/*
  Copyright 2012-2020 David Robillard <d@drobilla.net>
  Copyright 2013 Robin Gareus <robin@gareus.org>
  Copyright 2011-2012 Ben Loftis, Harrison Consoles

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/**
   @file x11.c
   @brief X11 implementation.
*/

#define _POSIX_C_SOURCE 199309L

#include "pugl/detail/x11.h"

#include "pugl/detail/implementation.h"
#include "pugl/detail/types.h"
#include "pugl/pugl.h"
#include "pugl/pugl_stub.h"

#include <X11/X.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>

#ifdef HAVE_XSYNC
#	include <X11/extensions/sync.h>
#	include <X11/extensions/syncconst.h>
#endif

#ifdef HAVE_XCURSOR
#	include <X11/Xcursor/Xcursor.h>
#	include <X11/cursorfont.h>
#endif

#include <sys/select.h>
#include <sys/time.h>

#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#ifndef MIN
#    define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif

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

enum WmClientStateMessageAction {
	WM_STATE_REMOVE,
	WM_STATE_ADD,
	WM_STATE_TOGGLE
};

static const long eventMask =
	(ExposureMask | StructureNotifyMask |
	 VisibilityChangeMask | FocusChangeMask |
	 EnterWindowMask | LeaveWindowMask | PointerMotionMask |
	 ButtonPressMask | ButtonReleaseMask | KeyPressMask | KeyReleaseMask);

static bool
puglInitXSync(PuglWorldInternals* impl)
{
#ifdef HAVE_XSYNC
	int                 syncMajor   = 0;
	int                 syncMinor   = 0;
	int                 errorBase   = 0;
	XSyncSystemCounter* counters    = NULL;
	int                 numCounters = 0;

	if (XSyncQueryExtension(impl->display, &impl->syncEventBase, &errorBase) &&
	    XSyncInitialize(impl->display, &syncMajor, &syncMinor) &&
	    (counters = XSyncListSystemCounters(impl->display, &numCounters))) {

		for (int n = 0; n < numCounters; ++n) {
			if (!strcmp(counters[n].name, "SERVERTIME")) {
				impl->serverTimeCounter = counters[n].counter;
				impl->syncSupported     = true;
				break;
			}
		}

		XSyncFreeSystemCounterList(counters);
	}
#else
	(void)impl;
#endif

	return false;
}

PuglWorldInternals*
puglInitWorldInternals(PuglWorldType type, PuglWorldFlags flags)
{
	if (type == PUGL_PROGRAM && (flags & PUGL_WORLD_THREADS)) {
		XInitThreads();
	}

	Display* display = XOpenDisplay(NULL);
	if (!display) {
		return NULL;
	}

	PuglWorldInternals* impl = (PuglWorldInternals*)calloc(
		1, sizeof(PuglWorldInternals));

	impl->display = display;

	// Intern the various atoms we will need
	impl->atoms.CLIPBOARD        = XInternAtom(display, "CLIPBOARD", 0);
	impl->atoms.UTF8_STRING      = XInternAtom(display, "UTF8_STRING", 0);
	impl->atoms.WM_PROTOCOLS     = XInternAtom(display, "WM_PROTOCOLS", 0);
	impl->atoms.WM_DELETE_WINDOW = XInternAtom(display, "WM_DELETE_WINDOW", 0);
	impl->atoms.PUGL_CLIENT_MSG  = XInternAtom(display, "_PUGL_CLIENT_MSG", 0);
	impl->atoms.NET_WM_NAME      = XInternAtom(display, "_NET_WM_NAME", 0);
	impl->atoms.NET_WM_STATE     = XInternAtom(display, "_NET_WM_STATE", 0);
	impl->atoms.NET_WM_STATE_DEMANDS_ATTENTION =
		XInternAtom(display, "_NET_WM_STATE_DEMANDS_ATTENTION", 0);

	// Open input method
	XSetLocaleModifiers("");
	if (!(impl->xim = XOpenIM(display, NULL, NULL, NULL))) {
		XSetLocaleModifiers("@im=");
		impl->xim = XOpenIM(display, NULL, NULL, NULL);
	}

	puglInitXSync(impl);
	XFlush(display);

	return impl;
}

void*
puglGetNativeWorld(PuglWorld* world)
{
	return world->impl->display;
}

PuglInternals*
puglInitViewInternals(void)
{
	PuglInternals* impl = (PuglInternals*)calloc(1, sizeof(PuglInternals));

#ifdef HAVE_XCURSOR
	impl->cursorShape = XC_arrow;
#endif

	return impl;
}

static PuglStatus
puglPollX11Socket(PuglWorld* world, const double timeout)
{
	if (XPending(world->impl->display) > 0) {
		return PUGL_SUCCESS;
	}

	const int fd   = ConnectionNumber(world->impl->display);
	const int nfds = fd + 1;
	int       ret  = 0;
	fd_set    fds;
	FD_ZERO(&fds); // NOLINT
	FD_SET(fd, &fds);

	if (timeout < 0.0) {
		ret = select(nfds, &fds, NULL, NULL, NULL);
	} else {
		const long     sec  = (long)timeout;
		const long     usec = (long)((timeout - (double)sec) * 1e6);
		struct timeval tv   = {sec, usec};
		ret = select(nfds, &fds, NULL, NULL, &tv);
	}

	return ret < 0 ? PUGL_UNKNOWN_ERROR : PUGL_SUCCESS;
}

static PuglView*
puglFindView(PuglWorld* world, const Window window)
{
	for (size_t i = 0; i < world->numViews; ++i) {
		if (world->views[i]->impl->win == window) {
			return world->views[i];
		}
	}

	return NULL;
}

static PuglStatus
updateSizeHints(const PuglView* view)
{
	if (!view->impl->win) {
		return PUGL_SUCCESS;
	}

