// 本地演示用 mock TTS 服务：实现 AI Lab 页面依赖的 /v1/audio/* 接口。
// 启动：node services/mock-tts/server.mjs（配合 .env.local 里 TTS_MOCK_UPSTREAM=http://127.0.0.1:8100）
// 真实上游为外部 TTS 引擎，需要服务端凭据；此服务仅用于无引擎环境下演示与联调。
import { createServer } from "node:http";

const PORT = Number(process.env.MOCK_TTS_PORT ?? 8100);
const SAMPLE_RATE = 22050;

const voices = [
  {
    id: "xiaoman", name: "小满", desc: "温暖亲和的女声，适合品牌宣传与产品介绍。",
    category: "通用女声", gender: "女声", genre: "温和", accent: "普通话", style: "亲切",
    styles: ["亲切", "自然"], preview: "/v1/previews/xiaoman.wav", range: [240, 400],
  },
  {
    id: "qingluo", name: "青落", desc: "清亮利落的女声，适合新闻播报与知识讲解。",
    category: "通用女声", gender: "女声", genre: "专业", accent: "普通话", style: "专业",
    styles: ["专业", "清晰"], preview: "/v1/previews/qingluo.wav", range: [260, 430],
  },
  {
    id: "tianxin", name: "甜芯", desc: "甜美活泼的女声，适合促销活动与社媒内容。",
    category: "通用女声", gender: "女声", genre: "甜美", accent: "台湾腔", style: "活泼",
    styles: ["活泼", "甜美"], preview: "/v1/previews/tianxin.wav", range: [280, 460],
  },
  {
    id: "mufan", name: "沐帆", desc: "低沉沉稳的男声，适合纪录片旁白与高端品牌。",
    category: "通用男声", gender: "男声", genre: "磁性", accent: "普通话", style: "沉稳",
    styles: ["沉稳", "磁性"], preview: "/v1/previews/mufan.wav", range: [110, 200],
  },
  {
    id: "haoran", name: "浩然", desc: "爽朗有力的男声，适合广告口号与活动主持。",
    category: "通用男声", gender: "男声", genre: "活力", accent: "普通话", style: "有力",
    styles: ["有力", "活力"], preview: "/v1/previews/haoran.wav", range: [130, 230],
  },
  {
    id: "awan", name: "阿万", desc: "带粤语口音的男声，适合大湾区本地化内容。",
    category: "通用男声", gender: "男声", genre: "温和", accent: "粤语", style: "自然",
    styles: ["自然"], preview: "/v1/previews/awan.wav", range: [120, 210],
  },
  {
    id: "doudou", name: "豆豆", desc: "元气满满的童声，适合儿歌故事与亲子内容。",
    category: "童声", gender: "童声", genre: "活泼", accent: "普通话", style: "可爱",
    styles: ["可爱", "活泼"], preview: "/v1/previews/doudou.wav", range: [300, 480],
  },
  {
    id: "dongbei-ge", name: "东北哥", desc: "幽默豪爽的东北男声，适合短视频与段子配音。",
    category: "情景演绎", gender: "男声", genre: "活力", accent: "东北腔", style: "幽默",
    styles: ["幽默", "豪爽"], preview: "/v1/previews/dongbei-ge.wav", range: [115, 205],
  },
];

const facets = {
  gender: [...new Set(voices.map((v) => v.gender))],
  genre: [...new Set(voices.map((v) => v.genre))],
  accent: [...new Set(voices.map((v) => v.accent))],
  style: [...new Set(voices.map((v) => v.style))],
};

function json(res, status, body) {
  res.writeHead(status, { "Content-Type": "application/json; charset=utf-8", "Access-Control-Allow-Origin": "*" });
  res.end(JSON.stringify(body));
}

// 极简 WAV 合成：按字符生成短音，<pause:ms> 生成静音。仅作演示，非真实语音。
function synthesizeWav(text, voiceId, speed) {
  const voice = voices.find((v) => v.id === voiceId) ?? voices[0];
  const rate = Math.min(4, Math.max(0.25, Number(speed) || 1));
  const segments = [];
  for (const part of String(text ?? "").split(/(<pause:\d+>)/)) {
    const pause = part.match(/^<pause:(\d+)>$/);
    if (pause) segments.push({ pauseMs: Math.min(10000, Math.max(50, Number(pause[1]))) });
    else if (part) segments.push({ chars: [...part] });
  }
  const samples = [];
  for (const segment of segments) {
    if (segment.pauseMs) {
      const silence = Math.floor((SAMPLE_RATE * segment.pauseMs) / 1000 / rate);
      samples.push(...new Array(silence).fill(0));
      continue;
    }
    for (const [index, ch] of segment.chars.entries()) {
      if (/\s/.test(ch)) {
        samples.push(...new Array(Math.floor(SAMPLE_RATE * 0.06 / rate)).fill(0));
        continue;
      }
      // 以字符与音色做种子生成 160–320Hz 的基频，让不同文本/音色听感有区分
      const seed = (ch.codePointAt(0) * 31 + voice.id.charCodeAt(0) * 7) % 1000 / 1000;
      const freq = voice.range[0] + seed * (voice.range[1] - voice.range[0]);
      const duration = 0.13 + ((index % 3) * 0.02);
      const count = Math.floor((SAMPLE_RATE * duration) / rate);
      for (let i = 0; i < count; i += 1) {
        const t = i / SAMPLE_RATE;
        const envelope = Math.min(1, i / (count * 0.15), (count - i) / (count * 0.25));
        const value = Math.sin(2 * Math.PI * freq * t) * 0.55 + Math.sin(2 * Math.PI * freq * 2 * t) * 0.18;
        samples.push(Math.round(Math.max(-1, Math.min(1, value * envelope)) * 32000));
      }
      samples.push(...new Array(Math.floor(SAMPLE_RATE * 0.025 / rate)).fill(0));
    }
  }
  const capped = samples.slice(0, SAMPLE_RATE * 30);
  const buffer = Buffer.alloc(44 + capped.length * 2);
  buffer.write("RIFF", 0);
  buffer.writeUInt32LE(36 + capped.length * 2, 4);
  buffer.write("WAVE", 8);
  buffer.write("fmt ", 12);
  buffer.writeUInt32LE(16, 16);
  buffer.writeUInt16LE(1, 20); // PCM
  buffer.writeUInt16LE(1, 22); // mono
  buffer.writeUInt32LE(SAMPLE_RATE, 24);
  buffer.writeUInt32LE(SAMPLE_RATE * 2, 28);
  buffer.writeUInt16LE(2, 32);
  buffer.writeUInt16LE(16, 34);
  buffer.write("data", 36);
  buffer.writeUInt32LE(capped.length * 2, 40);
  capped.forEach((value, i) => buffer.writeInt16LE(value, 44 + i * 2));
  return buffer;
}

