/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "ScreenHelperGTK.h"

#ifdef MOZ_X11
#  include <gdk/gdkx.h>
#  include <X11/Xlib.h>
#  include "X11UndefineNone.h"
#endif /* MOZ_X11 */
#ifdef MOZ_WAYLAND
#  include <gdk/gdkwayland.h>
#endif /* MOZ_WAYLAND */
#include <dlfcn.h>
#include <gtk/gtk.h>

#include "gfxPlatformGtk.h"
#include "mozilla/dom/DOMTypes.h"
#include "mozilla/Logging.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/ToString.h"
#include "mozilla/WidgetUtilsGtk.h"
#include "nsGtkUtils.h"
#include "nsTArray.h"
#include "nsWindow.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/StaticPrefs_widget.h"

struct wl_registry;

#ifdef MOZ_WAYLAND
#  include "nsWaylandDisplay.h"
#endif

namespace mozilla::widget {

#ifdef MOZ_LOGGING
static LazyLogModule sScreenLog("WidgetScreen");
#  define LOG_SCREEN(...) MOZ_LOG(sScreenLog, LogLevel::Debug, (__VA_ARGS__))
#else
#  define LOG_SCREEN(...)
#endif /* MOZ_LOGGING */

using GdkMonitor = struct _GdkMonitor;
class WaylandMonitor;

GdkWindow* ScreenHelperGTK::sRootWindow = nullptr;
StaticRefPtr<ScreenGetterGtk> ScreenHelperGTK::gLastScreenGetter;
int ScreenHelperGTK::gLastSerial = 0;

static GdkMonitor* GdkDisplayGetMonitor(GdkDisplay* aDisplay,
                                        unsigned int aMonitor) {
  static auto s_gdk_display_get_monitor = (GdkMonitor * (*)(GdkDisplay*, int))
      dlsym(RTLD_DEFAULT, "gdk_display_get_monitor");
  if (!s_gdk_display_get_monitor) {
    return nullptr;
  }
  return s_gdk_display_get_monitor(aDisplay, aMonitor);
}

static uint32_t GetGTKPixelDepth() {
  GdkVisual* visual = gdk_screen_get_system_visual(gdk_screen_get_default());
  return gdk_visual_get_depth(visual);
}

static already_AddRefed<Screen> MakeScreenGtk(unsigned int aMonitor,
                                              bool aIsHDR) {
  gint geometryScaleFactor =
      ScreenHelperGTK::GetGTKMonitorScaleFactor(aMonitor);
  GdkScreen* defaultScreen = gdk_screen_get_default();

  GdkRectangle workarea;
  gdk_screen_get_monitor_workarea(defaultScreen, aMonitor, &workarea);
  LayoutDeviceIntRect availRect(workarea.x * geometryScaleFactor,
                                workarea.y * geometryScaleFactor,
                                workarea.width * geometryScaleFactor,
                                workarea.height * geometryScaleFactor);

  DesktopToLayoutDeviceScale contentsScale(1.0);
  CSSToLayoutDeviceScale defaultCssScale(geometryScaleFactor);
  contentsScale.scale = geometryScaleFactor;

#ifdef MOZ_WAYLAND
  if (GdkIsWaylandDisplay()) {
    if (StaticPrefs::widget_wayland_fractional_scale_enabled()) {
      // Check if we're using fractional scale (see Bug 1985720).
      // In such case use workarea is already scaled by fractional scale factor.
      nsWaylandDisplay::MonitorConfig* config =
          WaylandDisplayGet()->GetMonitorConfig(workarea.x, workarea.y);
      (void)NS_WARN_IF(!config);
      if (config && workarea.width > config->pixelWidth / geometryScaleFactor &&
          workarea.height > config->pixelHeight / geometryScaleFactor) {
        float fractionalScale = (float)config->pixelWidth / workarea.width;
        LOG_SCREEN("Monitor %d uses fractional scale %f", aMonitor,
                   fractionalScale);
        availRect.width = config->pixelWidth;
        availRect.height = config->pixelHeight;
        defaultCssScale = CSSToLayoutDeviceScale(fractionalScale);
        contentsScale.scale = fractionalScale;
      }
    }
    // Don't report screen shift in Wayland, see bug 1795066.
    availRect.MoveTo(0, 0);
  }
#endif

