9router/open-sse/handlers/ttsCore.js

import { createErrorResult } from "../utils/error.js";
import { HTTP_STATUS } from "../config/runtimeConfig.js";
import { execFile } from "child_process";
import { promisify } from "util";
import { mkdtemp, readFile, rm } from "fs/promises";
import { tmpdir } from "os";
import { join } from "path";

const execFileAsync = promisify(execFile);

// ── Response Formatter (DRY) ───────────────────────────────────
function createTtsResponse(base64Audio, format, responseFormat) {
  const audioBuffer = Buffer.from(base64Audio, "base64");

  // JSON format: return base64 encoded audio
  if (responseFormat === "json") {
    return {
      success: true,
      response: new Response(JSON.stringify({ audio: base64Audio, format }), {
        headers: {
          "Content-Type": "application/json",
          "Access-Control-Allow-Origin": "*",
        },
      }),
    };
  }

  // Binary format (default): return raw MP3
  return {
    success: true,
    response: new Response(audioBuffer, {
      headers: {
        "Content-Type": `audio/${format}`,
        "Content-Length": String(audioBuffer.length),
        "Access-Control-Allow-Origin": "*",
      },
    }),
  };
}

// ── Token cache per engine ─────────────────────────────────────
const cache = {
  google: { token: null, tokenTime: 0 },
  bing:   { token: null, tokenTime: 0 },
};

const GOOGLE_REFRESH = 11 * 60 * 1000;
const BING_REFRESH   = 5 * 60 * 1000; // conservative: token TTL is 1h but refresh early

const UA = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36";
const SEC_CH_HEADERS = {
  "sec-ch-ua": '"Chromium";v="146", "Not-A.Brand";v="24", "Google Chrome";v="146"',
  "sec-ch-ua-arch": '"arm"',
  "sec-ch-ua-bitness": '"64"',
  "sec-ch-ua-full-version": '"146.0.7680.178"',
  "sec-ch-ua-full-version-list": '"Chromium";v="146.0.7680.178", "Not-A.Brand";v="24.0.0.0", "Google Chrome";v="146.0.7680.178"',
  "sec-ch-ua-mobile": "?0",
  "sec-ch-ua-model": '""',
  "sec-ch-ua-platform": '"macOS"',
  "sec-ch-ua-platform-version": '"15.1.0"',
};

// ── Google TTS ─────────────────────────────────────────────────
async function getGoogleToken() {
  const now = Date.now();
  if (cache.google.token && now - cache.google.tokenTime < GOOGLE_REFRESH) {
    return cache.google.token;
  }
  const res = await fetch("https://translate.google.com/", {
    headers: { "User-Agent": UA },
  });
  if (!res.ok) throw new Error(`Google translate fetch failed: ${res.status}`);
  const html = await res.text();
  const fSid = html.match(/"FdrFJe":"(.*?)"/)?.[ 1];
  const bl   = html.match(/"cfb2h":"(.*?)"/)?.[ 1];
  if (!fSid || !bl) throw new Error("Failed to parse Google token");
  cache.google.token = { "f.sid": fSid, bl };
  cache.google.tokenTime = now;
  return cache.google.token;
}

let _googleIdx = 0;
async function googleTts(text, lang) {
  const token = await getGoogleToken();
  const cleanText = text.replace(/[@^*()\\/\-_+=><"'\u201c\u201d\u3010\u3011]/g, " ").replaceAll(", ", ". ");
  const rpcId = "jQ1olc";
  const reqId = (++_googleIdx * 100000) + Math.floor(1000 + Math.random() * 9000);
  const query = new URLSearchParams({
    rpcids: rpcId,
    "f.sid": token["f.sid"],
    bl: token.bl,
    hl: lang,
    "soc-app": 1, "soc-platform": 1, "soc-device": 1,
    _reqid: reqId,
    rt: "c",
  });
  const payload = [cleanText, lang, null, "undefined", [0]];
  const body = new URLSearchParams();
  body.append("f.req", JSON.stringify([[[rpcId, JSON.stringify(payload), null, "generic"]]]));
  const res = await fetch(`https://translate.google.com/_/TranslateWebserverUi/data/batchexecute?${query}`, {
    method: "POST",
    headers: { "Content-Type": "application/x-www-form-urlencoded", "Referer": "https://translate.google.com/" },
    body: body.toString(),
  });
  if (!res.ok) throw new Error(`Google TTS failed: ${res.status}`);
  const data = await res.text();
  const split = JSON.parse(data.split("\n")[3]);
  const base64 = JSON.parse(split[0][2])[0];
  if (!base64 || base64.length < 100) throw new Error("Google TTS returned empty audio");
  return base64; // base64 MP3
}

