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ai-tik / server.js
Update server.js
ee894ee verified 6 months ago
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"use strict";

// ============================================================
// TikTok Would-You-Rather Bot — Express + CommonJS
// ============================================================
require("dotenv").config();
const express = require("express");
const axios = require("axios");
const fs = require("fs");
const path = require("path");
const crypto = require("crypto");
const jwt = require("jsonwebtoken");
const cookieParser = require("cookie-parser");
const { createCanvas } = require("canvas");
const ffmpeg = require("fluent-ffmpeg");
const { createSlideshow } = require("slideshow-video");
const cors = require("cors");

const app = express();

// ── CORS — must come before all routes ──────────────────────────────────────
// Allows the browser to send cookies when frontend and API share the same
// origin (content.nett.to). If you ever serve the frontend from a different
// origin, add it to the `origin` array below.
app.use(cors({
  origin: function(origin, callback) {
    // Allow same-origin requests (origin is undefined) and any content.nett.to origin
    const allowed = [
      "https://content.nett.to",
      "http://localhost:3000",
      "http://localhost:5173",
    ];
    if (!origin || allowed.includes(origin)) return callback(null, true);
    return callback(null, true); // allow all for now — tighten after confirming it works
  },
  credentials: true, // REQUIRED for cookies to be sent cross-origin
}));

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, "public")));

// ── Cookie debug (remove after confirming auth works) ───────────────────────
app.use((req, _res, next) => {
  if (req.path === "/me" || req.path.startsWith("/auth")) {
    console.log(`[${req.method} ${req.path}] cookies:`, req.cookies);
  }
  next();
});

// ============================================================
// CONFIG — fill before running
// ============================================================
const CONFIG = {
  TIKTOK_CLIENT_KEY: process.env.TIKTOK_CLIENT_KEY || "hh",
  TIKTOK_CLIENT_SECRET: process.env.TIKTOK_CLIENT_SECRET || "hh",
  TIKTOK_REDIRECT_URI: process.env.TIKTOK_REDIRECT_URI || "https://content.nett.to/auth/tiktok/callback",

  JWT_SECRET: process.env.JWT_SECRET || "key",
  LONGCAT_API_KEY: process.env.LONGCAT_API_KEY || "akkey",

  PORT: process.env.PORT || 3000,
  CHUNK_SIZE: 10 * 1024 * 1024, // 10MB
  JOBS_DIR: path.join(__dirname, "jobs"),

  // Set to false only if running behind an HTTP reverse proxy during dev
  IS_PROD: process.env.NODE_ENV !== "development",
};

// Ensure base jobs directory exists
if (!fs.existsSync(CONFIG.JOBS_DIR)) fs.mkdirSync(CONFIG.JOBS_DIR, { recursive: true });

/** Create per-job isolated directories and return their paths. */
function makeJobDirs(jobId) {
  const jobDir   = path.join(CONFIG.JOBS_DIR, jobId);
  const audioDir = path.join(jobDir, "audio");
  const framesDir = path.join(jobDir, "frames");
  const videosDir = path.join(jobDir, "video");
  [audioDir, framesDir, videosDir].forEach((d) => fs.mkdirSync(d, { recursive: true }));
  return { jobDir, audioDir, framesDir, videosDir };
}

// ============================================================
// JWT MIDDLEWARE
// ============================================================
function requireAuth(req, res, next) {
  const token = req.cookies?.wyr_token;
  if (!token) {
    return res.status(401).json({ error: "Not authenticated" });
  }
  try {
    req.user = jwt.verify(token, CONFIG.JWT_SECRET);
    next();
  } catch (err) {
    return res.status(401).json({ error: "Invalid or expired session" });
  }
}

// ============================================================
// ROUTE: GET /auth/tiktok
// Redirects user to TikTok OAuth consent screen
// ============================================================
app.get("/auth/tiktok", (req, res) => {
  const state = crypto.randomBytes(16).toString("hex");
  // Build URL manually — URLSearchParams double-encodes the redirect_uri,
  // which causes TikTok's server-side URI comparison to fail.
  const url =
    "https://www.tiktok.com/v2/auth/authorize/" +
    "?client_key=" + CONFIG.TIKTOK_CLIENT_KEY +
    "&scope=video.publish,video.upload,user.info.basic,user.info.profile,user.info.stats" +
    "&response_type=code" +
    "&redirect_uri=" + encodeURIComponent(CONFIG.TIKTOK_REDIRECT_URI) +
    "&state=" + state;
  res.redirect(url);
});

// ============================================================
// ROUTE: GET /auth/tiktok/callback
// Exchanges code for access token, returns JWT
// ============================================================
app.get("/auth/tiktok/callback", async (req, res) => {
  const { code, error, error_description } = req.query;

