/* This code shows an example of opening an audio stream */

/* Specify the Audio Stream format details that this application supports */
const APP_USB_HOST_AUDIO_STREAM_FORTMAT audioSpeakerStreamFormat =
{

    .streamDirection = USB_HOST_AUDIO_V1_0_DIRECTION_OUT,
    .format = USB_AUDIO_FORMAT_PCM,
    .nChannels = 2,
    .bitResolution = 16,
    .subFrameSize = 2,
    .samplingRate = 48000
};

bool isAudioDeviceAttached = false;
USB_HOST_AUDIO_V1_0_OBJ audioDeviceObj;

/*************************************************************/
/* Function to search for a specific Audio Stream */
/************************************************************/
USB_HOST_AUDIO_V1_0_STREAM_OBJ App_USBHostAudioSpeakerStreamFind
(
    USB_HOST_AUDIO_V1_0_OBJ audioDeviceObj,
    APP_USB_HOST_AUDIO_STREAM_FORTMAT audioStream,
    uint8_t* numberofStreamGroups
)
{
    USB_HOST_AUDIO_V1_0_RESULT result;
    USB_HOST_AUDIO_V1_0_STREAM_INFO streamInfo;

    /* Get Number of Stream Groups */
    *numberofStreamGroups = USB_HOST_AUDIO_V1_0_NumberOfStreamGroupsGet(audioDeviceObj);
    if (*numberofStreamGroups == 0)
    {
        return (USB_HOST_AUDIO_V1_0_STREAM_OBJ)0;
    }
    /* Get the First Stream Information in the Stream Group */
    result = USB_HOST_AUDIO_V1_0_StreamGetFirst(appData.audioDeviceObj, 0, &streamInfo);
    if (result == USB_HOST_AUDIO_V1_0_RESULT_SUCCESS)
    {
         /* Compare Audio Stream info */
        if ((streamInfo.format == audioStream.format)
            && (streamInfo.streamDirection == audioStream.streamDirection)
                    && (streamInfo.nChannels == audioStream.nChannels)
                    && (streamInfo.bitResolution == audioStream.bitResolution)
                    && (streamInfo.subFrameSize == audioStream.subFrameSize))
        {
            return streamInfo.streamObj;
        }
    }
    return (USB_HOST_AUDIO_V1_0_STREAM_OBJ)0;
}

/*************************************************************/
/* Audio attach event listener function */
/************************************************************/
void APP_USBHostAudioAttachEventListener
(
    USB_HOST_AUDIO_V1_0_OBJ audioObj,
    USB_HOST_AUDIO_V1_0_EVENT event,
    uintptr_t context
)
{
    /* This function gets called when the Audio v1.0 device is attached/detached. In this
     * example we let the application know that a device is attached and we
     * store the Audio v1.0 device object. This object will be required to open the
     * device. */
    switch (event)
    {
        case USB_HOST_AUDIO_V1_0_EVENT_ATTACH:
            if (isAudioDeviceAttached == false)
            {
                isAudioDeviceAttached = true;
                audioDeviceObj = audioObj;
            }
            else
            {
                /* This application supports only one Audio Device . Handle Error Here.*/
            }
        break;
        case USB_HOST_AUDIO_V1_0_EVENT_DETACH:
            if (isAudioDeviceAttached == true)
            {
                /* This means the device was detached. There is no event data
                 * associated with this event.*/
                isAudioDeviceAttached = false;
                break;
            }
        break;
    }
}

/*************************************************************/
/* Audio Tasks function */
/************************************************************/
void APP_Tasks ( void )
{
    USB_HOST_AUDIO_V1_0_RESULT audioResult;
    USB_HOST_AUDIO_V1_0_STREAM_RESULT streamResult;

    /* Check the application's current state. */
    switch ( appData.state )
    {
        case APP_STATE_BUS_ENABLE:

            /* Register a callback for Audio Device Attach. */
            audioResult = USB_HOST_AUDIO_V1_0_AttachEventHandlerSet
                          (
                              &APP_USBHostAudioAttachEventListener,
                              (uintptr_t)0
                          );

            if (audioResult == USB_HOST_AUDIO_V1_0_RESULT_SUCCESS )
            {
                /* Set Host Event Handler */
                USB_HOST_EventHandlerSet(APP_USBHostEventHandler, 0);
                USB_HOST_BusEnable(0);
                /* Advance application state */
                appData.state = APP_STATE_WAIT_FOR_BUS_ENABLE_COMPLETE;
            }
            break;

        case APP_STATE_WAIT_FOR_BUS_ENABLE_COMPLETE:
            if(USB_HOST_BusIsEnabled(0))
            {
                appData.state = APP_STATE_WAIT_FOR_DEVICE_ATTACH;
            }
            break;

        case APP_STATE_WAIT_FOR_DEVICE_ATTACH:
            /* Check if an Audio Device has been attached  */
            if(appData.isAudioDeviceAttached == true)
            {
                appData.nAudioStreamGroups = 0;
                /* Find an Audio Stream matching to our requirement */
                appData.ouStreamObj = App_USBHostAudioSpeakerStreamFind
                                      (
                                          appData.audioDeviceObj,
                                          audioSpeakerStreamFormat,
                                          &appData.nAudioStreamGroups
                                      );
                if (appData.nAudioStreamGroups == 0)
                {
                    appData.state = APP_STATE_ERROR;
                    break;
                }

                /* Open Audio Stream */
                appData.outStreamHandle = USB_HOST_AUDIO_V1_0_StreamOpen
                                          (
                                              appData.ouStreamObj
                                          );

                if (appData.outStreamHandle == USB_HOST_AUDIO_V1_0_STREAM_HANDLE_INVALID)
                {
                    appData.state = APP_STATE_ERROR;
                    break;
                }
            }
            break;

        default:
            break;
    }
}