	Display*   display   = view->world->impl->display;
	XSizeHints sizeHints = {0};

	if (!view->hints[PUGL_RESIZABLE]) {
		sizeHints.flags       = PBaseSize | PMinSize | PMaxSize;
		sizeHints.base_width  = (int)view->frame.width;
		sizeHints.base_height = (int)view->frame.height;
		sizeHints.min_width   = (int)view->frame.width;
		sizeHints.min_height  = (int)view->frame.height;
		sizeHints.max_width   = (int)view->frame.width;
		sizeHints.max_height  = (int)view->frame.height;
	} else {
		if (view->defaultWidth || view->defaultHeight) {
			sizeHints.flags       = PBaseSize;
			sizeHints.base_width  = view->defaultWidth;
			sizeHints.base_height = view->defaultHeight;
		}
		if (view->minWidth || view->minHeight) {
			sizeHints.flags      = PMinSize;
			sizeHints.min_width  = view->minWidth;
			sizeHints.min_height = view->minHeight;
		}
		if (view->maxWidth || view->maxHeight) {
			sizeHints.flags      = PMaxSize;
			sizeHints.max_width  = view->maxWidth;
			sizeHints.max_height = view->maxHeight;
		}
		if (view->minAspectX) {
			sizeHints.flags        |= PAspect;
			sizeHints.min_aspect.x  = view->minAspectX;
			sizeHints.min_aspect.y  = view->minAspectY;
			sizeHints.max_aspect.x  = view->maxAspectX;
			sizeHints.max_aspect.y  = view->maxAspectY;
		}
	}

	XSetNormalHints(display, view->impl->win, &sizeHints);
	return PUGL_SUCCESS;
}

#ifdef HAVE_XCURSOR
static PuglStatus
puglDefineCursorShape(PuglView* view, unsigned shape)
{
	PuglInternals* const impl    = view->impl;
	PuglWorld* const     world   = view->world;
	Display* const       display = world->impl->display;
	const Cursor         cur     = XcursorShapeLoadCursor(display, shape);

	if (cur) {
		XDefineCursor(display, impl->win, cur);
		XFreeCursor(display, cur);
		return PUGL_SUCCESS;
	}

	return PUGL_FAILURE;
}
#endif

PuglStatus
puglRealize(PuglView* view)
{
	PuglInternals* const impl    = view->impl;
	PuglWorld* const     world   = view->world;
	PuglX11Atoms* const  atoms   = &view->world->impl->atoms;
	Display* const       display = world->impl->display;

	impl->display = display;
	impl->screen  = DefaultScreen(display);

	if (!view->backend || !view->backend->configure) {
		return PUGL_BAD_BACKEND;
	} else if (view->frame.width == 0.0 && view->frame.height == 0.0) {
		if (view->defaultWidth == 0.0 && view->defaultHeight == 0.0) {
			return PUGL_BAD_CONFIGURATION;
		}

		const int screenWidth  = DisplayWidth(display, impl->screen);
		const int screenHeight = DisplayHeight(display, impl->screen);

		view->frame.width  = view->defaultWidth;
		view->frame.height = view->defaultHeight;
		view->frame.x      = screenWidth / 2.0 - view->frame.width / 2.0;
		view->frame.y      = screenHeight / 2.0 - view->frame.height / 2.0;
	}

	PuglStatus st = view->backend->configure(view);
	if (st || !impl->vi) {
		view->backend->destroy(view);
		return st ? st : PUGL_BACKEND_FAILED;
	}

	Window xParent = view->parent ? (Window)view->parent
	                              : RootWindow(display, impl->screen);

	Colormap cmap = XCreateColormap(
		display, xParent, impl->vi->visual, AllocNone);

	XSetWindowAttributes attr = {0};
	attr.colormap   = cmap;
	attr.event_mask = eventMask;

	const Window win = impl->win = XCreateWindow(
		display, xParent,
		(int)view->frame.x, (int)view->frame.y,
		(unsigned)view->frame.width, (unsigned)view->frame.height,
		0, impl->vi->depth, InputOutput,
		impl->vi->visual, CWColormap | CWEventMask, &attr);

	if ((st = view->backend->create(view))) {
		return st;
	}

	updateSizeHints(view);

	XClassHint classHint = { world->className, world->className };
	XSetClassHint(display, win, &classHint);

	if (view->title) {
		puglSetWindowTitle(view, view->title);
	}

	if (!view->parent) {
		XSetWMProtocols(display, win, &atoms->WM_DELETE_WINDOW, 1);
	}

	if (view->transientParent) {
		XSetTransientForHint(display, win, (Window)(view->transientParent));
	}

	// Create input context
	const XIMStyle im_style = XIMPreeditNothing | XIMStatusNothing;
	if (!(impl->xic = XCreateIC(world->impl->xim,
	                            XNInputStyle,   im_style,
	                            XNClientWindow, win,
	                            XNFocusWindow,  win,
	                            NULL))) {
		view->world->logFunc(view->world,
		                     PUGL_LOG_LEVEL_WARNING,
		                     "XCreateID failed\n");
	}

