#include <stdio.h> 
#include <stdlib.h>
#include <libperfstat.h>
#include <net/if_types.h>

#define DELTA(member) (net2[i].member - net1[i].member)

#ifndef FIRST_NETINTERFACE 
#define FIRST_NETINTERFACE ""
#endif

char * decode(uchar type) {
    switch(type) {
		case IFT_LOOP:
			return("loopback");

		case IFT_ISO88025:
			return("token-ring");

		case IFT_ETHER:
			return("ethernet");
    }
    return("other");
}

int main(int argc, char* argv[]) {
	int i, ret, tot;
	perfstat_netinterface_t * net1;
	perfstat_netinterface_t * net2;
	
	int seconds = 1;
	int times = 1;
	
	char str[512];
	char perfdata[1024];
	
	char * if_name;
	double in_packets;
	double in_errors;
	double in_Kbytes;
		
	double out_packets;
	double out_errors;
	double out_Kbytes;

	/* check how many perfstat_netinterface_t structures are available */
	tot = perfstat_netinterface(NULL, NULL, sizeof(perfstat_netinterface_t), 0);
	
	/* allocate enough memory for all the structures */
	net1 = malloc(sizeof(perfstat_netinterface_t) * tot);
	net2 = malloc(sizeof(perfstat_netinterface_t) * tot);

	/* ask to get all the structures available in one call */
	/* return code is number of structures returned */
	ret = perfstat_netinterface((perfstat_id_t *)FIRST_NETINTERFACE, net1, sizeof(perfstat_netinterface_t), tot);
	
	printf("Checked %d Interfaces\n",ret);
	
	strcpy(perfdata, " | ");

	for(int k = 0; k < times; k++) {
		sleep(seconds);
		ret = perfstat_netinterface((perfstat_id_t *)"", net2, sizeof(perfstat_netinterface_t), tot);
		
		if(ret <= 0) {
			printf("tot=%d ret=%d errno=%d\n",tot,ret,errno);
			perror("x");
			exit(42);
		}
		/* print statistics for each of the interfaces */
		if (ret > 0) { 
			for (i = 0; i < ret; i++) {
				if_name		= net2[i].name;
				in_packets	= (double)DELTA(ipackets)/(double)seconds;
				in_errors	= (double)DELTA(ierrors)/(double)seconds;
				in_Kbytes	= (double)DELTA(ibytes)/1024.0/(double)seconds;
				
				out_packets	= (double)DELTA(opackets)/(double)seconds;
				out_errors	= (double)DELTA(oerrors)/(double)seconds;
				out_Kbytes	= (double)DELTA(obytes)/1024.0/(double)seconds;
				
				sprintf(str, "%s_inKbytes=%.2fKB ", if_name, in_Kbytes);
				strcat(perfdata, str);
				sprintf(str, "%s_inPackets=%.2f ", if_name, in_packets);
				strcat(perfdata, str);
				sprintf(str, "%s_inErrors=%.2f ", if_name, in_errors);
				strcat(perfdata, str);
				
				sprintf(str, "%s_outKbytes=%.2fKB ", if_name, out_Kbytes);
				strcat(perfdata, str);
				sprintf(str, "%s_outPackets=%.2f ", if_name, out_packets);
				strcat(perfdata, str);
				sprintf(str, "%s_outErrors=%.2f ", if_name, out_errors);
				strcat(perfdata, str);
				
				/* printf("\nStatistics for interface : %s\n", net2[i].name);
				printf("------------------------\n");
				printf("type : %s\n", decode(net2[i].type));
				printf("\ninput statistics:\n");
				printf("number of packets/sec : %.2f\n",	(double)DELTA(ipackets)/(double)seconds);
				printf("number of errors/sec  : %.2f\n",	(double)DELTA(ierrors)/(double)seconds);
				printf("number of bytes/sec   : %.2f\n",	(double)DELTA(ibytes)/1024.0/(double)seconds);
				printf("\noutput statistics:\n");
				printf("number of packets/sec : %.2f\n",	(double)DELTA(opackets)/(double)seconds);
				printf("number of errors/sec  : %.2f\n",	(double)DELTA(oerrors)/(double)seconds);
				printf("number of bytes/sec   : %.2f\n", (double)DELTA(obytes)/1024.0/(double)seconds); */
			}
		}
		memcpy(net1, net2, sizeof(perfstat_netinterface_t) * tot );
	}
	
	printf("%s", perfdata);
	printf("\n");
	
	return 0;
}