/* Tanel Toova
 * 7-1
 *
 *
 */


#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string.h>

#define TRUE 1
#define FALSE 0

char command[80];
char prg[80];
char prgarg[80];
char *commands[]={"list","help","quit","users","calender",NULL};
char *real_commands[]={"ls","","","w","cal",NULL};
char *arguments[]={"-l","","","-s","-m",NULL};
pid_t fork_result;
int i;
int wcommand;
int abi;
//proccess to show help on screen
int help()
{
	fprintf(stdout, "\nLegaalsed käsklused on:\n"
			"CALENDER - Näitab kalendrit, kus nädala algust arvestatakse esmaspäevast\n"
			"USERS - kõigi sisse loginud kasutajate kuvamine\n"
			"LIST - kõigi kataloogis olevate failide kuvamine\n"
			"HELP - abiinfo (st. see mida Sa praegu loed)\n"
			"QUIT - programmi töö lõpetamine\n\n");
}

int main(void)
{	
	
	while(strcasecmp(command,"quit")!=0){ //while given command is not "quit"
		fprintf(stdout,"Anna käsklus: \n");
		fprintf(stdout,">");
		scanf("%s",command);
		wcommand=TRUE; //command is assumed to be wrong
		abi=FALSE; //it's assumed that help is not asked
		//compares given commands whith known ones
		for(i=0;commands[i]!=NULL;i++){ 
			if(strcasecmp(command,commands[i])==0){
				strcpy(prg,real_commands[i]);
				strcpy(prgarg,arguments[i]);
				wcommand=FALSE; //since command was recognised it's not wrong
				if(i==1){ //if the command was "help"
					wcommand=TRUE;
					abi=TRUE;
					help();
				}

			}
		}
		//if wrong command was given
		if(wcommand==TRUE && abi==FALSE){fprintf(stdout,"VIGA! Käsklus %s on tundmatu!\n",command);}
		//if right command and not command "help" was given
		if(wcommand==FALSE && abi==FALSE){fork_result=fork();}
		if(fork_result==-1 && wcommand==FALSE){
			fprintf(stderr,"VIGA! Child protsessi ei õnnestunud luua ...\n");
			exit(1);
		}
		//if fork was success
		if(fork_result==0 && wcommand==FALSE){
			execlp(prg,prg,prgarg,NULL);
		}else{
			wait(NULL); //parent wait's for child to end
		}
	
	}
	return(0);
}