21's identity binding,
// anything paid in period 4) do.
function requireUserSession(req) {
  const token = parseCookies(req)[USER_SESSION_COOKIE];
  if (!token) return null;
  const session = userSessions.findByToken(token);
  if (!session || session.kind !== "session") return null;
  return userStore.get(session.userId);
}

// Generic CRUD router for the three cold-start asset libraries (T3-T5) —
// GET list / POST create / PATCH update / DELETE, backed by store.js. The
// three entities' shapes differ (see MVCP M.3/M.4/M.5) but the routing and
// validation boilerplate is identical, so this is mounted three times below
// instead of copy-pasted.
function mountCrud(prefix, store, opts = {}) {
  const { requiredFields = [], sanitize = (b) => b, onCreate, onUpdate } = opts;

  function missingField(body) {
    return requiredFields.find((f) => {
      const v = body[f];
      return v === undefined || v === null || (typeof v === "string" && !v.trim());
    });
  }

  return function handle(pathname, req, res) {
    if (pathname === prefix && req.method === "GET") {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(store.list()));
      return true;
    }

    if (pathname === prefix && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const missing = missingField(body);
          if (missing) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: `${missing} required` }));
            return;
          }
          const item = store.create(sanitize(body));
          if (onCreate) onCreate(item, store);
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(item));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return true;
    }

    if (pathname.startsWith(`${prefix}/`) && req.method === "PATCH") {
      const id = pathname.slice(prefix.length + 1);
      readJsonBody(req)
        .then((body) => {
          // Partial update: only reject an explicit blank-out of a required
          // field, not the field's mere absence from this patch.
          const missing = requiredFields.find((f) => f in body && missingField({ [f]: body[f] }) === f);
          if (missing) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: `${missing} required` }));
            return;
          }
          const updated = store.update(id, sanitize(body, true));
          if (!updated) {
            res.writeHead(404, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "not found" }));
            return;
          }
          if (onUpdate) onUpdate(updated, store);
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(updated));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return true;
    }

    if (pathname.startsWith(`${prefix}/`) && req.method === "DELETE") {
      const id = pathname.slice(prefix.length + 1);
      const removed = store.remove(id);
      res.writeHead(removed ? 200 : 404, { "Content-Type": "application/json" });
      res.end(JSON.stringify({ deleted: removed }));
      return true;
    }

    return false;
  };
}

// isDefault is a singleton across the whole characters library (2 节:
// "第一期只允许同时有一个人物被设为默认") — enforced here rather than in
// store.js, which stays schema-agnostic.
function unsetOtherDefaultCharacters(item, store) {
  if (!item.isDefault) return;
  for (const c of store.list()) {
    if (c.id !== item.id && c.isDefault) store.update(c.id, { isDefault: false });
  }
}

const charactersCrud = mountCrud("/api/admin/characters", characters, {
  requiredFields: ["name", "imageUrl", "appearanceDescriptor"],
  sanitize: (body, isPatch) =>
    isPatch
      ? body
      : {
          name: body.name,
          imageUrl: body.imageUrl,
          tags: Array.isArray(body.tags) ? body.tags : [],
          source: "admin_seed",
          ownerUserId: null,
          appearanceDescriptor: body.appearanceDescriptor,
          isDefault: Boolean(body.isDefault),
          moderationStatus: "auto_passed",
          totalSegments: null,
          remainingSegments: null,
          status: "active",
        },
  onCreate: unsetOtherDefaultCharacters,
  onUpdate: unsetOtherDefaultCharacters,
});

const garmentsCrud = mountCrud("/api/admin/garments", garments, {
  requiredFields: ["name", "imageUrl", "appearanceDescriptor"],
  sanitize: (body, isPatch) =>
    isPatch
      ? body
      : {
          name: body.name,
          category: body.category || "",
          thumbnailUrl: body.thumbnailUrl || body.imageUrl,
          imageUrl: body.imageUrl,
          appearanceDescriptor: body.appearanceDescriptor,
          source: "admin_seed",
          ownerUserId: null,
          moderationStatus: "approved",
          isActive: body.isActive === undefined ? true : Boolean(body.isActive),
        },
});

const danceRefsCrud = mountCrud("/api/admin/dance-refs", danceRefs, {
  requiredFields: ["name", "videoUrl", "motionDescriptor"],
  sanitize: (body, isPatch) =>
    isPatch
      ? body
      : {
          name: body.name,
          videoUrl: body.videoUrl,
          styleTags: Array.isArray(body.styleTags) ? body.styleTags : [],
          durationSec: body.durationSec || null,
          motionDescriptor: body.motionDescriptor,
          copyrightSource: "test_placeholder",
          isActive: body.isActive === undefined ? true : Boolean(body.isActive),
        },
});

function h3ConsoleFetch(pathAndQuery, options) {
  return new Promise((resolve, reject) => {
    const proxyReq = http.request(
      {
        hostname: H3_CONSOLE_URL.hostname,
        port: H3_CONSOLE_URL.port || 80,
        path: `${H3_CONSOLE_URL.pathname}${pathAndQuery}`,
        method: (options && options.method) || "GET",
        headers: { Authorization: `Bearer ${H3_CONSOLE_TOKEN}`, "Content-Type": "application/json" },
      },
      (proxyRes) => {
        let data = "";
        proxyRes.on("data", (c) => (data += c));
        proxyRes.on("end", () => {
          try {
            resolve(JSON.parse(data));
          } catch (err) {
            reject(err);
          }
        });
      }
    );
    proxyReq.on("error", reject);
    if (options && options.body) proxyReq.write(JSON.stringify(options.body));
    proxyReq.end();
  });
}

function glmChat(messages) {
  return new Promise((resolve, reject) => {
    const body = JSON.stringify({ model: GLM_MODEL, messages, temperature: 0.7 });
    const req = https.request(
      {
        hostname: GLM_HOST,
        path: GLM_PATH,
        method: "POST",
        headers: { Authorization: `Bearer ${GLM_API_KEY}`, "Content-Type": "application/json", "Content-Length": Buffer.byteLength(body) },
      },
      (res) => {
        let data = "";
        res.on("data", (c) => (data += c));
        res.on("end", () => {
          try {
            resolve(JSON.parse(data));
          } catch (err) {
            reject(err);
          }
        });
      }
    );
    req.on("error", reject);
    req.setTimeout(15000, () => req.destroy(new Error("GLM request timed out")));
    req.write(body);
    req.end();
  });
}

// ---- T24: Stripe topup, with a mock fallback until a real test-mode key
// exists (2026-09-03: user said "先做一个 mock，我明天再给你真实测试的
// key") — createCheckoutSession() is the single seam both paths sit
// behind, matching T20/T25/T26's "one pluggable function" precedent. ----
const pendingMockCheckouts = new Map(); // token -> {userId, tierKey, expiresAt}
const MOCK_CHECKOUT_TTL_MS = 30 * 60 * 1000;

// Both the mock path (GET /api/credits/mock-checkout) and the real path
// (POST /api/credits/webhook) end up here — one place that actually moves
// money, so there's exactly one code path responsible for the
// ledger/idempotency bookkeeping (topup()'s paymentRef dedup, db.js).
function completeTopup({ userId, tierKey, paymentRef }) {
  const tier = pricing.get(tierKey);
  if (!tier || tier.kind !== "topup_tier" || !tier.isActive) {
    throw new Error(`unknown or inactive topup tier: ${tierKey}`);
  }
  return creditLedger.topup({ userId, amount: tier.credits, reason: "topup", paymentRef });
}

// Real Stripe path: plain REST via global fetch, no stripe npm SDK — this
// project has no package.json/dependencies, and Stripe's Checkout Sessions
// API is documented as plain form-encoded REST (same "use fetch, not a new
// dependency" call as forwardToH3Assets in uploads.js). Untested against a
// real Stripe account as of this commit — no test-mode key exists yet, see
// dev-plan-4.md §1.2 item 4.
async function createRealStripeCheckoutSession({ userId, tierKey, tier }) {
  const params = new URLSearchParams({
    mode: "payment",
    "line_items[0][quantity]": "1",
    "line_items[0][price_data][currency]": "usd",
    "line_items[0][price_data][unit_amount]": String(tier.priceCents),
    "line_items[0][price_data][product_data][name]": `${tier.credits} credits`,
    success_url: `${APP_BASE_URL}/dance.html?topup=success`,
    cancel_url: `${APP_BASE_URL}/dance.html?topup=cancelled`,
    "metadata[userId]": userId,
    "metadata[tierKey]": tierKey,
  });
  const res = await fetch("https://api.stripe.com/v1/checkout/sessions", {
    method: "POST",
    headers: { Authorization: `Bearer ${STRIPE_SECRET_KEY}`, "Content-Type": "application/x-www-form-urlencoded" },
    body: params,
  });
  const session = await res.json();
  if (!res.ok) throw new Error(session.error?.message || "Stripe checkout session creation failed");
  return session.url;
}

