/*
 * colour: change the screen colors to something new and interesting
 */
#include <stdio.h>
#include <stdarg.h>

#define FG_INDEX 30
#define BG_INDEX 40

#define COUNT(x) (sizeof x/sizeof x[0])

struct aa {
    char name[11];
    unsigned short value;
} attribs[] = {
    { "normal",    0 },
    { "bold",      1 },
    { "bright",    1 },
    { "underline", 4 },
    { "blinking",  5 },
    { "reverse",   7 },
    { "invisible", 8 }
};

struct aa colours[] = {
    { "black",     0 },
    { "red",       1 },
    { "green",     2 },
    { "yellow",    3 },
    { "blue",      4 },
    { "magenta",   5 },
    { "cyan",      6 },
    { "white",     7 }
};

/* getopt and friends
 */
extern int optind, opterr, optopt;
extern int getopt();
extern char *optarg;

char clear_screen=0;

/*
 * badboy() spits out an error message, then dies
 */
badboy(msg)
char *msg;
{
    va_list ptr;

    if (msg) {
	fprintf(stderr, "colour:");
	va_start(ptr, msg);
	vfprintf(stderr, msg, ptr);
	va_end(ptr);
	putc('\n', stderr);
    }
    fprintf(stderr, "usage: colour [-c?] [attrib] fg-colour [on bg-colour]\n");
    exit(1);
} /* badboy */


/*
 * pickout matches a name to a values in an aa array
 */
pickout(str, ary, size)
char *str;
struct aa *ary;
{
    while (size-- > 0)
	if (stricmp(ary->name, str) == 0)
	    return ary->value;
	else
	    ++ary;
    return -1;
} /* pickout */


/*
 * usage() emits an overly verbose message describing how colour
 * works.
 */
usage()
{
    register j, max;

    printf("usage:");

    max = COUNT(attribs);
    if (max < COUNT(colours))
	max = COUNT(colours);
    for (j=0; j<max; j++) {
	if (j == 0)
	    printf("\tcolour [-c?] {%-10s} %-10s [on %-10s]\n",
		    attribs[j].name, colours[j].name, colours[j].name);
	else if (j >= COUNT(colours))
	    printf("\t              %-10s\n", attribs[j].name);
	else
	    printf("\t              %-10s  %-10s     %s\n",
		    (j<COUNT(attribs)) ? attribs[j].name : "",
		    colours[j].name, colours[j].name);
    }
    printf("options:\n");
    printf("\t-c\tclear the screen after setting colours.\n");
    printf("\t-?\tprints this message.\n");
    exit(0);
} /* usage */


/*
 * colour, in mortal flesh
 */
main(argc, argv)
char **argv;
{
    int attrib[40];
    int attrcount=0, tattrib;
    int fg_col = (-1),
	bg_col = (-1);

    register i;
    char bfr[120];
    char c;

    opterr = 0;
    while (getopt(argc, argv, "c?") != EOF) {
	switch (optopt) {
	case 'c':   clear_screen = 1; break;
	case '?':   usage();
	default:    badboy("bad flag <%c>", optopt);
	}
    }
    argv += optind;
    argc -= optind;
    
    while (argc > 1 && (tattrib=pickout(*argv, attribs, COUNT(attribs))) >= 0) {
	if (tattrib == 0)
	    attrcount = 0;
	else if (attrcount < COUNT(attrib))
	    attrib[attrcount++] = tattrib;
	++argv, --argc;
    }

    if (argc == 3) {
	/* [attrib] colour on colour
	 */
	if (stricmp(argv[1], "on") != 0)
	    badboy((char*)0);
	if ((bg_col = pickout(argv[2], colours, COUNT(colours))) < 0)
	    badboy("invalid background colour");
    }
    else if (argc < 1)
	badboy((char*)0);
    else if (argc > 1)
	badboy("bad attribute");
    if ((fg_col=pickout(argv[0], colours, COUNT(colours))) < 0)
	badboy("invalid foreground colour");

    bfr[0] = 0;
    for (i=0; i<attrcount; i++)
	sprintf(bfr+strlen(bfr), ";%d", attrib[i]);
    if (fg_col >= 0)
	sprintf(bfr+strlen(bfr), ";%d", fg_col+FG_INDEX);
    if (bg_col >= 0)
	sprintf(bfr+strlen(bfr), ";%d", bg_col+BG_INDEX);

    if (clear_screen)
	printf("\033[0%sm\033[2J", bfr);
    else
	printf("\033[0%sm", bfr);
    fflush(stdout);
    exit(0);
} /* main */