// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/ozone/platform/wayland/host/wayland_window.h"

#include <stdint.h>
#include <wayland-cursor.h>

#include <algorithm>
#include <memory>
#include <optional>
#include <utility>

#include "base/auto_reset.h"
#include "base/containers/contains.h"
#include "base/feature_list.h"
#include "base/functional/bind.h"
#include "base/memory/scoped_refptr.h"
#include "base/notimplemented.h"
#include "base/notreached.h"
#include "base/numerics/safe_conversions.h"
#include "base/run_loop.h"
#include "base/task/single_thread_task_runner.h"
#include "ui/base/cursor/cursor.h"
#include "ui/base/cursor/mojom/cursor_type.mojom.h"
#include "ui/base/cursor/platform_cursor.h"
#include "ui/base/dragdrop/mojom/drag_drop_types.mojom.h"
#include "ui/base/dragdrop/os_exchange_data.h"
#include "ui/base/ui_base_features.h"
#include "ui/display/screen.h"
#include "ui/events/event.h"
#include "ui/events/event_target_iterator.h"
#include "ui/events/event_utils.h"
#include "ui/events/ozone/events_ozone.h"
#include "ui/events/platform/platform_event_source.h"
#include "ui/gfx/color_space.h"
#include "ui/gfx/geometry/point_f.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/geometry/rrect_f.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/native_widget_types.h"
#include "ui/gfx/overlay_priority_hint.h"
#include "ui/ozone/common/bitmap_cursor.h"
#include "ui/ozone/common/features.h"
#include "ui/ozone/platform/wayland/common/wayland_overlay_config.h"
#include "ui/ozone/platform/wayland/host/dump_util.h"
#include "ui/ozone/platform/wayland/host/wayland_async_cursor.h"
#include "ui/ozone/platform/wayland/host/wayland_bubble.h"
#include "ui/ozone/platform/wayland/host/wayland_connection.h"
#include "ui/ozone/platform/wayland/host/wayland_cursor_shape.h"
#include "ui/ozone/platform/wayland/host/wayland_data_drag_controller.h"
#include "ui/ozone/platform/wayland/host/wayland_event_source.h"
#include "ui/ozone/platform/wayland/host/wayland_frame_manager.h"
#include "ui/ozone/platform/wayland/host/wayland_output.h"
#include "ui/ozone/platform/wayland/host/wayland_output_manager.h"
#include "ui/ozone/platform/wayland/host/wayland_popup.h"
#include "ui/ozone/platform/wayland/host/wayland_screen.h"
#include "ui/ozone/platform/wayland/host/wayland_seat.h"
#include "ui/ozone/platform/wayland/host/wayland_subsurface.h"
#include "ui/ozone/platform/wayland/host/wayland_surface.h"
#include "ui/ozone/platform/wayland/mojom/wayland_overlay_config.mojom.h"
#include "ui/platform_window/common/platform_window_defaults.h"
#include "ui/platform_window/wm/wm_drag_handler.h"
#include "ui/platform_window/wm/wm_drop_handler.h"

namespace ui {
namespace {

using mojom::CursorType;
using mojom::DragOperation;

// Wayland compositors usually remove keyboard focus during drag
// sessions, thus modifier events are not sent, instead they are handled
// at server side, and clients are indirectly notified through, e.g:
// wl_data_offer.dnd_actions events.
// There is an open discussion about being more explicit about this on
// the spec: https://gitlab.freedesktop.org/wayland/wayland/-/issues/441
// For now, assume no keyboard modifiers info is available during dnd.
static constexpr int kWaylandDndModifiers = 0;

bool OverlayStackOrderCompare(const wl::WaylandOverlayConfig& i,
                              const wl::WaylandOverlayConfig& j) {
  return i.z_order < j.z_order;
}

}  // namespace

WaylandWindow::WaylandWindow(PlatformWindowDelegate* delegate,
                             WaylandConnection* connection)
    : delegate_(delegate),
      connection_(connection),
      accelerated_widget_(
          connection->window_manager()->AllocateAcceleratedWidget()),
      frame_manager_(std::make_unique<WaylandFrameManager>(this, connection)),
      wayland_overlay_delegation_enabled_(
          connection->viewporter() && connection->ShouldUseOverlayDelegation()),
      ui_task_runner_(base::SingleThreadTaskRunner::GetCurrentDefault()) {
  // Set a class property key, which allows |this| to be used for drag action.
  SetWmDragHandler(this, this);
}

WaylandWindow::~WaylandWindow() {
  CHECK(ui_task_runner_->BelongsToCurrentThread());
  shutting_down_ = true;

  PlatformEventSource::GetInstance()->RemovePlatformEventDispatcher(this);

  ReleaseCapture();

  if (wayland_overlay_delegation_enabled_) {
    connection_->window_manager()->RemoveSubsurface(GetWidget(),
                                                    primary_subsurface_.get());
    connection_->window_manager()->RecycleSubsurface(
        std::move(primary_subsurface_));
  }
  for (const auto& widget_subsurface : wayland_subsurfaces()) {
    connection_->window_manager()->RemoveSubsurface(GetWidget(),
                                                    widget_subsurface.get());
  }
  if (root_surface_) {
    connection_->window_manager()->RemoveWindow(GetWidget());
  }

  // This might have already been hidden and another window has been shown.
  // Thus, the parent will have another child popup. Do not reset it.
  if (parent_window_ && parent_window_->child_popup() == this) {
    parent_window_->set_child_popup(nullptr);
  }

  if (child_popup_) {
    child_popup_->set_parent_window(nullptr);
  }

  for (auto bubble : child_bubbles_) {
    bubble->set_parent_window(nullptr);
  }

  if (focus_client_) {
    focus_client_->OnKeyboardFocusChanged(false);
    if (connection_->SupportsTextInputFocus()) {
      focus_client_->OnTextInputFocusChanged(false);
    }
  }
}

void WaylandWindow::OnWindowLostCapture() {
  delegate_->OnLostCapture();
}

void WaylandWindow::UpdateWindowScale(bool update_bounds) {
  // Skip updating the scale (and thus also bounds) during shutdown as
  // `delegate_` might have already destroyed some of its state so that e.g. a
  // `GetMinimumSizeForWindow()` call might lead to a crash.
  if (shutting_down_) {
    return;
  }

  // `window_scale` is provided authoritatively by the Wayland compositor,
  // either via fractional-scale-v1 extension (ie: per-surface-scaling), or
  // inferred from the currently entereed wl_outputs (deprecated).
  const auto window_scale = connection_->UsePerSurfaceScaling()
                                ? GetPreferredScaleFactor()
                                : GetScaleFactorFromEnteredOutputs();
  SetWindowScale(window_scale.value_or(1.0f));

  // Propagate update to the popups.
  if (child_popup_) {
    child_popup_->UpdateWindowScale(update_bounds);
  }