// Mock path: no real payment happens, but the whole checkout -> redirect ->
// credited loop is real and testable today — T29's UI and topup()'s own
// dedup logic don't need to wait on a real Stripe key to be built and
// exercised end to end.
function createMockCheckoutUrl({ userId, tierKey }) {
  const token = crypto.randomUUID();
  pendingMockCheckouts.set(token, { userId, tierKey, expiresAt: Date.now() + MOCK_CHECKOUT_TTL_MS });
  return `/api/credits/mock-checkout?token=${token}`;
}

async function createCheckoutSession({ userId, tierKey }) {
  const tier = pricing.get(tierKey);
  if (!tier || tier.kind !== "topup_tier" || !tier.isActive) {
    throw new Error(`unknown or inactive topup tier: ${tierKey}`);
  }
  if (!STRIPE_SECRET_KEY) return { url: createMockCheckoutUrl({ userId, tierKey }) };
  return { url: await createRealStripeCheckoutSession({ userId, tierKey, tier }) };
}

// Stripe's documented signature scheme (Stripe-Signature header:
// "t=<timestamp>,v1=<hex hmac>"): HMAC-SHA256 over "<timestamp>.<raw body>"
// with the webhook signing secret, compared in constant time. Hand-rolled
// rather than the stripe SDK for the same "no new dependency" reason as
// the rest of this integration.
function verifyStripeWebhookSignature(rawBody, signatureHeader, secret) {
  if (!signatureHeader) return false;
  const parts = Object.fromEntries(
    signatureHeader
      .split(",")
      .map((kv) => kv.split("="))
      .filter((kv) => kv.length === 2)
  );
  if (!parts.t || !parts.v1) return false;
  const expected = crypto.createHmac("sha256", secret).update(`${parts.t}.${rawBody}`).digest("hex");
  let expectedBuf, actualBuf;
  try {
    expectedBuf = Buffer.from(expected, "hex");
    actualBuf = Buffer.from(parts.v1, "hex");
  } catch {
    return false;
  }
  return expectedBuf.length === actualBuf.length && crypto.timingSafeEqual(expectedBuf, actualBuf);
}

// Distilled from docs/h3skill.md (MiniMax's own H3 prompt-writing methodology) down to the one
// path that applies here: T2VA (no reference images — every chat prompt is plain text) on a clip
// fixed at ~10s (H3_GEN_PARAMS.frames / FPS). At that length it's one continuous shot, never a
// multi-cut montage — an earlier version asked for "shot-by-shot" and reliably got 4-5 fake cuts
// with timestamps running past the clip's own length, which the model can't actually deliver.
const PROMPT_OPTIMIZE_SYSTEM = `You are writing H3 text-to-video generation prompts (T2VA mode — no
reference images, pure text-to-video). Expand the user's short request (may be in Chinese or English)
into the official H3 three-field format, in this exact order, using these exact field labels:

integrated_multimodal_description: [Shot 1] one short style statement, e.g. "Live-action, cinematic."
Then describe, in one continuous unbroken shot (the clip is only about 10 seconds long — never split
into multiple shots or write more than [Shot 1]): the setting, the subject's specific action, and ONE
dominant camera movement using this vocabulary — Zoom In/Out, Push In/Pull Out, Pan Left/Right, Truck
Left/Right, Tilt Up/Down, Pedestal Up/Down, Arc Shot, Tracking Shot, Static Shot, Shake Slightly/
Strongly, POV, Roll Clockwise/Counterclockwise — stated as type + amplitude (small/large) + speed
(slow/fast). Describe light concretely: where it comes from, what it hits, what effect it creates.
Never use hollow quality words alone (8K, HD, masterpiece, stunning, cinematic used alone, beautiful,
high quality) — replace them with what is actually visible. 60-100 English words.

overall_soundscape: 1-4 English sentences describing the ambient environmental sound the scene would
naturally have.

non_diegetic_music: 1-3 English sentences describing the score the audience (not the characters) hears,
or exactly "N/A" if none fits.

Output only these three labeled fields in this exact order and exact labels, nothing else — no
preamble, no extra commentary, no markdown formatting.`;

// Best-effort — a viewer's short chat line ("一只猫跳舞") makes for a weak
// H3 prompt on its own. Never let a GLM outage or slow response block
// generation: on any failure this just falls back to the original text.
async function optimizePrompt(userPrompt) {
  if (!GLM_API_KEY) return userPrompt;
  try {
    const res = await glmChat([
      { role: "system", content: PROMPT_OPTIMIZE_SYSTEM },
      { role: "user", content: userPrompt },
    ]);
    const text = res.choices && res.choices[0] && res.choices[0].message && res.choices[0].message.content;
    return text ? text.trim() : userPrompt;
  } catch {
    return userPrompt;
  }
}

// ---- Live channel: shared virtual playhead + prompt queue ----
// Persisted to live-state.json (see saveLiveState/loadLiveState) so a
// restart resumes the schedule instead of starting cold; ensureSchedule's
// own past-entry trimming naturally handles a state file that's gone stale
// (server was down long enough that every persisted entry is in the past).
const FILLER_DURATION_MS = 30000; // keep the schedule filled at least this far ahead
const H3_GEN_PARAMS = { width: 480, height: 832, frames: 240, steps: 20, turbo: false, seed: 0 };
const FPS = 24;

// dance.html's own generation params (architecture.md 2.4: each channel
// keeps an independent H3_GEN_PARAMS even though the values happen to
// match live.html's today — don't merge the two constants).
const DANCE_GEN_PARAMS = { width: 480, height: 832, frames: 240, steps: 20, turbo: false, seed: 0 };

const initialLiveState = loadLiveState();
let schedule = initialLiveState.schedule; // [{clip, startAt, endAt, requestedBy?}]
let promptQueue = initialLiveState.promptQueue; // [{id, prompt, nickname?, status, clip?, error?, submittedAt, h3JobId?}]
let chatMessages = initialLiveState.chatMessages; // [{id, uid, nickname, text, createdAt, status}]

const initialDanceState = loadDanceState();
let danceSchedule = initialDanceState.danceSchedule; // [{videoId, startAt, endAt, requestedBy?}]
let danceQueue = initialDanceState.danceQueue; // [{id, garmentId, characterId, nickname?, status, jobId?, videoId?, error?, submittedAt, votes}]

// How often ensureSchedule/ensureDanceSchedule tick — configurable so tests
// don't have to wait out a real 2s to see a schedule fill.
const SCHEDULE_TICK_MS = Number(process.env.SCHEDULE_TICK_MS) || 2000;

// ---- chat + moderation ----
// ponytail: a starter blocklist, not a real content-policy list — swap in
// whatever the actual moderation requirements are. Substring match on the
// lowercased text; cheap and deterministic. Anything this doesn't catch
// (content that's fine as *text* but unsafe to *generate*) falls through to
// the H3 console's own generation-time safety checker — a rejected/failed
// job there just surfaces as a normal "failed" queue entry.
const BANNED_WORDS = ["色情", "porn", "自杀", "血腥暴力", "毒品"];
function moderateText(text) {
  const lower = text.toLowerCase();
  const hit = BANNED_WORDS.find((w) => lower.includes(w));
  if (hit) return { ok: false, reason: `包含违禁词` };
  return { ok: true };
}

const CHAT_HISTORY_LIMIT = 300;
function pushChatMessage(msg) {
  chatMessages.push(msg);
  if (chatMessages.length > CHAT_HISTORY_LIMIT) chatMessages = chatMessages.slice(-CHAT_HISTORY_LIMIT);
}
function updateChatStatus(id, status) {
  const msg = chatMessages.find((m) => m.id === id);
  if (msg) msg.status = status;
}

// Shared by /api/chat (after moderation) and /api/prompt (direct API use,
// e.g. testing) — looks up a library match or kicks off generation, exactly
// like before chat existed. `nickname` is optional (empty for /api/prompt).
function submitPromptToQueue(id, prompt, nickname) {
  const entry = { id, prompt, nickname: nickname || null, submittedAt: Date.now(), votes: [] };
  const match = findLibraryMatch(normalizePrompt(prompt));
  if (match) {
    entry.status = "matched";
    entry.clip = match;
    promptQueue.push(entry);
    return { status: "matched", clip: match };
  }
  entry.status = "generating";
  promptQueue.push(entry);
  generateForPrompt(entry); // fire and forget — polled via /api/live/state
  return { status: "generating", id: entry.id };
}

function normalizePrompt(s) {
  return s.trim().toLowerCase().replace(/\s+/g, " ");
}
function findLibraryMatch(promptNorm) {
  return getLibrary().find((c) => {
    const zh = normalizePrompt(c.prompt);
    const en = c.promptEn ? normalizePrompt(c.promptEn) : null;
    return (
      zh === promptNorm ||
      zh.includes(promptNorm) ||
      promptNorm.includes(zh) ||
      (en && (en === promptNorm || en.includes(promptNorm) || promptNorm.includes(en)))
    );
  });
}

// Idle fallback pick avoids anything played within this window, so a clip
// that just aired doesn't come back around too soon. Falls back to ignoring
// the cooldown (keeping only the immediate-repeat guard) if literally
// everything is on cooldown, rather than ever stalling the schedule.
const REPEAT_COOLDOWN_MS = 20 * 60 * 1000;

function markPlayed(id) {
  const lib = getLibrary();
  const clip = lib.find((c) => c.id === id);
  if (!clip) return;
  clip.lastPlayedAt = Date.now();
  clip.playCount = (clip.playCount || 0) + 1;
  saveLibrary(lib);
}

