// Copyright 2012-2022 David Robillard <d@drobilla.net>
// Copyright 2013 Robin Gareus <robin@gareus.org>
// Copyright 2011-2012 Ben Loftis, Harrison Consoles
// SPDX-License-Identifier: ISC

#include "x11.h"

#include "attributes.h"
#include "implementation.h"
#include "types.h"

#include "pugl/pugl.h"

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

#ifdef HAVE_XRANDR
#  include <X11/extensions/Xrandr.h>
#endif

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

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

#include <sys/select.h>

#include <limits.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

#ifdef __cplusplus
#  define PUGL_INIT_STRUCT \
    {}
#else
#  define PUGL_INIT_STRUCT \
    {                      \
      0                    \
    }
#endif

enum WmClientStateMessageAction {
  WM_STATE_REMOVE,
  WM_STATE_ADD,
  WM_STATE_TOGGLE
};

#define NUM_CURSORS ((unsigned)PUGL_CURSOR_UP_DOWN + 1u)

static const char* const cursor_names[NUM_CURSORS] = {
  "default",           // ARROW
  "text",              // CARET
  "crosshair",         // CROSSHAIR
  "pointer",           // HAND
  "not-allowed",       // NO
  "sb_h_double_arrow", // LEFT_RIGHT
  "sb_v_double_arrow"  // UP_DOWN
};

static bool
initXSync(PuglWorldInternals* const 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(const PuglWorldType type, const 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);
  impl->atoms.NET_WM_STATE_HIDDEN =
    XInternAtom(display, "_NET_WM_STATE_HIDDEN", 0);

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

  initXSync(impl);
  XFlush(display);

  return impl;
}

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

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

#ifdef HAVE_XCURSOR
  impl->cursorName = cursor_names[PUGL_CURSOR_ARROW];
#endif

  return impl;
}

static PuglStatus
pollX11Socket(PuglWorld* const 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*
findView(PuglWorld* const 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* const view)
{
  if (!view->impl->win) {
    return PUGL_SUCCESS;
  }

  Display*   display   = view->world->impl->display;
  XSizeHints sizeHints = PUGL_INIT_STRUCT;

  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
defineCursorName(PuglView* const view, const char* const name)
{
  PuglInternals* const impl    = view->impl;
  PuglWorld* const     world   = view->world;
  Display* const       display = world->impl->display;

  // Load cursor theme
  char* const theme = XcursorGetTheme(display);
  if (!theme) {
    return PUGL_FAILURE;
  }

  // Get the default size and cursor image from it
  const int           size  = XcursorGetDefaultSize(display);
  XcursorImage* const image = XcursorLibraryLoadImage(name, theme, size);
  if (!image) {
    return PUGL_BAD_PARAMETER;
  }

  // Load a cursor from the image
  const Cursor cur = XcursorImageLoadCursor(display, image);
  XcursorImageDestroy(image);
  if (!cur) {
    return PUGL_UNKNOWN_ERROR;
  }

  // Set the view's cursor to the new loaded one
  XDefineCursor(display, impl->win, cur);
  XFreeCursor(display, cur);
  return PUGL_SUCCESS;
}
#endif

PuglStatus
puglRealize(PuglView* const view)
{
  PuglInternals* const impl    = view->impl;
  PuglWorld* const     world   = view->world;
  PuglX11Atoms* const  atoms   = &view->world->impl->atoms;
  Display* const       display = world->impl->display;
  const int            screen  = DefaultScreen(display);
  const Window         root    = RootWindow(display, screen);
  const Window         parent  = view->parent ? (Window)view->parent : root;
  XSetWindowAttributes attr    = PUGL_INIT_STRUCT;
  PuglStatus           st      = PUGL_SUCCESS;

  // Ensure that we're unrealized and that a reasonable backend has been set
  if (impl->win) {
    return PUGL_FAILURE;
  }

  if (!view->backend || !view->backend->configure) {
    return PUGL_BAD_BACKEND;
  }

  // Set the size to the default if it has not already been set
  if (view->frame.width <= 0.0 && view->frame.height <= 0.0) {
    if (view->defaultWidth <= 0.0 || view->defaultHeight <= 0.0) {
      return PUGL_BAD_CONFIGURATION;
    }

    view->frame.width  = view->defaultWidth;
    view->frame.height = view->defaultHeight;
  }

  // Center top-level windows if a position has not been set
  if (!view->parent && view->frame.x <= 0.0 && view->frame.y <= 0.0) {
    const int screenWidth  = DisplayWidth(display, screen);
    const int screenHeight = DisplayHeight(display, screen);

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

  // Configure the backend to get the visual info
  impl->display = display;
  impl->screen  = screen;
  if ((st = view->backend->configure(view)) || !impl->vi) {
    view->backend->destroy(view);
    return st ? st : PUGL_BACKEND_FAILED;
  }