  // Redirect errors back to the frontend instead of returning raw JSON
  if (error) {
    console.error("TikTok OAuth error:", error, error_description);
    return res.redirect(`/?auth=error&msg=${encodeURIComponent(error_description || error)}`);
  }
  if (!code) {
    return res.redirect(`/?auth=error&msg=${encodeURIComponent("Missing authorization code")}`);
  }

  try {
    // Exchange code for access token
    const tokenRes = await axios.post(
      "https://open.tiktokapis.com/v2/oauth/token/",
      new URLSearchParams({
        client_key: CONFIG.TIKTOK_CLIENT_KEY,
        client_secret: CONFIG.TIKTOK_CLIENT_SECRET,
        code,
        grant_type: "authorization_code",
        redirect_uri: CONFIG.TIKTOK_REDIRECT_URI,
      }).toString(),
      { headers: { "Content-Type": "application/x-www-form-urlencoded" } }
    );

    const tokenData = tokenRes.data;
    console.log("Token exchange response:", JSON.stringify(tokenData));

    if (!tokenData.access_token) {
      console.error("Token exchange failed:", tokenData);
      return res.redirect(`/?auth=error&msg=${encodeURIComponent("Token exchange failed: " + (tokenData.message || JSON.stringify(tokenData)))}`);
    }

    const { access_token, refresh_token, open_id, expires_in } = tokenData;

    // Fetch basic user info — store in JWT so /me has a fallback
    let displayName = "TikTok User";
    let username = null;
    let avatarUrl = null;

    try {
      const userRes = await axios.get(
        "https://open.tiktokapis.com/v2/user/info/?fields=display_name,avatar_url,username",
        { headers: { Authorization: `Bearer ${access_token}` } }
      );
      const userData = userRes.data;
      console.log("User info response:", JSON.stringify(userData));
      displayName = userData.data?.user?.display_name || displayName;
      username    = userData.data?.user?.username || null;
      avatarUrl   = userData.data?.user?.avatar_url || null;
    } catch (userErr) {
      // Non-fatal — we still have the token, dashboard will load with partial info
      console.warn("Could not fetch user info during OAuth:", userErr.message);
    }

    // Issue our own JWT — store enough user info so /me can fallback to this
    const jwtPayload = {
      tiktok_access_token:  access_token,
      tiktok_refresh_token: refresh_token || null,
      tiktok_open_id:       open_id,
      display_name:         displayName,
      username,
      avatar_url:           avatarUrl,
    };

    const jwtToken = jwt.sign(jwtPayload, CONFIG.JWT_SECRET, {
      expiresIn: expires_in || 86400,
    });

    console.log(`✅ Auth success for ${displayName} (@${username}), setting cookie`);

    res.cookie("wyr_token", jwtToken, {
      httpOnly: true,
      sameSite: "lax",
      secure: CONFIG.IS_PROD, // false in dev (HTTP), true in prod (HTTPS)
      maxAge: (expires_in || 86400) * 1000,
      path: "/",
    });

    res.redirect("/"); // back to index.html
  } catch (err) {
    console.error("Auth error:", err.message, err.response?.data);
    res.redirect(`/?auth=error&msg=${encodeURIComponent(err.message)}`);
  }
});

// ============================================================
// ROUTE: GET /me   (protected)
// Returns TikTok user info for authenticated user
// ============================================================
app.get("/me", requireAuth, async (req, res) => {
  try {
    const userRes = await axios.get(
      "https://open.tiktokapis.com/v2/user/info/?fields=display_name,avatar_url,follower_count,following_count,likes_count,video_count,username",
      { headers: { Authorization: `Bearer ${req.user.tiktok_access_token}` } }
    );
    const data = userRes.data;

    if (data.error?.code !== "ok") {
      console.warn("/me TikTok API returned non-ok:", data.error);
      // Fall back to what we stored in the JWT during OAuth
      return res.json({
        user: {
          display_name:   req.user.display_name  || "TikTok User",
          username:       req.user.username       || null,
          avatar_url:     req.user.avatar_url     || null,
          follower_count: 0,
          video_count:    0,
          likes_count:    0,
        },
        _fallback: true, // tells the frontend this came from JWT cache
      });
    }

    res.json({ user: data.data.user });
  } catch (err) {
    console.warn("/me TikTok API error, falling back to JWT data:", err.message);
    // Still return something useful so the dashboard loads
    res.json({
      user: {
        display_name:   req.user.display_name  || "TikTok User",
        username:       req.user.username       || null,
        avatar_url:     req.user.avatar_url     || null,
        follower_count: 0,
        video_count:    0,
        likes_count:    0,
      },
      _fallback: true,
    });
  }
});

// ============================================================
// ROUTE: GET /auth/check  — debug: shows whether cookie arrived
// ============================================================
app.get("/auth/check", (req, res) => {
  const token = req.cookies?.wyr_token;
  if (!token) return res.json({ authenticated: false, reason: "no cookie" });
  try {
    const payload = jwt.verify(token, CONFIG.JWT_SECRET);
    res.json({ authenticated: true, user: payload.display_name, username: payload.username });
  } catch (e) {
    res.json({ authenticated: false, reason: e.message });
  }
});

// ============================================================
// ROUTE: POST /auth/logout  — clears the session cookie
// ============================================================
app.post("/auth/logout", (req, res) => {
  res.clearCookie("wyr_token", { path: "/" });
  res.json({ ok: true });
});


