/* xormenu: override-redirect focus-stealing menu probe.
 *
 * Exercises the compositor's X11 override-redirect focus handoff: a managed
 * frame window (its own tab) plus a separate override-redirect popup with
 * input hints, so mapping the popup makes the compositor stash the frame's
 * tab as its focus owner.  Closing the frame's tab while the popup is open
 * and then dismissing the popup must drop keyboard focus, not activate
 * freed memory (regression test for the or_focus_owner use-after-free).
 *
 * usage:
 *   xormenu frame            -- map a managed 400x300 frame, pump events
 *   xormenu menu <hold-s> [move]
 *                            -- map an OR input-hint popup, paint it
 *                               continuously (XWM only maps the wl surface
 *                               once the X window has buffer damage), keep
 *                               it up <hold-s> seconds, unmap, exit.
 *                               With "move", shift it +15px every second so
 *                               the compositor repositions it (geometry).
 *   xormenu probe <display>  -- exit 0 if an X display opens, 1 otherwise
 *                               (used to discover the compositor's lazy
 *                               Xwayland display)
 *
 * The frame and the menu are separate processes so the driver can kill the
 * frame (freeing the owner tab) while the menu stays mapped.
 */
#define _POSIX_C_SOURCE 200809L
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <time.h>
#include <unistd.h>

#define MENU_W 300
#define MENU_H 200

static void set_pid(Display *d, Window w) {
    pid_t pid = getpid();
    Atom a = XInternAtom(d, "_NET_WM_PID", False);
    XChangeProperty(d, w, a, XA_CARDINAL, 32, PropModeReplace,
                    (unsigned char *)&pid, 1);
}

static int frame_main(void) {
    Display *d = XOpenDisplay(NULL);
    if (!d) {
        fprintf(stderr, "xormenu: frame: cannot open display\n");
        return 1;
    }
    int scr = DefaultScreen(d);
    Window f = XCreateSimpleWindow(d, RootWindow(d, scr), 0, 0, 400, 300, 0,
                                   BlackPixel(d, scr), 0x404080UL);
    XStoreName(d, f, "xormenu-frame");
    set_pid(d, f);
    XMapWindow(d, f);
    XFlush(d);
    for (;;) {
        XEvent ev;
        XNextEvent(d, &ev);
    }
    return 0;
}

static int menu_main(int hold, bool move) {
    Display *d = XOpenDisplay(NULL);
    if (!d) {
        fprintf(stderr, "xormenu: menu: cannot open display\n");
        return 1;
    }
    int scr = DefaultScreen(d);
    XSetWindowAttributes attr = { .override_redirect = True };
    Window m = XCreateWindow(d, RootWindow(d, scr), 100, 100,
                             MENU_W, MENU_H, 0, CopyFromParent, InputOutput,
                             CopyFromParent, CWOverrideRedirect, &attr);
    XStoreName(d, m, "xormenu-menu");
    set_pid(d, m);
    XWMHints *h = XAllocWMHints();
    h->flags = InputHint;
    h->input = True;
    XSetWMHints(d, m, h);
    XFree(h);
    XFlush(d);
    /* Let the X server manager see the window before mapping: a back-to-back
       create+map can deliver MapNotify before management, losing the map. */
    sleep(2);
    XMapWindow(d, m);
    XFlush(d);
    /* Keep it painted: no buffer damage means no wl-surface map. */
    GC gc = XCreateGC(d, m, 0, NULL);
    XSetForeground(d, gc, 0x00C000UL);
    time_t t0 = time(NULL);
    struct timespec tick = { 0, 300 * 1000000L };
    int step = 0;
    while (time(NULL) - t0 < hold) {
        XFillRectangle(d, m, gc, 0, 0, MENU_W, MENU_H);
        if (move && ++step % 3 == 0) {
            /* Nudge the popup so the compositor repositions it. */
            XMoveWindow(d, m, 100 + step * 5, 100 + step * 5);
        }
        XFlush(d);
        nanosleep(&tick, NULL);
    }
    XUnmapWindow(d, m);
    XFlush(d);
    sleep(1);
    return 0;
}

int main(int argc, char **argv) {
    if (argc > 1 && strcmp(argv[1], "frame") == 0)
        return frame_main();
    if (argc > 1 && strcmp(argv[1], "menu") == 0)
        return menu_main(argc > 2 ? atoi(argv[2]) : 8,
                         argc > 3 && strcmp(argv[3], "move") == 0);
    if (argc > 1 && strcmp(argv[1], "probe") == 0 && argc > 2) {
        Display *d = XOpenDisplay(argv[2]);
        if (!d)
            return 1;
        XCloseDisplay(d);
        return 0;
    }
    fprintf(stderr, "usage: xormenu frame | menu <hold-s> | probe <display>\n");
    return 2;
}