  // Propagate update to the bubble windows.
  for (auto bubble : child_bubbles_) {
    bubble->UpdateWindowScale(update_bounds);
  }
}

void WaylandWindow::OnEnteredOutputScaleChanged() {
  // Display scale changes should not lead to surface scale updates unless
  // either per-surface scaling is disabled or wp-fractional-scale-v1 protocol
  // is unavailable.
  if (connection_->UsePerSurfaceScaling()) {
    return;
  }
  UpdateWindowScale(/*update_bounds=*/true);
}

gfx::AcceleratedWidget WaylandWindow::GetWidget() const {
  return accelerated_widget_;
}

void WaylandWindow::AddBubble(WaylandBubble* window) {
  child_bubbles_.push_back(window);
}

void WaylandWindow::RemoveBubble(WaylandBubble* window) {
  if (active_bubble_ == window) {
    active_bubble_ = nullptr;
    if (IsActive()) {
      delegate()->OnActivationChanged(true);
    }
  }
  child_bubbles_.erase(
      std::find(child_bubbles_.begin(), child_bubbles_.end(), window));
}

void WaylandWindow::ActivateBubble(WaylandBubble* window) {
  CHECK(!window || base::Contains(child_bubbles_, window));
  CHECK(!window || (window->AsWaylandBubble() &&
                    window->AsWaylandBubble()->activatable()));
  if (active_bubble_ == window) {
    return;
  }
  if (active_bubble_) {
    active_bubble_->delegate()->OnActivationChanged(false);
  }
  active_bubble_ = window;

  if (active_bubble_) {
    delegate()->OnActivationChanged(false);
    active_bubble_->delegate()->OnActivationChanged(true);
  } else {
    delegate()->OnActivationChanged(IsActive());
  }
}

void WaylandWindow::SetWindowScale(float new_scale) {
  DCHECK_GE(new_scale, 0.f);
  auto state = GetLatestRequestedState();
  state.window_scale = new_scale;
  // Note that we still need to call this even if the state does not change,
  // because we want requests directly from the client (us) to be applied
  // immediately, since that's what PlatformWindow expects. Also, RequestState
  // may modify the state before applying it.
  RequestStateFromClient(state);
}

std::optional<float> WaylandWindow::GetScaleFactorFromEnteredOutputs() {
  DCHECK(connection_->wayland_output_manager());
  const auto* output_manager = connection_->wayland_output_manager();
  auto preferred_outputs_id = GetPreferredEnteredOutputId();
  if (!preferred_outputs_id.has_value()) {
    // If no output was entered yet, use primary output. This is similar to what
    // PlatformScreen implementation is expected to return to higher layer.
    auto* primary_output = output_manager->GetPrimaryOutput();
    // Primary output is unknown. i.e: WaylandScreen was not created yet.
    if (!primary_output) {
      return std::nullopt;
    }
    preferred_outputs_id = primary_output->output_id();
  }

  auto* output = output_manager->GetOutput(preferred_outputs_id.value());
  // There can be a race between sending leave output event and destroying
  // wl_outputs. Thus, explicitly check if the output exist.
  if (!output || !output->IsReady()) {
    return std::nullopt;
  }
  return output->scale_factor();
}

std::optional<WaylandOutput::Id> WaylandWindow::GetPreferredEnteredOutputId() {
  // Child popups don't store entered outputs. Instead, take the window's
  // root parent window and use its preferred output.
  if (parent_window_) {
    return GetRootParentWindow()->GetPreferredEnteredOutputId();
  }

  // It can be either a toplevel window that hasn't entered any outputs yet, or
  // still a non toplevel window that doesn't have a parent (for example, a
  // wl_surface that is being dragged).
  if (root_surface_->entered_outputs().empty()) {
    // The nullcheck is necessary because some tests create mock screen
    // instead of emulating at wayland level.
    return std::nullopt;
  }

  // PlatformWindowType::kPopup are created as toplevel windows as well.
  DCHECK(type() == PlatformWindowType::kWindow ||
         type() == PlatformWindowType::kPopup);

  WaylandOutput::Id preferred_id = root_surface_->entered_outputs().front();
  const auto* output_manager = connection_->wayland_output_manager();

  // A window can be located on two or more displays. Thus, return the id of the
  // output that has the biggest scale factor. Otherwise, use the very first one
  // that was entered. This way, we can be sure that the contents of the Window
  // are rendered at correct dpi when a user moves the window between displays.
  for (WaylandOutput::Id output_id : root_surface_->entered_outputs()) {
    auto* output = output_manager->GetOutput(output_id);
    auto* preferred_output = output_manager->GetOutput(preferred_id);
    // The compositor may have told the surface to enter the output that the
    // client is not aware of.  In such an event, we cannot evaluate scales, and
    // can only return the default, which means falling back to the primary
    // display in the code that calls this. DCHECKS below are kept for trying to
    // catch the situation in developer's builds and find the way to reproduce
    // the issue. See crbug.com/1323635.
    DCHECK(output) << " output " << output_id << " not found!";
    DCHECK(preferred_output) << " output " << preferred_id << " not found!";
    if (!output || !preferred_output) {
      return std::nullopt;
    }

    if (output->scale_factor() > preferred_output->scale_factor()) {
      preferred_id = output_id;
    }
  }

  return preferred_id;
}

std::optional<float> WaylandWindow::GetPreferredScaleFactor() const {
  if (!root_surface_) {
    return std::nullopt;
  }
  return root_surface_->preferred_scale_factor();
}

void WaylandWindow::OnPointerFocusChanged(bool focused) {
  // Whenever the window gets the pointer focus back, the cursor shape must be
  // updated. Otherwise, it is invalidated upon wl_pointer::leave and is not
  // restored by the Wayland compositor.
  if (focused && async_cursor_) {
    async_cursor_->AddCursorLoadedCallback(base::BindOnce(
        &WaylandWindow::OnCursorLoaded, AsWeakPtr(), async_cursor_));
  }
}

void WaylandWindow::OnKeyboardFocusChanged(bool focused) {
  if (focus_client_) {
    focus_client_->OnKeyboardFocusChanged(focused);
  }
}

void WaylandWindow::OnTextInputFocusChanged(bool focused) {
  if (focus_client_) {
    focus_client_->OnTextInputFocusChanged(focused);
  }
}

bool WaylandWindow::HasPointerFocus() const {
  return this ==
         connection_->window_manager()->GetCurrentPointerFocusedWindow();
}

bool WaylandWindow::HasKeyboardFocus() const {
  return this ==
         connection_->window_manager()->GetCurrentKeyboardFocusedWindow();
}

void WaylandWindow::RemoveEnteredOutput(uint32_t output_id) {
  root_surface_->RemoveEnteredOutput(output_id);
}

bool WaylandWindow::StartDrag(
    const ui::OSExchangeData& data,
    int operations,
    mojom::DragEventSource source,
    gfx::NativeCursor cursor,
    bool can_grab_pointer,
    base::OnceClosure drag_started_callback,
    WmDragHandler::DragFinishedCallback drag_finished_callback,
    WmDragHandler::LocationDelegate* location_delegate) {
  if (!connection_->data_drag_controller()->StartSession(data, operations,
                                                         source)) {
    return false;
  }

  std::move(drag_started_callback).Run();

  DCHECK(drag_finished_callback_.is_null());
  drag_finished_callback_ = std::move(drag_finished_callback);

  base::RunLoop drag_loop(base::RunLoop::Type::kNestableTasksAllowed);
  drag_loop_quit_closure_ = drag_loop.QuitClosure();

  auto alive = AsWeakPtr();
  drag_loop.Run();
  if (!alive) {
    return false;
  }
  return true;
}

void WaylandWindow::UpdateDragImage(const gfx::ImageSkia& image,
                                    const gfx::Vector2d& offset) {
  if (connection_->data_drag_controller()->IsDragInProgress()) {
    connection_->data_drag_controller()->UpdateDragImage(image, offset);
  }
}

void WaylandWindow::CancelDrag() {
  // If this is an outgoing drag session, `CancelSession()` will end up calling
  // our `OnDragSessionClose()` method, which runs `drag_loop_quit_closure_`. If
  // this is an incoming drag session, there is no drag loop to quit (because
  // that's only set up in `StartDrag()`, i.e. for outgoing sessions), so we
  // don't need to do anything else here.
  connection_->data_drag_controller()->CancelSession();
}

void WaylandWindow::Show(bool inactive) {
  frame_manager_->MaybeProcessPendingFrame();
}

void WaylandWindow::Hide() {
  received_configure_event_ = false;

  if (primary_subsurface_) {
    primary_subsurface()->Hide();
  }
  for (auto& subsurface : wayland_subsurfaces_) {
    subsurface->Hide();
  }
  frame_manager_->Hide();