// Each job has: id, status, step, stepDetail, result, error, createdAt
//
// Possible statuses:  queued | running | done | failed
// Steps (in order):
//   1  generating_questions
//   2  generating_percentages
//   3  generating_tts          (stepDetail: "question X / Y")
//   4  building_video          (stepDetail: "rendering frames" | "encoding video")
//   5  uploading_to_tiktok     (stepDetail: "chunk X / Y" | "processing")
//   done
// ============================================================
const jobs = new Map();

function createJob() {
  const id = crypto.randomBytes(8).toString("hex");
  jobs.set(id, {
    id,
    status: "queued",
    step: null,
    stepDetail: null,
    progress: null,   // 0-100 where meaningful
    result: null,
    error: null,
    createdAt: new Date().toISOString(),
    updatedAt: new Date().toISOString(),
  });
  return id;
}

function updateJob(id, patch) {
  const job = jobs.get(id);
  if (!job) return;
  Object.assign(job, patch, { updatedAt: new Date().toISOString() });
}

// ============================================================
// ROUTE: POST /post   (protected)
// Body: { theme: "superpowers" }
// Returns immediately with job_id — poll GET /jobs/:id for progress
// ============================================================
app.post("/post", requireAuth, (req, res) => {
  const { theme } = req.body;
  if (!theme) return res.status(400).json({ error: "Missing theme in body" });

  const jobId = createJob();
  const jobDirs = makeJobDirs(jobId);

  // Fire and forget — pipeline runs in the background
  runPipeline(jobId, theme, req.user, jobDirs).catch(() => {}); // errors are stored on the job

  res.status(202).json({
    job_id: jobId,
    message: "Job queued. Poll GET /jobs/:id for live progress.",
    poll_url: `/jobs/${jobId}`,
  });
});

// ============================================================
// ROUTE: GET /jobs/:id   (protected)
// Returns current job state — designed to be polled every 2-3 s
// ============================================================
app.get("/jobs/:id", requireAuth, (req, res) => {
  const job = jobs.get(req.params.id);
  if (!job) return res.status(404).json({ error: "Job not found" });
  res.json(job);
});

// ============================================================
// ROUTE: GET /jobs   (protected)
// Returns all jobs for this server (newest first), capped at 50
// ============================================================
app.get("/jobs", requireAuth, (req, res) => {
  const all = [...jobs.values()]
    .sort((a, b) => new Date(b.createdAt) - new Date(a.createdAt))
    .slice(0, 50);
  res.json({ jobs: all });
});

// ============================================================
// PIPELINE — runs asynchronously, writes progress to job store
// ============================================================
async function runPipeline(jobId, theme, user, jobDirs) {
  const { jobDir, audioDir, framesDir, videosDir } = jobDirs;
  try {
    updateJob(jobId, { status: "running" });
    console.log(`\n🎬 [${jobId}] Starting pipeline for theme: "${theme}"`);

    // --- Step 1: Generate questions ---
    updateJob(jobId, { step: "generating_questions", stepDetail: "Asking AI for 15 questions…" });
    const questions = await generateQuestions(theme);
    updateJob(jobId, { stepDetail: `Got ${questions.length} questions` });
    console.log(`✅ [${jobId}] Got ${questions.length} questions`);

    // --- Step 2: Get percentages ---
    updateJob(jobId, { step: "generating_percentages", stepDetail: "Estimating vote splits…" });
    const questionsWithPercentages = await getPercentages(questions, theme);
    console.log(`✅ [${jobId}] Percentages added`);

    // --- Step 3: TTS audio ---
    updateJob(jobId, { step: "generating_tts", stepDetail: `0 / ${questionsWithPercentages.length} clips` });
    const audioFiles = await generateAllTTS(questionsWithPercentages, audioDir, (done, total) => {
      updateJob(jobId, {
        stepDetail: `${done} / ${total} audio clips`,
        progress: Math.round((done / total) * 100),
      });
    });
    console.log(`✅ [${jobId}] TTS done`);

    // --- Step 4: Build video ---
    updateJob(jobId, { step: "building_video", stepDetail: "Rendering frames…", progress: 0 });
    const { videoPath, questionsUsed, totalDuration } = await buildVideo(
      questionsWithPercentages,
      audioFiles,
      framesDir,
      videosDir,
      (framesDone, framesTotal) => {
        updateJob(jobId, {
          stepDetail: `Rendered ${framesDone} / ${framesTotal} frames`,
          progress: Math.round((framesDone / framesTotal) * 100),
        });
      }
    );
    updateJob(jobId, { stepDetail: `Encoding video (${questionsUsed} questions, ${totalDuration.toFixed(1)}s)`, progress: 100 });
    console.log(`✅ [${jobId}] Video ready: ${videoPath}`);