  // Create a colormap based on the visual info from the backend
  attr.colormap = XCreateColormap(display, parent, impl->vi->visual, AllocNone);

  // Set the event mask to request all of the event types we react to
  attr.event_mask |= ButtonPressMask;
  attr.event_mask |= ButtonReleaseMask;
  attr.event_mask |= EnterWindowMask;
  attr.event_mask |= ExposureMask;
  attr.event_mask |= FocusChangeMask;
  attr.event_mask |= KeyPressMask;
  attr.event_mask |= KeyReleaseMask;
  attr.event_mask |= LeaveWindowMask;
  attr.event_mask |= PointerMotionMask;
  attr.event_mask |= PropertyChangeMask;
  attr.event_mask |= StructureNotifyMask;
  attr.event_mask |= VisibilityChangeMask;

  // Create the window
  impl->win = XCreateWindow(display,
                            parent,
                            (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);

  // Create the backend drawing context/surface
  if ((st = view->backend->create(view))) {
    return st;
  }

#ifdef HAVE_XRANDR
  int ignored = 0;
  if (XRRQueryExtension(display, &ignored, &ignored)) {
    // Set refresh rate hint to the real refresh rate
    XRRScreenConfiguration* conf         = XRRGetScreenInfo(display, parent);
    short                   current_rate = XRRConfigCurrentRate(conf);

    view->hints[PUGL_REFRESH_RATE] = current_rate;
    XRRFreeScreenConfigInfo(conf);
  }
#endif

  updateSizeHints(view);

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

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

  if (parent == root) {
    XSetWMProtocols(display, impl->win, &atoms->WM_DELETE_WINDOW, 1);
  }

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

  // Create input context
  impl->xic = XCreateIC(world->impl->xim,
                        XNInputStyle,
                        XIMPreeditNothing | XIMStatusNothing,
                        XNClientWindow,
                        impl->win,
                        XNFocusWindow,
                        impl->win,
                        (XIM)0);

  puglDispatchSimpleEvent(view, PUGL_CREATE);

  return PUGL_SUCCESS;
}

PuglStatus
puglShow(PuglView* const view)
{
  PuglStatus st = view->impl->win ? PUGL_SUCCESS : puglRealize(view);

  if (!st) {
    XMapRaised(view->impl->display, view->impl->win);
    st = puglPostRedisplay(view);
  }

  return st;
}

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

void
puglFreeViewInternals(PuglView* const 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* const world)
{
  if (world->impl->xim) {
    XCloseIM(world->impl->xim);
  }
  XCloseDisplay(world->impl->display);
  free(world->impl->timers);
  free(world->impl);
}

static PuglKey
keySymToSpecial(const KeySym sym)
{
  // clang-format off
  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;
  }
  // clang-format on

  return (PuglKey)0;
}

static int
lookupString(XIC xic, XEvent* const xevent, char* const str, KeySym* const 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* const view, XEvent* const xevent, PuglEvent* const 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 PuglStatus
getAtomProperty(PuglView* const view,
                const Window    window,
                const Atom      property,
                unsigned long*  numValues,
                Atom**          values)
{
  Atom          actualType   = 0;
  int           actualFormat = 0;
  unsigned long bytesAfter   = 0;

  return (XGetWindowProperty(view->impl->display,
                             window,
                             property,
                             0,
                             LONG_MAX,
                             False,
                             XA_ATOM,
                             &actualType,
                             &actualFormat,
                             numValues,
                             &bytesAfter,
                             (unsigned char**)values) == Success)
           ? PUGL_SUCCESS
           : PUGL_FAILURE;
}

static PuglEvent
translateClientMessage(PuglView* const view, const XClientMessageEvent message)
{
  const PuglX11Atoms* const atoms = &view->world->impl->atoms;
  PuglEvent                 event = {{PUGL_NOTHING, 0}};

  if (message.message_type == atoms->WM_PROTOCOLS) {
    const Atom protocol = (Atom)message.data.l[0];
    if (protocol == atoms->WM_DELETE_WINDOW) {
      event.type = PUGL_CLOSE;
    }
  } else if (message.message_type == atoms->PUGL_CLIENT_MSG) {
    event.type         = PUGL_CLIENT;
    event.client.data1 = (uintptr_t)message.data.l[0];
    event.client.data2 = (uintptr_t)message.data.l[1];
  }

  return event;
}

static PuglEvent
translatePropertyNotify(PuglView* const view, XPropertyEvent message)
{
  const PuglX11Atoms* const atoms = &view->world->impl->atoms;