function voiceById(id) {
  return voices.find((v) => v.id === id);
}

const server = createServer((req, res) => {
  const url = new URL(req.url, `http://127.0.0.1:${PORT}`);
  if (req.method === "OPTIONS") {
    res.writeHead(204, {
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
      "Access-Control-Allow-Headers": "Content-Type",
    });
    return res.end();
  }
  if (req.method === "GET" && url.pathname === "/v1/audio/config") {
    return json(res, 200, {
      model: "qwen3-tts-mock",
      formats: ["wav"],
      default_format: "wav",
      speed: { min: 0.25, max: 4, default: 1 },
      pause: {
        supported: true, min_ms: 50, max_ms: 10000,
        presets: [{ ms: 500, label: "0.5s" }, { ms: 1000, label: "1s" }, { ms: 2000, label: "2s" }],
      },
    });
  }
  if (req.method === "GET" && url.pathname === "/v1/audio/voices") {
    return json(res, 200, {
      categories: [...new Set(voices.map((v) => v.category))],
      facets,
      voices: voices.map(({ range, ...voice }) => voice),
    });
  }
  const preview = req.method === "GET" && url.pathname.match(/^\/v1\/previews\/([\w-]+)\.wav$/);
  if (preview) {
    const voice = voiceById(preview[1]);
    if (!voice) return json(res, 404, { error: { message: "音色不存在" } });
    const audio = synthesizeWav(`你好，我是${voice.name}。`, voice.id, 1);
    res.writeHead(200, { "Content-Type": "audio/wav", "Content-Length": audio.length, "Access-Control-Allow-Origin": "*" });
    return res.end(audio);
  }
  if (req.method === "POST" && url.pathname === "/v1/audio/speech") {
    let raw = "";
    req.on("data", (chunk) => { raw += chunk; if (raw.length > 1_000_000) req.destroy(); });
    req.on("end", () => {
      let body = {};
      try { body = JSON.parse(raw || "{}"); } catch { return json(res, 400, { error: { message: "请求体不是合法 JSON" } }); }
      if (!voiceById(body.voice)) return json(res, 400, { error: { message: "音色不存在或未提供" } });
      if (!String(body.input ?? "").trim()) return json(res, 400, { error: { message: "文本不能为空" } });
      const audio = synthesizeWav(body.input, body.voice, body.speed);
      res.writeHead(200, { "Content-Type": "audio/wav", "Content-Length": audio.length, "Access-Control-Allow-Origin": "*" });
      res.end(audio);
    });
    return;
  }
  if (req.method === "POST" && url.pathname === "/v1/audio/clone-speech") {
    // 真人声音配音 mock：校验文本与声音样本后返回演示音频（非真实克隆）。
    let raw = "";
    req.on("data", (chunk) => { raw += chunk; if (raw.length > 16_000_000) req.destroy(); });
    req.on("end", () => {
      let body = {};
      try { body = JSON.parse(raw || "{}"); } catch { return json(res, 400, { error: { message: "请求体不是合法 JSON" } }); }
      if (!String(body.input ?? "").trim()) return json(res, 400, { error: { message: "文本不能为空" } });
      if (!String(body.reference_audio ?? "").startsWith("data:audio/")) return json(res, 400, { error: { message: "未提供声音样本 reference_audio" } });
      const audio = synthesizeWav(body.input, "xiaoman", body.speed);
      res.writeHead(200, { "Content-Type": "audio/wav", "Content-Length": audio.length, "Access-Control-Allow-Origin": "*" });
      res.end(audio);
    });
    return;
  }
  if (req.method === "GET" && url.pathname === "/healthz") return json(res, 200, { status: "ok" });
  json(res, 404, { error: { message: `mock-tts 未实现 ${req.method} ${url.pathname}` } });
});

server.listen(PORT, "127.0.0.1", () => {
  console.log(`[mock-tts] listening on http://127.0.0.1:${PORT}`);
});