#include <stdio.h>
#include <string.h>
#include "br_modbus.h"
#include <stdint.h>
#include "br_modbus_reg.h"


uint8_t * prv_rx_buffer;

static uint8_t BrMdBufferRes[256];
uint8_t BrMdBufferCmd[256] = {0};

uint8_t modbus_SlaveID = SLAVE_ID_DEFAULT;

uint8_t * modbus_FrameBuff;
uint8_t modbus_FrameCnt;

// Private function prototype.
void modbus_03_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen);
void modbus_06_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen);
void modbus_10_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen);




uint8_t modbus_extract_slaveid(void);
uint8_t modbus_extract_funcode(void);
uint16_t modbus_extract_startAddr(void);
uint8_t modbus_extract_size(void);
uint16_t modbus_extract_crc(uint8_t mFunCode);

uint16_t modbus_extract_06_val(void);
uint16_t modbus_extract_10_val(uint8_t idx);


void modbus_FrameClearBuff(void);
uint8_t modbus_FrameLoadByte(uint8_t aByte);
uint8_t modbus_FrameLoadWord(uint16_t aWord);

uint8_t modbus_extract_slaveid(void);
uint8_t modbus_extract_funcode(void);

/* --------------------------------------------------------------- */
uint16_t modbus_extract_10_bytenum(void);
uint16_t modbus_Retrieve16Value(uint8_t index);


static uint16_t modbus_crc16_v3( const unsigned char *buf, unsigned int len )
{
	static const uint16_t table[256] = {
	0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
	0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
	0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
	0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
	0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
	0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
	0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
	0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
	0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
	0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
	0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
	0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
	0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
	0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
	0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
	0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
	0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
	0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
	0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
	0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
	0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
	0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
	0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
	0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
	0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
	0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
	0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
	0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
	0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
	0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
	0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
	0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040 };

	uint8_t xor = 0;
	uint16_t crc = 0xFFFF;

	while(len--)
	{
		xor = (*buf++) ^ crc;
		crc >>= 8;
		crc ^= table[xor];
	}

	return crc;
}

// process modbus frame
ModbusStatus_t modbus_process(const uint8_t * buffer_cmd, uint8_t recv_len, uint8_t * buffer_resp, uint8_t * resp_len)
{
	uint8_t funCode;
	uint8_t slaveId;
	ModbusStatus_t status = MODBUS_STATUS_OK;

	memcpy(BrMdBufferCmd, buffer_cmd, recv_len);
	/* 提取slaveid */
	slaveId = modbus_extract_slaveid();

	/* 判断ID是否接受 */

	/* 提取funCode */
	funCode = modbus_extract_funcode();

	switch(funCode)
	{
	case 3:
		modbus_03_solver(slaveId, buffer_resp, resp_len);
		break;
	case 6:
		modbus_06_solver(slaveId, buffer_resp, resp_len);
		break;
	case 0x10:
		modbus_10_solver(slaveId, buffer_resp, resp_len);
	}
	return MODBUS_STATUS_OK;
}


uint8_t modbus_extract_slaveid(void)
{
	return BrMdBufferCmd[0];
}

uint8_t modbus_extract_funcode(void)
{
	return BrMdBufferCmd[MODBUS_FUN_CODE];
}

uint16_t modbus_extract_startAddr(void)
{
	return ((uint16_t)BrMdBufferCmd[MODBUS_START_ADDR_H]<<8) +
			BrMdBufferCmd[MODBUS_START_ADDR_L];
}

uint8_t modbus_extract_size(void)
{
	return ((uint16_t)BrMdBufferCmd[MODBUS_SIZE_H]<<8) +
			BrMdBufferCmd[MODBUS_SIZE_L];
}


uint16_t modbus_extract_crc(uint8_t mFunCode)
{
	uint16_t crcRecv = 0;
	uint16_t size = 0;
	if( mFunCode == 3U || mFunCode == 6U ) {
		crcRecv = (((uint16_t) BrMdBufferCmd[7] ) << 8) +
				BrMdBufferCmd[6];
	}
	if( mFunCode == 0x10)
	{

		size = modbus_extract_size();
		crcRecv = (((uint16_t) BrMdBufferCmd[8 + size * 2] ) << 8) +
				BrMdBufferCmd[7 + size * 2] ;
	}
	return crcRecv;
}


void modbus_03_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen)
{
	uint16_t startAddr, size;
	volatile uint16_t crcReceived,crcCalculate;
	uint8_t i;
	ModbusRegRwData_t rw_data;

	// get start reg address
	startAddr = modbus_extract_startAddr();
	size = modbus_extract_size();
	// get crc
	crcReceived = modbus_extract_crc(3);
	// calculate crc
	crcCalculate = modbus_crc16_v3(BrMdBufferCmd, 6);

	if(crcCalculate == crcReceived)
	{
		rw_data.slaveId = slaveId;
		rw_data.num = size;
		rw_data.operation = RW_OPERATION_READ;
		rw_data.startAddr = startAddr;
		
		if(modbus_reg_proxy(&rw_data) != 0)
		{
			/* 返回错误码 */
			printf("modbus_reg_proxy err!\n");
		}
		// clear frame buffer
		modbus_FrameClearBuff();
		// load adrress
		modbus_FrameLoadByte(modbus_SlaveID);
		// load fun code
		modbus_FrameLoadByte(3u);
		modbus_FrameLoadByte(size * 2);

