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

#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <sys/times.h>
#include <sys/unistd.h>

#define MAX_STR 50

oid anOID[256] = {1, 3, 6, 1, 2, 1, 25, 2, 3, 1, 3, 0};
oid anOID_len = 12;

int main(int argc, char** argv) {
	struct snmp_session session, *ss;
	struct snmp_pdu *pdu = NULL;
	struct snmp_pdu *response = NULL;		
	struct variable_list *vars = NULL;
	
	int status;	
	int konec = 0;
	
	double pom;
		
	char popis[MAX_STR];
	long velikost = 0;
	long pouzito = 0;
	long dostupne = 0;
	long pouzito_pr = 0;
	
	FILE *log;
	
	/* veci pro statistiku */
	clock_t zac, kon;
	struct tms cas;
	int tiku;
	
	float rozdil;
	float min = 1000000;
	float max = 0;
	float celkem = 0;
	int pocet = 0;
	
	struct timeval sendtv, rectv;
	struct tm *tm;
	
	/* inicializace aplikace */
	init_snmp("snmp-aplikace");
	
	/* inicializace relace */
	snmp_sess_init(&session);
	session.peername = argv[1];
	session.version = SNMP_VERSION_1;
	session.community = argv[2];
    	session.community_len = strlen(session.community);
	
	/* otevreni spojeni */
	ss = snmp_open(&session); 
    	if (!ss) {
		printf ("Spojeni se nepodarilo navazat.\n");
	        exit (1);
    	}	
	
	/* zapnuti logovani */
	if ((log = fopen ("vypis.log", "w")) == NULL) {
		printf ("%s\n", "Nepodarilo se vytvorit logovaci soubor.");
		exit (1);
	}
	
	/* vypis hlavicky */
	printf ("\n");
	printf ("%s\n", "Vypis tabulky hrStorageTable - 1.3.6.1.2.1.25.2.3");
	printf ("\n");
	printf ("%s\n", "Sloupec hrStorageDescr - 1.3.6.1.2.1.25.2.3.1.3");
	printf ("%s\n", "Sloupec hrStorageSize - 1.3.6.1.2.1.25.2.3.1.5");
	printf ("%s\n", "Sloupec hrStorageUsed - 1.3.6.1.2.1.25.2.3.1.6");
	
	printf ("\n");
    	printf ("%-18s %12s %12s %12s %15s\n", "Popis", "Velikost (kB)",
           "Pouzito", "Dostupne", "Pouzito (%)");	
	printf ("--------------------------------------------------------------------------------\n");
	
	/* tiky za sekundu */
	tiku = sysconf (_SC_CLK_TCK);
	
	while (konec == 0) {	
	
		pdu = snmp_pdu_create(SNMP_MSG_GETNEXT);	
		snmp_add_null_var(pdu, anOID, anOID_len);	
		pdu->variables->type = 6; 
		
		/* poslani zpravy + zapis do logu */
		zac = times (&cas);
		gettimeofday (&sendtv, NULL);
		status = snmp_synch_response(ss, pdu, &response);
		kon = times (&cas);
		gettimeofday (&rectv, NULL);
		
		rozdil = (kon - zac) / (double) tiku;
		celkem += rozdil;
		if (rozdil < min) min = rozdil;
		if (rozdil > max) max = rozdil;
		pocet++;

		
		fprintf (log, "Budu cist OID: ");
		fprint_objid (log, anOID, anOID_len);		
		
		tm = localtime (&sendtv.tv_sec);
		fprintf (log, "Poslan dotaz v case: %.2d:%.2d:%.2d.%.6d\n", tm->tm_hour, tm->tm_min, tm->tm_sec, (int)sendtv.tv_usec);
		
		tm = localtime (&rectv.tv_sec);
		fprintf(log, "Prijata odpoved v case: %.2d:%.2d:%.2d.%.6d\n", tm->tm_hour, tm->tm_min, tm->tm_sec, (int)rectv.tv_usec);
		
		fprintf (log, "\n");		
		
		
		if (status == STAT_SUCCESS && response->errstat == SNMP_ERR_NOERROR) {
		
			vars = response->variables;
			if (vars->type == ASN_OCTET_STR) {
				vars->val.string[vars->val_len] = '\0';
				
				switch (anOID[10]) {
					case 3:	 /* popis */
						strncpy (popis, vars->val.string, MAX_STR);
						break;
				}
				
			}
			else {
				/* ulozeni */
				switch (anOID[10]) {
					case 5:	/* velikost */
						velikost = *vars->val.integer;
						break;
					case 6: /* pouzito */
						pouzito = *vars->val.integer;
				}
				
				
				if (anOID[10] == 3) konec = 1;
			}
			
		} else {
			if (status == STAT_SUCCESS)
				fprintf(stderr, "Error in packet\nReason: %s\n",
					snmp_errstring(response->errstat));
			else
				snmp_sess_perror("snmpget", ss);
			
			}
	
		if (response) snmp_free_pdu (response);	
		
		/* pokud jsme mimo tabulku, vypis a dalsi zaznam */
		if (anOID[10] == 6) {
		   dostupne = velikost - pouzito;
		   pom = velikost / 100;
		   if (pom > 0) pouzito_pr = (long) (pouzito / pom);
		   else pouzito_pr = 0;
		   
		   printf ("%-18s %12ld %12ld %12ld %10ld%%\n", popis, velikost, pouzito, dostupne, pouzito_pr);
		   		   		
		}
		
		/* prejde se na dalsi sloupec */
		switch (anOID[10]) {
			case 3: anOID[10] = 5;
				break;
			case 5: anOID[10] = 6;
				break;
			case 6: anOID[10] = 3;
				anOID[11]++;
				break;
		
		}
		
	}
	
	/* vypis koncovych statistik */
  	fprintf (log, "\nMinimalni doba odezvy: %.3f [sec]\n", min);
  	fprintf (log, "Maximalni doba odezvy: %.3f [sec]\n", max);
  	fprintf (log, "Prumerna doba odezvy: %.3f [sec]\n", celkem/pocet);	
	
	/* ukonceni logovani */
	fclose (log);
	
	snmp_close(ss);		
			
	return 0;
}