  // Use workarea as screen rect on Wayland (Bug 1732682).
  LayoutDeviceIntRect rect;
  if (GdkIsX11Display()) {
    GdkRectangle monitor;
    gdk_screen_get_monitor_geometry(defaultScreen, aMonitor, &monitor);
    rect = LayoutDeviceIntRect(monitor.x * geometryScaleFactor,
                               monitor.y * geometryScaleFactor,
                               monitor.width * geometryScaleFactor,
                               monitor.height * geometryScaleFactor);
  } else {
    rect = availRect;
  }

  uint32_t pixelDepth = GetGTKPixelDepth();
  if (pixelDepth == 32) {
    // If a device uses 32 bits per pixel, it's still only using 8 bits
    // per color component, which is what our callers want to know.
    // (Some devices report 32 and some devices report 24.)
    pixelDepth = 24;
  }

  float dpi = 96.0f;
  gint heightMM = gdk_screen_get_monitor_height_mm(defaultScreen, aMonitor);
  if (heightMM > 0) {
    dpi = rect.height / (heightMM / MM_PER_INCH_FLOAT);
  }

  gint refreshRate = [&] {
    // Since gtk 3.22
    static auto s_gdk_monitor_get_refresh_rate = (int (*)(GdkMonitor*))dlsym(
        RTLD_DEFAULT, "gdk_monitor_get_refresh_rate");
    if (!s_gdk_monitor_get_refresh_rate) {
      return 0;
    }
    GdkMonitor* monitor =
        GdkDisplayGetMonitor(gdk_display_get_default(), aMonitor);
    if (!monitor) {
      return 0;
    }
    // Convert to Hz.
    return NSToIntRound(s_gdk_monitor_get_refresh_rate(monitor) / 1000.0f);
  }();

  LOG_SCREEN(
      "New monitor %d size [%d,%d -> %d x %d] depth %d scale %f CssScale %f  "
      "DPI %f refresh %d HDR %d]",
      aMonitor, rect.x, rect.y, rect.width, rect.height, pixelDepth,
      contentsScale.scale, defaultCssScale.scale, dpi, refreshRate, aIsHDR);
  return MakeAndAddRef<Screen>(
      rect, availRect, pixelDepth, pixelDepth, refreshRate, contentsScale,
      defaultCssScale, dpi, Screen::IsPseudoDisplay::No, Screen::IsHDR(aIsHDR));
}

#ifdef MOZ_WAYLAND
class WaylandMonitor {
 public:
  NS_INLINE_DECL_REFCOUNTING(WaylandMonitor)

  WaylandMonitor(ScreenGetterGtk* aScreenGetter, unsigned int aMonitor,
                 wl_output* aWlOutput);

  unsigned int GetMonitor() const { return mMonitor; }

  void SetHDR(bool aIsHDR) { mIsHDR = aIsHDR; }

  void ImageDescriptionReady();
  void ImageDescriptionDone();

  void Finish();

 private:
  ~WaylandMonitor();

  RefPtr<ScreenGetterGtk> mScreenGetter;
  unsigned int mMonitor = 0;

  wp_color_management_output_v1* mOutput = nullptr;
  wp_image_description_v1* mDescription = nullptr;

  bool mIsHDR = false;
};
#endif

class ScreenGetterGtk final {
 public:
  NS_INLINE_DECL_REFCOUNTING(ScreenGetterGtk)

  explicit ScreenGetterGtk(int aSerial, bool aHDRInfoOnly);
  void AddScreen(RefPtr<Screen> aScreen);
  bool AddScreenHDRAsync(unsigned int aMonitor);
  void Finish();

 protected:
  ~ScreenGetterGtk();

 private:
  AutoTArray<RefPtr<Screen>, 4> mScreenList;
#ifdef MOZ_WAYLAND
  AutoTArray<RefPtr<WaylandMonitor>, 4> mWaylandMonitors;
#endif
  int mSerial = 0;
  unsigned int mMonitorNum = 0;
  bool mHDRInfoOnly = false;
};

