Safari: Expecting input hint should not block microphone access

[compulim]

Version

master

Describe the bug

On Safari (Mac and iOS), if the microphone is being opened without user interactions, Safari will block the access.

Technical details

To detect whether Safari block or not:

async function canOpenMicrophone() {
  const audioContext = new AudioContext();

  try {
    if (audioContext.state === 'suspended') {
      return await Promise.race([
        audioContext.resume().then(() => true),
        new Promise(resolve => setImmediate(resolve)).then(() => false)
      ]);
    }

    return true;
  } finally {
    await audioContext.close();
  }
}

Note: the result of this call is asynchronous and code executed after the result will fail user interaction requirement.

To Reproduce

Steps to reproduce the behavior:

1. Go to sample 06.c
2. Click on microphone
3. Say "input hint expected"
4. Wait until the bot response completed synthesis

Expected behavior

The microphone will open. Or on Safari, it should never open.

Actual, the microphone is being opened, but Safari blocked access and suspended our code.

[Bug]

[compulim]

The check function is not reliable across platforms.

This is because on Firefox, it will always be "suspended" even resumed, until the user clicked agree on the microphone consent dialog.