/*
 *  Copyright (c) 2017, The OpenThread Authors.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file
 *   This file implements the OpenThread platform abstraction for UART communication.
 *
 */

#include <stddef.h>

#include "platform-emsk.h"
#include <utils/code_utils.h>
#include "openthread/platform/uart.h"

#include <stdio.h>
#define DBG(fmt, ...) printf(fmt, ##__VA_ARGS__)

enum
{
    kUartId            = BOARD_CONSOLE_UART_ID,
    kBaudRate          = BOARD_CONSOLE_UART_BAUD,
    kReceiveBufferSize = 128,
};

static void processReceive(void);
static void processTransmit(void);

static const uint8_t *sTransmitBuffer = NULL;
static uint16_t       sTransmitLength = 0;

static uint8_t  sReceiveBuffer[kReceiveBufferSize];
static uint16_t sReceiveHead = 0;

static DEV_UART *consoleUart;

otError otPlatUartEnable(void)
{
    int32_t stateUart = 0;
    otError error     = OT_ERROR_DROP;

    /* UART in embARC */
    consoleUart = uart_get_dev(BOARD_CONSOLE_UART_ID);

    otEXPECT_ACTION(!(consoleUart == NULL), DBG("Console UART is missing.\r\n"));

    stateUart = consoleUart->uart_open(BOARD_CONSOLE_UART_BAUD);

    if (stateUart == E_OPNED)
    {
        consoleUart->uart_control(UART_CMD_SET_BAUD, (void *)(BOARD_CONSOLE_UART_BAUD));
        error = OT_ERROR_NONE;
        DBG("Set Console UART Baudrate to %d.\r\n", BOARD_CONSOLE_UART_BAUD);
    }
    else if (stateUart == E_OK)
    {
        error = OT_ERROR_NONE;
        DBG("Open Console UART Successfully.\r\n");
    }
    else
    {
        DBG("Open Console UART Error.\r\n");
    }

exit:

    return error;
}

otError otPlatUartDisable(void)
{
    return OT_ERROR_NONE;
}

otError otPlatUartSend(const uint8_t *aBuf, uint16_t aBufLength)
{
    otError error = OT_ERROR_NONE;

    otEXPECT_ACTION(sTransmitBuffer == NULL, error = OT_ERROR_BUSY);

    sTransmitBuffer = aBuf;
    sTransmitLength = aBufLength;

exit:
    return error;
}

void processReceive(void)
{
    int32_t  rdAvail = 0;
    uint16_t remaining;

    consoleUart->uart_control(UART_CMD_GET_RXAVAIL, (void *)(&rdAvail));
    otEXPECT_ACTION(rdAvail > 0, ;);

    remaining = kReceiveBufferSize - sReceiveHead;

    if (rdAvail >= remaining)
    {
        consoleUart->uart_read((void *)(sReceiveBuffer + sReceiveHead), (uint32_t)remaining);
        otPlatUartReceived(sReceiveBuffer + sReceiveHead, remaining);
        sReceiveHead = 0;
        rdAvail -= (int32_t)remaining;
    }

    while (rdAvail >= kReceiveBufferSize)
    {
        consoleUart->uart_read((void *)(sReceiveBuffer + sReceiveHead), (uint32_t)kReceiveBufferSize);
        otPlatUartReceived(sReceiveBuffer + sReceiveHead, kReceiveBufferSize);
        rdAvail -= kReceiveBufferSize;
    }

    if (rdAvail > 0)
    {
        consoleUart->uart_read((void *)(sReceiveBuffer + sReceiveHead), (uint32_t)rdAvail);
        otPlatUartReceived(sReceiveBuffer + sReceiveHead, rdAvail);
        sReceiveHead += (uint16_t)rdAvail;
    }

exit:
    return;
}

void processTransmit(void)
{
    otEXPECT_ACTION(sTransmitBuffer != NULL, ;);

    consoleUart->uart_write((void *)sTransmitBuffer, (int32_t)sTransmitLength);

    sTransmitBuffer = NULL;
    otPlatUartSendDone();

exit:
    return;
}

void emskUartProcess(void)
{
    processReceive();
    processTransmit();
}