#ifdef MOZ_WAYLAND
void image_description_info_done(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1) {
  // Done is the latest event, unref WaylandMonitor
  RefPtr monitor = dont_AddRef(static_cast<WaylandMonitor*>(data));
  LOG_SCREEN("WaylandMonitor() [%p] image_description_info_done monitor %d",
             (void*)monitor, monitor->GetMonitor());
  monitor->ImageDescriptionDone();
}

/**
 * ICC profile matching the image description
 *
 * The icc argument provides a file descriptor to the client
 * which may be memory-mapped to provide the ICC profile matching
 * the image description. The fd is read-only, and if mapped then
 * it must be mapped with MAP_PRIVATE by the client.
 *
 * The ICC profile version and other details are determined by the
 * compositor. There is no provision for a client to ask for a
 * specific kind of a profile.
 * @param icc ICC profile file descriptor
 * @param icc_size ICC profile size, in bytes
 */
void image_description_info_icc_file(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    int32_t icc, uint32_t icc_size) {}
/**
 * primaries as chromaticity coordinates
 *
 * Delivers the primary color volume primaries and white point
 * using CIE 1931 xy chromaticity coordinates.
 *
 * Each coordinate value is multiplied by 1 million to get the
 * argument value to carry precision of 6 decimals.
 * @param r_x Red x * 1M
 * @param r_y Red y * 1M
 * @param g_x Green x * 1M
 * @param g_y Green y * 1M
 * @param b_x Blue x * 1M
 * @param b_y Blue y * 1M
 * @param w_x White x * 1M
 * @param w_y White y * 1M
 */
void image_description_info_primaries(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    int32_t r_x, int32_t r_y, int32_t g_x, int32_t g_y, int32_t b_x,
    int32_t b_y, int32_t w_x, int32_t w_y) {}
/**
 * named primaries
 *
 * Delivers the primary color volume primaries and white point
 * using an explicitly enumerated named set.
 * @param primaries named primaries
 */
void image_description_info_primaries_named(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t primaries) {}

