#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <byteswap.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <gfa/gfaserial.h>
#include "output.h"
#include "error.h"
#include "modbmst.h"

// Table of CRC values for high-order byte
static const uint8_t g_crcHi[] =
{
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
};

// Table of CRC values for low-order byte
static const uint8_t g_crcLo[] =
{
    0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
    0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
    0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
    0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
    0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
    0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
    0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
    0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
    0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
    0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
    0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
    0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
    0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
    0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
    0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
    0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
    0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
    0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
    0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
    0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
    0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
    0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
    0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
    0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
    0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
    0x43, 0x83, 0x41, 0x81, 0x80, 0x40
};

/////////////////////////////////////////////////////////////////////////////

#define _PING_SIGNATURE									0xA55A

/////////////////////////////////////////////////////////////////////////////

typedef struct _GFA_MB_MST
{
	HGFAMINEMST hMiNeMst;
	HMINETDEV hMiNeDev;
	int nVerbosity;
	FILE *pDumpCtx;
	uint32_t nBaudrate;
	uint16_t nModbusCtrlReg;
	struct timespec tsStart;
	uint8_t parity;
}GFA_MB_MST, *LPGFA_MB_MST;
typedef const GFA_MB_MST *LPCGFA_MB_MST;

/////////////////////////////////////////////////////////////////////////////

const struct timespec* Ns2Timespec(uint64_t nsTime, struct timespec *pts);
int64_t TimespecDiff(const struct timespec *pts1, const struct timespec *pts2);

/////////////////////////////////////////////////////////////////////////////

static uint16_t _Crc16(const void *pData, size_t nCbData)
{
	const uint8_t *pBuffer = (const uint8_t*)pData;
    uint8_t crcHi = 0xFF;	// high CRC byte initialized
    uint8_t crcLo = 0xFF;	// low CRC byte initialized
    unsigned int i;			// will index into CRC lookup

    while(nCbData--)
    {
        i = crcHi ^ *pBuffer++;
        crcHi = crcLo ^ g_crcHi[i];
        crcLo = g_crcLo[i];
    }

    return (((uint16_t)crcHi << 8) | (uint16_t)crcLo);
}

/////////////////////////////////////////////////////////////////////////////

static void _CpyUnalignedUint16(void *pTo, const void *pFrom, size_t nCntWords)
{
	size_t i, j;
	uint8_t *p1 = (uint8_t*)pTo;
	const uint8_t *p2 = (const uint8_t*)pFrom;
	for(i = 0; i < nCntWords; i++)
	{
		p2 += sizeof(uint16_t);
		for(j = 0; j < sizeof(uint16_t); j++)
		{
			*p1++ = *--p2;
		}
		p2 += sizeof(uint16_t);
	}
}

/////////////////////////////////////////////////////////////////////////////

HGFAMBMST GfaMbMstOpen(HGFAMINEMST hMiNeMst, uint32_t nBaudrate, uint8_t parity, uint16_t nModbusCtrlReg)
{
	if(hMiNeMst)
	{
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)malloc(sizeof(GFA_MB_MST));
		memset(pMst, 0, sizeof(GFA_MB_MST));
		pMst->hMiNeMst			= hMiNeMst;
		pMst->hMiNeDev			= GfaMininetMasterGetDeviceHandle(hMiNeMst);
		pMst->nBaudrate			= nBaudrate;
		pMst->parity			= parity;
		pMst->nModbusCtrlReg	= nModbusCtrlReg;
		pMst->nVerbosity		= 2;
		pMst->pDumpCtx			= stdout;
		GfaMininetMasterGetStartClock(hMiNeMst, &pMst->tsStart);
		return (HGFAMBMST)pMst;
	}

	errno = EINVAL;
	return NULL;
}

/////////////////////////////////////////////////////////////////////////////

void GfaMbMstClose(HGFAMBMST hMst)
{
	if(hMst)
	{
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;
		free(pMst);
	}
}

