/**
 *!
 * \file        b_mod_protocol.c
 * \version     v0.1.0
 * \date        2020/03/15
 * \author      Bean(notrynohigh@outlook.com)
 *******************************************************************************
 * @attention
 *
 * Copyright (c) 2020 Bean
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *******************************************************************************
 */

/*Includes ----------------------------------------------*/
#include "modules/inc/b_mod_protocol.h"
#if _PROTO_ENABLE
#include <string.h>
/**
 * \addtogroup BABYOS
 * \{
 */

/**
 * \addtogroup MODULES
 * \{
 */

/**
 * \addtogroup PROTOCOL
 * \{
 */

/**
 * \defgroup PROTOCOL_Private_TypesDefinitions
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup PROTOCOL_Private_Defines
 * \{
 */
#if _PROTO_ENCRYPT_ENABLE
#define _PROTO_TEA_DELTA 0x9e3779b9
const static uint32_t Keys[4] = {_SECRET_KEY1, _SECRET_KEY2, _SECRET_KEY3, _SECRET_KEY4};
#endif
/**
 * \}
 */

/**
 * \defgroup PROTOCOL_Private_Macros
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup PROTOCOL_Private_Variables
 * \{
 */

static bProtocolInfo_t bProtocolInfo;
/**
 * \}
 */

/**
 * \defgroup PROTOCOL_Private_FunctionPrototypes
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup PROTOCOL_Private_Functions
 * \{
 */
static uint8_t _bProtocolCalCheck(uint8_t *pbuf, bProtoLen_t len)
{
    uint8_t     tmp;
    bProtoLen_t i;
    tmp = pbuf[0];
    for (i = 1; i < len; i++)
    {
        tmp += pbuf[i];
    }
    return tmp;
}

#if _PROTO_ENCRYPT_ENABLE
static void _bProtocolEncryptGroup(uint32_t *text, uint32_t *key)
{
    uint32_t sum = 0, v0 = text[0], v1 = text[1];
    uint32_t k0 = key[0], k1 = key[1], k2 = key[2], k3 = key[3];
    int      i = 0;

    for (i = 0; i < 16; i++)
    {
        sum += _PROTO_TEA_DELTA;
        v0 += (v1 << 4) + k0 ^ v1 + sum ^ (v1 >> 5) + k1;
        v1 += (v0 << 4) + k2 ^ v0 + sum ^ (v0 >> 5) + k3;
    }
    text[0] = v0;
    text[1] = v1;
}

static void _bProtocolDecryptGroup(uint32_t *text, uint32_t *key)
{
    uint32_t sum = _PROTO_TEA_DELTA * 16, v0 = text[0], v1 = text[1];
    uint32_t k0 = key[0], k1 = key[1], k2 = key[2], k3 = key[3];
    int      i = 0;

    for (i = 0; i < 16; i++)
    {
        v1 -= (v0 << 4) + k2 ^ v0 + sum ^ (v0 >> 5) + k3;
        v0 -= (v1 << 4) + k0 ^ v1 + sum ^ (v1 >> 5) + k1;
        sum -= _PROTO_TEA_DELTA;
    }
    text[0] = v0;
    text[1] = v1;
}

static void _bProtocolEncrypt(uint8_t *text, uint32_t size)
{
    uint32_t number = size >> 3;
    int      i      = 0;

    if (size < 8)
    {
        return;
    }
    for (i = 0; i < number; i++)
    {
        _bProtocolEncryptGroup(&(((uint32_t *)text)[i * 2]), (uint32_t *)Keys);
    }
}

static void _bProtocolDecrypt(uint8_t *text, uint32_t size)
{
    uint32_t number = size >> 3;
    int      i      = 0;

    if (size < 8)
    {
        return;
    }

    for (i = 0; i < number; i++)
    {
        _bProtocolDecryptGroup(&(((uint32_t *)text)[i * 2]), (uint32_t *)Keys);
    }
}
#endif

/**
 * \}
 */

/**
 * \addtogroup PROTOCOL_Exported_Functions
 * \{
 */

/**
 * \brief Initialize protocol instance
 * \param id system id
 * \param f Dispatch Function \ref pdispatch
 * \retval Result
 *          \arg 0  OK
 *          \arg -1 ERR
 */
int bProtocolInit(bProtoID_t id, pdispatch f)
{
    if (f == NULL)
    {
        return -1;
    }
    bProtocolInfo.id = id;
    bProtocolInfo.f  = f;
    return 0;
}

/**
 * \brief Check ID and call dispatch function
 * \param pbuf Pointer to data buffer
 * \param len Amount of data
 * \retval Result
 *          \arg 0  OK
 *          \arg -1 ERR
 */
int bProtocolParse(uint8_t *pbuf, bProtoLen_t len)
{
    bProtocolHead_t *phead = (bProtocolHead_t *)pbuf;
    int              length;
    uint8_t          crc;
    if (pbuf == NULL || len < (sizeof(bProtocolHead_t) + 1))
    {
        return -1;
    }
#if _PROTO_ENCRYPT_ENABLE
    _bProtocolDecrypt(pbuf, len);
#endif
    if (phead->head != PROTOCOL_HEAD ||
        (phead->device_id != bProtocolInfo.id && (phead->device_id != INVALID_ID) &&
         (bProtocolInfo.id != INVALID_ID)))
    {
        return -1;
    }

    length = phead->len + sizeof(bProtocolHead_t);
    if (length > len)
    {
        return -1;
    }
    crc = _bProtocolCalCheck(pbuf, length - 1);
    if (crc != pbuf[length - 1])
    {
        b_log_e("crc error!%d %d", crc, pbuf[length - 1]);
        return -1;
    }
    return bProtocolInfo.f(phead->cmd, &pbuf[sizeof(bProtocolHead_t)], phead->len - 1);
}

/**
 * \brief Call this function after system ID changed
 * \param id System ID
 * \retval Result
 *          \arg 0  OK
 *          \arg -1 ERR
 */
int bProtocolSetID(bProtoID_t id)
{
    bProtocolInfo.id = id;
    return 0;
}

/**
 * \brief pack and start a TX request
 * \param cmd Protocol command
 * \param param Pointer to the command param
 * \param param_size size of the param
 * \param pbuf Pointer to the buffer that save the packed data
 * \retval Result
 *          \arg >0 Amount of data in the pbuf
 *          \arg -1 ERR
 */
int bProtocolPack(uint8_t cmd, uint8_t *param, bProtoLen_t param_size, uint8_t *pbuf)
{
    int              length = 0;
    bProtocolHead_t *phead;

    if ((param == NULL && param_size > 0) || pbuf == NULL)
    {
        return -1;
    }
    phead            = (bProtocolHead_t *)pbuf;
    phead->head      = PROTOCOL_HEAD;
    phead->device_id = bProtocolInfo.id;
    phead->cmd       = cmd;
    phead->len       = 1 + param_size;
    memcpy(&pbuf[sizeof(bProtocolHead_t)], param, param_size);
    length           = sizeof(bProtocolHead_t) + phead->len;
    pbuf[length - 1] = _bProtocolCalCheck(pbuf, length - 1);
#if _PROTO_ENCRYPT_ENABLE
    _bProtocolEncrypt(pbuf, length);
#endif
    return length;
}

/**
 * \}
 */

/**
 * \}
 */

/**
 * \}
 */

/**
 * \}
 */
#endif

/************************ Copyright (c) 2019 Bean *****END OF FILE****/