const express = require('express');
const router = express.Router();
const multer = require('multer');
const { litellmClient } = require('../utils/ai');
const { authMiddleware } = require('../middleware/auth');
var logger = require('../utils/logger');
var { gatewayUrl } = require('../utils/errors');
var { getLiteLLMHeaders } = require('../utils/litellm');

const upload = multer({ storage: multer.memoryStorage(), limits: { fileSize: 25 * 1024 * 1024 } });

// STT is intentionally routed only through LiteLLM.
function getTranscribeProvider() {
  var env = process.env.TRANSCRIBE_PROVIDER;
  if (env === 'litellm') return 'litellm';
  if (litellmClient) return 'litellm';
  return 'none';
}

function isTranscribeAvailable() {
  if (litellmClient) return true;
  return false;
}

var provider = getTranscribeProvider();
var available = isTranscribeAvailable();
console.log('🎙️  Transcribe provider:', provider + (available ? '' : ' (NOT CONFIGURED — browser speech only)'));

router.get('/transcribe/status', authMiddleware, (req, res) => {
  res.json({ available: available, provider: available ? provider : 'none' });
});

router.post('/transcribe', authMiddleware, upload.single('audio'), async (req, res) => {
  try {
    if (!req.file) return res.status(400).json({ error: 'No audio' });
    var startTime = Date.now();
    var fileSize  = req.file.size;

    // Get user's preferred STT model (if set), then admin DB default, then env
    var db = require('../db/database');
    var userPrefs = await db.get('SELECT stt_model FROM users WHERE id = ?', [req.user.id]);
    var userModel = userPrefs?.stt_model;
    var adminSttModel = await db.getSetting('stt.model') || '';

    console.log('[Transcribe] Received ' + (fileSize / 1024).toFixed(0) + 'KB audio (' + (req.file.mimetype || 'unknown') + ') via ' + provider + (userModel ? ' (user model: ' + userModel + ')' : ''));

    if (provider !== 'litellm' || !process.env.LITELLM_API_BASE) return res.status(400).json({ error: 'LITELLM_API_BASE not set.' });
    var sttModel = userModel || adminSttModel || process.env.LITELLM_STT_MODEL || '';
    if (!sttModel) return res.status(400).json({ error: 'No LiteLLM STT model configured.' });
    var mimeType = req.file.mimetype || 'audio/webm';
    var ext = mimeType.split('/')[1] || 'webm';

    var file = new File([req.file.buffer], 'audio.' + ext, { type: mimeType });
    var form = new FormData();
    form.append('file', file);
    form.append('model', sttModel);

    var sttResp = await fetch(gatewayUrl('/audio/transcriptions'), {
      method: 'POST', headers: getLiteLLMHeaders(), body: form,
    });
    if (!sttResp.ok) {
      var errBody = await sttResp.text();
      throw new Error('LiteLLM /audio/transcriptions ' + sttResp.status + ': ' + errBody.substring(0, 500));
    }
    var data = await sttResp.json();
    var text = (data && data.text) ? String(data.text).trim() : '';
    console.log('[Transcribe] LiteLLM/' + sttModel + ' done in ' + (Date.now() - startTime) + 'ms');
    logger.audit(req.user.id, 'transcribe', 'Transcribed audio via litellm', req, { category: 'clinical' });
    return res.json({ success: true, text: text, provider: 'litellm/' + sttModel, duration: Date.now() - startTime });

  } catch (err) {
    var detail = err.response && err.response.data
      ? JSON.stringify(err.response.data).substring(0, 500)
      : err.message;
    console.error('[Transcribe] Error (' + provider + '):', detail);
    res.status(500).json({ error: detail });
  }
});

module.exports = router;