/////////////////////////////////////////////////////////////////////////////

int GfaMbMstSetVerbosity(HGFAMBMST hMst, int nVerbosity)
{
	if(hMst)
	{
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;
		if(nVerbosity < 0)
			nVerbosity = 0;
		else if(nVerbosity > 4)
			nVerbosity = 4;
		pMst->nVerbosity = nVerbosity;
		return 0;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

ssize_t GfaMbMstCreateADU(uint8_t slvID, uint8_t func, const void *pData, size_t nCbData, LPMODBUS_RTU_ADU pAdu)
{
	if(	pAdu &&
		MODBUS_IS_VALID_SLAVE_ID(slvID))
	{
		uint16_t nCRC16;
		size_t nCbAdu = 2;

		pAdu->slvID	= slvID;
		pAdu->func	= func;

		if(pData && nCbData)
		{
			if((nCbData > MODBUS_MAX_DATA_PAYLOAD))
			{
				errno = ENOMEM;
				return -1;
			}

			memcpy(pAdu->b, pData, nCbData);
			nCbAdu += nCbData;
		}
		else
		{
			nCbData = 0;
		}

		nCRC16 = _Crc16(pAdu, nCbAdu);
		_CpyUnalignedUint16(&pAdu->b[nCbData], &nCRC16, 1);
		nCbAdu += sizeof(nCRC16);
		return nCbAdu;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

bool GfaMbMstValidateADU(uint8_t slvID, uint8_t func, LPCMODBUS_RTU_ADU pAdu, size_t nCbAdu, int *pnMbErr)
{
	bool bRet;
	uint16_t nCRC16Received, nCRC16Expected;
	if(pnMbErr)
		*pnMbErr = 0;
	if(pAdu->slvID != slvID)
	{
		errno = EPROTO;
		return false;
	}
	else if(pAdu->func != func)
	{
		if((pAdu->func != (func | MB_FUNC_ERROR_FLAG)) || (nCbAdu != 5))
		{
			errno = EPROTO;
			return false;
		}
		else if(pnMbErr)
			*pnMbErr = pAdu->b[0];
	}
	_CpyUnalignedUint16(&nCRC16Received, ((uint8_t*)pAdu) + nCbAdu - sizeof(uint16_t), sizeof(uint16_t));
	nCRC16Expected = _Crc16(pAdu, nCbAdu - sizeof(uint16_t));
	if(!(bRet = (nCRC16Received == nCRC16Expected)))
		errno = EPROTO;
	return bRet;
}

/////////////////////////////////////////////////////////////////////////////

void GfaMbMstWaitFrameDelay(HGFAMBMST hMst)
{
	if(hMst)
	{
		uint32_t nDelay, nBaudrate;
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;

		if(	!GfaMininetDeviceGetBaudrate(pMst->hMiNeDev, &nBaudrate) &&
			nBaudrate <= 19200)
			nDelay = (350000000 / nBaudrate + 5) / 10;
		else
			nDelay = 1750;
		usleep(nDelay);
	}
}

/////////////////////////////////////////////////////////////////////////////

ssize_t GfaMbMstSendADU(HGFAMBMST hMst, LPCMODBUS_RTU_ADU pAdu, size_t nCbAdu)
{
	if(hMst && pAdu && nCbAdu >= 4)
	{
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;
		GfaMbMstDumpADU(hMst, pAdu, nCbAdu, true, NULL);
		return GfaMininetDeviceTransmit(pMst->hMiNeDev, pAdu, nCbAdu);
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

ssize_t GfaMbMstRecvADU(HGFAMBMST hMst, LPMODBUS_RTU_ADU pAdu, size_t nCbAdu)
{
	if(hMst && pAdu && nCbAdu >= 4)
	{
		ssize_t nRet;
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;
		if((nRet = GfaMininetDeviceReceive(pMst->hMiNeDev, pAdu, nCbAdu)) > 0)
			GfaMbMstDumpADU(hMst, pAdu, nCbAdu, false, NULL);
		return nRet;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

void GfaMbMstDumpADU(HGFAMBMST hMst, LPCMODBUS_RTU_ADU pAdu, size_t nCbAdu, bool bTX, const char *pszAnnotation)
{
	if(hMst && pAdu && nCbAdu)
	{
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;
		FILE *pf = pMst->pDumpCtx;
		
		if(pf && (pMst->nVerbosity >= 4))
		{
			size_t i, nCbData = nCbAdu - 4;
			uint16_t nCRC16;
			struct timespec tsCur, tsIntv;
			clock_gettime(CLOCK_MONOTONIC, &tsCur);
			uint64_t nInterval = TimespecDiff(&tsCur, &pMst->tsStart);
			Ns2Timespec(nInterval, &tsIntv);

			if(nCbAdu >= 4)
			{
				fprintf(pf, "\n///////////////////////////////////////\n");
				fprintf(pf, "// Modbus - %ld.%03ld\n", tsIntv.tv_sec, tsIntv.tv_nsec / 1000000);
				fprintf(pf, "// %s:\n", bTX ? "TX" : "RX");
				fprintf(pf, "SlvID:  %02hhX (%hhu)\n", pAdu->slvID, pAdu->slvID);
				fprintf(pf, "Func:   %02hhX (%hhu)\n", pAdu->func, pAdu->func);
				fprintf(pf, "Data:   ");

				for(i = 0; i < nCbData; i++)
				{
					fprintf(pf, "[%02hhX]", (char)pAdu->b[i]);
				}

