/*
 *  Laboration 2 i C och UNIX
 *
 *  Komplett shell
 *  =========================================
 *
 *  Christian Ohlsson, di7chro@cse.kau.se
 *  Stefan Sonesson, di7stes@cse.kau.se
 *
 *  Karlstads Universitet, 991209
 *
 *
 *===========================================
*/
#include "lab2.h"

extern treePtr tree;

/*Array med alla inmatningar som gjorts*/
char *symTable[SYMTBLSIZE];

/*Global räknare för symTable*/
int place=0;

/*Kopierar alla WORD & NULL till symTable*/
int insert(char *str){
  if(str) symTable[place]=(char*)strdup(str);
  else    symTable[place]=str;
  return  place++;
}

/*Rensar symTable*/
void delTable() {
	int i=0;
	for(i=0 ; i<SYMTBLSIZE ; i++) symTable[i] = NULL;
	place=0;
}

/*Exekverar varje kommando som en egen process*/
void cmd(treePtr tPtr) {
	int pid, status;
	switch(pid=fork()){
		case -1:	printf("Could not fork. (cmd)\n"); break;
		case  0:	if((execvp(symTable[tPtr->index], &symTable[tPtr->index])) == -1) {
						fprintf(stderr, "Could not execute that.\n");
						exit(1);                     /* Child */
					}
					exit(1);	break;
		default: if((waitpid(pid, &status,0)) == -1) {     /* Parent */
						fprintf(stderr, "Could not wait. (cmd)\n");
						return;
						/*exit(1);*/
					}
					break;
	}
}

