import express from 'express';
import { fetch } from 'undici';

const ASR_TARGET = process.env.H5_ASR_TARGET ?? 'https://asr.tkmind.cn';
const ASR_MAX_BYTES = Number(process.env.H5_ASR_MAX_BYTES ?? 5 * 1024 * 1024);
const ASR_TIMEOUT_MS = Number(process.env.H5_ASR_TIMEOUT_MS ?? 45_000);

export function sanitizeAsrMessage(message) {
  if (!message || typeof message !== 'string') return '识别失败，请重试';
  const trimmed = message.trim();
  if (!trimmed) return '识别失败，请重试';
  if (/Failed to load audio|ffmpeg|Invalid data found when processing input|moov atom not found/i.test(trimmed)) {
    return '音频格式无法识别，请重新录制';
  }
  if (/timeout|timed out/i.test(trimmed)) return '识别超时，请重试';
  if (trimmed.length > 160) return `${trimmed.slice(0, 160)}…`;
  return trimmed;
}

export function attachAsrRoutes(api, deps) {
  const multipartRaw = express.raw({
    type: (req) => (req.headers['content-type'] ?? '').includes('multipart/form-data'),
    limit: ASR_MAX_BYTES,
  });

  // 登录校验由 api 全局中间件负责（req.currentUser）
  api.post('/asr/oneshot', multipartRaw, async (req, res) => {
    const contentType = req.headers['content-type'] ?? '';
    if (!contentType.includes('multipart/form-data')) {
      return deps.sendError(res, req, 400, 'invalid_request', 'Content-Type 必须为 multipart/form-data');
    }
    if (!req.body?.length) {
      return deps.sendError(res, req, 400, 'invalid_request', '音频内容为空');
    }

    const controller = new AbortController();
    const timer = setTimeout(() => controller.abort(), ASR_TIMEOUT_MS);
    try {
      const upstream = await fetch(`${ASR_TARGET}/asr/oneshot`, {
        method: 'POST',
        headers: { 'content-type': contentType },
        body: req.body,
        signal: controller.signal,
      });
      const text = await upstream.text();
      let payload = null;
      try {
        payload = JSON.parse(text);
      } catch {
        payload = null;
      }

      if (!upstream.ok) {
        const message = sanitizeAsrMessage(payload?.message ?? text ?? 'ASR 请求失败');
        console.warn('[asr] upstream HTTP error', upstream.status, message);
        return deps.sendError(res, req, upstream.status, 'asr_failed', message);
      }
      if (payload?.code !== 200) {
        const message = sanitizeAsrMessage(payload?.message ?? '识别失败');
        console.warn('[asr] upstream business error', payload?.code, message);
        return deps.sendError(res, req, 502, 'asr_failed', message);
      }
      return deps.sendData(res, req, { text: payload?.data?.text ?? '' });
    } catch (err) {
      const message =
        err instanceof Error && err.name === 'AbortError'
          ? '识别超时，请重试'
          : sanitizeAsrMessage(err instanceof Error ? err.message : 'ASR 请求失败');
      console.warn('[asr] proxy failed', message);
      return deps.sendError(res, req, 502, 'asr_failed', message);
    } finally {
      clearTimeout(timer);
    }
  });
}