  // Per https://wayland.app/protocols/xdg-shell#xdg_surface, the process of
  // mapping a shell surface comprises the following steps:
  //
  // (1) Ensuring no buffer is attached to its associated wl_surface.
  // (2) Creating the xdg_surface and its specific role surface (eg:
  //     xdg_toplevel), and set its metadata (eg: app_id, title, etc).
  // (3) Committing its wl_surface state; and then
  // (4) Waiting for the initial configure sequence. After that, a non-null
  //     buffer can be produced and attached to its underlying wl_surface.
  //
  // As `root_surface_` is reused for the whole WaylandWindow's lifetime, a
  // null buffer must be attached here and no buffer should be attached to it
  // until it is shown again.
  //
  // Note: `wl_surface_attach` is used directly here to ensure that the null
  // buffer attach request is actually issued. This is required for 2 reasons:
  //
  // - There are synchronization issues in interactive ui tests (eg: tab drag),
  // which lead to dnd start before a non-null buffer is attached to the origin
  // surface, i.e: `root_surface_->buffer_id() == 0` here.
  // - Weston, used in interactive ui infra, does not properly handle wl_surface
  // reuse, and raises a protocol error when no buffer is attached before a
  // previous surface unmapping.
  //
  // TODO(crbug.com/400894502): Investigate the issues described above.

  if (root_surface_) {
    wl_surface_attach(root_surface_->surface(), nullptr, 0, 0);
    root_surface_->Commit(false);
  }
}

void WaylandWindow::ClearInFlightRequestsSerial() {
  for (auto& request : in_flight_requests_) {
    request.serial = -1;
  }
}

void WaylandWindow::OnChannelDestroyed() {
  frame_manager_->ClearStates();
  base::circular_deque<std::pair<WaylandSubsurface*, wl::WaylandOverlayConfig>>
      subsurfaces_to_overlays;
  subsurfaces_to_overlays.reserve(wayland_subsurfaces_.size() +
                                  (primary_subsurface() ? 1 : 0));
  if (primary_subsurface()) {
    subsurfaces_to_overlays.emplace_back(primary_subsurface(),
                                         wl::WaylandOverlayConfig());
  }
  for (auto& subsurface : wayland_subsurfaces_) {
    subsurfaces_to_overlays.emplace_back(subsurface.get(),
                                         wl::WaylandOverlayConfig());
  }

  frame_manager_->RecordFrame(
      std::make_unique<WaylandFrame>(root_surface(), wl::WaylandOverlayConfig(),
                                     std::move(subsurfaces_to_overlays)));
}

// Plumbs LinuxUi's font scale into Wayland platform window's `ui_scale`, such
// that the window dip size is preserved but its UI contents gets resized and
// relaid out accordingly. It's supported only when per-surface scaling is
// enabled, and it's fully transparent for upper layers and GPU code, thus
// needing special handling when passing coordinates to/from API boundaries,
// such as, PlatformWindowDelegate, PlatforEventDispatcher, Wayland requests and
// events.
void WaylandWindow::OnFontScaleFactorChanged() {
  CHECK(connection_->IsUiScaleEnabled());
  UpdateWindowScale(/*update_bounds=*/false);
}

void WaylandWindow::DumpState(std::ostream& out) const {
  constexpr auto kWindowTypeToString =
      base::MakeFixedFlatMap<PlatformWindowType, const char*>(
          {{PlatformWindowType::kWindow, "window"},
           {PlatformWindowType::kPopup, "popup"},
           {PlatformWindowType::kMenu, "menu"},
           {PlatformWindowType::kTooltip, "tooltip"},
           {PlatformWindowType::kDrag, "drag"},
           {PlatformWindowType::kBubble, "bubble"}});
  out << "type=" << GetMapValueOrDefault(kWindowTypeToString, type_)
      << ", bounds_in_dip=" << GetBoundsInDIP().ToString()
      << ", bounds_in_pixels=" << GetBoundsInPixels().ToString()
      << ", restore_bounds_dip=" << restored_bounds_dip_.ToString()
      << ", overlay_delegation="
      << (wayland_overlay_delegation_enabled_ ? "enabled" : "disabled");
  if (has_touch_focus_) {
    out << ", has_touch_focus";
  }
  constexpr auto kOpacityToString =
      base::MakeFixedFlatMap<PlatformWindowOpacity, const char*>(
          {{PlatformWindowOpacity::kInferOpacity, "infer"},
           {PlatformWindowOpacity::kOpaqueWindow, "opaque"},
           {PlatformWindowOpacity::kTranslucentWindow, "translucent"}});
  out << ", opacity=" << GetMapValueOrDefault(kOpacityToString, opacity_);
  if (shutting_down_) {
    out << ", shutting_down";
  }
}

void WaylandWindow::Close() {
  delegate_->OnClosed();
}

bool WaylandWindow::IsVisible() const {
  NOTREACHED();
}

void WaylandWindow::PrepareForShutdown() {
  shutting_down_ = true;
  if (drag_finished_callback_) {
    OnDragSessionClose(DragOperation::kNone);
  }
}

void WaylandWindow::SetBoundsInPixels(const gfx::Rect& bounds_px) {
  // TODO(crbug.com/40218466): This is currently used only by unit tests.
  // Figure out how to migrate to test only methods.
  auto bounds_dip = delegate_->ConvertRectToDIP(bounds_px);
  SetBoundsInDIP(bounds_dip);
}

gfx::Rect WaylandWindow::GetBoundsInPixels() const {
  // TODO(crbug.com/40218466): This is currently used only by unit tests.
  // Figure out how to migrate to test only methods. For now, only the size
  // should be used outside of tests. Make up some reasonable value for origin.
  auto origin =
      delegate_->ConvertRectToPixels(applied_state_.bounds_dip).origin();
  auto size = applied_state_.size_px;
  return gfx::Rect(origin, size);
}

void WaylandWindow::SetBoundsInDIP(const gfx::Rect& bounds_dip) {
  auto state = GetLatestRequestedState();
  state.bounds_dip = bounds_dip;
  // Call this even if the bounds haven't changed, as requesting from the client
  // forces applying the state, which may (currently) not be applied if it was
  // throttled. Also, RequestState may modify the state before applying it.
  RequestStateFromClient(state);
}

gfx::Rect WaylandWindow::GetBoundsInDIP() const {
  return applied_state_.bounds_dip;
}

void WaylandWindow::OnSurfaceConfigureEvent() {
  if (received_configure_event_) {
    return;
  }
  received_configure_event_ = true;
  frame_manager_->MaybeProcessPendingFrame();
}

void WaylandWindow::SetTitle(const std::u16string& title) {}

void WaylandWindow::SetCapture() {
  // Wayland doesn't allow explicit grabs. Instead, it sends events to "entered"
  // windows. That is, if user enters their mouse pointer to a window, that
  // window starts to receive events. However, Chromium may want to reroute
  // these events to another window. In this case, tell the window manager that
  // this specific window has grabbed the events, and they will be rerouted in
  // WaylandWindow::DispatchEvent method.
  if (!HasCapture()) {
    connection_->window_manager()->GrabLocatedEvents(this);
  }
}

void WaylandWindow::ReleaseCapture() {
  if (HasCapture()) {
    connection_->window_manager()->UngrabLocatedEvents(this);
  }
  // See comment in SetCapture() for details on wayland and grabs.
}

void WaylandWindow::SetVideoCapture() {
  frame_manager_->SetVideoCapture();
}

void WaylandWindow::ReleaseVideoCapture() {
  frame_manager_->ReleaseVideoCapture();
}

bool WaylandWindow::HasCapture() const {
  return connection_->window_manager()->located_events_grabber() == this;
}

void WaylandWindow::SetFullscreen(bool fullscreen, int64_t target_display_id) {}

void WaylandWindow::Maximize() {}

void WaylandWindow::Minimize() {}

void WaylandWindow::Restore() {}

PlatformWindowState WaylandWindow::GetPlatformWindowState() const {
  // `window_state` is always `kNormal` for WaylandPopup and WaylandBubble.
  return applied_state().window_state;
}