// Consumed entries are spliced out immediately rather than left as
// status:"scheduled" — once a clip is in `schedule` it shows up via
// current/upNext, so keeping a second, never-cleared copy in promptQueue
// just grows forever and duplicates the same info.
// Returns {clip, requestedBy, chatId} — chatId lets the caller flip the
// originating chat message to "scheduled" once it's actually about to air.
// Among entries of the same status, the most-upvoted prompt goes first
// (ties broken by submission order) — lets chat bump a favorite to the
// front of the line instead of strict FIFO.
function voteCount(q) {
  return (q.votes || []).length;
}
// Shared by live's promptQueue and dance's freeQueue (T11) — takes the queue
// array as a param rather than closing over a module-scope variable so both
// channels' independent queues can use it.
function pickBestIndexByStatus(queue, status) {
  let bestIdx = -1;
  for (let i = 0; i < queue.length; i++) {
    const q = queue[i];
    if (q.status !== status) continue;
    if (bestIdx === -1) {
      bestIdx = i;
      continue;
    }
    const best = queue[bestIdx];
    if (voteCount(q) > voteCount(best)) bestIdx = i;
  }
  return bestIdx;
}
// Random-fill fallback shared by live's pickNextClip and dance's
// pickNextDanceClip (T11) — least-played-first within a cooldown-filtered
// pool, so idle filler time rotates evenly instead of a few clips dominating
// by chance. `pool` is caller-filtered (live excludes dance channel clips
// and vice versa, architecture.md 2.1: independent schedules per channel).
function pickLeastPlayedClip(pool, prevId) {
  if (!pool.length) return null;
  const notPrev = pool.length > 1 ? pool.filter((c) => c.id !== prevId) : pool;
  const now = Date.now();
  // Never-played clips (no lastPlayedAt) are always eligible — genuinely
  // random among everything that isn't on cooldown, no bias toward "fresh".
  const offCooldown = notPrev.filter((c) => !c.lastPlayedAt || now - c.lastPlayedAt > REPEAT_COOLDOWN_MS);
  const candidates = offCooldown.length ? offCooldown : notPrev;
  const minPlays = Math.min(...candidates.map((c) => c.playCount || 0));
  const leastPlayed = candidates.filter((c) => (c.playCount || 0) === minPlays);
  return leastPlayed[Math.floor(Math.random() * leastPlayed.length)];
}
function pickNextClip() {
  const readyIdx = pickBestIndexByStatus(promptQueue, "ready");
  if (readyIdx !== -1) {
    const q = promptQueue.splice(readyIdx, 1)[0];
    return { clip: q.clip, requestedBy: q.nickname, chatId: q.id };
  }
  const matchedIdx = pickBestIndexByStatus(promptQueue, "matched");
  if (matchedIdx !== -1) {
    const q = promptQueue.splice(matchedIdx, 1)[0];
    return { clip: q.clip, requestedBy: q.nickname, chatId: q.id };
  }

  // dance-channel clips (T8) don't belong in live.html's random filler pool
  // — the two channels keep independent schedules (architecture.md 2.1).
  const lib = getLibrary().filter((c) => c.channel !== "dance");
  if (!lib.length) return null;
  const prev = schedule.length ? schedule[schedule.length - 1].clip.id : null;
  const clip = pickLeastPlayedClip(lib, prev);
  return clip ? { clip, requestedBy: null, chatId: null } : null;
}

const FAILED_ENTRY_TTL_MS = 20000; // how long a "generation failed" entry stays visible before cleanup

function ensureSchedule() {
  const now = Date.now();
  while (schedule.length > 1 && schedule[1].endAt <= now) schedule.shift();
  while (schedule.length === 0 || schedule[schedule.length - 1].endAt < now + FILLER_DURATION_MS) {
    const picked = pickNextClip();
    if (!picked || !picked.clip) break;
    const { clip, requestedBy, chatId } = picked;
    markPlayed(clip.id);
    if (chatId) updateChatStatus(chatId, "scheduled");
    const startAt = schedule.length ? schedule[schedule.length - 1].endAt : now;
    schedule.push({ clip, startAt, endAt: startAt + clip.duration * 1000, requestedBy });
  }
  promptQueue = promptQueue.filter((q) => q.status !== "failed" || now - q.failedAt < FAILED_ENTRY_TTL_MS);

  for (const [cid, lastSeen] of viewers) if (now - lastSeen > VIEWER_TTL_MS) viewers.delete(cid);
  saveLiveState();
}
setInterval(ensureSchedule, SCHEDULE_TICK_MS);

// ---- viewer count: anyone whose /api/live/state poll landed in the last VIEWER_TTL_MS ----
const VIEWER_TTL_MS = 12000;
const viewers = new Map(); // clientId -> lastSeenAt
// dance.html keeps its own viewer count (T17) — the two channels' "在线人数"
// must not be summed together, they're separate rooms.
const danceViewers = new Map(); // clientId -> lastSeenAt

// ---- rate limiting: cheap per-IP throttle on prompt submission ----
const RATE_LIMIT_MAX = 3;
const RATE_LIMIT_WINDOW_MS = 5 * 60 * 1000;
const rateLimitHits = new Map(); // ip -> [timestamps]
function isRateLimited(ip) {
  const now = Date.now();
  const hits = (rateLimitHits.get(ip) || []).filter((t) => now - t < RATE_LIMIT_WINDOW_MS);
  hits.push(now);
  rateLimitHits.set(ip, hits);
  return hits.length > RATE_LIMIT_MAX;
}

// Runs in the background; never blocks the live schedule or the POST /api/prompt response.
// `entry.h3JobId` set (and persisted via saveLiveState) as soon as we have it,
// so a server restart mid-generation can resume polling instead of losing
// track of the job (see resumeGenerations() at startup).
async function generateForPrompt(entry) {
  try {
    if (!entry.h3JobId) {
      if (!entry.expandedPrompt) {
        entry.expandedPrompt = await optimizePrompt(entry.prompt);
        saveLiveState();
      }
      const submitted = await h3ConsoleFetch("/v1/videos", {
        method: "POST",
        body: { prompt: entry.expandedPrompt, ...H3_GEN_PARAMS },
      });
      if (!submitted.id) throw new Error(submitted.detail || "submit failed");
      entry.h3JobId = submitted.id;
      saveLiveState();
    }

    for (let i = 0; i < 120; i++) {
      await new Promise((r) => setTimeout(r, 5000));
      const job = await h3ConsoleFetch(`/v1/videos/${entry.h3JobId}`);
      if (job.deleted_at) throw new Error("job was deleted on the H3 console before it finished");
      if (job.status === "done") {
        const clip = {
          id: job.id,
          source: "h3console",
          prompt: entry.prompt,
          fullPrompt: entry.expandedPrompt || entry.prompt,
          width: job.req.width,
          height: job.req.height,
          duration: Math.round((job.req.frames / FPS) * 10) / 10,
          partition: job.partition,
          likes: 0,
          createdAt: Date.now(),
        };
        const lib = getLibrary();
        lib.push(clip);
        saveLibrary(lib);
        entry.status = "ready";
        entry.clip = clip;
        updateChatStatus(entry.id, "ready");
        saveLiveState();
        return;
      }
      if (job.status === "error" || job.status === "failed") throw new Error(job.error || "generation failed");
    }
    throw new Error("generation timed out");
  } catch (err) {
    entry.status = "failed";
    entry.error = err.message;
    entry.failedAt = Date.now();
    updateChatStatus(entry.id, "failed");
    saveLiveState();
  }
}

// Startup recovery: resume polling any generation that was mid-flight when
// the process last exited. Anything genuinely orphaned (no h3JobId — should
// never happen given the flow above) just gets dropped as failed.
function resumeGenerations() {
  for (const entry of promptQueue) {
    if (entry.status !== "generating") continue;
    if (entry.h3JobId) generateForPrompt(entry);
    else {
      entry.status = "failed";
      entry.error = "lost track of this generation across a restart";
      entry.failedAt = Date.now();
    }
  }
}

// ---- Dressup dance room: one-step generation orchestration (T8) ----
// Mirrors generateForPrompt's shape (submit -> persist h3JobId -> poll ->
// push a library.json clip on success) but for ref2va instead of plain
// text, and persisted in generationJobs (dressup-store.js) instead of
// live-state.json's promptQueue — this is an admin/batch-driven pipeline,
// not the viewer-facing live queue, so it shouldn't share that store.