#ifdef HAVE_XCURSOR
	puglDefineCursorShape(view, impl->cursorShape);
#endif

	puglDispatchSimpleEvent(view, PUGL_CREATE);

	return PUGL_SUCCESS;
}

PuglStatus
puglShowWindow(PuglView* view)
{
	PuglStatus st = PUGL_SUCCESS;

	if (!view->impl->win) {
		if ((st = puglRealize(view))) {
			return st;
		}
	}

	XMapRaised(view->impl->display, view->impl->win);
	puglPostRedisplay(view);

	return st;
}

PuglStatus
puglHideWindow(PuglView* view)
{
	XUnmapWindow(view->impl->display, view->impl->win);
	return PUGL_SUCCESS;
}

void
puglFreeViewInternals(PuglView* view)
{
	if (view && view->impl) {
		if (view->impl->xic) {
			XDestroyIC(view->impl->xic);
		}
		if (view->backend) {
			view->backend->destroy(view);
		}
		if (view->impl->display) {
			XDestroyWindow(view->impl->display, view->impl->win);
		}
		XFree(view->impl->vi);
		free(view->impl);
	}
}

void
puglFreeWorldInternals(PuglWorld* world)
{
	if (world->impl->xim) {
		XCloseIM(world->impl->xim);
	}
	XCloseDisplay(world->impl->display);
	free(world->impl->timers);
	free(world->impl);
}

static PuglKey
keySymToSpecial(KeySym sym)
{
	switch (sym) {
	case XK_F1:          return PUGL_KEY_F1;
	case XK_F2:          return PUGL_KEY_F2;
	case XK_F3:          return PUGL_KEY_F3;
	case XK_F4:          return PUGL_KEY_F4;
	case XK_F5:          return PUGL_KEY_F5;
	case XK_F6:          return PUGL_KEY_F6;
	case XK_F7:          return PUGL_KEY_F7;
	case XK_F8:          return PUGL_KEY_F8;
	case XK_F9:          return PUGL_KEY_F9;
	case XK_F10:         return PUGL_KEY_F10;
	case XK_F11:         return PUGL_KEY_F11;
	case XK_F12:         return PUGL_KEY_F12;
	case XK_Left:        return PUGL_KEY_LEFT;
	case XK_Up:          return PUGL_KEY_UP;
	case XK_Right:       return PUGL_KEY_RIGHT;
	case XK_Down:        return PUGL_KEY_DOWN;
	case XK_Page_Up:     return PUGL_KEY_PAGE_UP;
	case XK_Page_Down:   return PUGL_KEY_PAGE_DOWN;
	case XK_Home:        return PUGL_KEY_HOME;
	case XK_End:         return PUGL_KEY_END;
	case XK_Insert:      return PUGL_KEY_INSERT;
	case XK_Shift_L:     return PUGL_KEY_SHIFT_L;
	case XK_Shift_R:     return PUGL_KEY_SHIFT_R;
	case XK_Control_L:   return PUGL_KEY_CTRL_L;
	case XK_Control_R:   return PUGL_KEY_CTRL_R;
	case XK_Alt_L:       return PUGL_KEY_ALT_L;
	case XK_ISO_Level3_Shift:
	case XK_Alt_R:       return PUGL_KEY_ALT_R;
	case XK_Super_L:     return PUGL_KEY_SUPER_L;
	case XK_Super_R:     return PUGL_KEY_SUPER_R;
	case XK_Menu:        return PUGL_KEY_MENU;
	case XK_Caps_Lock:   return PUGL_KEY_CAPS_LOCK;
	case XK_Scroll_Lock: return PUGL_KEY_SCROLL_LOCK;
	case XK_Num_Lock:    return PUGL_KEY_NUM_LOCK;
	case XK_Print:       return PUGL_KEY_PRINT_SCREEN;
	case XK_Pause:       return PUGL_KEY_PAUSE;
	default: break;
	}
	return (PuglKey)0;
}

static int
lookupString(XIC xic, XEvent* xevent, char* str, KeySym* sym)
{
	Status status = 0;

#ifdef X_HAVE_UTF8_STRING
	const int n = Xutf8LookupString(xic, &xevent->xkey, str, 7, sym, &status);
#else
	const int n = XmbLookupString(xic, &xevent->xkey, str, 7, sym, &status);
#endif

	return status == XBufferOverflow ? 0 : n;
}

static void
translateKey(PuglView* view, XEvent* xevent, PuglEvent* event)
{
	const unsigned state  = xevent->xkey.state;
	const bool     filter = XFilterEvent(xevent, None);

	event->key.keycode = xevent->xkey.keycode;
	xevent->xkey.state = 0;

	// Lookup unshifted key
	char          ustr[8] = {0};
	KeySym        sym     = 0;
	const int     ufound  = XLookupString(&xevent->xkey, ustr, 8, &sym, NULL);
	const PuglKey special = keySymToSpecial(sym);

	event->key.key = ((special || ufound <= 0)
	                  ? special
	                  : puglDecodeUTF8((const uint8_t*)ustr));

	if (xevent->type == KeyPress && !filter && !special) {
		// Lookup shifted key for possible text event
		xevent->xkey.state = state;

		char      sstr[8] = {0};
		const int sfound  = lookupString(view->impl->xic, xevent, sstr, &sym);
		if (sfound > 0) {
			// Dispatch key event now
			puglDispatchEvent(view, event);

