!7

// Goes well with a headphone detector like #1027532

cmodule AudioFeedbackPreventer > DynPrintLogAndEnabled {
  // from end of talking to recognition coming in
  switchable double expectedDelay = 3.0;
  
  transient long talkingSince;
  transient LongRange lastTalked;
  
  start {
    dm_registerAs_direct audioFeedbackPreventer();
    dm_vmBus_onMessage talking(r { talkingSince = sysNow() });
    dm_vmBus_onMessage doneTalking(r {
      lastTalked = longRange(talkingSince, sysNow());
      talkingSince = 0;
    });
  }
  
  // API
  
  bool recognizedSpeechIsProbablyMyOwnUtterance(O... _) {
    if (isTrue(dm_haveHeadphones())) {
      // Voice output goes to headphones, so we can't hear it
      print("Assuming I can't hear myself (headphones)");
      false;
    }
    if (talkingSince != 0) true;
    if (lastTalked == null) false;
    double elapsed = elapsedSeconds_sysNow(lastTalked.end);
    bool b = elapsed <= expectedDelay;
    if (nempty(_)) print(asList(_));
    print("Time since my last utterance: " + formatDouble(elapsed, 1) + "s, guessing it is " + (b ? "" : "not ") + " my utterance");
    ret b;
  }
}