  PuglEvent event = {{PUGL_NOTHING, 0}};
  if (message.atom == atoms->NET_WM_STATE) {
    unsigned long numHints = 0;
    Atom*         hints    = NULL;
    if (getAtomProperty(
          view, view->impl->win, message.atom, &numHints, &hints)) {
      return event;
    }

    bool hidden = false;
    for (unsigned long i = 0; i < numHints; ++i) {
      if (hints[i] == atoms->NET_WM_STATE_HIDDEN) {
        hidden = true;
      }
    }

    if (hidden && view->visible) {
      event.type = PUGL_UNMAP;
    } else if (!hidden && !view->visible) {
      event.type = PUGL_MAP;
    }

    XFree(hints);
  }

  return event;
}

static PuglEvent
translateEvent(PuglView* const view, XEvent xevent)
{
  PuglEvent event = {{PUGL_NOTHING, 0}};
  event.any.flags = xevent.xany.send_event ? PUGL_IS_SEND_EVENT : 0;

  switch (xevent.type) {
  case ClientMessage:
    event = translateClientMessage(view, xevent.xclient);
    break;
  case PropertyNotify:
    event = translatePropertyNotify(view, xevent.xproperty);
    break;
  case VisibilityNotify:
    if (xevent.xvisibility.state == VisibilityFullyObscured) {
      event.type = PUGL_UNMAP;
    } else {
      event.type = PUGL_MAP;
    }
    break;
  case MapNotify:
    event.type = PUGL_MAP;
    break;
  case UnmapNotify:
    event.type = PUGL_UNMAP;
    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);
    if (xevent.xmotion.is_hint == NotifyHint) {
      event.motion.flags |= PUGL_IS_HINT;
    }
    break;
  case ButtonPress:
  case ButtonRelease:
    if (xevent.type == ButtonPress && 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;
      }
    } else 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 - 1;
      if (event.button.button == 1) {
        event.button.button = 2;
      } else if (event.button.button == 2) {
        event.button.button = 1;
      } else if (event.button.button >= 7) {
        event.button.button -= 4;
      }
    }
    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* const view)
{
  PuglInternals* const impl  = view->impl;
  XWindowAttributes    attrs = {0};

  if (!impl->win || !XGetWindowAttributes(impl->display, impl->win, &attrs)) {
    return PUGL_UNKNOWN_ERROR;
  }

  if (attrs.map_state != IsViewable) {
    return PUGL_FAILURE;
  }

  XSetInputFocus(impl->display, impl->win, RevertToNone, CurrentTime);
  return PUGL_SUCCESS;
}

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

PuglStatus
puglRequestAttention(PuglView* const 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);

  return XSendEvent(impl->display,
                    root,
                    False,
                    SubstructureNotifyMask | SubstructureRedirectMask,
                    &event)
           ? PUGL_SUCCESS
           : PUGL_UNKNOWN_ERROR;
}

PuglStatus
puglStartTimer(PuglView* const view, const uintptr_t id, const 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* const view, const 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
eventToX(PuglView* const view, const PuglEvent* const 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* const view, const PuglEvent* const event)
{
  XEvent xev = eventToX(view, event);

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

  return PUGL_UNSUPPORTED_TYPE;
}

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

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

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

static void
handleSelectionNotify(const PuglWorld* const world, PuglView* const 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 PuglStatus
handleSelectionRequest(const PuglWorld* const              world,
                       PuglView* const                     view,
                       const XSelectionRequestEvent* const 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;
  }

  return XSendEvent(
           world->impl->display, note.requestor, True, 0, (XEvent*)&note)
           ? PUGL_SUCCESS
           : PUGL_UNKNOWN_ERROR;
}

/// Flush pending configure and expose events for all views
PUGL_WARN_UNUSED_RESULT
static PuglStatus
flushExposures(PuglWorld* const world)
{
  PuglStatus st0 = PUGL_SUCCESS;
  PuglStatus st1 = PUGL_SUCCESS;
  PuglStatus st2 = PUGL_SUCCESS;

  for (size_t i = 0; i < world->numViews; ++i) {
    PuglView* const view = world->views[i];

    // Send update event so the application can trigger redraws
    if (view->visible) {
      puglDispatchSimpleEvent(view, PUGL_UPDATE);
    }

    // Copy and reset pending events (in case their handlers write new ones)
    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 (expose.type) {
      if (!(st0 = view->backend->enter(view, &expose.expose))) {
        if (configure.type) {
          st0 = puglConfigure(view, &configure);
        }

        st1 = puglExpose(view, &expose);
        st2 = view->backend->leave(view, &expose.expose);
      }
    } else if (configure.type) {
      if (!(st0 = view->backend->enter(view, NULL))) {
        st0 = puglConfigure(view, &configure);
        st1 = view->backend->leave(view, NULL);
      }
    }
  }

  return st0 ? st0 : st1 ? st1 : st2;
}

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

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

  return false;
}

static PuglStatus
dispatchX11Events(PuglWorld* const world)
{
  PuglStatus st0 = PUGL_SUCCESS;
  PuglStatus st1 = PUGL_SUCCESS;