// Forwards a store record's local upload to H3 Console's /v1/assets
// (S4 spike) the first time it's needed, then caches the result on the
// record so later generations reusing the same character/garment/dance-ref
// don't re-forward the same file (MVCP M.13).
async function ensureH3AssetUrl(store, record, localUrlField) {
  if (record.h3AssetUrl) return record.h3AssetUrl;
  const absPath = path.join(__dirname, record[localUrlField]);
  const asset = await forwardToH3Assets(absPath, H3_CONSOLE_BASE, H3_CONSOLE_TOKEN);
  store.update(record.id, { h3AssetUrl: asset.url });
  return asset.url;
}

function pickRefDanceVideo() {
  const pool = danceRefs.list().filter((d) => d.isActive);
  if (pool.length === 0) throw new Error("no active dance-refs available");
  return pool[Math.floor(Math.random() * pool.length)];
}

// 4.6 节去重缓存：相同 (characterId, garmentId) 组合直接复用已有产物。
function findExistingGeneratedVideo(characterId, garmentId) {
  return getLibrary().find((c) => c.channel === "dance" && c.characterId === characterId && c.garmentId === garmentId);
}

// Shared by the single-shot POST /api/admin/generate and the T9 batch
// endpoint: validates a (character, garment) pair, returns the cached clip
// if M.7's dedupe index already has one, otherwise queues a generationJobs
// record and fires generateDanceVideo (fire-and-forget — callers poll
// GET /api/admin/generate/:id or /api/admin/batch-gen/status for progress).
// Returns {status, body} so route handlers can just write it out.
function submitGeneration({ characterId, garmentId, refDanceVideoId, batchId }) {
  if (!characters.get(characterId) || !garments.get(garmentId)) {
    return { status: 400, body: { error: "characterId/garmentId must reference existing records" } };
  }
  const existing = findExistingGeneratedVideo(characterId, garmentId);
  if (existing) return { status: 200, body: { cached: true, clip: existing } };

  if (!refDanceVideoId) {
    try {
      refDanceVideoId = pickRefDanceVideo().id;
    } catch (err) {
      return { status: 400, body: { error: err.message } };
    }
  }
  const job = generationJobs.create({ characterId, garmentId, refDanceVideoId, batchId: batchId || null, status: "queued", h3JobId: null, error: null });
  generateDanceVideo(job).catch(() => {});
  return { status: 200, body: { cached: false, jobId: job.id } };
}

// job: a generationJobs record ({id, characterId, garmentId,
// refDanceVideoId, status, h3JobId, error, fullPrompt}). Mutates it via
// generationJobs.update and keeps the local variable in sync (store.js has
// no in-memory cache, so every update is a fresh read-modify-write).
async function generateDanceVideo(job, opts = {}) {
  const pollIntervalMs = opts.pollIntervalMs || Number(process.env.GENERATION_POLL_INTERVAL_MS) || 5000;
  try {
    const character = characters.get(job.characterId);
    const garment = garments.get(job.garmentId);
    const danceRef = danceRefs.get(job.refDanceVideoId);
    if (!character || !garment || !danceRef) throw new Error("missing character/garment/dance-ref record");

    if (!job.h3JobId) {
      if (!job.fullPrompt) {
        const built = buildStage2Prompt({ character, garment, danceRef });
        job = generationJobs.update(job.id, { fullPrompt: built.prompt });
      }

      const [characterAssetUrl, garmentAssetUrl, danceRefAssetUrl] = await Promise.all([
        ensureH3AssetUrl(characters, character, "imageUrl"),
        ensureH3AssetUrl(garments, garment, "imageUrl"),
        ensureH3AssetUrl(danceRefs, danceRef, "videoUrl"),
      ]);

      const submitted = await h3ConsoleFetch("/v1/videos", {
        method: "POST",
        body: {
          prompt: job.fullPrompt,
          ...DANCE_GEN_PARAMS,
          reference_image_urls: [characterAssetUrl, garmentAssetUrl],
          reference_video_urls: [danceRefAssetUrl],
        },
      });
      if (!submitted.id) throw new Error(submitted.detail || "submit failed");
      job = generationJobs.update(job.id, { h3JobId: submitted.id, status: "generating" });
    }

    // ponytail: H3's 4 GPUs run one sharded model, not 4 independent
    // workers (H3-CONSOLE.md /v1/status), so a batch of N jobs is served
    // ~serially — the Nth job in queue_position can sit "queued" for
    // N * ~700s before it even starts. A fixed poll-count budget doesn't
    // know about queue depth, so this is wall-clock and generous instead;
    // upgrade path if batches grow past a couple dozen: read `eta_seconds`/
    // `queue_position` off the poll response and size the deadline to that.
    const deadline = Date.now() + (opts.timeoutMs || Number(process.env.GENERATION_TIMEOUT_MS) || 2 * 60 * 60 * 1000);
    while (Date.now() < deadline) {
      await new Promise((r) => setTimeout(r, pollIntervalMs));
      let polled;
      try {
        polled = await h3ConsoleFetch(`/v1/videos/${job.h3JobId}`);
      } catch {
        // A single bad poll (H3 Console hiccup — non-JSON 500 page, dropped
        // connection) isn't a generation failure; the job itself is still
        // fine on H3's side. Skip this tick and retry on the next one,
        // bounded by the same deadline as everything else. Confirmed live
        // 2026-09-02: a 20-job batch's concurrent polling briefly 500'd H3
        // Console, and every job got marked "failed" over a transient
        // response even though H3 still had them queued/running.
        continue;
      }
      if (polled.deleted_at) throw new Error("job was deleted on the H3 console before it finished");
      if (polled.status === "done") {
        const clip = {
          id: polled.id,
          source: "h3console",
          // ingest.js's syncLibrary() only carries an entry forward as-is
          // when `edited` is true — otherwise it rebuilds the record from
          // the raw H3 job on its next periodic sync, which knows nothing
          // about channel/characterId/garmentId/refDanceVideoId and would
          // silently strip them (and leak this clip into the non-dance
          // pickNextClip() pool, since `channel` would be gone too).
          edited: true,
          channel: "dance",
          characterId: job.characterId,
          garmentId: job.garmentId,
          refDanceVideoId: job.refDanceVideoId,
          backend: "h3_console",
          priority: "normal",
          requestedByUserId: null,
          prompt: `${character.name} × ${garment.name}`,
          fullPrompt: job.fullPrompt,
          width: polled.req.width,
          height: polled.req.height,
          duration: Math.round((polled.req.frames / FPS) * 10) / 10,
          partition: polled.partition,
          likes: 0,
          createdAt: Date.now(),
        };
        const lib = getLibrary();
        lib.push(clip);
        saveLibrary(lib);
        generationJobs.update(job.id, { status: "done", generatedVideoId: clip.id });
        return clip;
      }
      if (polled.status === "error" || polled.status === "failed" || polled.status === "cancelled") {
        throw new Error(polled.error || `generation ${polled.status}`);
      }
    }
    throw new Error("generation timed out");
  } catch (err) {
    generationJobs.update(job.id, { status: "failed", error: err.message });
    throw err;
  }
}

// Startup recovery, same idea as resumeGenerations() but for generationJobs.
function resumeDressupGenerations() {
  for (const job of generationJobs.list()) {
    if (job.status !== "generating" && job.status !== "queued") continue;
    if (job.h3JobId) generateDanceVideo(job).catch(() => {});
    else generationJobs.update(job.id, { status: "failed", error: "lost track of this generation across a restart" });
  }
}

// ---- dance.html: independent playout schedule + free (mode-一/衣柜) queue (T11) ----
// Mirrors live's pickNextClip/ensureSchedule shape but pulls from
// danceQueue/danceSchedule instead, and picks its random-fill pool from
// channel:"dance" clips only.

function pickNextDanceClip() {
  const readyIdx = pickBestIndexByStatus(danceQueue, "ready");
  if (readyIdx !== -1) {
    const q = danceQueue.splice(readyIdx, 1)[0];
    return { videoId: q.videoId, requestedBy: q.nickname };
  }
  const pool = getLibrary().filter((c) => c.channel === "dance");
  if (!pool.length) return null;
  const prevVideoId = danceSchedule.length ? danceSchedule[danceSchedule.length - 1].videoId : null;
  const clip = pickLeastPlayedClip(pool, prevVideoId);
  return clip ? { videoId: clip.id, requestedBy: null } : null;
}

function ensureDanceSchedule() {
  const now = Date.now();

  // Reconcile in-flight picks against generationJobs — the store, not an
  // in-memory promise, is the source of truth (T8's resumeDressupGenerations
  // already re-polls H3 for jobs still running after a restart; this tick
  // just needs to notice when they land, restart or not).
  for (const q of danceQueue) {
    if (q.status !== "generating" || !q.jobId) continue;
    const job = generationJobs.get(q.jobId);
    if (!job) continue;
    if (job.status === "done") {
      q.status = "ready";
      q.videoId = job.generatedVideoId;
    } else if (job.status === "failed") {
      q.status = "failed";
      q.error = job.error;
      q.failedAt = now;
      // T27's paid path (userId/amountPaid only set there — free mode-一
      // picks have neither): refund on generation failure, per "共同后置
      // 流程"'s stated floor. Guarded by an existing-refund lookup rather
      // than trusting this branch only ever runs once — it normally does
      // (danceQueue entries only transition "generating" -> "failed" a
      // single time, this loop's own `q.status !== "generating"` guard
      // above prevents re-entry), but a crash between this write and
      // saveDanceState() persisting it could in principle replay the same
      // transition once after restart, and a duplicate refund is real
      // money, not a cosmetic bug.
      if (q.userId && q.amountPaid) {
        const alreadyRefunded = creditLedger.findByRelatedAssetAndReason(q.garmentId, "refund_stage2_fail").length > 0;
        if (!alreadyRefunded) {
          try {
            creditLedger.refund({ userId: q.userId, amount: q.amountPaid, reason: "refund_stage2_fail", relatedAssetId: q.garmentId });
          } catch (err) {
            // NO_SUCH_USER (deleted account) is the only realistic failure
            // here — refund only ever adds, so it can't hit
            // INSUFFICIENT_BALANCE. This branch won't be revisited (the
            // guard above only enters on "generating" -> "failed", a
            // one-time transition), so this is a genuine miss, not a
            // deferred retry — logged rather than silently dropped.
            console.error(`[refund_stage2_fail] failed to refund userId=${q.userId} garmentId=${q.garmentId}: ${err.message}`);
          }
        }
      }
    }
  }