    // --- Step 5: Upload to TikTok ---
    const caption = `Would You Rather: ${theme.charAt(0).toUpperCase() + theme.slice(1)} Edition 🤔 #wouldyourather #${theme.replace(/\s+/g, "")} #fyp`;
    updateJob(jobId, { step: "uploading_to_tiktok", stepDetail: "Initialising upload…", progress: 0 });

    const tiktokResult = await postToTikTok(
      user.tiktok_access_token,
      videoPath,
      caption,
      (chunkDone, chunkTotal) => {
        updateJob(jobId, {
          stepDetail: `Uploading chunk ${chunkDone} / ${chunkTotal}`,
          progress: Math.round((chunkDone / chunkTotal) * 100),
        });
      },
      (pollStatus, uploadedBytes) => {
        updateJob(jobId, {
          stepDetail: `TikTok processing: ${pollStatus}`,
          progress: null,
          tiktok_upload_status: pollStatus,
          tiktok_uploaded_bytes: uploadedBytes ?? null,
        });
      }
    );

    // publicaly_available_post_id is TikTok's documented field name (typo is in their API spec)
    const videoId = tiktokResult.publicaly_available_post_id?.[0] ?? null;

    // Build video URL using username (URL-safe handle), NOT display_name (may contain spaces/emoji)
    const urlHandle = user.username || null;

    updateJob(jobId, {
      status: "done",
      step: "done",
      stepDetail: "Published ✓",
      progress: 100,
      result: {
        theme,
        questions_generated: questions.length,
        questions_used: questionsUsed,
        estimated_duration_seconds: +totalDuration.toFixed(1),
        caption,
        // TikTok fields
        publish_id: tiktokResult.publish_id ?? null,
        tiktok_status: tiktokResult.status ?? "PUBLISH_COMPLETE",
        tiktok_video_id: videoId,
        tiktok_video_url: videoId && urlHandle
          ? `https://www.tiktok.com/@${urlHandle}/video/${videoId}`
          : null,
        tiktok_uploaded_bytes: tiktokResult.uploaded_bytes ?? null,
        tiktok_fail_reason: tiktokResult.fail_reason ?? null,
      },
    });

    console.log(`🎉 [${jobId}] Done! TikTok video id: ${videoId}`);

    // Clean up per-job temp files after a successful publish
    try {
      fs.rmSync(jobDir, { recursive: true, force: true });
    } catch (cleanErr) {
      console.warn(`[${jobId}] Cleanup warning:`, cleanErr.message);
    }
  } catch (err) {
    console.error(`❌ [${jobId}] Pipeline error:`, err.message);
    updateJob(jobId, {
      status: "failed",
      error: err.message,
    });
  }
}

// ============================================================
// ROUTE: POST /tiktok/webhook
// Handles TikTok webhook events
// ============================================================
app.post("/tiktok/webhook", (req, res) => {
  const challenge = req.body?.challenge;
  // TikTok sends a challenge on first verification
  if (challenge) return res.json({ challenge });

  const event = req.body;
  console.log("📬 Webhook event received:", JSON.stringify(event, null, 2));

  // Handle specific event types
  switch (event?.event) {
    case "video.publish":
      console.log("🎉 Video published:", event.data);
      break;
    case "new_follower":
      console.log("👤 New follower:", event.data);
      break;
    case "comment":
      console.log("💬 New comment:", event.data);
      break;
    default:
      console.log("📌 Unhandled event type:", event?.event);
  }

  res.json({ received: true });
});

// ============================================================
// AI: Generate Would-You-Rather questions via LongCat
// ============================================================
async function generateQuestions(theme) {
  const prompt = `You are generating content for a TikTok "Would You Rather" video about the theme: "${theme}".
Generate a pool of 15 questions. We will select as many as needed to fill at least 60 seconds based on actual audio length — so generate more than enough.
Respond ONLY in this exact XML format, no preamble, no explanation:
<questions>
  <question id="1">
    <text>Would you rather...</text>
    <option1>Option A</option1>
    <option2>Option B</option2>
    <tts>Would you rather have option A or option B?</tts>
  </question>
  <question id="2">
    ...
  </question>
</questions>
Rules:
- Keep option text SHORT (max 6 words each) so it fits on screen
- The tts field should be a natural spoken sentence for text-to-speech
- Make questions fun, engaging, and relevant to "${theme}"
- Options should be genuinely hard to choose between`;

  const response = await axios.post(
    "https://api.longcat.chat/anthropic/v1/messages",
    {
      model: "LongCat-Flash-Chat",
      max_tokens: 2000,
      messages: [{ role: "user", content: prompt }],
    },
    {
      headers: {
        "Content-Type": "application/json",
        "Authorization": `Bearer ${CONFIG.LONGCAT_API_KEY}`,
        "anthropic-version": "2023-06-01",
      },
    }
  );

  const data = response.data;
  const text = data.content?.[0]?.text || "";
  return parseQuestionsXML(text);
}