  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 = findView(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.expose, &event.expose);
    } else if (event.type == PUGL_CONFIGURE) {
      // Update configure event to be dispatched after loop
      view->impl->pendingConfigure = event;
    } else if (event.type == PUGL_MAP) {
      // Get initial window position and size
      XWindowAttributes attrs;
      XGetWindowAttributes(view->impl->display, view->impl->win, &attrs);

      // Build an initial configure event in case the WM doesn't send one
      PuglEvent configureEvent        = {{PUGL_CONFIGURE, 0}};
      configureEvent.configure.x      = (double)attrs.x;
      configureEvent.configure.y      = (double)attrs.y;
      configureEvent.configure.width  = (double)attrs.width;
      configureEvent.configure.height = (double)attrs.height;

      // Dispatch an initial configure (if necessary), then the map event
      st0 = puglDispatchEvent(view, &configureEvent);
      st1 = puglDispatchEvent(view, &event);
    } else {
      // Dispatch event to application immediately
      st0 = puglDispatchEvent(view, &event);
    }
  }

  return st0 ? st0 : st1;
}

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

PuglStatus
puglUpdate(PuglWorld* const world, const double timeout)
{
  const double startTime = puglGetTime(world);
  PuglStatus   st0       = PUGL_SUCCESS;
  PuglStatus   st1       = PUGL_SUCCESS;

  world->impl->dispatchingEvents = true;

  if (timeout < 0.0) {
    st0 = pollX11Socket(world, timeout);
    st0 = st0 ? st0 : dispatchX11Events(world);
  } else if (timeout <= 0.001) {
    st0 = dispatchX11Events(world);
  } else {
    const double endTime = startTime + timeout - 0.001;
    double       t       = startTime;
    while (!st0 && t < endTime) {
      if (!(st0 = pollX11Socket(world, endTime - t))) {
        st0 = dispatchX11Events(world);
      }

      t = puglGetTime(world);
    }
  }

  st1 = flushExposures(world);

  world->impl->dispatchingEvents = false;

  return st0 ? st0 : st1;
}

double
puglGetTime(const PuglWorld* const 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* const view)
{
  const PuglRect rect = {0, 0, view->frame.width, view->frame.height};

  return puglPostRedisplayRect(view, rect);
}

PuglStatus
puglPostRedisplayRect(PuglView* const view, const PuglRect rect)
{
  const PuglExposeEvent 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.expose, &event);
  } else if (view->visible) {
    // Not dispatching events, send an X expose so we wake up next time
    PuglEvent exposeEvent = {{PUGL_EXPOSE, 0}};
    exposeEvent.expose    = event;
    return puglSendEvent(view, &exposeEvent);
  }

  return PUGL_SUCCESS;
}

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

PuglStatus
puglSetWindowTitle(PuglView* const view, const char* const 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* const view, const PuglRect frame)
{
  if (view->impl->win) {
    if (!XMoveResizeWindow(view->world->impl->display,
                           view->impl->win,
                           (int)frame.x,
                           (int)frame.y,
                           (unsigned)frame.width,
                           (unsigned)frame.height)) {
      return PUGL_UNKNOWN_ERROR;
    }
  }

  view->frame = frame;
  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->maxWidth  = width;
  view->maxHeight = 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
puglSetTransientParent(PuglView* const view, const 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) {
    XSetSelectionOwner(impl->display, atoms->CLIPBOARD, impl->win, CurrentTime);
  }

  return st;
}

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

  const char* const name = cursor_names[index];
  if (!impl->win || impl->cursorName == name) {
    return PUGL_SUCCESS;
  }

  impl->cursorName = cursor_names[index];

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

// Semi-public platform API used by backends

PuglStatus
puglX11Configure(PuglView* view)
{
  PuglInternals* const impl = view->impl;
  XVisualInfo          pat  = PUGL_INIT_STRUCT;
  int                  n    = 0;

  pat.screen = impl->screen;
  if (!(impl->vi = XGetVisualInfo(impl->display, VisualScreenMask, &pat, &n))) {
    return PUGL_BAD_CONFIGURATION;
  }

  view->hints[PUGL_RED_BITS]   = impl->vi->bits_per_rgb;
  view->hints[PUGL_GREEN_BITS] = impl->vi->bits_per_rgb;
  view->hints[PUGL_BLUE_BITS]  = impl->vi->bits_per_rgb;
  view->hints[PUGL_ALPHA_BITS] = 0;

  return PUGL_SUCCESS;
}