			// "Return" a text event in its place
			event->text.type      = PUGL_TEXT;
			event->text.character = puglDecodeUTF8((const uint8_t*)sstr);
			memcpy(event->text.string, sstr, sizeof(sstr));
		}
	}
}

static uint32_t
translateModifiers(const unsigned xstate)
{
	return (((xstate & ShiftMask)   ? PUGL_MOD_SHIFT  : 0u) |
	        ((xstate & ControlMask) ? PUGL_MOD_CTRL   : 0u) |
	        ((xstate & Mod1Mask)    ? PUGL_MOD_ALT    : 0u) |
	        ((xstate & Mod4Mask)    ? PUGL_MOD_SUPER  : 0u));
}

static PuglEvent
translateEvent(PuglView* view, XEvent xevent)
{
	const PuglX11Atoms* atoms = &view->world->impl->atoms;

	PuglEvent event = {{PUGL_NOTHING, 0}};
	event.any.flags = xevent.xany.send_event ? PUGL_IS_SEND_EVENT : 0;

	switch (xevent.type) {
	case ClientMessage:
		if (xevent.xclient.message_type == atoms->WM_PROTOCOLS) {
			const Atom protocol = (Atom)xevent.xclient.data.l[0];
			if (protocol == atoms->WM_DELETE_WINDOW) {
				event.type = PUGL_CLOSE;
			}
		} else if (xevent.xclient.message_type == atoms->PUGL_CLIENT_MSG) {
			event.type         = PUGL_CLIENT;
			event.client.data1 = (uintptr_t)xevent.xclient.data.l[0];
			event.client.data2 = (uintptr_t)xevent.xclient.data.l[1];
		}
		break;
	case VisibilityNotify:
		view->visible = xevent.xvisibility.state != VisibilityFullyObscured;
		break;
	case MapNotify:
		event.type = PUGL_MAP;
		break;
	case UnmapNotify:
		event.type = PUGL_UNMAP;
		view->visible = false;
		break;
	case ConfigureNotify:
		event.type             = PUGL_CONFIGURE;
		event.configure.x      = xevent.xconfigure.x;
		event.configure.y      = xevent.xconfigure.y;
		event.configure.width  = xevent.xconfigure.width;
		event.configure.height = xevent.xconfigure.height;
		break;
	case Expose:
		event.type          = PUGL_EXPOSE;
		event.expose.x      = xevent.xexpose.x;
		event.expose.y      = xevent.xexpose.y;
		event.expose.width  = xevent.xexpose.width;
		event.expose.height = xevent.xexpose.height;
		break;
	case MotionNotify:
		event.type           = PUGL_MOTION;
		event.motion.time    = (double)xevent.xmotion.time / 1e3;
		event.motion.x       = xevent.xmotion.x;
		event.motion.y       = xevent.xmotion.y;
		event.motion.xRoot   = xevent.xmotion.x_root;
		event.motion.yRoot   = xevent.xmotion.y_root;
		event.motion.state   = translateModifiers(xevent.xmotion.state);
		event.motion.isHint  = (xevent.xmotion.is_hint == NotifyHint);
		break;
	case ButtonPress:
		if (xevent.xbutton.button >= 4 && xevent.xbutton.button <= 7) {
			event.type           = PUGL_SCROLL;
			event.scroll.time    = (double)xevent.xbutton.time / 1e3;
			event.scroll.x       = xevent.xbutton.x;
			event.scroll.y       = xevent.xbutton.y;
			event.scroll.xRoot   = xevent.xbutton.x_root;
			event.scroll.yRoot   = xevent.xbutton.y_root;
			event.scroll.state   = translateModifiers(xevent.xbutton.state);
			event.scroll.dx      = 0.0;
			event.scroll.dy      = 0.0;
			switch (xevent.xbutton.button) {
			case 4:
				event.scroll.dy        = 1.0;
				event.scroll.direction = PUGL_SCROLL_UP;
				break;
			case 5:
				event.scroll.dy        = -1.0;
				event.scroll.direction = PUGL_SCROLL_DOWN;
				break;
			case 6:
				event.scroll.dx        = -1.0;
				event.scroll.direction = PUGL_SCROLL_LEFT;
				break;
			case 7:
				event.scroll.dx        = 1.0;
				event.scroll.direction = PUGL_SCROLL_RIGHT;
				break;
			}
			// fallthru
		}
		// fallthru
	case ButtonRelease:
		if (xevent.xbutton.button < 4 || xevent.xbutton.button > 7) {
			event.button.type   = ((xevent.type == ButtonPress)
			                       ? PUGL_BUTTON_PRESS
			                       : PUGL_BUTTON_RELEASE);
			event.button.time   = (double)xevent.xbutton.time / 1e3;
			event.button.x      = xevent.xbutton.x;
			event.button.y      = xevent.xbutton.y;
			event.button.xRoot  = xevent.xbutton.x_root;
			event.button.yRoot  = xevent.xbutton.y_root;
			event.button.state  = translateModifiers(xevent.xbutton.state);
			event.button.button = xevent.xbutton.button;
		}
		break;
	case KeyPress:
	case KeyRelease:
		event.type       = ((xevent.type == KeyPress)
		                    ? PUGL_KEY_PRESS
		                    : PUGL_KEY_RELEASE);
		event.key.time   = (double)xevent.xkey.time / 1e3;
		event.key.x      = xevent.xkey.x;
		event.key.y      = xevent.xkey.y;
		event.key.xRoot  = xevent.xkey.x_root;
		event.key.yRoot  = xevent.xkey.y_root;
		event.key.state  = translateModifiers(xevent.xkey.state);
		translateKey(view, &xevent, &event);
		break;
	case EnterNotify:
	case LeaveNotify:
		event.type            = ((xevent.type == EnterNotify)
		                         ? PUGL_POINTER_IN
		                         : PUGL_POINTER_OUT);
		event.crossing.time   = (double)xevent.xcrossing.time / 1e3;
		event.crossing.x      = xevent.xcrossing.x;
		event.crossing.y      = xevent.xcrossing.y;
		event.crossing.xRoot  = xevent.xcrossing.x_root;
		event.crossing.yRoot  = xevent.xcrossing.y_root;
		event.crossing.state  = translateModifiers(xevent.xcrossing.state);
		event.crossing.mode   = PUGL_CROSSING_NORMAL;
		if (xevent.xcrossing.mode == NotifyGrab) {
			event.crossing.mode = PUGL_CROSSING_GRAB;
		} else if (xevent.xcrossing.mode == NotifyUngrab) {
			event.crossing.mode = PUGL_CROSSING_UNGRAB;
		}
		break;

