// Simply say what is to be said
public async Task SpeakWithDelay(string prompt)
{
if (this.isUsingSpeech)
{
int msRemainingDelay = await TextToSpeechServiceHelper.SpeakTextAsync(prompt);
await Task.Delay(msRemainingDelay);
}
}
// Start speaking, but stop if nobody is in front of camera
public async Task SpeakWhileCheckingPresence(string prompt)
{
if (this.isUsingSpeech)
{
int msTimeToSpeak = await TextToSpeechServiceHelper.SpeakTextAsync(prompt);
DateTime startSpeakTime = DateTime.Now;
DateTime endSpeakTime = startSpeakTime.AddMilliseconds(msTimeToSpeak);
while (DateTime.Now < endSpeakTime && this.isEngagingCustomer)
{
if (await SendOffIfNoFace())
{
break;
}
await Task.Delay(500); // we can be lax with timeout here, since we are not listening
}
}
}
// Verify that no face is in front of camera, cancel current speaking and speak send-off message if allowed
public async Task <bool> SendOffIfNoFace()
{
bool doSendOff = true;
// Verify that there is indeed no face there (we do not want to be too sensitive when customer looks away)
for (int i = 0; i < 20; i++)
{
if (this.cameraControl.NumFacesOnLastFrame != 0)
{
doSendOff = false;
break;
}
await Task.Delay(300); // TODO: tune this up for optimal customer experience
}
// Send off the customer
if (doSendOff)
{
if (this.isUsingSpeech)
{
await TextToSpeechServiceHelper.SpeakTextAsync("");
await Task.Delay(1000);
}
if (this.allowSendingOffMsg)
{
this.allowSendingOffMsg = false; // DRY
if (this.isUsingSpeech)
{
await TextToSpeechServiceHelper.SpeakTextAsync(this.sendoffMessage);
}
}
}
return(doSendOff);
}