/**
 * transfer characteristic as a power curve
 *
 * The color component transfer characteristic of this image
 * description is a pure power curve. This event provides the
 * exponent of the power function. This curve represents the
 * conversion from electrical to optical pixel or color values.
 *
 * The curve exponent has been multiplied by 10000 to get the
 * argument eexp value to carry the precision of 4 decimals.
 * @param eexp the exponent * 10000
 */
void image_description_info_tf_power(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t eexp) {}
/**
 * named transfer characteristic
 *
 * Delivers the transfer characteristic using an explicitly
 * enumerated named function.
 * @param tf named transfer function
 */
void image_description_info_tf_named(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t tf) {}
/**
 * primary color volume luminance range and reference white
 *
 * Delivers the primary color volume luminance range and the
 * reference white luminance level. These values include the
 * minimum display emission and ambient flare luminances, assumed
 * to be optically additive and have the chromaticity of the
 * primary color volume white point.
 *
 * The minimum luminance is multiplied by 10000 to get the argument
 * 'min_lum' value and carries precision of 4 decimals. The maximum
 * luminance and reference white luminance values are unscaled.
 * @param min_lum minimum luminance (cd/m²) * 10000
 * @param max_lum maximum luminance (cd/m²)
 * @param reference_lum reference white luminance (cd/m²)
 */
void image_description_info_luminances(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t min_lum, uint32_t max_lum, uint32_t reference_lum) {
  // Although WaylandMonitor is RefPtr here we don't want to unref it
  // we'll do that at image_description_info_done.
  auto* monitor = static_cast<WaylandMonitor*>(data);
  LOG_SCREEN(
      "WaylandMonitor() [%p] num [%d] Luminance min %d max %d reference %d",
      monitor, monitor->GetMonitor(), min_lum, max_lum, reference_lum);
  monitor->SetHDR(max_lum > reference_lum);
}
/**
 * target primaries as chromaticity coordinates
 *
 * Provides the color primaries and white point of the target
 * color volume using CIE 1931 xy chromaticity coordinates. This is
 * compatible with the SMPTE ST 2086 definition of HDR static
 * metadata for mastering displays.
 *
 * While primary color volume is about how color is encoded, the
 * target color volume is the actually displayable color volume. If
 * target color volume is equal to the primary color volume, then
 * this event is not sent.
 *
 * Each coordinate value is multiplied by 1 million to get the
 * argument value to carry precision of 6 decimals.
 * @param r_x Red x * 1M
 * @param r_y Red y * 1M
 * @param g_x Green x * 1M
 * @param g_y Green y * 1M
 * @param b_x Blue x * 1M
 * @param b_y Blue y * 1M
 * @param w_x White x * 1M
 * @param w_y White y * 1M
 */
void image_description_info_target_primaries(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    int32_t r_x, int32_t r_y, int32_t g_x, int32_t g_y, int32_t b_x,
    int32_t b_y, int32_t w_x, int32_t w_y) {}
/**
 * target luminance range
 *
 * Provides the luminance range that the image description is
 * targeting as the minimum and maximum absolute luminance L. These
 * values include the minimum display emission and ambient flare
 * luminances, assumed to be optically additive and have the
 * chromaticity of the primary color volume white point. This
 * should be compatible with the SMPTE ST 2086 definition of HDR
 * static metadata.
 *
 * This luminance range is only theoretical and may not correspond
 * to the luminance of light emitted on an actual display.
 *
 * Min L value is multiplied by 10000 to get the argument min_lum
 * value and carry precision of 4 decimals. Max L value is unscaled
 * for max_lum.
 * @param min_lum min L (cd/m²) * 10000
 * @param max_lum max L (cd/m²)
 */
void image_description_info_target_luminance(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t min_lum, uint32_t max_lum) {}
/**
 * target maximum content light level
 *
 * Provides the targeted max_cll of the image description.
 * max_cll is defined by CTA-861-H.
 *
 * This luminance is only theoretical and may not correspond to the
 * luminance of light emitted on an actual display.
 * @param max_cll Maximum content light-level (cd/m²)
 */
void image_description_info_target_max_cll(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t max_cll) {}
/**
 * target maximum frame-average light level
 *
 * Provides the targeted max_fall of the image description.
 * max_fall is defined by CTA-861-H.
 *
 * This luminance is only theoretical and may not correspond to the
 * luminance of light emitted on an actual display.
 * @param max_fall Maximum frame-average light level (cd/m²)
 */
void image_description_info_target_max_fall(
    void* data,
    struct wp_image_description_info_v1* wp_image_description_info_v1,
    uint32_t max_fall) {}

static const struct wp_image_description_info_v1_listener
    image_description_info_listener{image_description_info_done,
                                    image_description_info_icc_file,
                                    image_description_info_primaries,
                                    image_description_info_primaries_named,
                                    image_description_info_tf_power,
                                    image_description_info_tf_named,
                                    image_description_info_luminances,
                                    image_description_info_target_primaries,
                                    image_description_info_target_luminance,
                                    image_description_info_target_max_cll,
                                    image_description_info_target_max_fall};

void WaylandMonitor::ImageDescriptionDone() {
  LOG_SCREEN("WaylandMonitor() [%p] ImageDescriptionDone HDR %d", this, mIsHDR);
  if (mScreenGetter) {
    mScreenGetter->AddScreen(MakeScreenGtk(mMonitor, mIsHDR));
  }
}

void WaylandMonitor::ImageDescriptionReady() {
  LOG_SCREEN("WaylandMonitor() [%p] ImageDescriptionReady monitor %d", this,
             GetMonitor());

