<html>
    <head>
        <script src='media-file.js'></script>
        <script src='video-test.js'></script>
        <script>
            var video;
            var callbackId;

            var nextStep;

            function start()
            {
                findMediaElement();

                if (window.internals) {
                    internals.setMockMediaPlaybackTargetPickerEnabled(true);
                    internals.settings.setAllowsAirPlayForMediaPlayback(true);
                }

                consoleWrite('<br>** test initial callback when device is unavailable');

                video.remote.watchAvailability(step).then(setCallbackId).catch(failTest);
                nextStep = initial;
            }

            function setCallbackId(id)
            {
                callbackId = id;
            }

            function step(available)
            {
                consoleWrite(`CALLBACK( available=${available} )`);

                if (nextStep)
                    nextStep(available);
            }

            function initial(available)
            {
                consoleWrite('<br>** simulate device becoming available');
                if (window.internals)
                    internals.setMockMediaPlaybackTargetPickerState('Sleepy TV', 'DeviceAvailable');
                nextStep = haveTarget;
            }

            function haveTarget(available)
            {
                consoleWrite('<br>** test initial callback when device is available');

                video.remote.cancelWatchAvailability(callbackId);
                video.remote.watchAvailability(step).then(setCallbackId).catch(failTest);
                nextStep = initialWithTarget;
            }

            function initialWithTarget(available)
            {
                consoleWrite('<br>** simulate device becoming unavailable');
                if (window.internals)
                    internals.setMockMediaPlaybackTargetPickerState('Sleepy TV', 'DeviceUnavailable');
                nextStep = endTest;

            }
        </script>
    </head>

    <body onload='start()'>
        <video controls></video>
        <p>Test that 'RemotePlaybackAvailabilityCallback' callback is called when playback devices come and go.</p>
    </body>
</html>