Add browser-local Piper WebAssembly speech

piper-runtime.js

@@ -0,0 +1,42 @@
+const version = document.querySelector('#frontend-version')?.textContent || 'dev';
+const workerUrl = `/tts/piper-wasm-v1/piper-worker.js?v=${encodeURIComponent(version)}`;
+let worker;
+let requestId = 0;
+const pending = new Map();
+
+function getWorker() {
+  if (worker) return worker;
+  worker = new Worker(workerUrl);
+  worker.onmessage = event => {
+    const message = event.data || {};
+    const request = pending.get(message.id);
+    if (!request) return;
+    if (message.type === 'progress') {
+      request.onProgress?.(message.progress);
+    } else {
+      pending.delete(message.id);
+      if (message.type === 'audio') request.resolve(new Blob([message.audio], {type: 'audio/x-wav'}));
+      else request.reject(new Error(message.error || 'Piper-arbetaren misslyckades.'));
+    }
+  };
+  worker.onerror = event => {
+    const error = new Error(event.message || 'Piper-arbetaren kunde inte startas.');
+    for (const request of pending.values()) request.reject(error);
+    pending.clear();
+    worker?.terminate();
+    worker = null;
+  };
+  return worker;
+}
+
+window.GamePiper = {
+  voiceId: 'sv_SE-nst-medium',
+  synthesize(text, onProgress) {
+    return new Promise((resolve, reject) => {
+      const id = ++requestId;
+      pending.set(id, {resolve, reject, onProgress});
+      try { getWorker().postMessage({id, text: String(text)}); }
+      catch (error) { pending.delete(id); reject(error); }
+    });
+  },
+};