// ============================================================
// AI: Get percentage estimates for each question
// ============================================================
async function getPercentages(questions, theme) {
  const questionsText = questions
    .map((q, i) => `Q${i + 1}: "${q.option1}" vs "${q.option2}"`)
    .join("\n");

  const prompt = `For a TikTok "Would You Rather" video about "${theme}", estimate what percentage of people would choose each option based on general public preference patterns.
Questions:
${questionsText}
Respond ONLY in this exact XML format:
<percentages>
  <question id="1">
    <pct1>65</pct1>
    <pct2>35</pct2>
  </question>
  <question id="2">
    <pct1>40</pct1>
    <pct2>60</pct2>
  </question>
</percentages>
Rules:
- pct1 + pct2 must always equal 100
- Be realistic, vary the splits (not always 50/50)
- Only output the XML, nothing else`;

  const response = await axios.post(
    "https://api.longcat.chat/anthropic/v1/messages",
    {
      model: "LongCat-Flash-Chat",
      max_tokens: 800,
      messages: [{ role: "user", content: prompt }],
    },
    {
      headers: {
        "Content-Type": "application/json",
        "Authorization": `Bearer ${CONFIG.LONGCAT_API_KEY}`,
        "anthropic-version": "2023-06-01",
      },
    }
  );

  const data = response.data;
  const text = data.content?.[0]?.text || "";
  const percentages = parsePercentagesXML(text);

  return questions.map((q, i) => {
    const p = percentages[i];
    const pct1 = p?.pct1 ?? 50;
    const pct2 = p?.pct2 ?? (100 - pct1); // guarantee sum = 100
    return { ...q, pct1, pct2 };
  });
}

// ============================================================
// TTS: Download audio for each question
// ============================================================
async function generateAllTTS(questions, audioDir, onProgress) {
  const audioFiles = [];
  for (let i = 0; i < questions.length; i++) {
    const q = questions[i];
    const ttsText = encodeURIComponent(q.tts);
    const url = `https://api.bk9.dev/tools/tts?q=${ttsText}&lang=en`;
    const audioPath = path.join(audioDir, `q${i + 1}.mp3`);

    const res = await axios.get(url, { responseType: "arraybuffer" });

    // Guard: TTS API sometimes returns a JSON error body with HTTP 200.
    // Writing that to disk produces a corrupt "mp3" that ffprobe can't read.
    const firstBytes = Buffer.from(res.data).slice(0, 3).toString("hex");
    const isMp3 = firstBytes.startsWith("494433") || firstBytes.startsWith("fffb") || firstBytes.startsWith("fff3") || firstBytes.startsWith("fff2");
    if (!isMp3) {
      const preview = Buffer.from(res.data).slice(0, 200).toString("utf8");
      throw new Error(`TTS API returned non-MP3 data for question ${i + 1}. Preview: ${preview}`);
    }

    fs.writeFileSync(audioPath, res.data);
    audioFiles.push(audioPath);

    if (onProgress) onProgress(i + 1, questions.length);
  }
  return audioFiles;
}

// ============================================================
// VIDEO: Render a single frame as PNG using canvas
// ============================================================
async function renderFrame(question, phase, outputPath) {
  // 1080x1920 (TikTok portrait)
  const W = 1080, H = 1920;
  const canvas = createCanvas(W, H);
  const ctx = canvas.getContext("2d");

  // Background
  ctx.fillStyle = "#111111";
  ctx.fillRect(0, 0, W, H);

  if (phase === "question") {
    // ---- QUESTION PHASE ----
    // Question text at top
    ctx.fillStyle = "#FFFFFF";
    ctx.font = "bold 58px sans-serif";
    ctx.textAlign = "center";
    wrapText(ctx, "Would You Rather...", W / 2, 200, W - 80, 70);

    // Divider line
    ctx.strokeStyle = "#444444";
    ctx.lineWidth = 4;
    ctx.beginPath();
    ctx.moveTo(0, H / 2);
    ctx.lineTo(W, H / 2);
    ctx.stroke();

    // Option 1 — RED (top half)
    ctx.fillStyle = "#CC0000";
    ctx.fillRect(0, 320, W, H / 2 - 320);
    ctx.fillStyle = "#FFFFFF";
    ctx.font = "bold 72px sans-serif";
    ctx.textAlign = "center";
    wrapText(ctx, question.option1, W / 2, 520, W - 100, 85);

    // Option 2 — BLUE (bottom half)
    ctx.fillStyle = "#0055CC";
    ctx.fillRect(0, H / 2, W, H / 2 - 100);
    ctx.fillStyle = "#FFFFFF";
    ctx.font = "bold 72px sans-serif";
    ctx.textAlign = "center";
    wrapText(ctx, question.option2, W / 2, H / 2 + 200, W - 100, 85);

    // OR badge in center
    ctx.fillStyle = "#FFFFFF";
    ctx.beginPath();
    ctx.arc(W / 2, H / 2, 70, 0, Math.PI * 2);
    ctx.fill();
    ctx.fillStyle = "#111111";
    ctx.font = "bold 52px sans-serif";
    ctx.textAlign = "center";
    ctx.fillText("OR", W / 2, H / 2 + 18);

  } else {
    // ---- RESULT PHASE ----
    const winner1 = question.pct1 >= question.pct2;

    // Option 1 block
    ctx.fillStyle = "#CC0000";
    ctx.fillRect(0, 0, W, H / 2 - 10);
    ctx.fillStyle = "#FFFFFF";
    ctx.font = "bold 64px sans-serif";
    ctx.textAlign = "center";
    wrapText(ctx, question.option1, W / 2, 280, W - 80, 76);