  while (danceSchedule.length > 1 && danceSchedule[1].endAt <= now) danceSchedule.shift();
  while (danceSchedule.length === 0 || danceSchedule[danceSchedule.length - 1].endAt < now + FILLER_DURATION_MS) {
    const picked = pickNextDanceClip();
    if (!picked || !picked.videoId) break;
    const clip = getLibrary().find((c) => c.id === picked.videoId);
    if (!clip) break; // stale/removed videoId — guard rather than schedule a dead entry
    markPlayed(clip.id);
    const startAt = danceSchedule.length ? danceSchedule[danceSchedule.length - 1].endAt : now;
    danceSchedule.push({ videoId: picked.videoId, startAt, endAt: startAt + clip.duration * 1000, requestedBy: picked.requestedBy });
  }
  danceQueue = danceQueue.filter((q) => q.status !== "failed" || now - q.failedAt < FAILED_ENTRY_TTL_MS);

  for (const [cid, lastSeen] of danceViewers) if (now - lastSeen > VIEWER_TTL_MS) danceViewers.delete(cid);
  saveDanceState();
}
setInterval(ensureDanceSchedule, SCHEDULE_TICK_MS);

http
  .createServer((req, res) => {
    if (req.url.startsWith("/fal/")) {
      const proxyReq = https.request(
        {
          hostname: FAL_HOST,
          path: req.url.slice(4),
          method: req.method,
          headers: { ...req.headers, host: FAL_HOST },
        },
        (proxyRes) => {
          res.writeHead(proxyRes.statusCode, proxyRes.headers);
          proxyRes.pipe(res);
        }
      );
      proxyReq.on("error", (err) => {
        res.writeHead(502, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: { message: err.message } }));
      });
      req.pipe(proxyReq);
      return;
    }

    const pathname = req.url.split("?")[0];

    if (pathname === "/api/admin/login" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          if (!ADMIN_PASSWORD || body.password !== ADMIN_PASSWORD) {
            res.writeHead(401, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "invalid password" }));
            return;
          }
          const token = crypto.randomUUID();
          adminSessions.set(token, Date.now() + ADMIN_SESSION_TTL_MS);
          res.writeHead(200, {
            "Content-Type": "application/json",
            "Set-Cookie": `${ADMIN_SESSION_COOKIE}=${token}; HttpOnly; Path=/; Max-Age=${Math.floor(ADMIN_SESSION_TTL_MS / 1000)}; SameSite=Lax`,
          });
          res.end(JSON.stringify({ ok: true }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/admin/logout" && req.method === "POST") {
      const token = parseCookies(req)[ADMIN_SESSION_COOKIE];
      if (token) adminSessions.delete(token);
      res.writeHead(200, {
        "Content-Type": "application/json",
        "Set-Cookie": `${ADMIN_SESSION_COOKIE}=; HttpOnly; Path=/; Max-Age=0`,
      });
      res.end(JSON.stringify({ ok: true }));
      return;
    }

    // Viewer account auth (dev-plan-3.md T19) — entirely separate from the
    // /api/admin/* gate right below. Registering/logging in is always
    // optional: /api/dance/* keeps working on the plain viewer_uid cookie
    // with no session at all (see requireUserSession's doc comment).
    if (pathname === "/api/auth/register" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const email = (body.email || "").trim().toLowerCase();
          const password = body.password || "";
          if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "invalid email" }));
            return;
          }
          if (password.length < 8) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "password must be at least 8 characters" }));
            return;
          }
          // T21: an existing anonymous viewer_uid/viewer_nickname cookie
          // (set client-side by live.html/dance.html, plaintext, never
          // trusted for anything sensitive) gets carried onto the new
          // account — history isn't rewritten, but future votes/plays from
          // this browser stay attributed to the same identity.
          const existingCookies = parseCookies(req);
          let user;
          try {
            user = userStore.create({
              email,
              passwordHash: hashPassword(password),
              nickname: existingCookies.viewer_nickname || null,
              legacyUid: existingCookies.viewer_uid || null,
            });
          } catch (err) {
            if (err.code === "EMAIL_TAKEN") {
              res.writeHead(409, { "Content-Type": "application/json" });
              res.end(JSON.stringify({ error: "email already registered" }));
              return;
            }
            throw err;
          }
          const session = userSessions.create({ userId: user.id, kind: "session", expiresAt: Date.now() + USER_SESSION_TTL_MS });
          // T20: fire off the verification email. sendVerificationEmail is
          // the entire integration seam — see its own comment.
          const verifySession = userSessions.create({ userId: user.id, kind: "email_verify", expiresAt: Date.now() + EMAIL_VERIFY_TTL_MS });
          const devVerifyUrl = sendVerificationEmail(user.email, verifySession.token);
          const responseBody = { id: user.id, email: user.email, emailVerified: user.emailVerified, nickname: user.nickname };
          if (process.env.NODE_ENV !== "production") responseBody.devVerifyUrl = devVerifyUrl;
          res.writeHead(200, {
            "Content-Type": "application/json",
            "Set-Cookie": `${USER_SESSION_COOKIE}=${session.token}; HttpOnly; Path=/; Max-Age=${Math.floor(USER_SESSION_TTL_MS / 1000)}; SameSite=Lax`,
          });
          res.end(JSON.stringify(responseBody));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/auth/login" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const email = (body.email || "").trim().toLowerCase();
          const password = body.password || "";
          const user = userStore.findByEmail(email);
          // Deliberately the same error for "no such email" and "wrong
          // password" — distinguishing the two lets an attacker enumerate
          // which emails are registered.
          if (!user || !verifyPassword(password, user.passwordHash)) {
            res.writeHead(401, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "invalid email or password" }));
            return;
          }
          const session = userSessions.create({ userId: user.id, kind: "session", expiresAt: Date.now() + USER_SESSION_TTL_MS });
          const setCookies = [`${USER_SESSION_COOKIE}=${session.token}; HttpOnly; Path=/; Max-Age=${Math.floor(USER_SESSION_TTL_MS / 1000)}; SameSite=Lax`];
          // T21: push the account's bound identity back onto this browser,
          // even if it showed up with no viewer_uid cookie at all or a
          // fresh one from a different device — otherwise logging in from
          // a clean browser would silently start a new anonymous identity,
          // which for anything vote-limited defeats the point of binding
          // it to an account in the first place.
          if (user.legacyUid) setCookies.push(viewerIdentityCookie("viewer_uid", user.legacyUid));
          if (user.nickname) setCookies.push(viewerIdentityCookie("viewer_nickname", user.nickname));
          res.writeHead(200, { "Content-Type": "application/json", "Set-Cookie": setCookies });
          res.end(JSON.stringify({ id: user.id, email: user.email, emailVerified: user.emailVerified, nickname: user.nickname }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    // T20: single-use — the email_verify session is revoked on success, so
    // a second visit to the same link (or an expired one) hits the same
    // "invalid or expired" error rather than silently re-succeeding.
    if (pathname === "/api/auth/verify" && req.method === "GET") {
      const params = new URLSearchParams(req.url.split("?")[1] || "");
      const token = params.get("token") || "";
      const verifySession = userSessions.findByToken(token);
      if (!verifySession || verifySession.kind !== "email_verify") {
        res.writeHead(400, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "invalid or expired verification link" }));
        return;
      }
      userStore.update(verifySession.userId, { emailVerified: true });
      userSessions.revoke(token);
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify({ ok: true }));
      return;
    }

    if (pathname === "/api/auth/logout" && req.method === "POST") {
      const token = parseCookies(req)[USER_SESSION_COOKIE];
      if (token) userSessions.revoke(token);
      res.writeHead(200, {
        "Content-Type": "application/json",
        "Set-Cookie": `${USER_SESSION_COOKIE}=; HttpOnly; Path=/; Max-Age=0`,
      });
      res.end(JSON.stringify({ ok: true }));
      return;
    }

    // Debug-only endpoint, per T19's own acceptance criteria — fine to
    // keep past this task too (a real account page will want it), but
    // intentionally minimal for now.
    if (pathname === "/api/auth/me" && req.method === "GET") {
      const user = requireUserSession(req);
      if (!user) {
        res.writeHead(401, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "unauthorized" }));
        return;
      }
      res.writeHead(200, { "Content-Type": "application/json" });
      // creditBalance riding along here (T29) rather than a dedicated
      // /api/credits/balance endpoint — it's the same "logged-in user's own
      // state" this route already exists to serve, and refreshAuthState()
      // in live.html/dance.html (T22) already polls this after every login.
      res.end(JSON.stringify({ id: user.id, email: user.email, emailVerified: user.emailVerified, nickname: user.nickname, creditBalance: user.creditBalance }));
      return;
    }