	case FocusIn:
	case FocusOut:
		event.type = (xevent.type == FocusIn) ? PUGL_FOCUS_IN : PUGL_FOCUS_OUT;
		event.focus.mode = PUGL_CROSSING_NORMAL;
		if (xevent.xfocus.mode == NotifyGrab) {
			event.focus.mode = PUGL_CROSSING_GRAB;
		} else if (xevent.xfocus.mode == NotifyUngrab) {
			event.focus.mode = PUGL_CROSSING_UNGRAB;
		}
		break;

	default:
		break;
	}

	return event;
}

PuglStatus
puglGrabFocus(PuglView* view)
{
	XSetInputFocus(
		view->impl->display, view->impl->win, RevertToNone, CurrentTime);
	return PUGL_SUCCESS;
}

bool
puglHasFocus(const PuglView* view)
{
	int    revertTo      = 0;
	Window focusedWindow = 0;
	XGetInputFocus(view->impl->display, &focusedWindow, &revertTo);
	return focusedWindow == view->impl->win;
}

PuglStatus
puglRequestAttention(PuglView* view)
{
	PuglInternals* const      impl  = view->impl;
	const PuglX11Atoms* const atoms = &view->world->impl->atoms;
	XEvent                    event = {0};

	event.type                 = ClientMessage;
	event.xclient.window       = impl->win;
	event.xclient.format       = 32;
	event.xclient.message_type = atoms->NET_WM_STATE;
	event.xclient.data.l[0]    = WM_STATE_ADD;
	event.xclient.data.l[1]    = (long)atoms->NET_WM_STATE_DEMANDS_ATTENTION;
	event.xclient.data.l[2]    = 0;
	event.xclient.data.l[3]    = 1;
	event.xclient.data.l[4]    = 0;

	const Window root = RootWindow(impl->display, impl->screen);
	XSendEvent(impl->display,
	           root,
	           False,
	           SubstructureNotifyMask | SubstructureRedirectMask,
	           &event);

	return PUGL_SUCCESS;
}

PuglStatus
puglStartTimer(PuglView* view, uintptr_t id, double timeout)
{
#ifdef HAVE_XSYNC
	if (view->world->impl->syncSupported) {
		XSyncValue value;
		XSyncIntToValue(&value, (int)floor(timeout * 1000.0));

		PuglWorldInternals*  w       = view->world->impl;
		Display* const       display = w->display;
		const XSyncCounter   counter = w->serverTimeCounter;
		const XSyncTestType  type    = XSyncPositiveTransition;
		const XSyncTrigger   trigger = {counter, XSyncRelative, value, type};
		XSyncAlarmAttributes attr    = {trigger, value, True, XSyncAlarmActive};
		const XSyncAlarm     alarm   = XSyncCreateAlarm(display, 0x17, &attr);
		const PuglTimer      timer   = {alarm, view, id};

		if (alarm != None) {
			for (size_t i = 0; i < w->numTimers; ++i) {
				if (w->timers[i].view == view && w->timers[i].id == id) {
					// Replace existing timer
					XSyncDestroyAlarm(w->display, w->timers[i].alarm);
					w->timers[i] = timer;
					return PUGL_SUCCESS;
				}
			}

			// Add new timer
			const size_t size           = ++w->numTimers * sizeof(timer);
			w->timers                   = (PuglTimer*)realloc(w->timers, size);
			w->timers[w->numTimers - 1] = timer;
			return PUGL_SUCCESS;
		}
	}
#else
	(void)view;
	(void)id;
	(void)timeout;
#endif

	return PUGL_FAILURE;
}

PuglStatus
puglStopTimer(PuglView* view, uintptr_t id)
{
#ifdef HAVE_XSYNC
	PuglWorldInternals* w = view->world->impl;

	for (size_t i = 0; i < w->numTimers; ++i) {
		if (w->timers[i].view == view && w->timers[i].id == id) {
			XSyncDestroyAlarm(w->display, w->timers[i].alarm);

			if (i == w->numTimers - 1) {
				memset(&w->timers[i], 0, sizeof(PuglTimer));
			} else {
				memmove(w->timers + i,
				        w->timers + i + 1,
				        sizeof(PuglTimer) * (w->numTimers - i - 1));

				memset(&w->timers[i], 0, sizeof(PuglTimer));
			}

			--w->numTimers;
			return PUGL_SUCCESS;
		}
	}
#else
	(void)view;
	(void)id;
#endif

