/* 
 * modbuslog
 *
 * Copyright (C) 2011 Jonathan McCrohan
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

// gcc modbuslog.c -o modbuslog `pkg-config --libs --cflags libmodbus libconfig`


#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>

#include <libconfig.h>
#include <modbus.h>

#define SLAVE_ID 1
#define START_ADDRESS 0
#define NUMBER_REGISTERS 14
#define DEBUG 1

int main(int argc, char *argv[])
{

const char *CONFIG_FILE = "modbuslog.cfg";

 config_t cfg;
 //config_setting_t *setting;

 const char *modbus_device_address;
 int modbus_baud_rate;
 int modbus_data_bits;
 const char *modbus_parity;
 int modbus_stop_bits;

 config_init(&cfg);


  if(!config_read_file(&cfg, CONFIG_FILE))
  {
    fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
            config_error_line(&cfg), config_error_text(&cfg));
    config_destroy(&cfg);
    fprintf(stderr, "Unable to find CONFIG_FILE.\n");
    return -1;
  }

 modbus_t *ctx;
 uint16_t tab_reg[64];
 int rc;
 int i;

 if(!(config_lookup_string(&cfg, "modbus.device", &modbus_device_address)
	&& config_lookup_int(&cfg, "modbus.baud", &modbus_baud_rate)
	&& config_lookup_int(&cfg, "modbus.data_bits", &modbus_data_bits)
	&& config_lookup_string(&cfg, "modbus.parity", &modbus_parity)
	&& config_lookup_int(&cfg, "modbus.stop_bits", &modbus_stop_bits))
){
	fprintf(stderr, "Check modbus configuration in configuration file.\n");
	return -1;
}

 if(DEBUG){
  printf("%s %d %c %d %d\n",modbus_device_address, modbus_baud_rate, modbus_parity[0], modbus_data_bits, modbus_stop_bits);
 }

ctx = modbus_new_rtu(modbus_device_address, modbus_baud_rate, modbus_parity[0], modbus_data_bits, modbus_stop_bits);

modbus_set_slave(ctx, SLAVE_ID);
modbus_set_debug(ctx, DEBUG);

if (ctx == NULL) {
    fprintf(stderr, "Unable to create libmodbus object.\n");
    return -1;
}


if (modbus_connect(ctx) == -1) {
    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
    modbus_free(ctx);
    return -1;
}

rc = modbus_read_input_registers(ctx, START_ADDRESS, NUMBER_REGISTERS, tab_reg);


if (rc == -1) {
    fprintf(stderr, "ERROR: %s\n", modbus_strerror(errno));
    return -1;
}


for (i=0; i < rc; i=i+2) {
    printf("reg[%d]=%d\n", i, tab_reg[i]+tab_reg[i+1]);
}


modbus_close(ctx);
modbus_free(ctx);

    return 0;
}