		for(i = 0; i < size; i++)
		{
			modbus_FrameLoadWord(rw_data.registers[i]);
		}

		// crcCalculate = HAL_CRC_Calculate(&hcrc, (uint32_t *)&modbus_FrameBuff, modbus_FrameCnt);
		crcCalculate = modbus_crc16_v3(BrMdBufferRes, modbus_FrameCnt);
		modbus_FrameLoadByte(crcCalculate & 0x00FF);
		modbus_FrameLoadByte((crcCalculate & 0xFF00) >> 8);
		*resLen = modbus_FrameCnt;
		memcpy(resBuffer, BrMdBufferRes, *resLen);
	}
}




void modbus_06_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen)
{
	uint16_t startAddr, val, crcCal, crcRecv;
	ModbusRegRwData_t rw_data;


	startAddr = modbus_extract_startAddr();

	crcCal = modbus_crc16_v3(BrMdBufferCmd, 6);
	crcRecv = modbus_extract_crc(6);

	if( crcCal == crcRecv ) {
		val = modbus_extract_06_val();
		rw_data.slaveId = slaveId;
		rw_data.num = 1;
		rw_data.operation = RW_OPERATION_WRITE;
		rw_data.startAddr = startAddr;

		rw_data.registers[0] = val;
		if(modbus_reg_proxy(&rw_data) != 0)
		{
			/* 返回错误码 */
//			printf("modbus_reg_proxy err!\n");
			;
		}

		modbus_FrameClearBuff();
		modbus_FrameLoadByte(modbus_SlaveID);
		modbus_FrameLoadByte(6U);
		modbus_FrameLoadWord(startAddr);
		modbus_FrameLoadWord(val);
		modbus_FrameLoadWord(crcCal>>8 | crcCal << 8);
		*resLen = modbus_FrameCnt;
		memcpy(resBuffer, BrMdBufferRes, *resLen);
	}
	else
	{
		/* 校验码错误处理 */
	}

}

void modbus_10_solver(uint8_t slaveId, uint8_t * resBuffer, uint8_t * resLen)
{
	uint16_t address, byte_num, val, crcCal, crcRecv, size;
	uint8_t idx = 0;
	ModbusRegRwData_t rw_data = {0};

	address = modbus_extract_startAddr();
	byte_num = modbus_extract_10_bytenum();
	size = modbus_extract_size();

	crcCal = modbus_crc16_v3(BrMdBufferCmd, 7 + byte_num);
	crcRecv = modbus_extract_crc(0x10);


	if( crcCal == crcRecv ) {
		rw_data.slaveId = slaveId;
		rw_data.num = size;
		rw_data.operation = RW_OPERATION_WRITE;
		rw_data.startAddr = address;

		for(idx=0; idx<size; idx++)
		{
			val = modbus_extract_10_val(idx);
			rw_data.registers[idx] = val;
		}

		if(modbus_reg_proxy(&rw_data) != 0)
		{
			/* 返回错误码 */
//			printf("modbus_reg_proxy err!\n");
			;
		}


		/* ----------------------------------------- */

		modbus_FrameClearBuff();
		modbus_FrameLoadByte(modbus_SlaveID);
		modbus_FrameLoadByte(0x10u);
		modbus_FrameLoadWord(address);
		modbus_FrameLoadWord(size);
		crcCal = modbus_crc16_v3(BrMdBufferRes, modbus_FrameCnt);
		modbus_FrameLoadWord(crcCal>>8 | crcCal << 8);
		*resLen = modbus_FrameCnt;
		memcpy(resBuffer, BrMdBufferRes, *resLen);
	}
	else
	{
		/* 校验码错误处理 */
	}
}


uint16_t modbus_extract_10_bytenum(void)
{
	return BrMdBufferCmd[6];
}


uint16_t modbus_extract_10_val(uint8_t idx)
{
	return ((uint16_t)BrMdBufferCmd[7 + idx*2]<<8) +
			BrMdBufferCmd[8 + idx*2];
}

uint16_t modbus_extract_06_val(void)
{
	return ((uint16_t)BrMdBufferCmd[MODBUS_06_VAL_H]<<8) +
			BrMdBufferCmd[MODBUS_06_VAL_L];
}

uint8_t modbus_RetrieveSlaveID(void)
{
	return prv_rx_buffer[MODBUS_SLAVE_ID];
}



void modbus_FrameClearBuff(void){
	modbus_FrameCnt = 0;
}


uint8_t modbus_FrameLoadByte(uint8_t aByte)
{
	uint8_t status;

	if(modbus_FrameCnt == 255) {
		status = 1;
	}
	else {
		BrMdBufferRes[modbus_FrameCnt] = aByte;
		modbus_FrameCnt++;
		status = 0;
	}
	return status;
}


uint8_t modbus_FrameLoadWord(uint16_t aWord)
{
	uint8_t status;

	if(modbus_FrameCnt == 254)
	{
		status = 1;
	}
	else
	{
		BrMdBufferRes[modbus_FrameCnt] = (uint8_t)((aWord&0xFF00)>>8);
		modbus_FrameCnt++;
		BrMdBufferRes[modbus_FrameCnt] = (uint8_t)(aWord&0x00FF);
		modbus_FrameCnt++;
		status = 0;
	}
	return status;
}