void WaylandWindow::Activate() {
  ActivateBubble(nullptr);
}

void WaylandWindow::Deactivate() {
  ActivateBubble(nullptr);
}

void WaylandWindow::SetUseNativeFrame(bool use_native_frame) {
  // Do nothing here since only shell surfaces can handle server-side
  // decoration.
}

bool WaylandWindow::ShouldUseNativeFrame() const {
  // Always returns false here since only shell surfaces can handle server-side
  // decoration.
  return false;
}

void WaylandWindow::SetCursor(scoped_refptr<PlatformCursor> platform_cursor) {
  DCHECK(platform_cursor);

  auto async_cursor = WaylandAsyncCursor::FromPlatformCursor(platform_cursor);

  if (async_cursor_ == async_cursor) {
    return;
  }

  async_cursor_ = async_cursor;
  async_cursor->AddCursorLoadedCallback(base::BindOnce(
      &WaylandWindow::OnCursorLoaded, AsWeakPtr(), async_cursor));
}

void WaylandWindow::MoveCursorTo(const gfx::Point& location) {
  NOTIMPLEMENTED();
}

void WaylandWindow::ConfineCursorToBounds(const gfx::Rect& bounds) {
  NOTIMPLEMENTED();
}

void WaylandWindow::SetRestoredBoundsInDIP(const gfx::Rect& bounds) {
  restored_bounds_dip_ = bounds;
}

gfx::Rect WaylandWindow::GetRestoredBoundsInDIP() const {
  return restored_bounds_dip_;
}

bool WaylandWindow::ShouldWindowContentsBeTransparent() const {
  // Wayland compositors always support translucency.
  return true;
}

void WaylandWindow::SetAspectRatio(const gfx::SizeF& aspect_ratio) {
  NOTIMPLEMENTED_LOG_ONCE();
}

void WaylandWindow::SetWindowIcons(const gfx::ImageSkia& window_icon,
                                   const gfx::ImageSkia& app_icon) {
  NOTIMPLEMENTED_LOG_ONCE();
}

void WaylandWindow::SizeConstraintsChanged() {}

bool WaylandWindow::ShouldUpdateWindowShape() const {
  return false;
}

bool WaylandWindow::CanDispatchEvent(const PlatformEvent& event) {
  return CanAcceptEvent(*event);
}

uint32_t WaylandWindow::DispatchEvent(const PlatformEvent& native_event) {
  Event* event = static_cast<Event*>(native_event);

  if (event->IsLocatedEvent()) {
    auto* event_grabber =
        connection_->window_manager()->located_events_grabber();
    auto* root_parent_window = GetRootParentWindow();

    // We must reroute the events to the event grabber iff these windows belong
    // to the same root parent window. For example, there are 2 top level
    // Wayland windows. One of them (window_1) has a child menu window that is
    // the event grabber. If the mouse is moved over the window_1, it must
    // reroute the events to the event grabber. If the mouse is moved over the
    // window_2, the events mustn't be rerouted, because that belongs to another
    // stack of windows. Remember that Wayland sends local surface coordinates,
    // and continuing rerouting all the events may result in events sent to the
    // grabber even though the mouse is over another root window.
    //
    bool send_to_grabber =
        event_grabber &&
        root_parent_window == event_grabber->GetRootParentWindow();
    if (send_to_grabber) {
      WaylandEventSource::ConvertEventToTarget(event_grabber,
                                               event->AsLocatedEvent());
      Event::DispatcherApi(event).set_target(event_grabber);
    }

    // Wayland sends locations in DIP but dispatch code expects pixels, so they
    // need to be translated to physical pixels.
    auto scale = applied_state().window_scale;
    event->AsLocatedEvent()->set_location_f(
        gfx::ScalePoint(event->AsLocatedEvent()->location_f(), scale, scale));

    if (send_to_grabber) {
      event_grabber->DispatchEventToDelegate(event);
      // The event should be handled by the grabber, so don't send to next
      // dispacher.
      return POST_DISPATCH_STOP_PROPAGATION;
    }
  }

  if (event->IsKeyEvent()) {
    if (active_bubble()) {
      // Typically wl_keyboard.enter and leave are not called for
      // wl_subsurfaces. So automatically dispatch to active_bubble() as they
      // need it to traverse menu options, or type in text boxes.
      auto* bubble = active_bubble();
      while (bubble->active_bubble()) {
        bubble = bubble->active_bubble();
      }
      return bubble->DispatchEventToDelegate(event);
    } else {
      // When no active_bubble present, dispatch all keyboard events to the root
      // window.
      return GetRootParentWindow()->DispatchEventToDelegate(event);
    }
  }

  return DispatchEventToDelegate(event);
}

// EventTarget:
bool WaylandWindow::CanAcceptEvent(const Event& event) {
#if DCHECK_IS_ON()
  if (!disable_null_target_dcheck_for_test_) {
    DCHECK(event.target());
  }
#endif
  return this == event.target();
}

EventTarget* WaylandWindow::GetParentTarget() {
  return nullptr;
}

std::unique_ptr<EventTargetIterator> WaylandWindow::GetChildIterator() const {
  NOTREACHED();
}

EventTargeter* WaylandWindow::GetEventTargeter() {
  return nullptr;
}

void WaylandWindow::HandleSurfaceConfigure(uint32_t serial) {
  NOTREACHED()
      << "Only shell surfaces must receive HandleSurfaceConfigure calls.";
}

WaylandWindow::WindowStates::WindowStates() = default;
WaylandWindow::WindowStates::~WindowStates() = default;

std::string WaylandWindow::WindowStates::ToString() const {
  std::string states = "";
  if (is_maximized) {
    states += "maximized ";
  }
  if (is_fullscreen) {
    states += "fullscreen ";
  }
  if (is_activated) {
    states += "activated ";
  }
  if (is_suspended) {
    states += "suspended ";
  }
  if (is_minimized) {
    states += "minimized ";
  }
  if (states.empty()) {
    states = "<default>";
  } else {
    base::TrimString(states, " ", &states);
  }
  states += "; tiled_edges: ";
  std::string tiled = "";
  if (tiled_edges.left) {
    tiled += "left ";
  }
  if (tiled_edges.right) {
    tiled += "right ";
  }
  if (tiled_edges.top) {
    tiled += "top ";
  }
  if (tiled_edges.bottom) {
    tiled += "bottom ";
  }
  if (tiled.empty()) {
    tiled = "<none>";
  } else {
    base::TrimString(tiled, " ", &tiled);
  }
  states += tiled;
  return states;
}

void WaylandWindow::HandleToplevelConfigure(int32_t widht,
                                            int32_t height,
                                            const WindowStates& window_states) {
  NOTREACHED()
      << "Only shell toplevels must receive HandleToplevelConfigure calls.";
}

void WaylandWindow::HandleToplevelConfigureWithOrigin(
    int32_t x,
    int32_t y,
    int32_t width,
    int32_t height,
    const WindowStates& window_states) {
  NOTREACHED() << "Only shell toplevels must receive "
                  "HandleToplevelConfigureWithOrigin calls.";
}

void WaylandWindow::HandlePopupConfigure(const gfx::Rect& bounds_dip) {
  NOTREACHED() << "Only shell popups must receive HandlePopupConfigure calls.";
}

void WaylandWindow::OnCloseRequest() {
  delegate_->OnCloseRequest();
}

void WaylandWindow::OnDragEnter(const gfx::PointF& point, int operations) {
  WmDropHandler* drop_handler = GetWmDropHandler(*this);
  if (!drop_handler) {
    return;
  }
  // Wayland sends locations in DIP and drag handler also expects DIP locations,
  // though the Wayland compositor is not aware of chromium's internal UI scale,
  // hence the translation below.
  const gfx::PointF scaled_point_dip =
      gfx::ScalePoint(point, 1.0f / applied_state().ui_scale);
  drop_handler->OnDragEnter(scaled_point_dip, operations, kWaylandDndModifiers);
}

void WaylandWindow::OnDragDataAvailable(std::unique_ptr<OSExchangeData> data) {
  WmDropHandler* drop_handler = GetWmDropHandler(*this);
  if (!drop_handler) {
    return;
  }
  drop_handler->OnDragDataAvailable(std::move(data));
}

