// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_OZONE_PUBLIC_PLATFORM_SCREEN_H_
#define UI_OZONE_PUBLIC_PLATFORM_SCREEN_H_

#include <optional>
#include <set>
#include <string>
#include <vector>

#include "base/component_export.h"
#include "base/values.h"
#include "ui/gfx/gpu_extra_info.h"
#include "ui/gfx/native_ui_types.h"

namespace base {
class TimeDelta;
}  // namespace base

namespace display {
class Display;
class DisplayObserver;
}  // namespace display

namespace gfx {
class Point;
class Rect;
}  // namespace gfx

namespace ui {

// PlatformScreen is an abstract base class for an interface to an Ozone
// platform's functionality exposed to Chrome via display::Screen.
//
// Additionally, may notify DisplayObservers with global workspace changes.
//
// Recall that in Chrome, a |Screen| is the union of all attached |Display|
// instances. The |Screen|'s coordinate system is in DIP pixels (so that
// it can reasonably support |Display|s of differing pixel densities.) The
// |Screen|'s origin is the top-left corner of the primary |Display| in the
// |Screen|. Coordinates increase down and to the right.
//
// TODO(rjkroege): Add ascii art?
class COMPONENT_EXPORT(OZONE_BASE) PlatformScreen {
 public:
  PlatformScreen();

  PlatformScreen(const PlatformScreen&) = delete;
  PlatformScreen& operator=(const PlatformScreen&) = delete;

  virtual ~PlatformScreen();

  // Provide a |display::Display| for each physical display available to Chrome.
  virtual const std::vector<display::Display>& GetAllDisplays() const = 0;

  // Returns the |Display| whose origin (top left corner) is 0,0 in the
  // |Screen|.
  virtual display::Display GetPrimaryDisplay() const = 0;

  // Returns the Display occupied by |widget|.
  // TODO(rjkroege) This method might be unused?
  // TODO(rjkroege): How should we support unified mode?
  virtual display::Display GetDisplayForAcceleratedWidget(
      gfx::AcceleratedWidget widget) const = 0;

  // Returns cursor position in DIPs relative to the |Screen|'s origin.
  // TODO(rjkroege): Verify these semantics.
  virtual gfx::Point GetCursorScreenPoint() const = 0;

  virtual bool IsAcceleratedWidgetUnderCursor(
      gfx::AcceleratedWidget widget) const;

  virtual gfx::AcceleratedWidget GetAcceleratedWidgetAtScreenPoint(
      const gfx::Point& point_in_dip) const = 0;

  // Returns top level accelerated widget at |point| ignoring |ignore|.
  virtual gfx::AcceleratedWidget GetLocalProcessWidgetAtPoint(
      const gfx::Point& point_in_dip,
      const std::set<gfx::AcceleratedWidget>& ignore) const;

  // Returns the |Display| nearest the specified point. |point| must be in DIPs.
  virtual display::Display GetDisplayNearestPoint(
      const gfx::Point& point_in_dip) const = 0;

  // Returns the |Display| that most closely intersects the provided rect if one
  // exists.
  // TODO(rjk): Update the code to track this.
  virtual display::Display GetDisplayMatching(
      const gfx::Rect& match_rect) const = 0;

  // Object which suspends the platform-specific screensaver for the duration of
  // its existence.
  class PlatformScreenSaverSuspender {
   public:
    PlatformScreenSaverSuspender() = default;

    PlatformScreenSaverSuspender(const PlatformScreenSaverSuspender&) = delete;
    PlatformScreenSaverSuspender& operator=(
        const PlatformScreenSaverSuspender&) = delete;

    // Causes the platform-specific screensaver to be un-suspended iff this is
    // the last remaining instance.
    virtual ~PlatformScreenSaverSuspender() = 0;
  };

  // Suspends the platform-specific screensaver until the returned
  // |PlatformScreenSaverSuspender| is destructed, or returns nullptr if
  // suspension failed. This method allows stacking multiple overlapping calls,
  // such that the platform-specific screensaver will not be un-suspended until
  // all returned |PlatformScreenSaverSuspender| instances have been destructed.
  virtual std::unique_ptr<PlatformScreenSaverSuspender> SuspendScreenSaver();

  // Returns whether the screensaver is currently running.
  virtual bool IsScreenSaverActive() const;

  // Calculates idle time.
  virtual base::TimeDelta CalculateIdleTime() const;

  // Adds/Removes display observers.
  virtual void AddObserver(display::DisplayObserver* observer) = 0;
  virtual void RemoveObserver(display::DisplayObserver* observer) = 0;

  // Returns currently used workspace. If a platform does not support this, the
  // empty string is returned.
  virtual std::string GetCurrentWorkspace();

  // Returns human readable description of the window manager, desktop, and
  // other system properties related to the compositing.
  virtual base::ListValue GetGpuExtraInfo(
      const gfx::GpuExtraInfo& gpu_extra_info);

  // Returns the preferred scale factor for a |widget|, if any. Used, for
  // example, in Wayland implementation when wp-fractional-scale protocol is
  // available.
  virtual std::optional<float> GetPreferredScaleFactorForAcceleratedWidget(
      gfx::AcceleratedWidget widget) const;

  // Returns true when running in headless mode.
  virtual bool IsHeadless() const;

 protected:
  void StorePlatformNameIntoListOfValues(base::ListValue& values,
                                         const std::string& platform_name);
};

}  // namespace ui

#endif  // UI_OZONE_PUBLIC_PLATFORM_SCREEN_H_