    // Option 1 percentage
    ctx.font = `bold 150px sans-serif`;
    ctx.fillStyle = winner1 ? "#00FF88" : "#FF4444";
    ctx.fillText(`${question.pct1}%`, W / 2, 680);

    // Divider
    ctx.fillStyle = "#111111";
    ctx.fillRect(0, H / 2 - 10, W, 20);

    // Option 2 block
    ctx.fillStyle = "#0055CC";
    ctx.fillRect(0, H / 2 + 10, W, H / 2 - 10);
    ctx.fillStyle = "#FFFFFF";
    ctx.font = "bold 64px sans-serif";
    ctx.textAlign = "center";
    wrapText(ctx, question.option2, W / 2, H / 2 + 230, W - 80, 76);

    // Option 2 percentage
    ctx.font = `bold 150px sans-serif`;
    ctx.fillStyle = !winner1 ? "#00FF88" : "#FF4444";
    ctx.fillText(`${question.pct2}%`, W / 2, H / 2 + 600);
  }

  const buffer = canvas.toBuffer("image/png");
  fs.writeFileSync(outputPath, buffer);
}

// ============================================================
// VIDEO: Build full video from frames + audio
// ============================================================

/** Return the duration (seconds) of an audio file via ffprobe. */
function probeAudioDuration(filePath) {
  return new Promise((resolve, reject) => {
    ffmpeg.ffprobe(filePath, (err, metadata) => {
      if (err) return reject(err);
      const dur = metadata?.format?.duration;
      if (!dur) return reject(new Error(`Could not read duration of ${filePath}`));
      resolve(parseFloat(dur));
    });
  });
}

/**
 * Per-question timing:
 *   question frame = actual TTS duration + 0.5s buffer
 *   result frame   = max(2.5s, audioDuration * 0.6)
 *
 * The result duration scales slightly with TTS length so longer questions
 * get a bit more reveal time, but the minimum is always 2.5s — long enough
 * to read two percentages comfortably.
 */
function calcDurations(audioDuration) {
  const questionDuration = +(audioDuration + 0.5).toFixed(3);
  const resultDuration   = +Math.max(2.5, audioDuration * 0.6).toFixed(3);
  return { questionDuration, resultDuration };
}

async function buildVideo(questions, audioFiles, framesDir, videosDir, onProgress) {
  // ------------------------------------------------------------------
  // 1. Probe every TTS file up-front so we know real durations.
  // ------------------------------------------------------------------
  const audioDurations = await Promise.all(audioFiles.map(probeAudioDuration));

  // ------------------------------------------------------------------
  // 2. Figure out how many questions to include.
  //    Rule: keep adding questions until total >= 60 s, then always
  //    finish that question (never cut mid-question). If we somehow
  //    exhaust all 15 before reaching 60 s, just use all of them.
  // ------------------------------------------------------------------
  const TARGET = 60; // seconds
  let runningTotal = 0;
  let useCount = 0;

  for (let i = 0; i < questions.length; i++) {
    const { questionDuration, resultDuration } = calcDurations(audioDurations[i]);
    runningTotal += questionDuration + resultDuration;
    useCount = i + 1;
    if (runningTotal >= TARGET) break; // crossed 60 s — finish this question and stop
  }

  const usedQuestions  = questions.slice(0, useCount);
  const usedAudio      = audioFiles.slice(0, useCount);
  const usedDurations  = audioDurations.slice(0, useCount);

  console.log(
    `⏱  Selected ${useCount} questions — estimated total ${runningTotal.toFixed(1)}s`
  );

  // ------------------------------------------------------------------
  // 3. Render frames and build image list with per-image durations.
  //    slideshow-video handles all the ffmpeg complexity internally.
  // ------------------------------------------------------------------
  const slideImages = [];

  for (let i = 0; i < usedQuestions.length; i++) {
    const q = usedQuestions[i];
    const { questionDuration, resultDuration } = calcDurations(usedDurations[i]);

    const qFrame = path.join(framesDir, `q${i + 1}_question.png`);
    await renderFrame(q, "question", qFrame);
    slideImages.push({ filePath: qFrame, duration: Math.round(questionDuration * 1000) }); // ms

    const rFrame = path.join(framesDir, `q${i + 1}_result.png`);
    await renderFrame(q, "result", rFrame);
    slideImages.push({ filePath: rFrame, duration: Math.round(resultDuration * 1000) }); // ms

    if (onProgress) onProgress(i + 1, usedQuestions.length);
  }

  // ------------------------------------------------------------------
  // 4. Concatenate audio files.
  // ------------------------------------------------------------------
  const audioDir = path.dirname(usedAudio[0]);
  const combinedAudio = path.join(audioDir, "combined.mp3");
  await concatAudio(usedAudio, combinedAudio, audioDir);

  console.log(`🎬 Building video with slideshow-video: ${slideImages.length} slides`);

  const response = await createSlideshow(slideImages, combinedAudio, {
    // No transitionOptions — omitting it entirely gives true instant cuts.
    // transitionDuration: 0 does NOT disable transitions; it still runs the
    // filter graph and causes frame-timing issues. Omit the block instead.
    ffmpegOptions: {
      showFfmpegOutput: true,
      showFfmpegCommand: true,
      fps: 30,
      videoCodec: "libx264",
      x264Preset: "fast",
      pixelFormat: "yuv420p",   // explicit — TikTok requires this; library default but be safe
      streamCopyAudio: true,    // combinedAudio is already a clean 44100Hz stereo MP3 — no need to re-encode
    },
    outputOptions: {
      outputBuffer: false,
      outputDir: videosDir,
    },
  });

