// Taken from https://github.com/mackstann/tinywm

#include <X11/Xlib.h>

#define MODMASK Mod1Mask

#define MAX(a, b) ((a) > (b) ? (a) : (b))

int main() {
    Display* dpy;
    XWindowAttributes attr;

    // Used to store the state of the cursor when resizing
    XButtonEvent start;

    XEvent ev;

    if(!(dpy = XOpenDisplay(0x0))) return 1;

    XGrabKey(dpy, XKeysymToKeycode(dpy, XStringToKeysym("F1")), MODMASK, DefaultRootWindow(dpy), True, GrabModeAsync, GrabModeAsync);
    XGrabButton(dpy, 1, MODMASK, DefaultRootWindow(dpy), True, ButtonPressMask|ButtonReleaseMask|PointerMotionMask, GrabModeAsync, GrabModeAsync, None, None);
    XGrabButton(dpy, 3, MODMASK, DefaultRootWindow(dpy), True, ButtonPressMask|ButtonReleaseMask|PointerMotionMask, GrabModeAsync, GrabModeAsync, None, None);

    start.subwindow = None;

    for (;;) {
        XNextEvent(dpy, &ev);

        if (ev.type == KeyPress && ev.xkey.subwindow != None) {
            XRaiseWindow(dpy, ev.xkey.subwindow);
        } else if (ev.type == ButtonPress && ev.xbutton.subwindow != None) {
            XGetWindowAttributes(dpy, ev.xbutton.subwindow, &attr);
            start = ev.xbutton;
        } else if (ev.type == MotionNotify && start.subwindow != None) {
            int xdiff = ev.xbutton.x_root - start.x_root;
            int ydiff = ev.xbutton.y_root - start.y_root;
            XMoveResizeWindow(dpy, start.subwindow,
                attr.x + (start.button==1 ? xdiff : 0),
                attr.y + (start.button==1 ? ydiff : 0),
                MAX(1, attr.width + (start.button==3 ? xdiff : 0)),
                MAX(1, attr.height + (start.button==3 ? ydiff : 0)));
        } else if (ev.type == ButtonRelease) {
            start.subwindow = None;
        }
    }

    return 0;
}