  // Ref WaylandMonitor to stay here until image_description_info_done
  // callback.
  AddRef();
  wp_image_description_info_v1_add_listener(
      wp_image_description_v1_get_information(mDescription),
      &image_description_info_listener, this);
}

void image_description_failed(void* aData,
                              struct wp_image_description_v1* aImageDescription,
                              uint32_t aCause, const char* aMsg) {
  LOG_SCREEN("imageDescriptionFailed [%p]", aData);
  RefPtr waylandMonitor = dont_AddRef(static_cast<WaylandMonitor*>(aData));
  waylandMonitor->ImageDescriptionDone();
}

void image_description_ready(void* aData,
                             struct wp_image_description_v1* aImageDescription,
                             uint32_t aIdentity) {
  RefPtr waylandMonitor = dont_AddRef(static_cast<WaylandMonitor*>(aData));
  waylandMonitor->ImageDescriptionReady();
}

WaylandMonitor::WaylandMonitor(ScreenGetterGtk* aScreenGetter,
                               unsigned int aMonitor, wl_output* aWlOutput)
    : mScreenGetter(aScreenGetter), mMonitor(aMonitor) {
  MOZ_COUNT_CTOR(WaylandMonitor);

  LOG_SCREEN("WaylandMonitor()[%p] monitor %d", this, mMonitor);

  mOutput = wp_color_manager_v1_get_output(
      WaylandDisplayGet()->GetColorManager(), aWlOutput);

  static const struct wp_color_management_output_v1_listener listener{
      [](void* data,
         struct wp_color_management_output_v1* wp_color_management_output_v1) {
#  if MOZ_LOGGING
        auto* monitor = static_cast<WaylandMonitor*>(data);
        LOG_SCREEN("WaylandMonitor() [%p] image_description_changed %d",
                   monitor, monitor->GetMonitor());
#  endif
        ScreenHelperGTK::RequestRefreshScreens();
      }};
  wp_color_management_output_v1_add_listener(mOutput, &listener, this);

  // AddRef this to keep it live until callback
  AddRef();
  mDescription = wp_color_management_output_v1_get_image_description(mOutput);

  static const struct wp_image_description_v1_listener
      monitor_image_description_listener{image_description_failed,
                                         image_description_ready};
  wp_image_description_v1_add_listener(
      mDescription, &monitor_image_description_listener, this);
}

void WaylandMonitor::Finish() {
  LOG_SCREEN("WaylandMonitor::Finish() [%p]", this);

  MozClearPointer(mOutput, wp_color_management_output_v1_destroy);
  MozClearPointer(mDescription, wp_image_description_v1_destroy);

  // We need to wait with WaylandMonitor release until mOutput/mDescription
  // are deleted.
  AddRef();
  static const struct wl_callback_listener listener{
      [](void* aData, struct wl_callback* callback, uint32_t time) {
        RefPtr monitor = dont_AddRef(static_cast<WaylandMonitor*>(aData));
        LOG_SCREEN("WaylandMonitor::FinishCallback() [%p] ", aData);
      }};
  wl_callback_add_listener(wl_display_sync(WaylandDisplayGetWLDisplay()),
                           &listener, this);
  mScreenGetter = nullptr;
}

WaylandMonitor::~WaylandMonitor() {
  LOG_SCREEN("WaylandMonitor::~WaylandMonitor() [%p]", this);
  MOZ_COUNT_DTOR(WaylandMonitor);
  MOZ_DIAGNOSTIC_ASSERT(!mScreenGetter);
  MOZ_DIAGNOSTIC_ASSERT(!mDescription);
  MOZ_DIAGNOSTIC_ASSERT(!mOutput);
}

