KeySelector/server/routes/recognize.js

const express = require('express');
const router = express.Router();
const multer = require('multer');
const fs = require('fs');
const os = require('os');
const path = require('path');
const axios = require('axios');
const FormData = require('form-data');
const crypto = require('crypto');
const db = require('../db');

// Upload audio to system temp folder
const upload = multer({ dest: os.tmpdir() });

// ACRCloud Identification helper
async function identifyACRCloud(buffer) {
  const host = process.env.ACRCLOUD_HOST;
  const accessKey = process.env.ACRCLOUD_ACCESS_KEY;
  const accessSecret = process.env.ACRCLOUD_ACCESS_SECRET;

  if (!host || !accessKey || !accessSecret) return null;

  const timestamp = Math.floor(Date.now() / 1000);
  const stringToSign = [
    'POST',
    '/v1/identify',
    accessKey,
    'audio',
    '1',
    timestamp
  ].join('\n');

  const signature = crypto
    .createHmac('sha1', accessSecret)
    .update(Buffer.from(stringToSign, 'utf-8'))
    .digest()
    .toString('base64');

  const form = new FormData();
  form.append('sample', buffer, { filename: 'sample.webm' });
  form.append('sample_bytes', buffer.length);
  form.append('access_key', accessKey);
  form.append('data_type', 'audio');
  form.append('signature_version', '1');
  form.append('signature', signature);
  form.append('timestamp', timestamp);

  const url = host.startsWith('http') ? `${host}/v1/identify` : `https://${host}/v1/identify`;
  const response = await axios.post(url, form, {
    headers: form.getHeaders(),
    timeout: 8000
  });

  const data = response.data;
  if (data.status && data.status.code === 0 && data.metadata && data.metadata.music && data.metadata.music.length > 0) {
    const music = data.metadata.music[0];
    const title = music.title;
    const artist = music.artists ? music.artists.map(a => a.name).join(' & ') : 'Unknown Artist';
    const score = music.score ? `${music.score}%` : '95%';
    return { title, artist, matchScore: score };
  }

  return null;
}

// AudD Identification helper
async function identifyAudD(buffer) {
  const token = process.env.AUDD_API_TOKEN || process.env.AUDD_API_KEY;
  if (!token) return null;

  const form = new FormData();
  form.append('file', buffer, { filename: 'sample.webm' });
  form.append('api_token', token);
  form.append('return', 'apple_music,spotify');

  const response = await axios.post('https://api.audd.io/', form, {
    headers: form.getHeaders(),
    timeout: 8000
  });

  if (response.data && response.data.status === 'success' && response.data.result) {
    const r = response.data.result;
    return {
      title: r.title,
      artist: r.artist,
      matchScore: '98%',
      cover_url: r.spotify && r.spotify.images && r.spotify.images[0] ? r.spotify.images[0].url : null
    };
  }

  return null;
}

// POST /api/recognize
router.post('/', upload.single('audio'), async (req, res) => {
  if (!req.file) {
    return res.status(400).json({ error: 'No audio file uploaded.' });
  }

  const filePath = req.file.path;

  try {
    const audioBuffer = fs.readFileSync(filePath);

    // 1. Check configured providers
    const hasAcr = !!(process.env.ACRCLOUD_HOST && process.env.ACRCLOUD_ACCESS_KEY);
    const hasAudd = !!(process.env.AUDD_API_TOKEN || process.env.AUDD_API_KEY);

    if (!hasAcr && !hasAudd) {
      return res.json({
        status: 'not_configured',
        message: 'Kein Audio-Erkennungs-Key hinterlegt. Bitte ACRCloud (kostenlos) oder AudD in .env eintragen. Nutze solange die manuelle Suche.'
      });
    }

    let match = null;
    if (hasAcr) {
      match = await identifyACRCloud(audioBuffer);
    }
    if (!match && hasAudd) {
      match = await identifyAudD(audioBuffer);
    }

    if (!match) {
      return res.json({
        status: 'not_found',
        message: 'Kein passender Track erkannt. Spiele das Audio lauter ab oder nutze die Suche.'
      });
    }

    // 2. Track recognized! Check local PostgreSQL database first
    const existing = await db.findTrack(match.artist, match.title);
    let key = existing ? existing.camelot_key : null;
    let bpm = existing ? existing.bpm : null;
    let musicKey = existing ? existing.music_key : null;
    let isCorrected = existing ? existing.is_corrected : false;
    let coverUrl = existing ? existing.cover_url : match.cover_url;

    res.json({
      status: 'success',
      data: {
        title: match.title,
        artist: match.artist,
        matchScore: match.matchScore,
        key: key,
        bpm: bpm,
        musicKey: musicKey,
        isCorrected: isCorrected,
        cover_url: coverUrl,
        preview_url: existing ? existing.preview_url : null,
        duration_sec: existing ? existing.duration_sec : null,
        energy: existing ? existing.energy : null,
        danceability: existing ? existing.danceability : null,
        happiness: existing ? existing.happiness : null
      }
    });

  } catch (err) {
    console.error('[Recognize] Recognition error:', err.message);
    res.status(500).json({ error: 'Audio recognition failed: ' + err.message });
  } finally {
    fs.unlink(filePath, () => {});
  }
});

module.exports = router;