#include <stdio.h>
#include <ctype.h>

/*
	A replacement for COMMAND.COM

	T. Jennings 28 Dec 84

	Docs? You cant be serious ...

*/

version = 0;			/* initial (ahem) version */
char drive = 'A';
unsigned rnd;			/* fake random number */

#define same(s1,s2) (strcmp(s1,s2) == 0)

main() {

long l;
char ln[132];
char cmd[80],*arg,*cp;

	for (l= 10000L; l > 0L; l--);		/* look busy */

	cprintf("Current date is Tue  1-01-1980\r\n");
	get(ln,"Enter New date: ");
	cprintf("Current time is 0:01:21.32\r\n");
	get(ln,"Enter new time: ");

	cprintf("\r\n\r\nThe IBM Personal Computer DOS\r\n");
	cprintf("Version 2.00 (C)Copywrong IBM Corp 1981, 1982, 1983 so there\r\n");


/* Now the fun starts */

	drive= 'A';
	while (1) {
		cprintf("%c>",drive);
		drive+= 7; if (drive > 'Z') drive= 'A';
		get(ln,"");			/* get command line */
		arg= cmd;			/* copy of command name */
		cp= ln;
		while (*cp && (*cp != ' '))
			*arg++= *cp++;
		*arg= '\0';			/* terminate cmd name */
		while (*cp && (*cp == ' '))	/* skip spaces, etc */
			++cp;
		arg= cp;			/* arg is cmd tail */

		if (same(cmd,"dir")) dir();
		else if (same(cmd,"ver")) ver();
		else if (same(cmd,"cd")) cd(arg);
		else if (same(cmd,"chdir")) cd(arg);
		else if (same(cmd,"date")) date(arg);
		else if (same(cmd,"time")) time(arg);
		else if (same(cmd,"ren")) del(arg);
		else if (same(cmd,"del")) del(arg);
		else if (same(cmd,"erase")) del(arg);
		else if (same(cmd,"prompt")) prompt(arg);
		else if (same(cmd,"set")) set(arg);
		else if (same(cmd,"exit")) exitc();
		else if (same(cmd,"plugh")) goway();
		else if (strlen(cmd) > 0) command(cmd,arg);
	}
}
/* Go away */

goway() {
	cprintf("\r\n");
	cprintf("COMMAND.EXE -- 28 Dec 84 T. Jennings\r\n");
	exit();
}
/* Display wrong MSDOS version */

ver() {
	version += 137;
	cprintf("IBM Personal Computer DOS version 2.%d\r\n",version);
	cprintf("\r\n");
}

/* DOS prompt */

prompt() {

	cprintf("But I like the prompt as it is\r\n");
	cprintf("\r\n");
}
/* set environment */

set(s)
char *s;
{
	if (strlen(s)) cprintf("%s? ",s);
	cprintf("That sounds interesting\r\n");
	cprintf("\r\n");
}
/* Exit program */

exitc() {

	cprintf("No, I am not going away.\r\n");
	cprintf("\r\n");
}
/* delete some files */

del() {
	disk(); disk();

	if (chance(50)) dosmsg();
	else cprintf("File not found\r\n");
	cprintf("\r\n");
}
/* dont list disk files */

dir() {

	if (chance(30)) dosmsg();
	else {
		disk();
		cprintf("Volume in drive %c: label fell off\r\n",drive);
		disk(); disk();
		cprintf("Directory of  %c:\\\r\n",drive);
		cprintf("\r\nFile not frammished\r\n");
	}
	cprintf("\r\n");
}
/* Refuse to change directories */

cd(arg)
char *arg;
{
	if (chance(40)) dosmsg();
	else cprintf("Invalid directory\r\n");
	cprintf("\r\n");
}
/* Set the time */

time() {
	if (chance(35)) cprintf("Time? Who has time?\r\n");
	else if (chance(15)) cprintf("I forget\r\n");
	else cprintf("Buy a watch\r\n");
	cprintf("\r\n");
}

/* Set the date */

date() {
	if (chance(25)) cprintf("My birthday!\r\n");
	else if (chance(25)) cprintf("Most banks give out calendars, why not ask for one next time you're in?\r\n");
	else cprintf("Sometime after 1980\r\n");
	cprintf("\r\n");
}
/* Display a prompt, input a line of text, convert it to all
lower case. While we're at it, generate a fake random number by
continually incrementing an integer while waiting for a key. */

get(l,p)
char l[];
char *p;
{
int i,j;
char c;

	cprintf("%s",p);
	i= 0;
	while (1) {
		while (! (c= bdos(6,0xff))) rnd += 17;

/* Backspace and delete: MOST of the time, do it right. Once in a while,
backspace by deleting the whole line, and restoring it all except the
last deleted character. */

		if ((c == 8) || (c == 127)) {
			if (i > 0) {
				if (chance(30)) {
					for (j= i; j--;) cprintf("\010 \010");
					--i;
					for (j= 0; j < i; j++) bdos(6,l[j]);

				} else {
					--i;
					cprintf("\010 \010");
				}
			}

/* since control-c probably means banging on the keyboard in frustration,
be nasty. */

		} else if (c == 3) {
			switch (rnd % 4) {
				case 0: cprintf("Ouch!\07\r\n"); break;
				case 1: cprintf("Cut it out!\r\n"); break;
				case 2: cprintf("Stop it!\r\n"); break;
				case 3: cprintf("That hurts!\r\n"); break;
			}
			i= 0;
			break;

/* Carriage return: be merciful */

		} else if (c == 13) {
			cprintf("\r\n");
			break;

/* Tabs are fun. Space over a random number of spaces */

		} else if (c == 9) {
			for (j= (rnd % 6) + 4; j > 0; --j) {
				bdos(6,' ');
				l[i++]= ' ';
			}

/* Control characters: normal until I figure out what to do */

		} else if (c < ' ') {
			cprintf("^%c",c + '@');

		} else {
			bdos(6,c);
			l[i++]= c;
		}
	}

	l[i]= '\0';
	for (i= 0; l[i]; i++) l[i]= tolower(l[i]);
}

/* Chance: the number given is a percentage of 100, return true if
we are in range. */

chance(n)
int n;
{
	return(n > (rnd % 100));
}
/* make the disk look busy. */

disk() {

int n,i;
long l;

	for (i= 2; i--;) {
		n= open("foo",0);
		for (l= 1000L; l > 0L; l--);
		if (n != -1) close(n);
	}
}
/* Randomly choose a DOS message */

dosmsg() {
int i;

	i= rnd % 10;
	switch (i) {

		case 0: cprintf("What was that? I wasnt paying attention\r\n"); break;
		case 1: cprintf("Invalid directory\r\n"); break;
		case 2: cprintf("Insufficient disk space\r\n"); break;
		case 3: cprintf("Do you hear music?\r\n"); break;
		case 4: cprintf("Invalid number of parameters\r\n"); break;
		case 5: cprintf("Duplicate File name or File not found or I lost it\r\n"); break;
		case 6: cprintf("I see no  FILES  here\r\n"); break;
		case 7: cprintf("Nothing happens\r\n"); break;
		case 8: cprintf("Insufficient memory\r\n"); break;
		case 9: cprintf("Error creating file or pipe\r\n"); break;
		default: printf("rnd = %d default?\r\n",i); break;
	}
}

/* "execute" a command */

command() {
	disk(); disk(); disk();
	cprintf("Bad commmmmmmand or file name\r\n");
}