int WaylandWindow::OnDragMotion(const gfx::PointF& point, int operations) {
  WmDropHandler* drop_handler = GetWmDropHandler(*this);
  if (!drop_handler) {
    return 0;
  }
  // Wayland sends locations in DIP and drag handler also expects DIP locations,
  // though the Wayland compositor is not aware of chromium's internal UI scale,
  // hence the translation below.
  const gfx::PointF scaled_point_dip =
      gfx::ScalePoint(point, 1.0f / applied_state().ui_scale);
  return drop_handler->OnDragMotion(scaled_point_dip, operations,
                                    kWaylandDndModifiers);
}

void WaylandWindow::OnDragDrop() {
  WmDropHandler* drop_handler = GetWmDropHandler(*this);
  if (!drop_handler) {
    return;
  }
  drop_handler->OnDragDrop(kWaylandDndModifiers);
}

void WaylandWindow::OnDragLeave() {
  WmDropHandler* drop_handler = GetWmDropHandler(*this);
  if (!drop_handler) {
    return;
  }
  drop_handler->OnDragLeave();
}

void WaylandWindow::OnDragSessionClose(DragOperation operation) {
  if (!drag_finished_callback_) {
    // WaylandWindow::PrepareForShutdown() is already called. This window
    // is about to shut down. Do nothing and return.
    return;
  }
  std::move(drag_finished_callback_).Run(operation);
  // Skip releasing any pointer buttons for the case of a window drag driven by
  // the data drag controller.
  // TODO: crbug.com/40238145 - Refactor this per discussion at
  // crrev.com/c/5570335/comment/0b8811fc_818028c9/.
  if (!connection()->data_drag_controller()->IsWindowDragSessionRunning()) {
    connection()->event_source()->ReleasePressedPointerButtons(
        this, EventTimeForNow());
  }
  std::move(drag_loop_quit_closure_).Run();
}

bool WaylandWindow::Initialize(PlatformWindowInitProperties properties) {
  root_surface_ = std::make_unique<WaylandSurface>(connection_, this);
  if (!root_surface_->Initialize()) {
    LOG(ERROR) << "Failed to create wl_surface";
    return false;
  }

  SetWaylandExtension(this, this);

  PlatformWindowDelegate::State state;
  state.bounds_dip = properties.bounds;

  // Make sure we don't store empty bounds, or else later on we might send an
  // xdg_toplevel.set_window_geometry() request with zero width and height,
  // which will result in a protocol error:
  // "The width and height of the effective window geometry must be greater than
  // zero. Setting an invalid size will raise an invalid_size error."
  // This can happen when a test doesn't set `properties.bounds`, but there have
  // also been crashes in production because of this (crbug.com/1435478).
  if (state.bounds_dip.IsEmpty()) {
    // If bounds are not specified, place the window on the appropriate display,
    // if supported.
    auto* screen = display::Screen::GetScreen();
    DCHECK(screen) << "A TestScreen must be instantiated for tests creating "
                      "windows with no initial bounds.";
    state.bounds_dip = gfx::Rect({0, 0}, {1, 1});
  }

  opacity_ = properties.opacity;
  type_ = properties.type;

  connection_->window_manager()->AddWindow(GetWidget(), this);

  if (!OnInitialize(std::move(properties), &state)) {
    return false;
  }

  // Properties contain DIP bounds, whose value is derived from the current
  // window's DIP bounds, which is ui-scale'd. Thus, besides initializing ui
  // scale, the pixel size must be scaled accordingly. Both scale and bounds
  // might get updated later in the window configuration process.
  state.ui_scale = connection_->window_manager()->DetermineUiScale();
  state.size_px = gfx::ScaleToEnclosingRectIgnoringError(
                      gfx::Rect(state.bounds_dip.size()),
                      state.window_scale * state.ui_scale)
                      .size();

  applied_state_ = state;
  latched_state_ = state;

  if (wayland_overlay_delegation_enabled_) {
    primary_subsurface_ =
        std::make_unique<WaylandSubsurface>(connection_, this);
    if (!primary_subsurface_->surface()) {
      return false;
    }
    connection_->window_manager()->AddSubsurface(GetWidget(),
                                                 primary_subsurface_.get());
  }

  PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(this);
  delegate_->OnAcceleratedWidgetAvailable(GetWidget());

  std::vector<gfx::Rect> region{gfx::Rect{latched_state().size_px}};
  root_surface_->set_opaque_region(region);
  root_surface_->ApplyPendingState();

  connection_->Flush();

  return true;
}

void WaylandWindow::SetWindowGeometry(
    const PlatformWindowDelegate::State& state) {}

gfx::Vector2d WaylandWindow::GetWindowGeometryOffsetInDIP() const {
  const auto& insets_dip =
      delegate()->CalculateInsetsInDIP(GetPlatformWindowState());
  return {insets_dip.left(), insets_dip.top()};
}

WaylandWindow* WaylandWindow::GetRootParentWindow() {
  return parent_window_ ? parent_window_->GetRootParentWindow() : this;
}

void WaylandWindow::OnEnteredOutput() {
  // Wayland does weird things for menus so instead of tracking outputs that
  // we entered or left, we take that from the parent window and ignore this
  // event.
  if (AsWaylandPopup()) {
    return;
  }
  OnEnteredOutputScaleChanged();
}

void WaylandWindow::OnLeftOutput() {
  // Wayland does weird things for menus so instead of tracking outputs that
  // we entered or left, we take that from the parent window and ignore this
  // event.
  if (AsWaylandPopup()) {
    return;
  }
  OnEnteredOutputScaleChanged();
}

WaylandWindow* WaylandWindow::GetTopMostChildWindow() {
  return child_popup_ ? child_popup_->GetTopMostChildWindow() : this;
}

WaylandWindow* WaylandWindow::GetXdgParentWindow() {
  auto* xdg_parent_window = parent_window();
  while (xdg_parent_window && !xdg_parent_window->AsWaylandToplevelWindow() &&
         !xdg_parent_window->AsWaylandPopup()) {
    xdg_parent_window = xdg_parent_window->parent_window();
  }
  return xdg_parent_window;
}

bool WaylandWindow::IsOpaqueWindow() const {
  return opacity_ == ui::PlatformWindowOpacity::kOpaqueWindow;
}

bool WaylandWindow::IsActive() const {
  // Please read the comment where the IsActive method is declared.
  return false;
}

bool WaylandWindow::IsSuspended() const {
  return false;
}

WaylandBubble* WaylandWindow::AsWaylandBubble() {
  return nullptr;
}

WaylandPopup* WaylandWindow::AsWaylandPopup() {
  return nullptr;
}

WaylandToplevelWindow* WaylandWindow::AsWaylandToplevelWindow() {
  return nullptr;
}

uint32_t WaylandWindow::DispatchEventToDelegate(
    const PlatformEvent& native_event) {
  EventResult result = DispatchEventFromNativeUiEvent(
      native_event, base::BindOnce(&PlatformWindowDelegate::DispatchEvent,
                                   base::Unretained(delegate_)));
  if (result == ER_UNHANDLED) {
    return POST_DISPATCH_NONE;
  }

  return !!(result & ER_SKIPPED) ? POST_DISPATCH_PERFORM_DEFAULT
                                 : POST_DISPATCH_STOP_PROPAGATION;
}

std::unique_ptr<WaylandSurface> WaylandWindow::TakeWaylandSurface() {
  DCHECK(shutting_down_);
  DCHECK(root_surface_);
  root_surface_->UnsetRootWindow();
  return std::move(root_surface_);
}

bool WaylandWindow::RequestSubsurface() {
  auto subsurface = std::make_unique<WaylandSubsurface>(connection_, this);
  if (!subsurface->surface()) {
    return false;
  }
  connection_->window_manager()->AddSubsurface(GetWidget(), subsurface.get());
  subsurface_stack_above_.push_back(subsurface.get());
  auto result = wayland_subsurfaces_.emplace(std::move(subsurface));
  DCHECK(result.second);
  return true;
}

bool WaylandWindow::ArrangeSubsurfaceStack(size_t above, size_t below) {
  while (wayland_subsurfaces_.size() < above + below) {
    if (!RequestSubsurface()) {
      return false;
    }
  }