	return PUGL_FAILURE;
}

static XEvent
puglEventToX(PuglView* view, const PuglEvent* event)
{
	XEvent xev          = {0};
	xev.xany.send_event = True;

	switch (event->type) {
	case PUGL_EXPOSE: {
		const double x = floor(event->expose.x);
		const double y = floor(event->expose.y);
		const double w = ceil(event->expose.x + event->expose.width) - x;
		const double h = ceil(event->expose.y + event->expose.height) - y;

		xev.xexpose.type    = Expose;
		xev.xexpose.serial  = 0;
		xev.xexpose.display = view->impl->display;
		xev.xexpose.window  = view->impl->win;
		xev.xexpose.x       = (int)x;
		xev.xexpose.y       = (int)y;
		xev.xexpose.width   = (int)w;
		xev.xexpose.height  = (int)h;
		break;
	}

	case PUGL_CLIENT:
		xev.xclient.type         = ClientMessage;
		xev.xclient.serial       = 0;
		xev.xclient.send_event   = True;
		xev.xclient.display      = view->impl->display;
		xev.xclient.window       = view->impl->win;
		xev.xclient.message_type = view->world->impl->atoms.PUGL_CLIENT_MSG;
		xev.xclient.format       = 32;
		xev.xclient.data.l[0]    = (long)event->client.data1;
		xev.xclient.data.l[1]    = (long)event->client.data2;
		break;

	default:
		break;
	}

	return xev;
}

PuglStatus
puglSendEvent(PuglView* view, const PuglEvent* event)
{
	XEvent xev = puglEventToX(view, event);

	if (xev.type) {
		if (XSendEvent(view->impl->display, view->impl->win, False, 0, &xev)) {
			return PUGL_SUCCESS;
		}
	}

	return PUGL_UNSUPPORTED_TYPE;
}

#ifndef PUGL_DISABLE_DEPRECATED
PuglStatus
puglWaitForEvent(PuglView* view)
{
	XEvent xevent;
	XPeekEvent(view->impl->display, &xevent);
	return PUGL_SUCCESS;
}
#endif

static void
mergeExposeEvents(PuglEvent* dst, const PuglEvent* src)
{
	if (!dst->type) {
		*dst = *src;
	} else {
		const double max_x = MAX(dst->expose.x + dst->expose.width,
		                         src->expose.x + src->expose.width);
		const double max_y = MAX(dst->expose.y + dst->expose.height,
		                         src->expose.y + src->expose.height);

		dst->expose.x      = MIN(dst->expose.x, src->expose.x);
		dst->expose.y      = MIN(dst->expose.y, src->expose.y);
		dst->expose.width  = max_x - dst->expose.x;
		dst->expose.height = max_y - dst->expose.y;
	}
}

static void
handleSelectionNotify(const PuglWorld* world, PuglView* view)
{
	uint8_t*      str  = NULL;
	Atom          type = 0;
	int           fmt  = 0;
	unsigned long len  = 0;
	unsigned long left = 0;

	XGetWindowProperty(world->impl->display,
	                   view->impl->win,
	                   XA_PRIMARY,
	                   0,
	                   0x1FFFFFFF,
	                   False,
	                   AnyPropertyType,
	                   &type,
	                   &fmt,
	                   &len,
	                   &left,
	                   &str);

	if (str && fmt == 8 && type == world->impl->atoms.UTF8_STRING &&
	    left == 0) {
		puglSetBlob(&view->clipboard, str, len);
	}

	XFree(str);
}

static void
handleSelectionRequest(const PuglWorld*              world,
                       PuglView*                     view,
                       const XSelectionRequestEvent* request)
{
	XSelectionEvent note = {SelectionNotify,
	                        request->serial,
	                        False,
	                        world->impl->display,
	                        request->requestor,
	                        request->selection,
	                        request->target,
	                        None,
	                        request->time};

	const char* type = NULL;
	size_t      len  = 0;
	const void* data = puglGetInternalClipboard(view, &type, &len);
	if (data && request->selection == world->impl->atoms.CLIPBOARD &&
	    request->target == world->impl->atoms.UTF8_STRING) {
		note.property = request->property;
		XChangeProperty(world->impl->display,
		                note.requestor,
		                note.property,
		                note.target,
		                8,
		                PropModeReplace,
		                (const uint8_t*)data,
		                (int)len);
	} else {
		note.property = None;
	}

	XSendEvent(world->impl->display, note.requestor, True, 0, (XEvent*)&note);
}

/// Flush pending configure and expose events for all views
static void
flushExposures(PuglWorld* world)
{
	for (size_t i = 0; i < world->numViews; ++i) {
		PuglView* const view = world->views[i];

		if (view->visible) {
			puglDispatchSimpleEvent(view, PUGL_UPDATE);
		}

		const PuglEvent configure = view->impl->pendingConfigure;
		const PuglEvent expose    = view->impl->pendingExpose;

		view->impl->pendingConfigure.type = PUGL_NOTHING;
		view->impl->pendingExpose.type    = PUGL_NOTHING;

		if (configure.type || expose.type) {
			view->backend->enter(view, expose.type ? &expose.expose : NULL);
			puglDispatchEventInContext(view, &configure);
			puglDispatchEventInContext(view, &expose);
			view->backend->leave(view, expose.type ? &expose.expose : NULL);
		}
	}
}

