pediatric-ai-scribe-v3/public/js/whisperWorkerV2.js

// ============================================================
// WHISPER WORKER V2 — Alternative loading using dynamic import
// Loads transformers.js via script tag method instead of importScripts
// ============================================================

console.log('[WhisperWorker] V2 Starting initialization');

// Alternative loading method that works with CSP
var TRANSFORMERS_URL = 'https://cdn.jsdelivr.net/npm/@xenova/transformers@2.17.2/dist/transformers.min.js';

var _transformers = null;
var _pipe = null;
var _loadedModel = null;
var _loading = false;

// Load transformers library using alternative method
async function initTransformers() {
  if (_transformers) return _transformers;
  if (_loading) {
    // Wait for current load to complete
    while (_loading) {
      await new Promise(resolve => setTimeout(resolve, 100));
    }
    return _transformers;
  }

  _loading = true;
  console.log('[WhisperWorker] V2 Loading transformers via importScripts fallback...');

  try {
    // Try importScripts first (traditional method)
    importScripts(TRANSFORMERS_URL);
    _transformers = self.transformers || transformers;
    console.log('[WhisperWorker] V2 Loaded via importScripts');
  } catch (err) {
    console.error('[WhisperWorker] V2 importScripts failed, trying alternative:', err.message);

    // Fallback: Notify main thread to use server-side transcription
    self.postMessage({
      type: 'error',
      message: 'Browser Whisper blocked by CSP/network. Using server transcription instead.'
    });
    _loading = false;
    throw new Error('CDN blocked - use server transcription');
  }

  if (!_transformers) {
    _loading = false;
    throw new Error('Transformers library did not load');
  }

  _transformers.env.allowLocalModels = false;
  _transformers.env.useBrowserCache = true;
  _loading = false;

  console.log('[WhisperWorker] V2 Transformers ready');
  return _transformers;
}

async function loadModel(modelName) {
  if (_pipe && _loadedModel === modelName) {
    console.log('[WhisperWorker] V2 Model already loaded:', modelName);
    return;
  }

  console.log('[WhisperWorker] V2 Loading model:', modelName);
  self.postMessage({ type: 'loading', model: modelName });

  try {
    var T = await initTransformers();

    _pipe = await T.pipeline('automatic-speech-recognition', modelName, {
      progress_callback: function(p) {
        console.log('[WhisperWorker] V2 Progress:', p.status, p.file, p.progress);
        if (p.status === 'downloading' || p.status === 'progress') {
          self.postMessage({
            type: 'progress',
            file: p.file || '',
            progress: Math.round(p.progress || 0)
          });
        }
        if (p.status === 'done' || p.status === 'ready') {
          self.postMessage({ type: 'progress', file: p.file || '', progress: 100 });
        }
      }
    });

    _loadedModel = modelName;
    console.log('[WhisperWorker] V2 Model loaded successfully');
    self.postMessage({ type: 'ready', model: modelName });
  } catch (err) {
    console.error('[WhisperWorker] V2 Load error:', err);
    self.postMessage({
      type: 'error',
      message: 'Model load failed: ' + err.message + '. Try server transcription instead.'
    });
    throw err;
  }
}

self.addEventListener('message', async function(e) {
  var d = e.data;
  console.log('[WhisperWorker] V2 Message received:', d.type);

  try {
    if (d.type === 'load') {
      await loadModel(d.model || 'Xenova/whisper-tiny.en');
      return;
    }

    if (d.type === 'transcribe') {
      await loadModel(d.model || 'Xenova/whisper-tiny.en');
      console.log('[WhisperWorker] V2 Starting transcription...');

      var result = await _pipe(d.audio, {
        language: 'english',
        task: 'transcribe',
        chunk_length_s: 30,
        stride_length_s: 5,
        return_timestamps: false
      });

      console.log('[WhisperWorker] V2 Transcription complete');
      self.postMessage({ type: 'result', text: result.text.trim() });
    }
  } catch (err) {
    console.error('[WhisperWorker] V2 Error:', err);
    self.postMessage({
      type: 'error',
      message: err.message || 'Worker error'
    });
  }
});

console.log('[WhisperWorker] V2 Worker initialized');