				_CpyUnalignedUint16(&nCRC16, &pAdu->b[i], 1);
				fprintf(pf, "\nCRC16:  %02hX (%hu)\n", nCRC16, nCRC16);
				if(pszAnnotation)
				fprintf(pf, "Annot.: %s\n", pszAnnotation);
			}
			else
			{
				fprintf(pf, "\n///////////////////////////////////////\n");
				fprintf(pf, "// Modbus - %ld:%03ld\n", tsIntv.tv_sec, tsIntv.tv_nsec / 1000000);
				fprintf(pf, "// %s:\n", bTX ? "TX" : "RX");
				fprintf(pf, "Invalid Modbus-Frame!\n");
			}

			fprintf(pf, "\n");
			fflush(pf);
		}
	}
}

/////////////////////////////////////////////////////////////////////////////

ssize_t GfaMbMstReadHoldingRegisters(HGFAMBMST hMst, uint8_t slvID, uint16_t nRegStart, uint16_t nRegCount, void *pRegs)
{
	if(hMst && pRegs && nRegCount > 0)
	{
		int nMBErr;
		ssize_t nRet;
		uint8_t func = MB_FUNC_READ_HOLDING_REGISTERS;
		MODBUS_RTU_ADU adu;
		size_t nCbExpt = 5 + (nRegCount * sizeof(uint16_t));
		uint8_t ri[4];

		_CpyUnalignedUint16(&ri[0], &nRegStart, 1);
		_CpyUnalignedUint16(&ri[2], &nRegCount, 1);

		if((nRet = GfaMbMstCreateADU(slvID, func, &ri, sizeof(ri), &adu)) < 0)
			return nRet;

		if((nRet = GfaMbMstSendADU(hMst, &adu, nRet)) < 0)
			return nRet;

		if((nRet = GfaMbMstRecvADU(hMst, &adu, nCbExpt)) <= 0)
			return -1;
		
		if(!GfaMbMstValidateADU(slvID, func, &adu, nRet, &nMBErr))
			return -1;
		
		if(nMBErr)
		{
			errno = MAKE_GFA_MODBUS_ERROR(nMBErr);
			return -1;
		}
		else if(nRet != (int)(5 + nRegCount * sizeof(uint16_t)))
		{
			errno = EPROTO;
			return -1;
		}
		else if(adu.b[0] != (nRegCount * sizeof(uint16_t)))
		{
			errno = EPROTO;
			return -1;
		}

		_CpyUnalignedUint16(pRegs, &adu.b[1], nRegCount);
		return 0;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

ssize_t GfaMbMstWriteMultipleRegisters(HGFAMBMST hMst, uint8_t slvID, uint16_t nRegStart, uint16_t nRegCount, const void *pRegs)
{
	if(hMst && pRegs && nRegCount > 0)
	{
		int nMBErr;
		ssize_t nRet;
		MODBUS_RTU_ADU adu;
		uint8_t func = MB_FUNC_WRITE_MULTIPLE_REGISTERS;
		uint8_t data[MODBUS_MAX_DATA_PAYLOAD];

		_CpyUnalignedUint16(&data[0], &nRegStart, 1);
		_CpyUnalignedUint16(&data[2], &nRegCount, 1);
		data[4] = (uint8_t)(nRegCount * sizeof(uint16_t));
		_CpyUnalignedUint16(&data[5], pRegs, nRegCount);

		if((nRet = GfaMbMstCreateADU(slvID, func, &data, 5 + nRegCount * sizeof(uint16_t), &adu)) < 0)
			return -1;

		if((nRet = GfaMbMstSendADU(hMst, &adu, nRet)) < 0)
			return -1;

		if((nRet = GfaMbMstRecvADU(hMst, &adu, 8)) <= 0)
			return -1;
		