  // response.filePath is the actual output file written by slideshow-video
  const videoPath = response.filePath;
  if (!videoPath || !fs.existsSync(videoPath)) {
    throw new Error(`slideshow-video did not produce an output file. Response: ${JSON.stringify(response)}`);
  }

  const fileSize = fs.statSync(videoPath).size;
  if (fileSize < 50 * 1024) {
    throw new Error(`Video output is only ${(fileSize / 1024).toFixed(1)} KB — encoding likely failed.`);
  }
  console.log(`✅ Video encoded: ${(fileSize / 1024 / 1024).toFixed(2)} MB → ${videoPath}`);

  return { videoPath, questionsUsed: useCount, totalDuration: runningTotal };
}

// ============================================================
// AUDIO: Concatenate mp3 files using ffmpeg
// ============================================================
function concatAudio(files, output, audioDir) {
  const listPath = path.join(audioDir, "audio_list.txt");
  const content = files.map((f) => `file '${f}'`).join("\n");
  fs.writeFileSync(listPath, content);

  return new Promise((resolve, reject) => {
    ffmpeg()
      .input(listPath)
      .inputOptions(["-f concat", "-safe 0"])
      .outputOptions([
        "-acodec libmp3lame", // re-encode so mismatched bitrates/sample-rates never cause failures
        "-ar 44100",
        "-ac 2",
        "-q:a 2",           // VBR ~190kbps — good quality, small file
      ])
      .output(output)
      .on("end", resolve)
      .on("error", reject)
      .run();
  });
}

// ============================================================
// TIKTOK: Post video via Content Posting API
// ============================================================
async function postToTikTok(accessToken, videoPath, caption, onChunkProgress, onPollProgress) {
  // ── Step 1: Query creator info (REQUIRED before init per TikTok docs) ──────
  // TikTok will reject the init call if you skip this. It also tells us which
  // privacy_level values are valid for this account — hardcoding one that isn't
  // in the list causes a 400.
  const creatorRes = await axios.post(
    "https://open.tiktokapis.com/v2/post/publish/creator_info/query/",
    {},
    { headers: { Authorization: `Bearer ${accessToken}`, "Content-Type": "application/json; charset=UTF-8" } }
  );
  const creatorData = creatorRes.data;
  if (creatorData.error?.code !== "ok") {
    throw new Error(`creator_info/query failed: ${JSON.stringify(creatorData.error)}`);
  }
  const {
    privacy_level_options = ["SELF_ONLY"],
    duet_disabled  = false,
    stitch_disabled = false,
    comment_disabled = false,
  } = creatorData.data;

  // Always use SELF_ONLY — unaudited API clients are restricted to private
  // viewership by TikTok. Sending any other value (even one in privacy_level_options)
  // causes a 403 on the upload PUT. The account must also be set to private.
  // After passing TikTok's audit, change this to pick the most permissive option.
  const privacy_level = "SELF_ONLY";
  console.log(`🔒 Creator privacy options: ${privacy_level_options.join(", ")} → using: ${privacy_level} (unaudited app restriction)`);

  // ── Step 2: Compute chunk layout ────────────────────────────────────────────
  const videoSizeBytes = fs.statSync(videoPath).size;
  // TikTok rules: each chunk must be 5 MB–64 MB (last chunk can be smaller).
  // For files ≤ 64 MB: upload as one chunk = entire file (no minimum issue).
  // For files > 64 MB: split into 10 MB chunks.
  const MAX_SINGLE = 64 * 1024 * 1024;
  const chunkSize  = videoSizeBytes <= MAX_SINGLE ? videoSizeBytes : CONFIG.CHUNK_SIZE;
  const totalChunks = Math.ceil(videoSizeBytes / chunkSize);
  console.log(`📤 Upload: ${(videoSizeBytes / 1024 / 1024).toFixed(2)} MB, ${totalChunks} chunk(s) of ${(chunkSize / 1024 / 1024).toFixed(1)} MB`);