/*Hanterar pipes och ställer om fildescriptorer*/
void pipa(treePtr tPtr) {
	int status, pfd[2];
	if((pipe(pfd)) == -1) {
		fprintf(stderr, "Pipe failed. (pipa) \n");
		return;
	}
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed. (pipa)\n");break;
		case 0 :	if((dup2(pfd[1], 1)) == -1) {			/* Child 1 */
						fprintf(stderr, "Could not dup.(pipa)\n");			
						exit(1);
					}
					if((close(pfd[0])) == -1) {
						fprintf(stderr, "Could not close filedescriptor.(pipa)\n");
						exit(1);
					}
					doTree(tPtr->left);
					exit(1);	break;
		default:													/* Parent 1 */
		switch(fork()) {
			case -1:	fprintf(stderr, "Fork failed(pipa)\n");break;
			case 0 :	if((dup2(pfd[0], 0)) == -1) {        /* Child 2 */
							fprintf(stderr, "Could not dup(pipa).\n");
							exit(1);
						}
						if((close(pfd[1])) == -1) {
							fprintf(stderr, "Could not close filedescriptor.(pipa)\n");
							exit(1);
						}
						doTree(tPtr->right);
						exit(1); break;
		default:	if((close(pfd[0])) == -1) {     		/* Parent 2 */
						fprintf(stderr, "Could not close filedescriptor 0.(pipa)\n");
						exit(1);
					}
					if((close(pfd[1])) == -1) {		
						fprintf(stderr, "Could not close filedescriptor 1.(pipa)\n");
						exit(1);
					}
					if((wait(&status)) == -1) {
						fprintf(stderr, "Could not wait.(pipa)\n");
						exit(1);
					}
					if((wait(&status)) == -1) {
						fprintf(stderr, "Could not wait.(pipa)\n");
						exit(1);
					}
					break;
		}
		break;
	}
}
/*Hanterar semikolon, Kör vänster-delen om
  semikolonet, och när det är klart körs högerdelen*/
void semi(treePtr tPtr) {
	int status;
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed. (semi)\n");break;
		case 0 :	doTree(tPtr->left);								/* Child */
					exit(1);
					break;
		default:	if((wait(&status)) == -1) {					/* Parent */
						fprintf(stderr, "Could not wait.(semi)\n");
						exit(-1);
					}
		    		if(tPtr->right)
		    			doTree(tPtr->right);
		    		break;
	}	
}
/*Ställer om utmatningsfil från STDOUT till utfil
  Om filen finns, trunkeras den*/
void great(treePtr tPtr) {
	int fd, status;
	if((fd=open(symTable[tPtr->right->index],O_CREAT|O_TRUNC|O_WRONLY, PERMS))==-1) {
		fprintf(stderr, "Could not open file. (great)\n");
		exit(1);
	}
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed\n"); break;
		case 0 :	if((dup2(fd, 1)) == -1) {         /* Child */
						fprintf(stderr, "Could not dup. (great)\n");
						exit(1);
					}
					doTree(tPtr->left);
					exit(1); break;
		default:	if((wait(&status)) == -1) {       /* Parent */
						fprintf(stderr, "Could not wait. (great)\n");
						exit(1);
					}
					break;
	}
	if((close(fd)) == -1) {
		fprintf(stderr, "Could not close file. (great)\n");
		exit(1);
	}
}
/*Ställer om indirigering från STDIN till fil*/
void less(treePtr tPtr) {
	int fd, status;
	if((fd=open(symTable[tPtr->right->index], O_RDONLY, PERMS))==-1){
		fprintf(stderr, "Could not open file (less)\n");
		return;
	}
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed\n"); break;
		case 0 :	if((dup2(fd, 0)) == -1) {     /* Child */
						fprintf(stderr, "Could not dup.(less)\n");
						exit(1);
					}
					doTree(tPtr->left);
					exit(1); break;
		default:	if((wait(&status)) == -1) {   /* Parent */
						fprintf(stderr, "Could not wait.(less)\n");
						exit(1);
					}       		
					break;
	}
	if((close(fd)) == -1) {
		fprintf(stderr, "Could not close file.(less)\n");
		exit(1);
	}
}
/*Kör processer utan att de behöver invänta den andre*/
void and(treePtr tPtr) {
	int status;
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed. (and)\n");break;
		case  0:	if(tPtr->left)  doTree(tPtr->left);		/* Child */
					exit(0);
					break;
		default:	if(tPtr->right) doTree(tPtr->right);   /* Parent */
		    		break;
	}	
}
/*Ställer om utmatningsfil från STDOUT till utfil
  Om filen finns, appendas den*/
void dblarr(treePtr tPtr) {
	int fd, status;
	if((fd=open(symTable[tPtr->right->index],O_CREAT|O_APPEND|O_WRONLY, PERMS))==-1) {
		fprintf(stderr, "Could not open file. (dblarr)\n");
		exit(1);
	}
	switch(fork()) {
		case -1:	fprintf(stderr, "Fork failed\n"); break;
		case  0:	if((dup2(fd, 1)) == -1) {
						fprintf(stderr, "Could not dup. (dblarr)\n");
						exit(1);
					}       		
					doTree(tPtr->left);
					exit(1); break;
		default:	if((wait(&status)) == -1) {
						fprintf(stderr, "Could not wait. (dblarr)\n");
						exit(1);
					}       		
					break;
	}
	if((close(fd)) == -1) {
		fprintf(stderr, "Could not close file. (dblarr)\n");
		exit(1);
	}       		

}
/*Anropar rätt funktion beroende på metatecken*/
void doTree(treePtr tPtr) {
	if(tPtr->nodeType == 0)			cmd(tPtr);
	if(tPtr->nodeType == PIPE) 	pipa(tPtr);
	if(tPtr->nodeType == SEMI) 	semi(tPtr);
	if(tPtr->nodeType == GREAT) 	great(tPtr);
	if(tPtr->nodeType == LESS) 	less(tPtr);
	if(tPtr->nodeType == AND) 		and(tPtr);
	if(tPtr->nodeType == DBLARR) 	dblarr(tPtr);
	delTable();
}
/*Anropar Lex och Yacc med yyparse och sedan exeveras trädet*/
int main() {
	signal(SIGTERM, SIG_IGN);
	signal(SIGKILL, SIG_IGN);
  	signal(SIGCHLD,SIG_IGN);
   signal(SIGINT,SIG_IGN);
	system("clear");
	write(1, "Welcome to WARPshell 1.0\n",26);
	while(1) {
		fflush(stdout);
		write(1,"C:\\> ",5);
		yyparse();
		if(tree) doTree(tree);
	}
	return 1;
}