#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <X11/Xlib.h>
#include <X11/extensions/Xxf86dga.h>

static int stop;

void sighandler(int sig)
{
    printf("Terminating\n");
    stop = 1;
}

int main (void)
{
    Display *dpy;
    int err, event;
    XDGAMode *modes;
    int nmodes;
    Window root, child;
    int rx, ry, wx, wy;
    unsigned int mask;


    dpy = XOpenDisplay(NULL);

    if (!XF86DGAQueryExtension(dpy, &err, &event))
        goto error;

    int major = 2, minor = 0;
    XF86DGAQueryVersion(dpy, &major, &minor);

    XGrabButton(dpy, AnyButton, AnyModifier, DefaultRootWindow(dpy), False,
                    ButtonPressMask | ButtonReleaseMask,
                    GrabModeSync, GrabModeAsync,
                    None, None);

    modes = XDGAQueryModes(dpy, DefaultScreen(dpy), &nmodes);

    if (nmodes == 0)
        goto error;

    signal(SIGINT, sighandler);

    XQueryPointer(dpy, DefaultRootWindow(dpy), &root, &child,
            &rx, &ry, &wx, &wy, &mask);

    printf("Current button mask: %#x\n", mask & ~255);
    printf("Waiting for button press + release\n");
    while (!stop)
    {
        if (!XPending(dpy)) {
            usleep(30000);
            continue;
        }
        XEvent ev;
        XNextEvent(dpy, &ev);
        printf ("event %d\n", ev.xany.type);

        if (ev.xany.type == ButtonPress) {
            printf("Button press received\n");
            XDGASetMode(dpy, DefaultScreen(dpy), modes[0].num);
            XF86DGADirectVideo(dpy, DefaultScreen(dpy), XF86DGADirectMouse | XF86DGADirectKeyb);

            XDGASelectInput(dpy, DefaultScreen(dpy),
                            ButtonPressMask | ButtonReleaseMask | PointerMotionMask);
            XAllowEvents(dpy, AsyncBoth, CurrentTime);
            XFlush(dpy);
        }
        XQueryPointer(dpy, DefaultRootWindow(dpy), &root, &child,
                      &rx, &ry, &wx, &wy, &mask);

        printf("Button mask: %#x\n", mask & ~255);

    }


    XFree(modes);
    XDGASetMode(dpy, 0, 0);
    XCloseDisplay(dpy);

    return 0;

error:
    printf ("error occured.\n");
    return 1;
}