  DCHECK(subsurface_stack_below_.size() + subsurface_stack_above_.size() >=
         above + below);

  if (subsurface_stack_above_.size() < above) {
    auto splice_start = subsurface_stack_below_.begin();
    for (size_t i = 0; i < below; ++i) {
      ++splice_start;
    }
    subsurface_stack_above_.splice(subsurface_stack_above_.end(),
                                   subsurface_stack_below_, splice_start,
                                   subsurface_stack_below_.end());

  } else if (subsurface_stack_below_.size() < below) {
    auto splice_start = subsurface_stack_above_.end();
    for (size_t i = 0; i < below - subsurface_stack_below_.size(); ++i) {
      --splice_start;
    }
    subsurface_stack_below_.splice(subsurface_stack_below_.end(),
                                   subsurface_stack_above_, splice_start,
                                   subsurface_stack_above_.end());
  }

  DCHECK(subsurface_stack_below_.size() >= below);
  DCHECK(subsurface_stack_above_.size() >= above);
  return true;
}

bool WaylandWindow::CommitOverlays(
    uint32_t frame_id,
    const gfx::FrameData& data,
    std::vector<wl::WaylandOverlayConfig>& overlays) {
  if (overlays.empty()) {
    return true;
  }

  // Wayland submits from front to back. A simple reverse can avoid a full sort.
  std::reverse(overlays.begin(), overlays.end());
  if (!std::is_sorted(overlays.begin(), overlays.end(),
                      OverlayStackOrderCompare)) {
    // |overlays| is sorted from bottom to top.
    std::sort(overlays.begin(), overlays.end(), OverlayStackOrderCompare);
  }

  // Find the location where z_oder becomes non-negative.
  wl::WaylandOverlayConfig value;
  auto split = std::lower_bound(overlays.begin(), overlays.end(), value,
                                OverlayStackOrderCompare);
  DCHECK(split == overlays.end() || (*split).z_order >= 0);
  size_t num_primary_planes =
      (split != overlays.end() && (*split).z_order == 0) ? 1 : 0;
  size_t num_background_planes =
      (overlays.front().z_order == INT32_MIN) ? 1 : 0;

  size_t above = (overlays.end() - split) - num_primary_planes;
  size_t below = (split - overlays.begin()) - num_background_planes;

  // Re-arrange the list of subsurfaces to fit the |overlays|. Request extra
  // subsurfaces if needed.
  if (!ArrangeSubsurfaceStack(above, below)) {
    return false;
  }

  gfx::SizeF visual_size = (*overlays.begin()).bounds_rect.size();
  float buffer_scale = (*overlays.begin()).surface_scale_factor;

  if (!wayland_overlay_delegation_enabled_) {
    DCHECK_EQ(overlays.size(), 1u);
    frame_manager_->RecordFrame(std::make_unique<WaylandFrame>(
        frame_id, data, root_surface(), std::move(*overlays.begin())));
    return true;
  }

  base::circular_deque<std::pair<WaylandSubsurface*, wl::WaylandOverlayConfig>>
      subsurfaces_to_overlays;
  subsurfaces_to_overlays.reserve(
      std::max(overlays.size() - num_background_planes,
               wayland_subsurfaces_.size() + 1));

  subsurfaces_to_overlays.emplace_back(
      primary_subsurface(),
      num_primary_planes ? std::move(*split) : wl::WaylandOverlayConfig());

  {
    // Iterate through |subsurface_stack_below_|, setup subsurfaces and place
    // them in corresponding order. Commit wl_buffers once a subsurface is
    // configured.
    auto overlay_iter = split - 1;
    for (auto iter = subsurface_stack_below_.begin();
         iter != subsurface_stack_below_.end(); ++iter, --overlay_iter) {
      if (overlay_iter >= overlays.begin() + num_background_planes) {
        subsurfaces_to_overlays.emplace_front(*iter, std::move(*overlay_iter));
      } else {
        // If there're more subsurfaces requested that we don't need at the
        // moment, hide them.
        subsurfaces_to_overlays.emplace_front(*iter,
                                              wl::WaylandOverlayConfig());
      }
    }

    // Iterate through |subsurface_stack_above_|, setup subsurfaces and place
    // them in corresponding order. Commit wl_buffers once a subsurface is
    // configured.
    overlay_iter = split + num_primary_planes;
    for (auto iter = subsurface_stack_above_.begin();
         iter != subsurface_stack_above_.end(); ++iter, ++overlay_iter) {
      if (overlay_iter < overlays.end()) {
        subsurfaces_to_overlays.emplace_back(*iter, std::move(*overlay_iter));
      } else {
        // If there're more subsurfaces requested that we don't need at the
        // moment, hide them.
        subsurfaces_to_overlays.emplace_back(*iter, wl::WaylandOverlayConfig());
      }
    }
  }

  // Configuration of the root_surface
  wl::WaylandOverlayConfig root_config;
  if (num_background_planes) {
    root_config = std::move(overlays.front());
  } else {
    root_config = wl::WaylandOverlayConfig(
        gfx::OverlayPlaneData(
            INT32_MIN, gfx::OverlayTransform::OVERLAY_TRANSFORM_NONE,
            gfx::RectF(visual_size), gfx::RectF(),
            root_surface()->use_blending(), gfx::Rect(),
            root_surface()->opacity(), gfx::OverlayPriorityHint::kNone,
            gfx::RRectF(), gfx::ColorSpace::CreateSRGB(), std::nullopt),
        nullptr, root_surface()->buffer_id(), buffer_scale);
  }

  frame_manager_->RecordFrame(std::make_unique<WaylandFrame>(
      frame_id, data, root_surface(), std::move(root_config),
      std::move(subsurfaces_to_overlays)));

  return true;
}

void WaylandWindow::UpdateCursorShape(scoped_refptr<BitmapCursor> cursor) {
  DCHECK(cursor);
  CHECK(cursor->type() == CursorType::kNone ||
        base::IsValueInRangeForNumericType<int>(
            cursor->cursor_image_scale_factor()));

  std::optional<uint32_t> shape =
      WaylandCursorShape::ShapeFromType(cursor->type());

  // Round cursor scale factor to ceil as wl_surface.set_buffer_scale accepts
  // only integers.
  if (cursor->type() == CursorType::kNone) {  // Hide the cursor.
    connection_->SetCursorBitmap(
        {}, gfx::Point(), std::ceil(cursor->cursor_image_scale_factor()));
  } else if (connection_->wayland_cursor_shape() && shape.has_value()) {
    // Prefer Wayland server-side cursor support, as the compositor knows better
    // how to draw the cursor.
    connection_->wayland_cursor_shape()->SetCursorShape(shape.value());
  } else if (cursor->platform_data()) {  // Check for theme-provided cursor.
    connection_->SetPlatformCursor(
        reinterpret_cast<wl_cursor*>(cursor->platform_data()),
        std::ceil(cursor->cursor_image_scale_factor()));
  } else if (!cursor->bitmaps()
                  .empty()) {  // Use client-side bitmap cursors as fallback.
    // Translate physical pixels to DIPs.
    gfx::Point hotspot_in_dips = gfx::ScaleToRoundedPoint(
        cursor->hotspot(), 1.0f / cursor->cursor_image_scale_factor());
    connection_->SetCursorBitmap(
        cursor->bitmaps(), hotspot_in_dips,
        std::ceil(cursor->cursor_image_scale_factor()));
  }
}