bool ScreenGetterGtk::AddScreenHDRAsync(unsigned int aMonitor) {
  MOZ_DIAGNOSTIC_ASSERT(WaylandDisplayGet()->GetColorManager());
  GdkMonitor* monitor =
      GdkDisplayGetMonitor(gdk_display_get_default(), aMonitor);
  if (!monitor) {
    LOG_SCREEN(
        "ScreenGetterGtk::AddScreenHDRAsync() [%p] failed to get monitor %d",
        this, aMonitor);
    return false;
  }
  static auto s_gdk_wayland_monitor_get_wl_output =
      (struct wl_output * (*)(GdkMonitor*))
          dlsym(RTLD_DEFAULT, "gdk_wayland_monitor_get_wl_output");
  if (!s_gdk_wayland_monitor_get_wl_output) {
    LOG_SCREEN(
        "ScreenGetterGtk::AddScreenHDRAsync() missing "
        "gdk_wayland_monitor_get_wl_output");
    return false;
  }
  auto wlOutput = s_gdk_wayland_monitor_get_wl_output(monitor);
  if (!wlOutput) {
    LOG_SCREEN("ScreenGetterGtk::AddScreenHDRAsync() missing wl_output");
    return false;
  }

  LOG_SCREEN("ScreenGetterGtk::AddScreenHDR() [%p] monitor %d", this, aMonitor);
  mWaylandMonitors.AppendElement(new WaylandMonitor(this, aMonitor, wlOutput));
  return true;
}
#endif

void ScreenGetterGtk::Finish() {
#ifdef MOZ_WAYLAND
  LOG_SCREEN("ScreenGetterGtk::Finish() [%p]", this);
  for (auto& monitor : mWaylandMonitors) {
    monitor->Finish();
  }
  mWaylandMonitors.Clear();
#endif
}

RefPtr<Screen> ScreenHelperGTK::GetScreenForWindow(nsWindow* aWindow) {
  static auto s_gdk_display_get_monitor_at_window =
      (GdkMonitor * (*)(GdkDisplay*, GdkWindow*))
          dlsym(RTLD_DEFAULT, "gdk_display_get_monitor_at_window");

  if (!s_gdk_display_get_monitor_at_window) {
    LOG_SCREEN("  failed, missing Gtk helpers");
    return nullptr;
  }

  GdkWindow* gdkWindow = aWindow->GetToplevelGdkWindow();
  if (!gdkWindow) {
    LOG_SCREEN("  failed, can't get GdkWindow");
    return nullptr;
  }

  GdkDisplay* display = gdk_display_get_default();
  GdkMonitor* monitor = s_gdk_display_get_monitor_at_window(display, gdkWindow);
  if (!monitor) {
    LOG_SCREEN("  failed, can't get monitor for GdkWindow");
    return nullptr;
  }

  int index = -1;
  while (GdkMonitor* m = GdkDisplayGetMonitor(display, ++index)) {
    if (m == monitor) {
      RefPtr<Screen> screen =
          ScreenManager::GetSingleton().CurrentScreenList().SafeElementAt(
              index);
      if (!screen) {
        LOG_SCREEN(
            "GetScreenForWindow() [%p] [%d] found monitor %p but no screen",
            aWindow, index, monitor);
        return nullptr;
      }
      LOG_SCREEN("GetScreenForWindow() [%p] [%d] screen %s", aWindow, index,
                 ToString(screen->GetRect()).c_str());
      return screen.forget();
    }
  }

  LOG_SCREEN("  Couldn't find monitor %p", monitor);
  return nullptr;
}

void ScreenGetterGtk::AddScreen(RefPtr<Screen> aScreen) {
  mScreenList.AppendElement(std::move(aScreen));
  MOZ_DIAGNOSTIC_ASSERT(mScreenList.Length() <= mMonitorNum);

  // We're waiting for all screens to fill in
  if (mScreenList.Length() < mMonitorNum) {
    return;
  }

  auto finish = MakeScopeExit([&] { Finish(); });

  if (mSerial != ScreenHelperGTK::GetLastSerial()) {
    MOZ_DIAGNOSTIC_ASSERT(mSerial <= ScreenHelperGTK::GetLastSerial());
    LOG_SCREEN(
        "ScreenGetterGtk::AddScreen() [%p]: rejected, old wrong serial %d "
        "latest "
        "%d",
        this, mSerial, ScreenHelperGTK::GetLastSerial());
    return;
  }

  // Check if any screen supports HDR.
  if (mHDRInfoOnly) {
    bool supportsHDR = false;
    for (const auto& screen : mScreenList) {
      supportsHDR |= screen->GetIsHDR();
    }
    if (!supportsHDR) {
      LOG_SCREEN("ScreenGetterGtk::AddScreen() [%p]: no HDR support", this);
      return;
    }
  }

