/***************************************************************************
 * Copyright (c) 2024 Microsoft Corporation
 * Copyright (c) 2026-present Eclipse ThreadX contributors
 *
 * This program and the accompanying materials are made available under the
 * terms of the MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 **************************************************************************/

/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** USBX Component                                                        */
/**                                                                       */
/**   Device Audio Class                                                  */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

#define UX_SOURCE_CODE


/* Include necessary system files.  */

#include "ux_api.h"
#include "ux_device_class_audio.h"
#include "ux_device_stack.h"


#if defined(UX_DEVICE_STANDALONE)
/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _ux_device_class_audio_write_task_function          PORTABLE C      */
/*                                                           6.3.0        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Yajun Xia, Microsoft Corporation                                    */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function is the background task of the audio stream write.     */
/*                                                                        */
/*    It's for standalone mode.                                           */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    audio_class                                 Address of audio class  */
/*                                                container               */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    State machine status                                                */
/*    UX_STATE_EXIT                         Device not configured         */
/*    UX_STATE_IDLE                         No streaming transfer running */
/*    UX_STATE_WAIT                         Streaming transfer running    */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    _ux_device_stack_transfer_run         Run transfer state machine    */
/*    _ux_utility_memory_copy               Copy memory                   */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    USBX Device Stack                                                   */
/*                                                                        */
/**************************************************************************/
UINT _ux_device_class_audio_write_task_function(UX_DEVICE_CLASS_AUDIO_STREAM *stream)
{
UX_SLAVE_DEVICE                 *device;
UX_SLAVE_ENDPOINT               *endpoint;
UX_SLAVE_TRANSFER               *transfer;
UCHAR                           *next_pos;
UX_DEVICE_CLASS_AUDIO_FRAME     *next_frame;
ULONG                           transfer_length;
ULONG                           actual_length;
UINT                            status;


    /* Get the pointer to the device.  */
    device = stream -> ux_device_class_audio_stream_audio -> ux_device_class_audio_device;

    /* Check if the device is configured.  */
    if (device -> ux_slave_device_state != UX_DEVICE_CONFIGURED)
    {
        stream -> ux_device_class_audio_stream_task_state = UX_STATE_EXIT;
        return(UX_STATE_EXIT);
    }

    /* Get the endpoint.  */
    endpoint = stream -> ux_device_class_audio_stream_endpoint;

    /* No endpoint ready, maybe it's alternate setting 0.  */
    if (endpoint == UX_NULL)
        return(UX_STATE_IDLE);

    /* Check if background transfer task is started.  */
    if (stream -> ux_device_class_audio_stream_task_state == UX_DEVICE_CLASS_AUDIO_STREAM_RW_STOP)
        return(UX_STATE_IDLE);

    /* Get transfer instance.  */
    transfer = &endpoint -> ux_slave_endpoint_transfer_request;

    /* If not started yet, prepare data, reset transfer and start polling.  */
    if (stream -> ux_device_class_audio_stream_task_state == UX_DEVICE_CLASS_AUDIO_STREAM_RW_START)
    {

        /* Next state: transfer wait.  */
        stream -> ux_device_class_audio_stream_task_state = UX_DEVICE_CLASS_AUDIO_STREAM_RW_WAIT;

        /* Start frame transfer anyway (even ZLP).  */
        transfer_length = stream -> ux_device_class_audio_stream_transfer_pos -> ux_device_class_audio_frame_length;

#if UX_DEVICE_ENDPOINT_BUFFER_OWNER == 0

        /* Stack owns buffer, copy data to it.  */
        if (transfer_length)
            _ux_utility_memory_copy(transfer -> ux_slave_transfer_request_data_pointer,
                stream -> ux_device_class_audio_stream_transfer_pos -> ux_device_class_audio_frame_data, transfer_length); /* Use case of memcpy is verified. */
#else

        /* Zero copy: directly use frame buffer to transfer.  */
        transfer -> ux_slave_transfer_request_data_pointer = stream ->
                    ux_device_class_audio_stream_transfer_pos -> ux_device_class_audio_frame_data;
#endif

        /* Reset transfer state.  */
        UX_SLAVE_TRANSFER_STATE_RESET(transfer);
    }

    /* Get current transfer length.  */
    transfer_length = stream -> ux_device_class_audio_stream_transfer_pos -> ux_device_class_audio_frame_length;

    /* Run transfer states.  */
    status = _ux_device_stack_transfer_run(transfer, transfer_length, transfer_length);

    /* Error case.  */
    if (status < UX_STATE_NEXT)
    {

        /* Error on background transfer task start.  */
        stream -> ux_device_class_audio_stream_task_state = UX_STATE_RESET;
        stream -> ux_device_class_audio_stream_task_status =
                        transfer -> ux_slave_transfer_request_completion_code;

        /* Error notification!  */
        _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_TRANSFER_ERROR);
        return(UX_STATE_EXIT);
    }

    /* Success case.  */
    if (status == UX_STATE_NEXT)
    {

        /* Next state: start.  */
        stream -> ux_device_class_audio_stream_task_state = UX_DEVICE_CLASS_AUDIO_STREAM_RW_START;
        stream -> ux_device_class_audio_stream_task_status =
                        transfer -> ux_slave_transfer_request_completion_code;

        /* Frame sent, free it.  */
        stream -> ux_device_class_audio_stream_transfer_pos -> ux_device_class_audio_frame_length = 0;

        /* Get actual transfer length.  */
        actual_length = transfer -> ux_slave_transfer_request_actual_length;

        /* Calculate next position.  */
        next_pos = (UCHAR *)stream -> ux_device_class_audio_stream_transfer_pos;
        next_pos += stream -> ux_device_class_audio_stream_frame_buffer_size;
        if (next_pos >= stream -> ux_device_class_audio_stream_buffer + stream -> ux_device_class_audio_stream_buffer_size)
            next_pos = stream -> ux_device_class_audio_stream_buffer;
        next_frame = (UX_DEVICE_CLASS_AUDIO_FRAME *)next_pos;

        /* Underflow check!  */
        if (transfer_length)
        {

            /* Advance position.  */
            stream -> ux_device_class_audio_stream_transfer_pos = next_frame;

            /* Error trap!  */
            if (next_frame -> ux_device_class_audio_frame_length == 0)
            {
                _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_BUFFER_OVERFLOW);
                stream -> ux_device_class_audio_stream_buffer_error_count ++;
            }
        }
        else
        {

            /* Advance position if next payload available.  */
            if (next_frame -> ux_device_class_audio_frame_length)
                stream -> ux_device_class_audio_stream_transfer_pos = next_frame;
            else
            {

                /* Error trap!  */
                _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_BUFFER_OVERFLOW);
                stream -> ux_device_class_audio_stream_buffer_error_count ++;
            }
        }

        /* Invoke notification callback.  */
        if (stream -> ux_device_class_audio_stream_callbacks.ux_device_class_audio_stream_frame_done != UX_NULL)
            stream -> ux_device_class_audio_stream_callbacks.ux_device_class_audio_stream_frame_done(stream, actual_length);
    }

    /* Keep waiting.  */
    return(UX_STATE_WAIT);
}
#endif