void WaylandWindow::OnCursorLoaded(scoped_refptr<WaylandAsyncCursor> cursor,
                                   scoped_refptr<BitmapCursor> bitmap_cursor) {
  if (HasPointerFocus() && async_cursor_ == cursor && bitmap_cursor) {
    UpdateCursorShape(bitmap_cursor);
  }
}

void WaylandWindow::ProcessPendingConfigureState(uint32_t serial) {
  // For values not specified in pending_configure_state_, use the latest
  // requested values.
  auto state = GetLatestRequestedState();

  if (pending_configure_state_.window_state.has_value()) {
    state.window_state = pending_configure_state_.window_state.value();
  }
  if (pending_configure_state_.bounds_dip.has_value()) {
    state.bounds_dip = pending_configure_state_.bounds_dip.value();
  }
  if (pending_configure_state_.size_px.has_value()) {
    state.size_px = pending_configure_state_.size_px.value();
  }
  if (pending_configure_state_.tiled_edges.has_value()) {
    state.tiled_edges = pending_configure_state_.tiled_edges.value();
  }

  if (state.bounds_dip.IsEmpty() &&
      GetPlatformWindowState() == PlatformWindowState::kMinimized &&
      in_flight_requests_.empty()) {
    // In exo, widget creation is deferred until the surface has contents and
    // |initial_show_state_| for a widget is ignored. Exo sends a configure
    // callback with empty bounds expecting client to suggest a size.
    // For the window activated from minimized state,
    // the saved window placement should be set as window geometry.
    state.bounds_dip = GetBoundsInDIP();
    // As per spec, width and height must be greater than zero.
    if (state.bounds_dip.IsEmpty()) {
      state.bounds_dip = gfx::Rect(0, 0, 1, 1);
    }
  }

  RequestStateFromServer(state, serial);

  // Reset values.
  pending_configure_state_ = PendingConfigureState();

  // If we get a configure which is immediately applied and latched (meaning
  // that the configure does nothing), we will have immediately acked it, and we
  // can immediately commit it. See crbug.com/340500574.
  if (state == applied_state_ && state == latched_state_ &&
      in_flight_requests_.empty()) {
    root_surface_->Commit(/*flush=*/true);
  }
}

void WaylandWindow::RequestStateFromServer(PlatformWindowDelegate::State state,
                                           int64_t serial) {
  RequestState(state, serial, /*force=*/false);
}

void WaylandWindow::RequestStateFromClient(
    PlatformWindowDelegate::State state) {
  // In general, client requested changes should not be throttled so force
  // apply this.
  RequestState(state, /*serial=*/-1, /*force=*/true);
}

void WaylandWindow::RequestState(PlatformWindowDelegate::State state,
                                 int64_t serial,
                                 bool force) {
  LOG_IF(WARNING, in_flight_requests_.size() > 100u)
      << "The queue of configures is longer than 100!";

  // If we called re-entrantly into `RequestState` from
  // `MaybeApplyLatestStateRequest`, save this call to execute later.
  // TODO(crbug.com/40058672): Remove this.
  if (applying_state_) {
    reentrant_requests_.emplace_back(state, serial, force);
    return;
  }

  // If there are no in-flight requests, then the applied state should be the
  // latched state, because in flight configure requests are only removed on
  // latch.
  if (in_flight_requests_.empty()) {
    // Currently, we have a hack that overrides `applied_state_.window_state`
    // when the window state change is requested from the client. In such case,
    // `applied_state_` may take a different window state value from
    // `latched_state_` when the server side sends configure event.
    // TODO(crbug.com/40276379): Check window state is equal between
    // `applied_state_` and `latched_state_` as well.
    auto applied_state_copy = applied_state_;
    // Override `applied_state_.window_state` as the same value as
    // `latched_state_` to exclude `window_state` from equivalence check.
    applied_state_copy.window_state = latched_state_.window_state;
    CHECK_EQ(applied_state_copy, latched_state_);
  }

  // ui_scale determines how the window content, ie: UI, will be laid out and
  // sized. See WaylandWindowManager::DetermineUiScale docs for more details.
  const float new_ui_scale = connection_->window_manager()->DetermineUiScale();
  state.bounds_dip = gfx::ScaleToEnclosingRectIgnoringError(
      state.bounds_dip, state.ui_scale / new_ui_scale);
  state.ui_scale = new_ui_scale;

  // Adjust state values if necessary.
  state.bounds_dip = AdjustBoundsToConstraintsDIP(state.bounds_dip);

  const float scale = state.window_scale * state.ui_scale;

  // Upper layers (eg //cc) convert the window size from DIP to pixels
  // independently from the window origin. For example, for a window whose
  // bounds are arbitrary `x,y w x h` in DIP, //cc translates its origin (x,y)
  // and size (w x h) to pixels independently from each other. Translating the
  // whole rect from DIPs to pixels might generate a 1px difference that cause
  // render artifacts - see https://issues.chromium.org/40876438 for details.
  state.size_px = gfx::ScaleToEnclosingRectIgnoringError(
                      gfx::Rect(state.bounds_dip.size()), scale)
                      .size();

  StateRequest req{.state = state, .serial = serial};
  if (in_flight_requests_.empty()) {
    in_flight_requests_.push_back(req);
  } else {
    // Propagate largest serial number so far, if we have one, since we
    // can have configure requests with no serial number (value -1).
    req.serial = std::max(req.serial, in_flight_requests_.back().serial);

    if (!in_flight_requests_.back().applied) {
      // If the last request has not been applied yet, overwrite it since
      // there's no point in requesting an old state.
      in_flight_requests_.back() = req;
    } else if (in_flight_requests_.back().state == req.state) {
      // If we already asked for this configure state, we can send back a higher
      // wayland serial for ack while needing a lower viz_seq.
      in_flight_requests_.back().serial = req.serial;
    } else {
      in_flight_requests_.push_back(req);
    }
  }

  MaybeApplyLatestStateRequest(force);
}

void WaylandWindow::ProcessSequencePoint(int64_t viz_seq) {
  // If the sequence number is -1, it means there was a GPU process crash.
  // In this case, latch any existing frames.
  if (viz_seq == -1) {
    viz_seq = INT64_MAX;
  }

  // Find last applied configure request satisfied by |seq|.
  auto iter = in_flight_requests_.end();
  for (auto i = in_flight_requests_.begin(); i != in_flight_requests_.end();
       ++i) {
    // The sequence number of each request should strictly monotonically
    // increase, since each request needs to produce a new sequence point.
    // Any requests that don't have a sequence id (-1) will be treated as
    // done if they have been applied. To latch a request, our sequence
    // number must be greater than or equal to the request's sequence
    // number.
    if (i->viz_seq > viz_seq && i->viz_seq != -1) {
      break;
    }

    if (i->applied) {
      iter = i;
    }
  }

  if (iter == in_flight_requests_.end()) {
    return;
  }

  if (UseTestConfigForPlatformWindows()) {
    const auto end = std::next(iter);
    for (auto i = in_flight_requests_.begin(); i != end; ++i) {
      // We need to set `latest_latched_viz_seq_for_testing_` to the highest viz
      // seq for all requests at or before the last request we latch.
      latest_latched_viz_seq_for_testing_ =
          std::max(i->viz_seq, latest_latched_viz_seq_for_testing_);
    }
  }

  // Latch the latest state which was actually applied.
  LatchStateRequest(*iter);

  in_flight_requests_.erase(in_flight_requests_.begin(), ++iter);