  LOG_SCREEN(
      "ScreenGetterGtk::AddScreen() [%p]: Set screens, serial %d HDR only %d",
      this, mSerial, mHDRInfoOnly);

  ScreenManager::Refresh(std::move(mScreenList));
}

ScreenGetterGtk::ScreenGetterGtk(int aSerial, bool aHDRInfoOnly)
    : mSerial(aSerial),
      mMonitorNum(gdk_screen_get_n_monitors(gdk_screen_get_default())),
      mHDRInfoOnly(aHDRInfoOnly) {
  LOG_SCREEN(
      "ScreenGetterGtk()::ScreenGetterGtk() [%p] HDR only [%d] monitor num %d",
      this, aHDRInfoOnly, mMonitorNum);
#ifdef MOZ_WAYLAND
  LOG_SCREEN("HDR Protocol %s",
             GdkIsWaylandDisplay() && WaylandDisplayGet()->IsHDREnabled()
                 ? "present"
                 : "missing");
#endif

  for (unsigned int i = 0; i < mMonitorNum; i++) {
#ifdef MOZ_WAYLAND
    if (GdkIsWaylandDisplay() && WaylandDisplayGet()->IsHDREnabled()) {
      if (AddScreenHDRAsync(i)) {
        continue;
      }
    }
#endif
    AddScreen(MakeScreenGtk(i, /* aIsHDR */ false));
  }
}

ScreenGetterGtk::~ScreenGetterGtk() {
  LOG_SCREEN("ScreenGetterGtk::~ScreenGetterGtk() [%p]", this);
}

void ScreenHelperGTK::RequestRefreshScreens(bool aInitialRefresh) {
  LOG_SCREEN("ScreenHelperGTK::RequestRefreshScreens()");

  gLastSerial++;

  if (gLastScreenGetter) {
    gLastScreenGetter->Finish();
  }
  gLastScreenGetter =
      new ScreenGetterGtk(gLastSerial, /* aHDRInfoOnly */ aInitialRefresh);
}

gint ScreenHelperGTK::GetGTKMonitorScaleFactor(gint aMonitor) {
  MOZ_ASSERT(NS_IsMainThread());
  GdkScreen* screen = gdk_screen_get_default();
  return aMonitor < gdk_screen_get_n_monitors(screen)
             ? gdk_screen_get_monitor_scale_factor(screen, aMonitor)
             : 1;
}

float ScreenHelperGTK::GetGTKMonitorFractionalScaleFactor(gint aMonitor) {
#ifdef MOZ_WAYLAND
  if (GdkIsWaylandDisplay()) {
    auto& screens = widget::ScreenManager::GetSingleton().CurrentScreenList();
    auto scale = (size_t)aMonitor < screens.Length()
                     ? screens[aMonitor]->GetContentsScaleFactor()
                     : 1.0f;
    LOG_SCREEN(
        "ScreenHelperGTK::GetGTKMonitorFractionalScaleFactor(%d) scale %f",
        aMonitor, scale);
    return scale;
  }
#endif
  // Fractional scale is not supported on X11, fallback to ceiled one.
  return GetGTKMonitorScaleFactor(aMonitor);
}

static void monitors_changed(GdkScreen* aScreen, gpointer unused) {
  LOG_SCREEN("Received monitors-changed event");
  ScreenHelperGTK::RequestRefreshScreens();
}

static void screen_resolution_changed(GdkScreen* aScreen, GParamSpec* aPspec,
                                      gpointer unused) {
  LOG_SCREEN("Received resolution-changed event");
  ScreenHelperGTK::RequestRefreshScreens();
}

static GdkFilterReturn root_window_event_filter(GdkXEvent* aGdkXEvent,
                                                GdkEvent* aGdkEvent,
                                                gpointer aClosure) {
#ifdef MOZ_X11
  static Atom netWorkareaAtom =
      XInternAtom(GDK_WINDOW_XDISPLAY(gdk_get_default_root_window()),
                  "_NET_WORKAREA", X11False);
  XEvent* xevent = static_cast<XEvent*>(aGdkXEvent);