    // T24: credit topup. Login + emailVerified matches M.10's "任何扣积分/
    // 写用户资产的接口" rule — a topup adds money rather than spending it,
    // but still needs an accountable identity before a real charge runs.
    if (pathname === "/api/credits/checkout" && req.method === "POST") {
      const user = requireUserSession(req);
      if (!user) {
        res.writeHead(401, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "login required" }));
        return;
      }
      if (!user.emailVerified) {
        res.writeHead(403, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "email verification required before purchasing credits" }));
        return;
      }
      readJsonBody(req)
        .then(async (body) => {
          try {
            const session = await createCheckoutSession({ userId: user.id, tierKey: (body.tierKey || "").trim() });
            res.writeHead(200, { "Content-Type": "application/json" });
            res.end(JSON.stringify(session));
          } catch (err) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: err.message }));
          }
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    // Dev-only completion of a mock checkout created above — simulates the
    // browser landing back from Stripe's hosted page after a successful
    // payment. Only ever reachable via a token this same process handed
    // out (createMockCheckoutUrl), so there's nothing to authenticate here
    // beyond "does this token exist and is it unused."
    if (pathname === "/api/credits/mock-checkout" && req.method === "GET") {
      const token = new URL(req.url, "http://x").searchParams.get("token") || "";
      const pending = pendingMockCheckouts.get(token);
      pendingMockCheckouts.delete(token); // single-use, same spirit as T20's email-verify tokens
      if (!pending || pending.expiresAt < Date.now()) {
        res.writeHead(400, { "Content-Type": "text/plain" });
        res.end("invalid or expired mock checkout token");
        return;
      }
      try {
        completeTopup({ userId: pending.userId, tierKey: pending.tierKey, paymentRef: `mock_${token}` });
        res.writeHead(302, { Location: "/dance.html?topup=success" });
        res.end();
      } catch (err) {
        res.writeHead(400, { "Content-Type": "text/plain" });
        res.end(err.message);
      }
      return;
    }

    // Real Stripe webhook — only meaningful once a real
    // STRIPE_WEBHOOK_SECRET is configured (tomorrow, per the user).
    // Refuses anything it can't verify rather than trusting an
    // unsigned/unverifiable request, even before a secret exists
    // (dev-plan-4.md T24's explicit acceptance criterion).
    if (pathname === "/api/credits/webhook" && req.method === "POST") {
      readRawTextBody(req)
        .then((rawBody) => {
          if (!STRIPE_WEBHOOK_SECRET || !verifyStripeWebhookSignature(rawBody, req.headers["stripe-signature"], STRIPE_WEBHOOK_SECRET)) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "signature verification failed" }));
            return;
          }
          let event;
          try {
            event = JSON.parse(rawBody);
          } catch {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "invalid JSON" }));
            return;
          }
          if (event.type === "checkout.session.completed") {
            const session = event.data.object;
            try {
              // event.id, not session.id: Stripe's at-least-once
              // redelivery resends the same event id for the same
              // occurrence, which is exactly what topup()'s paymentRef
              // dedup (db.js) keys on.
              completeTopup({ userId: session.metadata.userId, tierKey: session.metadata.tierKey, paymentRef: event.id });
            } catch (err) {
              // Already-applied duplicates are handled inside topup()
              // itself (returns the existing row, doesn't throw) — a throw
              // here means something genuinely went wrong (unknown tier,
              // missing user), not a benign redelivery.
              res.writeHead(400, { "Content-Type": "application/json" });
              res.end(JSON.stringify({ error: err.message }));
              return;
            }
          }
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ received: true }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "failed to read request body" }));
        });
      return;
    }

    if (pathname.startsWith("/api/admin/") && !isAdminAuthed(req)) {
      res.writeHead(401, { "Content-Type": "application/json" });
      res.end(JSON.stringify({ error: "unauthorized" }));
      return;
    }

    if (charactersCrud(pathname, req, res)) return;
    if (garmentsCrud(pathname, req, res)) return;
    if (danceRefsCrud(pathname, req, res)) return;

    // T30: manual balance correction, e.g. a support gesture ("sorry about
    // the failed generation that didn't auto-refund, here's some credits")
    // or clawing back an abused promo. Always attributable — see
    // adminActorUserId's doc comment.
    if (pathname === "/api/admin/credit/adjust" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const userId = (body.userId || "").trim();
          const delta = Number(body.delta);
          if (!userId || !userStore.get(userId) || !Number.isFinite(delta) || delta === 0) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "userId (must reference an existing user) and a non-zero numeric delta are required" }));
            return;
          }
          try {
            const row = creditLedger.adjust({ userId, delta, reason: (body.reason || "admin_adjust").trim(), actorUserId: adminActorUserId(req) });
            res.writeHead(200, { "Content-Type": "application/json" });
            res.end(JSON.stringify(row));
          } catch (err) {
            const status = err.code === "INSUFFICIENT_BALANCE" ? 400 : 500;
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: err.message }));
          }
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/admin/generate" && req.method === "GET") {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(generationJobs.list()));
      return;
    }

    if (pathname === "/api/admin/generate" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const { status, body: respBody } = submitGeneration(body);
          res.writeHead(status, { "Content-Type": "application/json" });
          res.end(JSON.stringify(respBody));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname.startsWith("/api/admin/generate/") && req.method === "GET") {
      const job = generationJobs.get(pathname.slice("/api/admin/generate/".length));
      if (!job) {
        res.writeHead(404, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "not found" }));
        return;
      }
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(job));
      return;
    }

    // T9 冷启动批量生成：{characterId, garmentIds[], refDanceVideoIds?[]}.
    // No refDanceVideoIds given -> one job per garment, each with its own
    // random active dance-ref (same as the single-generate default).
    // refDanceVideoIds given -> full garmentIds x refDanceVideoIds cross
    // product, so an operator can pin specific reference dances.
    // Every combo goes through submitGeneration, so the M.7 dedupe cache
    // (same characterId+garmentId already generated) is honored per combo,
    // not just per batch.
    if (pathname === "/api/admin/batch-gen" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const { characterId, garmentIds, refDanceVideoIds } = body;
          if (!characters.get(characterId) || !Array.isArray(garmentIds) || garmentIds.length === 0) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "characterId must exist and garmentIds must be a non-empty array" }));
            return;
          }
          const batchId = crypto.randomUUID();
          const refCombos = Array.isArray(refDanceVideoIds) && refDanceVideoIds.length > 0 ? refDanceVideoIds : [undefined];
          const results = [];
          for (const garmentId of garmentIds) {
            for (const refDanceVideoId of refCombos) {
              const { status, body: respBody } = submitGeneration({ characterId, garmentId, refDanceVideoId, batchId });
              results.push({ garmentId, refDanceVideoId: refDanceVideoId || null, status, ...respBody });
            }
          }
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ batchId, results }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/admin/batch-gen/status" && req.method === "GET") {
      const batchId = new URL(req.url, "http://x").searchParams.get("batchId");
      if (!batchId) {
        res.writeHead(400, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "batchId query param required" }));
        return;
      }
      const jobs = generationJobs.list().filter((j) => j.batchId === batchId);
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(jobs));
      return;
    }

    // ---- dance.html: public viewer-facing endpoints (T11/T12/T15/T17) ----
    // No admin auth (T6 only gates /api/admin/*) — these are the free,
    // anonymous, 模式一 (衣柜选衣服) path. 模式二 (付费传衣服) is T27,
    // below, and does require login+emailVerified on its own. 模式三 isn't
    // built yet (第五期).

    if (pathname === "/api/dance/wardrobe" && req.method === "GET") {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(garments.list().filter((g) => g.isActive)));
      return;
    }

    // T28/T29 need pricing (spend_garment's cost, topup_tier options) on
    // the client before any purchase decision — public/unauthenticated on
    // purpose, same reasoning as GET /api/dance/wardrobe above.
    if (pathname === "/api/pricing" && req.method === "GET") {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(pricing.list().filter((p) => p.isActive)));
      return;
    }

    if (pathname === "/api/dance/live/state" && req.method === "GET") {
      ensureDanceSchedule();
      const now = Date.now();
      const params = new URL(req.url, "http://x").searchParams;
      const cid = params.get("cid");
      const uid = params.get("uid") || null;
      if (cid) danceViewers.set(cid, now);
      let idx = danceSchedule.findIndex((s) => s.startAt <= now && now < s.endAt);
      if (idx === -1) idx = danceSchedule.length - 1;
      const cur = danceSchedule[idx];
      const lib = getLibrary();
      const joinClip = (videoId) => lib.find((c) => c.id === videoId) || null;
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(
        JSON.stringify({
          now,
          watching: danceViewers.size,
          current: cur ? { clip: joinClip(cur.videoId), startAt: cur.startAt, endAt: cur.endAt, requestedBy: cur.requestedBy || null } : null,
          upNext: danceSchedule.slice(idx + 1, idx + 4).map((s) => ({ ...(joinClip(s.videoId) || {}), requestedBy: s.requestedBy || null })),
          queue: danceQueue
            .filter((q) => ["generating", "failed"].includes(q.status))
            .slice()
            .sort((a, b) => voteCount(b) - voteCount(a))
            .map((q) => ({
              id: q.id,
              garmentId: q.garmentId,
              nickname: q.nickname,
              status: q.status,
              error: q.error,
              votes: voteCount(q),
              voted: uid ? (q.votes || []).includes(uid) : false,
            })),
        })
      );
      return;
    }