static bool
handleTimerEvent(PuglWorld* world, XEvent xevent)
{
#ifdef HAVE_XSYNC
	if (xevent.type == world->impl->syncEventBase + XSyncAlarmNotify) {
		XSyncAlarmNotifyEvent* notify = ((XSyncAlarmNotifyEvent*)&xevent);

		for (size_t i = 0; i < world->impl->numTimers; ++i) {
			if (world->impl->timers[i].alarm == notify->alarm) {
				PuglEvent event = {{PUGL_TIMER, 0}};
				event.timer.id  = world->impl->timers[i].id;
				puglDispatchEvent(world->impl->timers[i].view,
				                  (const PuglEvent*)&event);
			}
		}

		return true;
	}
#else
	(void)world;
	(void)xevent;
#endif

	return false;
}

static PuglStatus
puglDispatchX11Events(PuglWorld* world)
{
	const PuglX11Atoms* const atoms = &world->impl->atoms;

	// Flush output to the server once at the start
	Display* display = world->impl->display;
	XFlush(display);

	// Process all queued events (without further flushing)
	while (XEventsQueued(display, QueuedAfterReading) > 0) {
		XEvent xevent;
		XNextEvent(display, &xevent);

		if (handleTimerEvent(world, xevent)) {
			continue;
		}

		PuglView* view = puglFindView(world, xevent.xany.window);
		if (!view) {
			continue;
		}

		// Handle special events
		PuglInternals* const impl = view->impl;
		if (xevent.type == KeyRelease && view->hints[PUGL_IGNORE_KEY_REPEAT]) {
			XEvent next;
			if (XCheckTypedWindowEvent(display, impl->win, KeyPress, &next) &&
			    next.type == KeyPress &&
			    next.xkey.time == xevent.xkey.time &&
			    next.xkey.keycode == xevent.xkey.keycode) {
				continue;
			}
		} else if (xevent.type == FocusIn) {
			XSetICFocus(impl->xic);
		} else if (xevent.type == FocusOut) {
			XUnsetICFocus(impl->xic);
		} else if (xevent.type == SelectionClear) {
			puglSetBlob(&view->clipboard, NULL, 0);
		} else if (xevent.type == SelectionNotify &&
		           xevent.xselection.selection == atoms->CLIPBOARD &&
		           xevent.xselection.target == atoms->UTF8_STRING &&
		           xevent.xselection.property == XA_PRIMARY) {
			handleSelectionNotify(world, view);
		} else if (xevent.type == SelectionRequest) {
			handleSelectionRequest(world, view, &xevent.xselectionrequest);
		}

		// Translate X11 event to Pugl event
		const PuglEvent event = translateEvent(view, xevent);

		if (event.type == PUGL_EXPOSE) {
			// Expand expose event to be dispatched after loop
			mergeExposeEvents(&view->impl->pendingExpose, &event);
		} else if (event.type == PUGL_CONFIGURE) {
			// Expand configure event to be dispatched after loop
			view->impl->pendingConfigure = event;
			view->frame.x                = event.configure.x;
			view->frame.y                = event.configure.y;
			view->frame.width            = event.configure.width;
			view->frame.height           = event.configure.height;
		} else if (event.type == PUGL_MAP && view->parent) {
			XWindowAttributes attrs;
			XGetWindowAttributes(view->impl->display, view->impl->win, &attrs);

			const PuglEventConfigure configure = {
			    PUGL_CONFIGURE, 0, attrs.x, attrs.y, attrs.width, attrs.height};

			puglDispatchEvent(view, (const PuglEvent*)&configure);
			puglDispatchEvent(view, &event);
		} else {
			// Dispatch event to application immediately
			puglDispatchEvent(view, &event);
		}
	}

	return PUGL_SUCCESS;
}

#ifndef PUGL_DISABLE_DEPRECATED
PuglStatus
puglProcessEvents(PuglView* view)
{
	return puglUpdate(view->world, 0.0);
}
#endif

PuglStatus
puglUpdate(PuglWorld* world, double timeout)
{
	const double startTime = puglGetTime(world);
	PuglStatus   st        = PUGL_SUCCESS;

	world->impl->dispatchingEvents = true;

	if (timeout < 0.0) {
		st = puglPollX11Socket(world, timeout);
		st = st ? st : puglDispatchX11Events(world);
	} else if (timeout <= 0.001) {
		st = puglDispatchX11Events(world);
	} else {
		const double endTime = startTime + timeout - 0.001;
		for (double t = startTime; t < endTime; t = puglGetTime(world)) {
			if ((st = puglPollX11Socket(world, endTime - t)) ||
			    (st = puglDispatchX11Events(world))) {
				break;
			}
		}
	}

	flushExposures(world);

	world->impl->dispatchingEvents = false;

	return st;
}

double
puglGetTime(const PuglWorld* world)
{
	struct timespec ts;
	clock_gettime(CLOCK_MONOTONIC, &ts);
	return ((double)ts.tv_sec + (double)ts.tv_nsec / 1000000000.0) -
	       world->startTime;
}

PuglStatus
puglPostRedisplay(PuglView* view)
{
	const PuglRect rect = { 0, 0, view->frame.width, view->frame.height };

	return puglPostRedisplayRect(view, rect);
}

PuglStatus
puglPostRedisplayRect(PuglView* view, PuglRect rect)
{
	const PuglEventExpose event = {
		PUGL_EXPOSE, 0, rect.x, rect.y, rect.width, rect.height
	};

	if (view->world->impl->dispatchingEvents) {
		// Currently dispatching events, add/expand expose for the loop end
		mergeExposeEvents(&view->impl->pendingExpose, (const PuglEvent*)&event);
	} else if (view->visible) {
		// Not dispatching events, send an X expose so we wake up next time
		return puglSendEvent(view, (const PuglEvent*)&event);
	}

	return PUGL_SUCCESS;
}

PuglNativeView
puglGetNativeWindow(PuglView* view)
{
	return (PuglNativeView)view->impl->win;
}