  // Now a new state is latched we may want to apply previously throttled
  // requests.
  MaybeApplyLatestStateRequest(/*force=*/false);
}

gfx::Rect WaylandWindow::AdjustBoundsToConstraintsPx(
    const gfx::Rect& bounds_px) {
  gfx::Rect adjusted_bounds_px = bounds_px;
  if (const auto min_size = delegate_->GetMinimumSizeForWindow()) {
    gfx::Size min_size_in_px =
        delegate()->ConvertRectToPixels(gfx::Rect(*min_size)).size();
    if (min_size_in_px.width() > 0 &&
        adjusted_bounds_px.width() < min_size_in_px.width()) {
      adjusted_bounds_px.set_width(min_size_in_px.width());
    }
    if (min_size_in_px.height() > 0 &&
        adjusted_bounds_px.height() < min_size_in_px.height()) {
      adjusted_bounds_px.set_height(min_size_in_px.height());
    }
  }
  if (const auto max_size = delegate_->GetMaximumSizeForWindow()) {
    gfx::Size max_size_in_px =
        delegate()->ConvertRectToPixels(gfx::Rect(*max_size)).size();
    if (max_size_in_px.width() > 0 &&
        adjusted_bounds_px.width() > max_size_in_px.width()) {
      adjusted_bounds_px.set_width(max_size_in_px.width());
    }
    if (max_size_in_px.height() > 0 &&
        adjusted_bounds_px.height() > max_size_in_px.height()) {
      adjusted_bounds_px.set_height(max_size_in_px.height());
    }
  }
  return adjusted_bounds_px;
}

gfx::Rect WaylandWindow::AdjustBoundsToConstraintsDIP(
    const gfx::Rect& bounds_dip) {
  gfx::Rect adjusted_bounds_dip = bounds_dip;
  if (const auto min_size_dip = delegate_->GetMinimumSizeForWindow()) {
    if (min_size_dip->width() > 0 &&
        adjusted_bounds_dip.width() < min_size_dip->width()) {
      adjusted_bounds_dip.set_width(min_size_dip->width());
    }
    if (min_size_dip->height() > 0 &&
        adjusted_bounds_dip.height() < min_size_dip->height()) {
      adjusted_bounds_dip.set_height(min_size_dip->height());
    }
  }
  if (const auto max_size_dip = delegate_->GetMaximumSizeForWindow()) {
    if (max_size_dip->width() > 0 &&
        adjusted_bounds_dip.width() > max_size_dip->width()) {
      adjusted_bounds_dip.set_width(max_size_dip->width());
    }
    if (max_size_dip->height() > 0 &&
        adjusted_bounds_dip.height() > max_size_dip->height()) {
      adjusted_bounds_dip.set_height(max_size_dip->height());
    }
  }
  return adjusted_bounds_dip;
}

void WaylandWindow::LatchStateRequest(const StateRequest& req) {
  // Latch the most up to date state we have a frame back for.
  auto old_state = std::exchange(latched_state_, req.state);
  // Ack is sent when the state request holds a valid serial value.
  const bool ack_configure = req.serial != -1;

  // Update the geometry if:
  // - either bounds, tiling or insets has changed since the latest latched
  //   request; or
  // - acking state corresponding to the very first configure sequence.
  if (req.state.bounds_dip.size() != old_state.bounds_dip.size() ||
      req.state.tiled_edges != old_state.tiled_edges ||
      delegate()->CalculateInsetsInDIP(req.state.window_state) !=
          delegate()->CalculateInsetsInDIP(old_state.window_state) ||
      (ack_configure &&
       old_state.window_state == PlatformWindowState::kUnknown &&
       req.state.window_state != PlatformWindowState::kUnknown)) {
    SetWindowGeometry(req.state);
  }
  UpdateWindowMask();
  if (ack_configure) {
    AckConfigure(req.serial);
  }
}

void WaylandWindow::MaybeApplyLatestStateRequest(bool force) {
  // Calling `MaybeApplyLatestStateRequest` re-entrantly is hard to reason about
  // and also can lead to memory corruption during accesses to
  // `in_flight_requests_`.
  CHECK(!applying_state_)
      << "MaybeApplyLatestStateRequest called re-entrantly.";
  auto setter =
      std::make_optional<base::AutoReset<bool>>(&applying_state_, true);

  if (in_flight_requests_.empty()) {
    return;
  }

  if (!force) {
    int in_flight_applied = std::ranges::count_if(
        in_flight_requests_,
        [](const StateRequest& req) { return req.applied; });

    // Allow at most 3 configure requests to be waited on at a time.
    constexpr int MAX_IN_FLIGHT_REQUESTS = 3;
    if (in_flight_applied >= MAX_IN_FLIGHT_REQUESTS) {
      return;
    }
  }

  auto& latest = in_flight_requests_.back();
  if (latest.applied) {
    return;
  }
  latest.applied = true;

  // Set the applied state here so it can be used by e.g. OnBoundsChanged to
  // pick up the new bounds.
  auto old = applied_state_;
  applied_state_ = latest.state;

  // OnStateUpdate may return -1 if the state update does not require a new
  // frame to be considered synchronized. For example, this can happen if the
  // old and new states are the same, or it only changes the origin of the
  // bounds.
  latest.viz_seq = delegate()->OnStateUpdate(old, latest.state);

  if (UseTestConfigForPlatformWindows()) {
    latest_applied_viz_seq_for_testing_ = std::max(
        latest_applied_viz_seq_for_testing_,
        std::ranges::max(in_flight_requests_, {}, [](const StateRequest& req) {
          return req.viz_seq;
        }).viz_seq);
  }

  // `ProcessSequencePoint` may re-entrantly call
  // `MaybeApplyLatestStateRequest`. This is safe as long as we do not hold
  // references to `in_flight_requests_` after here.
  setter.reset();

  // Process any requests added re-entrantly. We need to move the requests out
  // of `reentrant_requests_` here because each re-entrant request may also add
  // its own re-entrant requests. This implementation preserves ordering of
  // requests as if they were added one by one by essentially performing a
  // pre-order traversal when re-entrant requests add their own re-entrant
  // requests (and so on). We only need to process re-entrant requests here,
  // because re-entrant requests can only be added during the re-entrant
  // critical section above. So, if we ensure `reentrant_requests_` is empty
  // directly after the critical section above finishes, we maintain the
  // invariant that `reentrant_requests_` is always empty outside of the
  // critical section.
  auto reentrant_requests = std::move(reentrant_requests_);
  reentrant_requests_.clear();
  for (const auto& [req_state, req_serial, req_force] : reentrant_requests) {
    RequestState(req_state, req_serial, req_force);
  }

  // If we have state requests which don't require synchronization to latch, or
  // if no frames will be produced, ack them immediately. Using -2 (or any
  // negative number that isn't -1) will cause all requests with viz_seq==-1 to
  // be latched. We don't use -1 because ProcessSequencePoint has a special case
  // to re-map -1 to a large number to handle GPU process crashes.
  constexpr int64_t kLatchAllWithoutVizSeq = -2;
  ProcessSequencePoint(kLatchAllWithoutVizSeq);

  // Latch in tests immediately if the test config is set.
  // Otherwise, such tests as interactive_ui_tests fail.
  if (UseTestConfigForPlatformWindows() && latch_immediately_for_testing_) {
    ProcessSequencePoint(INT64_MAX);
  }
}

PlatformWindowDelegate::State WaylandWindow::GetLatestRequestedState() const {
  return in_flight_requests_.empty() ? applied_state_
                                     : in_flight_requests_.back().state;
}

void WaylandWindow::RoundTripQueue() {
  connection()->RoundTripQueue();
}

bool WaylandWindow::HasInFlightRequestsForState() const {
  CHECK(UseTestConfigForPlatformWindows());
  return WaylandWindow::HasInFlightRequestsForStateForTesting();
}

int64_t WaylandWindow::GetVizSequenceIdForAppliedState() const {
  CHECK(UseTestConfigForPlatformWindows());
  return latest_applied_viz_seq_for_testing_;
}

int64_t WaylandWindow::GetVizSequenceIdForLatchedState() const {
  CHECK(UseTestConfigForPlatformWindows());
  return latest_latched_viz_seq_for_testing_;
}

void WaylandWindow::SetLatchImmediately(bool latch_immediately) {
  latch_immediately_for_testing_ = latch_immediately;
}

void WaylandWindow::ForceApplyWindowStateDoNotUse(
    PlatformWindowState window_state) {
  applied_state_.window_state = window_state;
}

}  // namespace ui