  // ── Step 3: Init upload ──────────────────────────────────────────────────────
  const initRes = await axios.post(
    "https://open.tiktokapis.com/v2/post/publish/video/init/",
    {
      post_info: {
        title: caption,
        privacy_level,
        disable_duet:    duet_disabled,
        disable_comment: comment_disabled,
        disable_stitch:  stitch_disabled,
        video_cover_timestamp_ms: 1000,
      },
      source_info: {
        source: "FILE_UPLOAD",
        video_size:        videoSizeBytes,
        chunk_size:        chunkSize,
        total_chunk_count: totalChunks,
      },
    },
    { headers: { Authorization: `Bearer ${accessToken}`, "Content-Type": "application/json; charset=UTF-8" } }
  );

  const initData = initRes.data;
  if (initData.error?.code !== "ok") {
    throw new Error(`Init upload failed (HTTP 200 but error in body): ${JSON.stringify(initData.error)}`);
  }

  const { publish_id, upload_url } = initData.data;

  // ── Step 4: Upload chunks ────────────────────────────────────────────────────
  const fd = fs.openSync(videoPath, "r");
  try {
    for (let i = 0; i < totalChunks; i++) {
      const start    = i * chunkSize;
      const end      = Math.min(start + chunkSize, videoSizeBytes) - 1;
      const chunkLen = end - start + 1;
      const chunk    = Buffer.allocUnsafe(chunkLen);
      fs.readSync(fd, chunk, 0, chunkLen, start);

      const uploadRes = await axios.put(upload_url, chunk, {
        headers: {
          "Content-Range": `bytes ${start}-${end}/${videoSizeBytes}`,
          "Content-Type":  "video/mp4",
          "Content-Length": chunkLen,
        },
        maxBodyLength: Infinity,
        maxContentLength: Infinity,
      });
      console.log(`   Chunk ${i + 1}/${totalChunks} uploaded — status ${uploadRes.status}`);
      if (onChunkProgress) onChunkProgress(i + 1, totalChunks);
    }
  } finally {
    fs.closeSync(fd);
  }

  // Poll status
  for (let attempt = 1; attempt <= 15; attempt++) {
    await new Promise((r) => setTimeout(r, 5000));
    const statusRes = await axios.post(
      "https://open.tiktokapis.com/v2/post/publish/status/fetch/",
      { publish_id },
      {
        headers: {
          Authorization: `Bearer ${accessToken}`,
          "Content-Type": "application/json; charset=UTF-8",
        },
      }
    );
    const statusData = statusRes.data;
    const status = statusData.data?.status;
    console.log(`   Poll ${attempt}: ${status}`);
    if (onPollProgress) onPollProgress(status, statusData.data?.uploaded_bytes);
    if (status === "PUBLISH_COMPLETE") return statusData.data;
    if (status === "FAILED") throw new Error(`Post failed: ${JSON.stringify(statusData.data)}`);
  }
  throw new Error("Timed out waiting for post");
}

// ============================================================
// HELPERS: XML parsers
// ============================================================
function parseQuestionsXML(xml) {
  const questions = [];
  const qRegex = /<question[^>]*>([\s\S]*?)<\/question>/g;
  let match;
  while ((match = qRegex.exec(xml)) !== null) {
    const block = match[1];
    questions.push({
      text: extractTag(block, "text"),
      option1: extractTag(block, "option1"),
      option2: extractTag(block, "option2"),
      tts: extractTag(block, "tts"),
    });
  }
  if (questions.length === 0) throw new Error("No questions parsed from AI response:\n" + xml);
  return questions;
}

function parsePercentagesXML(xml) {
  const results = [];
  const qRegex = /<question[^>]*>([\s\S]*?)<\/question>/g;
  let match;
  while ((match = qRegex.exec(xml)) !== null) {
    const block = match[1];
    const pct1 = parseInt(extractTag(block, "pct1"), 10) || 50;
    const pct2 = parseInt(extractTag(block, "pct2"), 10) || 50;
    results.push({ pct1, pct2 });
  }
  return results;
}

function extractTag(xml, tag) {
  const match = xml.match(new RegExp(`<${tag}>([\\s\\S]*?)<\\/${tag}>`));
  return match ? match[1].trim() : "";
}

// ============================================================
// HELPERS: Canvas text wrapping
// ============================================================
function wrapText(ctx, text, x, y, maxWidth, lineHeight) {
  const words = text.split(" ");
  let line = "";
  let currentY = y;
  for (let n = 0; n < words.length; n++) {
    const testLine = line + words[n] + " ";
    const metrics = ctx.measureText(testLine);
    if (metrics.width > maxWidth && n > 0) {
      ctx.fillText(line.trim(), x, currentY);
      line = words[n] + " ";
      currentY += lineHeight;
    } else {
      line = testLine;
    }
  }
  ctx.fillText(line.trim(), x, currentY);
}

// ============================================================
// START
// ============================================================
app.listen(7860, () => {
  console.log(`\n🚀 TikTok Would-You-Rather Bot running on port ${CONFIG.PORT}`);
  console.log(`\nEndpoints:`);
  console.log(`  GET  /auth/tiktok             → Start TikTok OAuth`);
  console.log(`  GET  /auth/tiktok/callback    → OAuth callback (set as redirect URI in TikTok app)`);
  console.log(`  GET  /me                      → Your TikTok info (requires JWT)`);
  console.log(`  POST /post                    → Generate & post a WYR video (requires JWT)`);
  console.log(`  POST /tiktok/webhook          → TikTok webhook receiver\n`);
});