/*
 * Copyright 2008 Red Hat, Inc.
 *
 * MIT licensed.  See: http://www.opensource.org/licenses/mit-license.php
 *
 * gcc -std=c99 -o xrrprimary xrrprimary.c -lXrandr -lXext -lX11
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <X11/X.h>
#include <X11/Xmd.h>
#include <X11/Xlib.h>
#include <X11/Xproto.h>
#include <X11/extensions/Xrandr.h>

int main(int argc, char **argv)
{
    Display *dpy = XOpenDisplay(NULL);
    XRRScreenResources *rr;
    XRROutputInfo *oi;

    XSynchronize(dpy, 1);

    if (argc == 1) {
	printf("usage: xrrprimary [get | set output]\n");
	return 1;
    }

    rr = XRRGetScreenResources(dpy, DefaultRootWindow(dpy));

    if (argc == 2 && !strcmp(argv[1], "get")) {
	RROutput output = XRRGetOutputPrimary(dpy, DefaultRootWindow(dpy));

	if (output) {
	    oi = XRRGetOutputInfo(dpy, rr, output);
	    printf("%s (0x%x)\n", oi->name, output);
	    XRRFreeOutputInfo(oi);
	} else {
	    printf("None\n");
	}
    }

    if (argc == 3 && !strcmp(argv[1], "set")) {
	RROutput output;

	if (isalpha(argv[2][0])) { /* it's a name */
	    for (int i = 0; i < rr->noutput; i++) {
		oi = XRRGetOutputInfo(dpy, rr, rr->outputs[i]);
		if (!strcmp(oi->name, argv[2]))
		    output = rr->outputs[i];
		XRRFreeOutputInfo(oi);
	    }
	} else { /* it's an XID */
	    output = strtol(argv[2], NULL, 0);
	}

	if (output)
	    XRRSetOutputPrimary(dpy, DefaultRootWindow(dpy), output);
    }

    XSync(dpy, 1);
    XCloseDisplay(dpy);

    return 0;
}