Function useVoiceIntegration

src/hooks/useVoiceIntegration.tsx:118–347

({
  setInputValueRaw,
  inputValueRef,
  insertTextRef
}: UseVoiceIntegrationArgs)

  interimRange: InterimRange | null;
};
export function useVoiceIntegration({
  setInputValueRaw,
  inputValueRef,
  insertTextRef
}: UseVoiceIntegrationArgs): UseVoiceIntegrationResult {
  const {
    addNotification
  } = useNotifications();

  // Tracks the input content before/after the cursor when voice starts,
  // so interim transcripts can be inserted at the cursor position without
  // clobbering surrounding user text.
  const voicePrefixRef = useRef<string | null>(null);
  const voiceSuffixRef = useRef<string>('');
  // Tracks the last input value this hook wrote (via anchor, interim effect,
  // or handleVoiceTranscript). If inputValueRef.current diverges, the user
  // submitted or edited — both write paths bail to avoid clobbering. This is
  // the only guard that correctly handles empty-prefix-empty-suffix: a
  // startsWith('')/endsWith('') check vacuously passes, and a length check
  // can't distinguish a cleared input from a never-set one.
  const lastSetInputRef = useRef<string | null>(null);

  // Strip trailing hold-key chars (and optionally capture the voice
  // anchor). Called during warmup (to clean up chars that leaked past
  // stopImmediatePropagation — listener order is not guaranteed) and
  // on activation (with anchor=true to capture the prefix/suffix around
  // the cursor for interim transcript placement). The caller passes the
  // exact count it expects to strip so pre-existing chars at the
  // boundary are preserved (e.g. the "v" in "hav" when hold-key is "v").
  // The floor option sets a minimum trailing count to leave behind
  // (during warmup this is the count we intentionally let through, so
  // defensive cleanup only removes leaks). Returns the number of
  // trailing chars remaining after stripping. When nothing changes, no
  // state update is performed.
  const stripTrailing = useCallback((maxStrip: number, {
    char = ' ',
    anchor = false,
    floor = 0
  }: StripOpts = {}) => {
    const prev = inputValueRef.current;
    const offset = insertTextRef.current?.cursorOffset ?? prev.length;
    const beforeCursor = prev.slice(0, offset);
    const afterCursor = prev.slice(offset);
    // When the hold key is space, also count full-width spaces (U+3000)
    // that a CJK IME may have inserted for the same physical key.
    // U+3000 is BMP single-code-unit so indices align with beforeCursor.
    const scan = char === ' ' ? normalizeFullWidthSpace(beforeCursor) : beforeCursor;
    let trailing = 0;
    while (trailing < scan.length && scan[scan.length - 1 - trailing] === char) {
      trailing++;
    }
    const stripCount = Math.max(0, Math.min(trailing - floor, maxStrip));
    const remaining = trailing - stripCount;
    const stripped = beforeCursor.slice(0, beforeCursor.length - stripCount);
    // When anchoring with a non-space suffix, insert a gap space so the
    // waveform cursor sits on the gap instead of covering the first
    // suffix letter. The interim transcript effect maintains this same
    // structure (prefix + leading + interim + trailing + suffix), so