// ── Bing TTS ───────────────────────────────────────────────────
async function getBingToken() {
  const now = Date.now();
  if (cache.bing.token && now - cache.bing.tokenTime < BING_REFRESH) {
    return cache.bing.token;
  }
  const res = await fetch("https://www.bing.com/translator", {
    headers: { "User-Agent": UA, "Accept-Language": "vi,en-US;q=0.9,en;q=0.8" },
  });
  if (!res.ok) throw new Error(`Bing translator fetch failed: ${res.status}`);
  const rawCookies = res.headers.getSetCookie?.() || [];
  const cookie = rawCookies.map((c) => c.split(";")[0]).join("; ");
  const html = await res.text();
  const match = html.match(/params_AbusePreventionHelper\s*=\s*\[([^,]+),([^,]+),/);
  if (!match) throw new Error("Failed to parse Bing token");
  cache.bing.token = { key: match[1], token: match[2].replace(/"/g, ""), cookie };
  cache.bing.tokenTime = now;
  return cache.bing.token;
}

async function bingTtsRequest(text, voiceId, token) {
  const parts = voiceId.split("-");
  const xmlLang = parts.slice(0, 2).join("-");
  const gender = voiceId.toLowerCase().includes("male") ? "Male" : "Female";
  const ssml = `<speak version='1.0' xml:lang='${xmlLang}'><voice xml:lang='${xmlLang}' xml:gender='${gender}' name='${voiceId}'><prosody rate='0.00%'>${text}</prosody></voice></speak>`;
  const body = new URLSearchParams();
  body.append("ssml", ssml);
  body.append("token", token.token);
  body.append("key", token.key);
  return fetch("https://www.bing.com/tfettts?isVertical=1&&IG=1&IID=translator.5023&SFX=1", {
    method: "POST",
    body: body.toString(),
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      "Accept": "*/*",
      "Origin": "https://www.bing.com",
      "Referer": "https://www.bing.com/translator",
      "User-Agent": UA,
      ...(token.cookie ? { "Cookie": token.cookie } : {}),
    },
  });
}

async function bingTts(text, voiceId) {
  let token = await getBingToken();
  let res = await bingTtsRequest(text, voiceId, token);

  // On 429/captcha: invalidate cache and retry once with fresh token
  if (res.status === 429 || res.status === 403) {
    cache.bing.token = null;
    cache.bing.tokenTime = 0;
    token = await getBingToken();
    res = await bingTtsRequest(text, voiceId, token);
  }

  if (!res.ok) {
    const body = await res.text().catch(() => "");
    throw new Error(`Bing TTS failed: ${res.status}${body ? " - " + body : ""}`);
  }
  const buf = await res.arrayBuffer();
  if (buf.byteLength < 1024) throw new Error("Bing TTS returned empty audio");
  return Buffer.from(buf).toString("base64"); // base64 MP3
}

// ── Local Device TTS (macOS `say` + ffmpeg) ───────────────────
let _localVoicesCache = null;

export async function fetchLocalDeviceVoices() {
  if (_localVoicesCache) return _localVoicesCache;
  try {
    const { stdout } = await execFileAsync("say", ["-v", "?"]);
    const voices = [];
    for (const line of stdout.split("\n")) {
      // Format: "Name   locale   # sample"
      const m = line.match(/^([^\s].*?)\s{2,}([a-z]{2}_[A-Z]{2})/);
      if (!m) continue;
      const name   = m[1].trim();
      const locale = m[2].trim(); // e.g. en_US
      const lang   = locale.split("_")[0];
      const country = locale.split("_")[1];
      voices.push({ id: name, name, locale, lang, country, gender: "" });
    }
    _localVoicesCache = voices;
    return voices;
  } catch {
    return [];
  }
}