  switch (xevent->type) {
    case PropertyNotify: {
      XPropertyEvent* propertyEvent = &xevent->xproperty;
      if (propertyEvent->atom == netWorkareaAtom) {
        LOG_SCREEN("X11 Work area size changed");
        ScreenHelperGTK::RequestRefreshScreens();
      }
    } break;
    default:
      break;
  }
#endif

  return GDK_FILTER_CONTINUE;
}

#ifdef MOZ_WAYLAND
/* static */
void ScreenHelperGTK::ScreensPrefChanged(const char* aPrefIgnored,
                                         void* aDataIgnored) {
  LOG_SCREEN("ScreenHelperGTK::ScreensPrefChanged()");
  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
  ScreenHelperGTK::RequestRefreshScreens();
}
#endif

ScreenHelperGTK::ScreenHelperGTK() {
  LOG_SCREEN("ScreenHelperGTK::ScreenHelperGTK() created");
  GdkScreen* defaultScreen = gdk_screen_get_default();
  if (!defaultScreen) {
    // Sometimes we don't initial X (e.g., xpcshell)
    MOZ_LOG(sScreenLog, LogLevel::Debug,
            ("defaultScreen is nullptr, running headless"));
    return;
  }
  sRootWindow = gdk_get_default_root_window();
  MOZ_ASSERT(sRootWindow);
  g_object_ref(sRootWindow);

  // GDK_PROPERTY_CHANGE_MASK ==> PropertyChangeMask, for PropertyNotify
  gdk_window_set_events(sRootWindow,
                        GdkEventMask(gdk_window_get_events(sRootWindow) |
                                     GDK_PROPERTY_CHANGE_MASK));

  g_signal_connect(defaultScreen, "monitors-changed",
                   G_CALLBACK(monitors_changed), this);
  // Use _after to ensure this callback is run after gfxPlatformGtk.cpp's
  // handler.
  g_signal_connect_after(defaultScreen, "notify::resolution",
                         G_CALLBACK(screen_resolution_changed), this);
#ifdef MOZ_X11
  gdk_window_add_filter(sRootWindow, root_window_event_filter, this);
#endif

  // Get initial screen list without async HDR info to have something
  // to paint to.
  AutoTArray<RefPtr<Screen>, 4> screenList;
  gint numScreens = gdk_screen_get_n_monitors(defaultScreen);
  for (gint i = 0; i < numScreens; i++) {
    screenList.AppendElement(MakeScreenGtk(i, /* aIsHDR */ false));
  }
  ScreenManager::Refresh(std::move(screenList));

#ifdef MOZ_WAYLAND
  if (GdkIsWaylandDisplay() && WaylandDisplayGet()->IsHDREnabled()) {
    LOG_SCREEN("ScreenHelperGTK() query HDR Wayland display");
    RequestRefreshScreens(/* aInitialRefresh */ true);
  }
  Preferences::RegisterCallback(
      ScreenHelperGTK::ScreensPrefChanged,
      nsDependentCString(
          StaticPrefs::GetPrefName_widget_wayland_fractional_scale_enabled()));
#endif
}

int ScreenHelperGTK::GetMonitorCount() {
  return gdk_screen_get_n_monitors(gdk_screen_get_default());
}

ScreenHelperGTK::~ScreenHelperGTK() {
  LOG_SCREEN("ScreenHelperGTK::~ScreenHelperGTK() deleted");
  if (sRootWindow) {
    g_signal_handlers_disconnect_by_data(gdk_screen_get_default(), this);
    gdk_window_remove_filter(sRootWindow, root_window_event_filter, this);
    g_object_unref(sRootWindow);
    sRootWindow = nullptr;
  }
  if (gLastScreenGetter) {
    gLastScreenGetter->Finish();
  }
  gLastScreenGetter = nullptr;
}

}  // namespace mozilla::widget