PuglStatus
puglSetWindowTitle(PuglView* view, const char* title)
{
	Display*                  display = view->world->impl->display;
	const PuglX11Atoms* const atoms   = &view->world->impl->atoms;

	puglSetString(&view->title, title);

	if (view->impl->win) {
		XStoreName(display, view->impl->win, title);
		XChangeProperty(display, view->impl->win, atoms->NET_WM_NAME,
		                atoms->UTF8_STRING, 8, PropModeReplace,
		                (const uint8_t*)title, (int)strlen(title));
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglSetFrame(PuglView* view, const PuglRect frame)
{
	view->frame = frame;

	if (view->impl->win &&
	    !XMoveResizeWindow(view->world->impl->display, view->impl->win,
	                       (int)frame.x, (int)frame.y,
	                       (unsigned)frame.width, (unsigned)frame.height)) {
		return PUGL_UNKNOWN_ERROR;
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglSetDefaultSize(PuglView* const view, const int width, const int height)
{
	view->defaultWidth  = width;
	view->defaultHeight = height;
	return updateSizeHints(view);
}

PuglStatus
puglSetMinSize(PuglView* const view, const int width, const int height)
{
	view->minWidth  = width;
	view->minHeight = height;
	return updateSizeHints(view);
}

PuglStatus
puglSetMaxSize(PuglView* const view, const int width, const int height)
{
	view->minWidth  = width;
	view->minHeight = height;
	return updateSizeHints(view);
}

PuglStatus
puglSetAspectRatio(PuglView* const view,
                   const int       minX,
                   const int       minY,
                   const int       maxX,
                   const int       maxY)
{
	view->minAspectX = minX;
	view->minAspectY = minY;
	view->maxAspectX = maxX;
	view->maxAspectY = maxY;

	return updateSizeHints(view);
}

PuglStatus
puglSetTransientFor(PuglView* view, PuglNativeView parent)
{
	Display* display = view->world->impl->display;

	view->transientParent = parent;

	if (view->impl->win) {
		XSetTransientForHint(display, view->impl->win,
		                     (Window)view->transientParent);
	}

	return PUGL_SUCCESS;
}

const void*
puglGetClipboard(PuglView* const    view,
                 const char** const type,
                 size_t* const      len)
{
	PuglInternals* const      impl  = view->impl;
	const PuglX11Atoms* const atoms = &view->world->impl->atoms;

	const Window owner = XGetSelectionOwner(impl->display, atoms->CLIPBOARD);
	if (owner != None && owner != impl->win) {
		// Clear internal selection
		puglSetBlob(&view->clipboard, NULL, 0);

		// Request selection from the owner
		XConvertSelection(impl->display,
		                  atoms->CLIPBOARD,
		                  atoms->UTF8_STRING,
		                  XA_PRIMARY,
		                  impl->win,
		                  CurrentTime);

		// Run event loop until data is received
		while (!view->clipboard.data) {
			puglUpdate(view->world, -1.0);
		}
	}

	return puglGetInternalClipboard(view, type, len);
}

PuglStatus
puglSetClipboard(PuglView* const   view,
                 const char* const type,
                 const void* const data,
                 const size_t      len)
{
	PuglInternals* const      impl  = view->impl;
	const PuglX11Atoms* const atoms = &view->world->impl->atoms;

	PuglStatus st = puglSetInternalClipboard(view, type, data, len);
	if (st) {
		return st;
	}

	XSetSelectionOwner(impl->display, atoms->CLIPBOARD, impl->win, CurrentTime);
	return PUGL_SUCCESS;
}

#ifdef HAVE_XCURSOR
static const unsigned cursor_nums[] = {
    XC_arrow,             // ARROW
    XC_xterm,             // CARET
    XC_crosshair,         // CROSSHAIR
    XC_hand2,             // HAND
    XC_pirate,            // NO
    XC_sb_h_double_arrow, // LEFT_RIGHT
    XC_sb_v_double_arrow, // UP_DOWN
};
#endif

PuglStatus
puglSetCursor(PuglView* view, PuglCursor cursor)
{
#ifdef HAVE_XCURSOR
	PuglInternals* const impl  = view->impl;
	const unsigned       index = (unsigned)cursor;
	const unsigned       count = sizeof(cursor_nums) / sizeof(cursor_nums[0]);
	if (index >= count) {
		return PUGL_BAD_PARAMETER;
	}

	const unsigned shape = cursor_nums[index];
	if (!impl->win || impl->cursorShape == shape) {
		return PUGL_SUCCESS;
	}

	impl->cursorShape = cursor_nums[index];

	return puglDefineCursorShape(view, impl->cursorShape);
#else
	(void)view;
	(void)cursor;
	return PUGL_FAILURE;
#endif
}

const PuglBackend*
puglStubBackend(void)
{
	static const PuglBackend backend = {
	    puglX11StubConfigure,
	    puglStubCreate,
	    puglStubDestroy,
	    puglStubEnter,
	    puglStubLeave,
	    puglStubGetContext,
	};

	return &backend;
}