async function localDeviceTts(text, voiceId) {
  const dir = await mkdtemp(join(tmpdir(), "tts-"));
  const aiffPath = join(dir, "out.aiff");
  const mp3Path  = join(dir, "out.mp3");
  try {
    const args = voiceId ? ["-v", voiceId, "-o", aiffPath, text] : ["-o", aiffPath, text];
    await execFileAsync("say", args);
    await execFileAsync("ffmpeg", ["-y", "-i", aiffPath, "-codec:a", "libmp3lame", "-qscale:a", "4", mp3Path]);
    const buf = await readFile(mp3Path);
    return buf.toString("base64");
  } finally {
    await rm(dir, { recursive: true, force: true });
  }
}

// ── Voices list (Edge TTS public endpoint) ─────────────────────
let _voicesCache = null;
let _voicesCacheTime = 0;
const VOICES_TTL = 24 * 60 * 60 * 1000;

export async function fetchEdgeTtsVoices() {
  const now = Date.now();
  if (_voicesCache && now - _voicesCacheTime < VOICES_TTL) return _voicesCache;
  const res = await fetch(
    "https://speech.platform.bing.com/consumer/speech/synthesize/readaloud/voices/list?trustedclienttoken=6A5AA1D4EAFF4E9FB37E23D68491D6F4",
    { headers: { "User-Agent": UA } }
  );
  if (!res.ok) throw new Error(`Edge TTS voices fetch failed: ${res.status}`);
  const voices = await res.json();
  _voicesCache = voices;
  _voicesCacheTime = now;
  return voices;
}

// ── ElevenLabs TTS ─────────────────────────────────────────────
const _elevenlabsVoicesCache = new Map(); // Cache by API key

export async function fetchElevenLabsVoices(apiKey) {
  if (!apiKey) throw new Error("ElevenLabs API key required");
  
  const now = Date.now();
  const cached = _elevenlabsVoicesCache.get(apiKey);
  if (cached && now - cached.time < VOICES_TTL) {
    return cached.voices;
  }
  
  const res = await fetch("https://api.elevenlabs.io/v1/voices", {
    headers: {
      "xi-api-key": apiKey,
      "Content-Type": "application/json",
    },
  });
  
  if (!res.ok) throw new Error(`ElevenLabs voices fetch failed: ${res.status}`);
  const data = await res.json();
  // Normalize: add lang from labels.language for grouping
  const voices = (data.voices || []).map((v) => ({
    ...v,
    lang: v.labels?.language || "en",
  }));
  _elevenlabsVoicesCache.set(apiKey, { voices, time: now });
  return voices;
}

async function elevenlabsTts(text, voiceId, apiKey, modelId = "eleven_flash_v2_5") {
  const res = await fetch(`https://api.elevenlabs.io/v1/text-to-speech/${voiceId}`, {
    method: "POST",
    headers: {
      "xi-api-key": apiKey,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      text,
      model_id: modelId,
      voice_settings: {
        stability: 0.5,
        similarity_boost: 0.75,
      },
    }),
  });

  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err?.detail?.message || `ElevenLabs TTS failed: ${res.status}`);
  }

  const buf = await res.arrayBuffer();
  if (buf.byteLength < 1024) throw new Error("ElevenLabs TTS returned empty audio");
  return Buffer.from(buf).toString("base64");
}

// ── Voice Fetcher Registry (DRY) ───────────────────────────────
export const VOICE_FETCHERS = {
  "edge-tts": fetchEdgeTtsVoices,
  "local-device": fetchLocalDeviceVoices,
  "elevenlabs": fetchElevenLabsVoices,
  // google-tts: uses hardcoded language codes
  // openai: uses hardcoded voices from providerModels.js
};