		if(!GfaMbMstValidateADU(slvID, func, &adu, nRet, &nMBErr))
			return -1;
		
		if(nMBErr)
		{
			errno = MAKE_GFA_MODBUS_ERROR(nMBErr);
			return -1;
		}
		else if(nRet != 8)
		{
			errno = EPROTO;
			return -1;
		}
		else if((bswap_16(adu.w[0]) != nRegStart) || (bswap_16(adu.w[1]) != nRegCount))
		{
			errno = EPROTO;
			return -1;
		}
		
		return 0;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

int GfaMbMstPing(HGFAMBMST hMst, uint8_t slvID)
{
	if(hMst)
	{
		static uint8_t b = 0;
		int nMBErr;
		ssize_t nRet;
		MODBUS_RTU_ADU adu;
		uint8_t func = MB_FUNC_DIAGNOSTIC;
		uint16_t nEcho = ++b;
		nEcho |= (~b << 8);
		uint16_t data[2] = {bswap_16(MB_SUBFUNC_RETURN_QUERY_DATA), nEcho};

		if((nRet = GfaMbMstCreateADU(slvID, func, &data, sizeof(data), &adu)) < 0)
			return -1;

		if((nRet = GfaMbMstSendADU(hMst, &adu, nRet)) < 0)
			return -1;

		adu.w[0] = ~MB_SUBFUNC_RETURN_QUERY_DATA;
		adu.w[1] = ~adu.w[1];
		adu.w[2] = 0;
		
		if((nRet = GfaMbMstRecvADU(hMst, &adu, 8)) <= 0)
			return -1;
		
		if(!GfaMbMstValidateADU(slvID, func, &adu, nRet, &nMBErr))
			return -1;
		
		if(nMBErr)
		{
			errno = MAKE_GFA_MODBUS_ERROR(nMBErr);
			return -1;
		}
		else if(nRet != 8)
		{
			errno = EPROTO;
			return -1;
		}
		else if((adu.w[0] != data[0]) || (adu.w[1] != data[1]))
		{
			errno = EPROTO;
			return -1;
		}
		
		return 0;
	}

	errno = EINVAL;
	return -1;
}

/////////////////////////////////////////////////////////////////////////////

int GfaMbMstBootloaderExecute(HGFAMBMST hMst, uint8_t slvID)
{
	if(hMst)
	{
		int nRet, nErr;
		GFA_SER_CFG_PARAMS scp, scpSave;
		struct timeval tvRX = {0, 500000};
		uint16_t regs[2];
		LPGFA_MB_MST pMst = (LPGFA_MB_MST)hMst;

		if(GfaMininetDeviceGetConfigParams(pMst->hMiNeDev, &scp, sizeof(scp)) != sizeof(scp))
			return -1;
		memcpy(&scpSave, &scp, sizeof(scpSave));
		scp.parity	= pMst->parity;
		scp.baud	= pMst->nBaudrate;
		if(GfaMininetDeviceSetConfigParams(pMst->hMiNeDev, &scp, sizeof(scp)) != 0)
			return -1;

		GfaMininetMasterSaveTimeouts(pMst->hMiNeMst);
		GfaMininetMasterSetTimeouts(pMst->hMiNeMst, &tvRX, NULL);

		TRACE4("Reading modbus registers %hu and %hu.\n", pMst->nModbusCtrlReg, pMst->nModbusCtrlReg + 1);

        if((nRet = GfaMbMstReadHoldingRegisters(hMst, slvID, pMst->nModbusCtrlReg, 2, regs)) == 0)
        {
			GfaMbMstWaitFrameDelay(hMst);

			TRACE4("Writing modbus registers %hu and %hu - values: 0x%04hX and 0x%04hX\n", pMst->nModbusCtrlReg + 2, pMst->nModbusCtrlReg + 3, regs[0], regs[1]);

            if((nRet = GfaMbMstWriteMultipleRegisters(hMst, slvID, pMst->nModbusCtrlReg + 2, 2, regs)) == 0)
				usleep(GFA_BOOTLOADER_EXEC_WAIT_TIME * 1000);
		}

		nErr = errno;
		GfaMininetMasterRestoreTimeouts(pMst->hMiNeMst);
		if(GfaMininetDeviceSetConfigParams(pMst->hMiNeDev, &scpSave, sizeof(scpSave)) != 0)
			return -1;
		errno = nErr;
		return nRet;
	}

	errno = EINVAL;
	return -1;
}