    // P.1 免费模式一：{garmentId, nickname?}. Uses the single配置的直播默认
    // 人物 (characters.isDefault) — 3.1 节: 免费用户不能指定/上传人物。
    // Reuses submitGeneration (T8/T9) whole — same M.7 dedupe cache — then
    // hands the result to danceQueue for ensureDanceSchedule to pick up.
    if (pathname === "/api/dance/pick" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const garment = garments.get(body.garmentId);
          if (!garment || !garment.isActive) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "garmentId must reference an active garment" }));
            return;
          }
          const defaultCharacter = characters.list().find((c) => c.isDefault);
          if (!defaultCharacter) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "no default character configured" }));
            return;
          }
          const { status, body: respBody } = submitGeneration({ characterId: defaultCharacter.id, garmentId: garment.id });
          if (status !== 200) {
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify(respBody));
            return;
          }
          const entry = {
            id: crypto.randomUUID(),
            garmentId: garment.id,
            characterId: defaultCharacter.id,
            nickname: (body.nickname || "").trim() || null,
            submittedAt: Date.now(),
            votes: [],
          };
          if (respBody.cached) {
            entry.status = "ready";
            entry.videoId = respBody.clip.id;
          } else {
            entry.status = "generating";
            entry.jobId = respBody.jobId;
          }
          danceQueue.push(entry);
          saveDanceState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ status: entry.status, id: entry.id, videoId: entry.videoId || null }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    // T27 模式二: 付费传衣服. 需登录 + emailVerified (M.10). Order matters —
    // moderation runs before any garments record or spend exists (a
    // rejected upload leaves nothing behind); the garment record is
    // created before spend so the ledger row can carry relatedAssetId, and
    // is rolled back (garments.remove) if the spend or the generation
    // submission itself fails, so a failed/rejected attempt never leaves a
    // phantom garment in the library. Async generation failures (after
    // this handler has already responded) are refunded from
    // ensureDanceSchedule's tick instead — see its own comment.
    if (pathname === "/api/dance/upload-garment" && req.method === "POST") {
      const user = requireUserSession(req);
      if (!user) {
        res.writeHead(401, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "login required" }));
        return;
      }
      if (!user.emailVerified) {
        res.writeHead(403, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "email verification required before uploading a garment" }));
        return;
      }
      const boundary = boundaryFromContentType(req.headers["content-type"] || "");
      if (!boundary) {
        res.writeHead(400, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "expected multipart/form-data" }));
        return;
      }
      readRawBody(req)
        .then(async (raw) => {
          const filePart = parseMultipart(raw, boundary).find((p) => p.name === "file");
          if (!filePart) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "missing file field" }));
            return;
          }
          const sniffed = sniffImageType(filePart.data);
          if (!sniffed) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "unrecognized image type (expected jpeg/png/webp)" }));
            return;
          }
          const defaultCharacter = characters.list().find((c) => c.isDefault);
          if (!defaultCharacter) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "no default character configured" }));
            return;
          }

          let relPath, absPath;
          try {
            ({ relPath } = stripMetadataAndSave(filePart.data, sniffed));
            absPath = path.join(__dirname, relPath);
          } catch {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "failed to process image" }));
            return;
          }

          const moderation = await moderateGarmentImage(absPath, relPath);
          if (!moderation.approved) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "image rejected by moderation", reason: moderation.reason }));
            return;
          }

          const appearanceDescriptor = await describeGarmentImage(absPath);
          const garment = garments.create({
            name: `${user.nickname || user.email.split("@")[0]} 上传`,
            category: "",
            thumbnailUrl: relPath,
            imageUrl: relPath,
            appearanceDescriptor,
            source: "user_paid",
            ownerUserId: user.id,
            moderationStatus: "approved",
            isActive: true,
          });

          const spendGarment = pricing.get("spend_garment");
          const amount = spendGarment ? spendGarment.credits : 0;
          let spendRow;
          try {
            spendRow = creditLedger.spend({ userId: user.id, amount, reason: "spend_garment", relatedAssetId: garment.id });
          } catch (err) {
            garments.remove(garment.id);
            const status = err.code === "INSUFFICIENT_BALANCE" ? 402 : 500;
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: err.message }));
            return;
          }

          const { status, body: respBody } = submitGeneration({ characterId: defaultCharacter.id, garmentId: garment.id });
          if (status !== 200) {
            creditLedger.refund({ userId: user.id, amount, reason: "refund_stage2_fail", relatedAssetId: garment.id });
            garments.remove(garment.id);
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify(respBody));
            return;
          }

          const entry = {
            id: crypto.randomUUID(),
            garmentId: garment.id,
            characterId: defaultCharacter.id,
            nickname: user.nickname || null,
            userId: user.id,
            amountPaid: amount,
            submittedAt: Date.now(),
            votes: [],
          };
          if (respBody.cached) {
            entry.status = "ready";
            entry.videoId = respBody.clip.id;
          } else {
            entry.status = "generating";
            entry.jobId = respBody.jobId;
          }
          danceQueue.push(entry);
          saveDanceState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ status: entry.status, id: entry.id, garmentId: garment.id, videoId: entry.videoId || null, creditsSpent: amount, balanceAfter: spendRow.balanceAfter }));
        })
        .catch((err) => {
          if (res.writableEnded) return;
          const status = err.code === "PAYLOAD_TOO_LARGE" ? 413 : 400;
          res.writeHead(status, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: err.message || "upload failed" }));
        });
      return;
    }

    if (pathname.startsWith("/api/dance/queue/vote/") && req.method === "POST") {
      const id = pathname.slice("/api/dance/queue/vote/".length);
      readJsonBody(req)
        .then((body) => {
          const uid = (body.uid || "").trim();
          if (!uid) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "uid required" }));
            return;
          }
          const entry = danceQueue.find((q) => q.id === id);
          if (!entry || !["generating", "ready", "failed"].includes(entry.status)) {
            res.writeHead(404, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "not found" }));
            return;
          }
          if (!Array.isArray(entry.votes)) entry.votes = [];
          const i = entry.votes.indexOf(uid);
          const voted = i === -1;
          if (voted) entry.votes.push(uid);
          else entry.votes.splice(i, 1);
          saveDanceState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ votes: entry.votes.length, voted }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/library") {
      const sort = new URL(req.url, "http://x").searchParams.get("sort") || "newest";
      const lib = getLibrary().slice();
      const sorters = {
        newest: (a, b) => b.createdAt - a.createdAt,
        oldest: (a, b) => a.createdAt - b.createdAt,
        top: (a, b) => (b.likes || 0) - (a.likes || 0) || b.createdAt - a.createdAt,
      };
      lib.sort(sorters[sort] || sorters.newest);
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(lib));
      return;
    }

    if (pathname === "/api/live/state") {
      ensureSchedule();
      const now = Date.now();
      const params = new URL(req.url, "http://x").searchParams;
      const cid = params.get("cid");
      const uid = params.get("uid") || null;
      if (cid) viewers.set(cid, now);
      let idx = schedule.findIndex((s) => s.startAt <= now && now < s.endAt);
      if (idx === -1) idx = schedule.length - 1;
      const cur = schedule[idx];
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(
        JSON.stringify({
          now,
          watching: viewers.size,
          current: cur ? { clip: cur.clip, startAt: cur.startAt, endAt: cur.endAt, requestedBy: cur.requestedBy || null } : null,
          upNext: schedule.slice(idx + 1, idx + 4).map((s) => ({ ...s.clip, requestedBy: s.requestedBy || null })),
          queue: promptQueue
            .filter((q) => ["matched", "generating", "failed"].includes(q.status))
            .slice()
            .sort((a, b) => voteCount(b) - voteCount(a))
            .map((q) => ({
              id: q.id,
              prompt: q.prompt,
              nickname: q.nickname,
              status: q.status,
              error: q.error,
              votes: voteCount(q),
              voted: uid ? (q.votes || []).includes(uid) : false,
            })),
        })
      );
      return;
    }

    if (pathname === "/api/prompt" && req.method === "POST") {
      if (isRateLimited(req.socket.remoteAddress)) {
        res.writeHead(429, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: `最多每 ${RATE_LIMIT_WINDOW_MS / 60000} 分钟提交 ${RATE_LIMIT_MAX} 次，请稍后再试` }));
        return;
      }
      readJsonBody(req)
        .then((body) => {
          const prompt = (body.prompt || "").trim();
          if (!prompt || prompt.length > 300) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "prompt required, max 300 chars" }));
            return;
          }
          const result = submitPromptToQueue(Date.now().toString(36), prompt, null);
          saveLiveState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(result));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/chat" && req.method === "GET") {
      const cid = new URL(req.url, "http://x").searchParams.get("cid");
      if (cid) viewers.set(cid, Date.now());
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(chatMessages.slice(-100)));
      return;
    }

    if (pathname === "/api/chat" && req.method === "POST") {
      if (isRateLimited(req.socket.remoteAddress)) {
        res.writeHead(429, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: `最多每 ${RATE_LIMIT_WINDOW_MS / 60000} 分钟发送 ${RATE_LIMIT_MAX} 条，请稍后再试` }));
        return;
      }
      readJsonBody(req)
        .then((body) => {
          const uid = (body.uid || "").trim();
          const nickname = (body.nickname || "").trim().slice(0, 20);
          const text = (body.text || "").trim();
          if (!uid || !nickname || !text || text.length > 300) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "uid, nickname, text required, text max 300 chars" }));
            return;
          }
          const id = `${Date.now().toString(36)}${Math.random().toString(36).slice(2, 6)}`;
          const msg = { id, uid, nickname, text, createdAt: Date.now() };

          const mod = moderateText(text);
          if (!mod.ok) {
            msg.status = "rejected";
            msg.rejectReason = mod.reason;
            pushChatMessage(msg);
            saveLiveState();
            res.writeHead(200, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ status: "rejected", reason: mod.reason }));
            return;
          }