// ── OpenAI TTS ───────────────────────────────────────────────────────────────
async function handleOpenAiTts({ model, input, credentials, responseFormat = "mp3" }) {
  if (!credentials?.apiKey) {
    return createErrorResult(HTTP_STATUS.UNAUTHORIZED, "No OpenAI API key configured");
  }

  // model format: "tts-model/voice" e.g. "tts-1/alloy" or "gpt-4o-mini-tts/nova"
  let ttsModel = "gpt-4o-mini-tts";
  let voice = "alloy";
  if (model && model.includes("/")) {
    const parts = model.split("/");
    if (parts.length === 2) {
      [ttsModel, voice] = parts;
    }
  } else if (model) {
    voice = model;
  }

  const baseUrl = (credentials.baseUrl || "https://api.openai.com").replace(/\/+$/, "");
  const res = await fetch(`${baseUrl}/v1/audio/speech`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": `Bearer ${credentials.apiKey}`,
    },
    body: JSON.stringify({ model: ttsModel, voice, input }),
  });

  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    return createErrorResult(res.status, err?.error?.message || `OpenAI TTS failed: ${res.status}`);
  }

  const buf = await res.arrayBuffer();
  const base64 = Buffer.from(buf).toString("base64");
  return createTtsResponse(base64, "mp3", responseFormat);
}

// ── TTS Provider Registry (DRY) ────────────────────────────────
const TTS_PROVIDERS = {
  "google-tts": {
    synthesize: async (text, model) => {
      const base64 = await googleTts(text, model || "en");
      return { base64, format: "mp3" };
    },
    requiresCredentials: false,
  },
  "edge-tts": {
    synthesize: async (text, model) => {
      const base64 = await bingTts(text, model || "vi-VN-HoaiMyNeural");
      return { base64, format: "mp3" };
    },
    requiresCredentials: false,
  },
  "local-device": {
    synthesize: async (text, model) => {
      const base64 = await localDeviceTts(text, model);
      return { base64, format: "mp3" };
    },
    requiresCredentials: false,
  },
  "elevenlabs": {
    synthesize: async (text, model, credentials) => {
      if (!credentials?.apiKey) {
        throw new Error("ElevenLabs API key required");
      }
      // model format: "voice_id" or "model_id/voice_id"
      let modelId = "eleven_flash_v2_5";
      let voiceId = model;
      if (model && model.includes("/")) {
        [modelId, voiceId] = model.split("/");
      }
      const base64 = await elevenlabsTts(text, voiceId, credentials.apiKey, modelId);
      return { base64, format: "mp3" };
    },
    requiresCredentials: true,
  },
  "openai": {
    synthesize: async (text, model, credentials, responseFormat) => {
      return await handleOpenAiTts({ model, input: text, credentials, responseFormat });
    },
    requiresCredentials: true,
  },
};

// ── Core handler ───────────────────────────────────────────────
/**
 * Synthesize text to audio.
 * @param {object} options
 * @param {string} options.provider     - "google-tts" | "edge-tts" | "local-device" | "openai"
 * @param {string} options.model        - voice/lang id
 * @param {string} options.input        - text to synthesize
 * @param {object} [options.credentials] - required for openai
 * @param {string} [options.responseFormat] - "mp3" (default) | "json" (base64)
 * @returns {Promise<{success, response, status?, error?}>}
 */
export async function handleTtsCore({ provider, model, input, credentials, responseFormat = "mp3" }) {
  if (!input?.trim()) {
    return createErrorResult(HTTP_STATUS.BAD_REQUEST, "Missing required field: input");
  }

  const ttsProvider = TTS_PROVIDERS[provider];
  if (!ttsProvider) {
    return createErrorResult(HTTP_STATUS.BAD_REQUEST, `Provider '${provider}' does not support TTS via this route.`);
  }

  try {
    const result = await ttsProvider.synthesize(input.trim(), model, credentials, responseFormat);
    
    // OpenAI returns full response object
    if (result.success !== undefined) return result;
    
    // Other providers return { base64, format }
    return createTtsResponse(result.base64, result.format, responseFormat);
  } catch (err) {
    return createErrorResult(HTTP_STATUS.BAD_GATEWAY, err.message || "TTS synthesis failed");
  }
}