narrator support

frontend/src/narrator.ts

@@ -0,0 +1,65 @@
+export interface NarratorSettings {
+  enabled: boolean
+  rate: number
+  pitch: number
+  voice: string
+  verbosity: 'brief' | 'normal' | 'verbose'
+  sounds: boolean
+}
+
+export const defaultNarratorSettings: NarratorSettings = {
+  enabled: false,
+  rate: 1.0,
+  pitch: 1.0,
+  voice: '',
+  verbosity: 'normal',
+  sounds: true,
+}
+
+let settings: NarratorSettings = { ...defaultNarratorSettings }
+
+export function updateSettings(s: NarratorSettings) {
+  settings = s
+}
+
+export function isSupported(): boolean {
+  return 'speechSynthesis' in window
+}
+
+export function getVoices(): SpeechSynthesisVoice[] {
+  if (!isSupported()) return []
+  return window.speechSynthesis.getVoices()
+}
+
+export function cancel() {
+  if (!isSupported()) return
+  window.speechSynthesis.cancel()
+}
+
+export function speak(text: string, interrupt = true) {
+  if (!isSupported() || !settings.enabled) return
+  if (interrupt) cancel()
+
+  const utterance = new SpeechSynthesisUtterance(text)
+  utterance.rate = settings.rate
+  utterance.pitch = settings.pitch
+
+  if (settings.voice) {
+    const voices = getVoices()
+    const match = voices.find(v => v.name === settings.voice)
+    if (match) utterance.voice = match
+  }
+
+  window.speechSynthesis.speak(utterance)
+}
+
+// voices load async - call this early so they're ready
+export function preloadVoices() {
+  if (!isSupported()) return
+  getVoices()
+  if (window.speechSynthesis.onvoiceschanged !== undefined) {
+    window.speechSynthesis.onvoiceschanged = () => {}
+  }
+}
+
+preloadVoices()