          msg.status = "approved";
          pushChatMessage(msg);
          const result = submitPromptToQueue(id, text, nickname);
          msg.status = result.status; // "matched" | "generating"
          saveLiveState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(result));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname === "/api/admin/library" && req.method === "POST") {
      readJsonBody(req)
        .then((body) => {
          const prompt = (body.prompt || "").trim();
          const videoUrl = (body.videoUrl || "").trim();
          if (!prompt || !videoUrl) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "prompt and videoUrl required" }));
            return;
          }
          const clip = {
            id: `manual-${Date.now().toString(36)}${Math.random().toString(36).slice(2, 6)}`,
            source: "manual",
            edited: true,
            prompt,
            promptEn: (body.promptEn || "").trim(),
            fullPrompt: (body.fullPrompt || prompt).trim(),
            videoUrl,
            width: body.width || null,
            height: body.height || null,
            duration: body.duration || null,
            partition: "manual",
            likes: 0,
            createdAt: Date.now(),
            // channel: "dance" puts this clip in dance.html's pool
            // (pickNextClip filters on it, architecture.md 2.1); anything
            // else stays out of it and is live.html's/text-channel pool.
            channel: body.channel === "dance" ? "dance" : undefined,
          };
          const lib = getLibrary();
          lib.push(clip);
          saveLibrary(lib);
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(clip));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname.startsWith("/api/admin/library/") && req.method === "PATCH") {
      const id = pathname.slice("/api/admin/library/".length);
      readJsonBody(req)
        .then((body) => {
          const lib = getLibrary();
          const clip = lib.find((c) => c.id === id);
          if (!clip) {
            res.writeHead(404, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "not found" }));
            return;
          }
          for (const field of ["prompt", "promptEn", "fullPrompt", "videoUrl"]) {
            if (typeof body[field] === "string" && body[field].trim()) clip[field] = body[field].trim();
          }
          if (body.channel === "dance" || body.channel === "video") clip.channel = body.channel === "dance" ? "dance" : undefined;
          // Storing a videoUrl (whether this clip started as h3console or
          // manual) means /lib/video/:id should serve that directly instead
          // of proxying the H3 console — see the handler below.
          if (body.videoUrl) clip.source = "manual";
          // Marks this entry as admin-owned so the periodic H3 library sync
          // (ingest.js's syncLibrary) carries it forward as-is instead of
          // overwriting it with a freshly re-extracted prompt.
          clip.edited = true;
          saveLibrary(lib);
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify(clip));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname.startsWith("/api/admin/library/") && req.method === "DELETE") {
      const id = pathname.slice("/api/admin/library/".length);
      const lib = getLibrary();
      const clip = lib.find((c) => c.id === id);
      if (!clip) {
        res.writeHead(404, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "not found" }));
        return;
      }
      saveLibrary(lib.filter((c) => c.id !== id));
      // Without this, the next periodic syncLibrary() would just re-add it —
      // it's still a "done" job on the H3 console until explicitly deleted there too.
      const cleanup = clip.source === "h3console" ? h3ConsoleFetch(`/v1/videos/${id}`, { method: "DELETE" }).catch(() => {}) : Promise.resolve();
      cleanup.then(() => {
        res.writeHead(200, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ deleted: true }));
      });
      return;
    }

    if (pathname.startsWith("/api/queue/vote/") && req.method === "POST") {
      const id = pathname.slice("/api/queue/vote/".length);
      readJsonBody(req)
        .then((body) => {
          const uid = (body.uid || "").trim();
          if (!uid) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "uid required" }));
            return;
          }
          const entry = promptQueue.find((q) => q.id === id);
          if (!entry || !["matched", "generating", "ready"].includes(entry.status)) {
            res.writeHead(404, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "not found" }));
            return;
          }
          if (!Array.isArray(entry.votes)) entry.votes = [];
          const i = entry.votes.indexOf(uid);
          const voted = i === -1;
          if (voted) entry.votes.push(uid);
          else entry.votes.splice(i, 1);
          saveLiveState();
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ votes: entry.votes.length, voted }));
        })
        .catch(() => {
          res.writeHead(400, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ error: "invalid JSON body" }));
        });
      return;
    }

    if (pathname.startsWith("/api/like/") && req.method === "POST") {
      const id = pathname.slice("/api/like/".length);
      const lib = getLibrary();
      const clip = lib.find((c) => c.id === id);
      if (!clip) {
        res.writeHead(404, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "not found" }));
        return;
      }
      clip.likes = (clip.likes || 0) + 1;
      saveLibrary(lib);
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify({ likes: clip.likes }));
      return;
    }

    if (pathname === "/api/admin/upload" && req.method === "POST") {
      const boundary = boundaryFromContentType(req.headers["content-type"] || "");
      if (!boundary) {
        res.writeHead(400, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "expected multipart/form-data" }));
        return;
      }
      readRawBody(req)
        .then((body) => {
          const filePart = parseMultipart(body, boundary).find((p) => p.name === "file");
          if (!filePart) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "missing file field" }));
            return;
          }
          const sniffed = sniffImageType(filePart.data);
          if (!sniffed) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "unrecognized image type (expected jpeg/png/webp)" }));
            return;
          }
          try {
            const { relPath } = stripMetadataAndSave(filePart.data, sniffed);
            res.writeHead(200, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ url: relPath }));
          } catch {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "failed to process image" }));
          }
        })
        .catch((err) => {
          if (res.writableEnded) return;
          try {
            const status = err.code === "PAYLOAD_TOO_LARGE" ? 413 : 400;
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: err.message }));
          } catch {
            // socket already gone (e.g. destroyed for exceeding the size cap)
          }
        });
      return;
    }

    if (pathname === "/api/admin/upload-video" && req.method === "POST") {
      const boundary = boundaryFromContentType(req.headers["content-type"] || "");
      if (!boundary) {
        res.writeHead(400, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "expected multipart/form-data" }));
        return;
      }
      readRawBody(req, 50 * 1024 * 1024)
        .then((body) => {
          const filePart = parseMultipart(body, boundary).find((p) => p.name === "file");
          if (!filePart) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "missing file field" }));
            return;
          }
          const sniffed = sniffVideoType(filePart.data);
          if (!sniffed) {
            res.writeHead(400, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: "unrecognized video type (expected mp4)" }));
            return;
          }
          const { relPath } = saveVideoUpload(filePart.data, sniffed);
          res.writeHead(200, { "Content-Type": "application/json" });
          res.end(JSON.stringify({ url: relPath }));
        })
        .catch((err) => {
          if (res.writableEnded) return;
          try {
            const status = err.code === "PAYLOAD_TOO_LARGE" ? 413 : 400;
            res.writeHead(status, { "Content-Type": "application/json" });
            res.end(JSON.stringify({ error: err.message }));
          } catch {
            // socket already gone (e.g. destroyed for exceeding the size cap)
          }
        });
      return;
    }

    if (pathname.startsWith("/uploads/")) {
      const rel = pathname.slice("/uploads/".length);
      const abs = path.join(UPLOADS_DIR, rel);
      if (!abs.startsWith(UPLOADS_DIR + path.sep)) {
        res.writeHead(403);
        res.end("Forbidden");
        return;
      }
      fs.readFile(abs, (err, data) => {
        if (err) {
          res.writeHead(404);
          res.end("Not found");
          return;
        }
        res.writeHead(200, { "Content-Type": MIME[path.extname(abs)] || "application/octet-stream" });
        res.end(data);
      });
      return;
    }

    if (pathname.startsWith("/lib/video/")) {
      const id = pathname.slice("/lib/video/".length);
      const clip = getLibrary().find((c) => c.id === id);
      if (clip && clip.videoUrl) {
        res.writeHead(302, { Location: clip.videoUrl });
        res.end();
        return;
      }
      if (!H3_CONSOLE_URL) {
        res.writeHead(500, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: "H3_CONSOLE_BASE not configured" }));
        return;
      }
      const upstreamHeaders = { Authorization: `Bearer ${H3_CONSOLE_TOKEN}` };
      if (req.headers.range) upstreamHeaders.range = req.headers.range;
      const proxyReq = http.request(
        {
          hostname: H3_CONSOLE_URL.hostname,
          port: H3_CONSOLE_URL.port || 80,
          path: `${H3_CONSOLE_URL.pathname}/v1/videos/${id}/file`,
          method: "GET",
          headers: upstreamHeaders,
        },
        (proxyRes) => {
          res.writeHead(proxyRes.statusCode, proxyRes.headers);
          proxyRes.pipe(res);
        }
      );
      proxyReq.on("error", (err) => {
        res.writeHead(502, { "Content-Type": "application/json" });
        res.end(JSON.stringify({ error: { message: err.message } }));
      });
      proxyReq.end();
      return;
    }
    const filePath = path.join(__dirname, pathname === "/" ? "/index.html" : pathname);
    fs.readFile(filePath, (err, data) => {
      if (err) {
        res.writeHead(404);
        res.end("Not found");
        return;
      }
      res.writeHead(200, { "Content-Type": MIME[path.extname(filePath)] || "application/octet-stream" });
      res.end(data);
    });
  })
  .listen(PORT, () => console.log(`http://localhost:${PORT}`));

resumeGenerations();
resumeDressupGenerations();

// Auto-sync the library from the H3 Console so content added there directly
// (not through our own /api/prompt) shows up without a manual `node ingest.js`.
const LIBRARY_SYNC_INTERVAL_MS = 5 * 60 * 1000;
syncLibrary()
  .then((n) => console.log(`library synced — ${n} clips`))
  .catch((err) => console.error(`library sync failed: ${err.message}`));
setInterval(() => {
  syncLibrary().catch((err) => console.error(`library sync failed: ${err.message}`));
}, LIBRARY_SYNC_INTERVAL_MS);