// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_DISPLAY_SCREEN_H_
#define UI_DISPLAY_SCREEN_H_

#include <set>
#include <vector>

#include "base/macros.h"
#include "ui/display/display.h"
#include "ui/display/display_export.h"
#include "ui/gfx/native_widget_types.h"

namespace gfx {
class Point;
class Rect;
}

namespace display {
class DisplayObserver;

// A utility class for getting various info about screen size, displays,
// cursor position, etc.
//
// Also, can notify DisplayObservers about global workspace changes. The
// availability of that functionality depends on a platform.
//
// Note that this class does not represent an individual display connected to a
// computer -- see the Display class for that. A single Screen object exists
// regardless of the number of connected displays.
class DISPLAY_EXPORT Screen {
 public:
  Screen();
  virtual ~Screen();

  // Retrieves the single Screen object.
  static Screen* GetScreen();

  // Sets the global screen. Returns the previously installed screen, if any.
  // NOTE: this does not take ownership of |screen|. Tests must be sure to reset
  // any state they install.
  static Screen* SetScreenInstance(Screen* instance);

  // Returns the current absolute position of the mouse pointer.
  virtual gfx::Point GetCursorScreenPoint() = 0;

  // Returns true if the cursor is directly over |window|.
  virtual bool IsWindowUnderCursor(gfx::NativeWindow window) = 0;

  // Returns the window at the given screen coordinate |point|.
  virtual gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) = 0;

  // Finds the topmost visible chrome window at |screen_point|. This should
  // return nullptr if |screen_point| is in another program's window which
  // occludes the topmost chrome window. Ignores the windows in |ignore|, which
  // contain windows such as the tab being dragged right now.
  virtual gfx::NativeWindow GetLocalProcessWindowAtPoint(
      const gfx::Point& point,
      const std::set<gfx::NativeWindow>& ignore) = 0;

  // Returns the number of displays.
  // Mirrored displays are excluded; this method is intended to return the
  // number of distinct, usable displays.
  virtual int GetNumDisplays() const = 0;

  // Returns the list of displays that are currently available.
  virtual const std::vector<Display>& GetAllDisplays() const = 0;

  // Returns the display nearest the specified window.
  // If the window is NULL or the window is not rooted to a display this will
  // return the primary display.
  virtual Display GetDisplayNearestWindow(gfx::NativeWindow window) const = 0;

  // Returns the display nearest the specified view. It may still use the window
  // that contains the view (i.e. if a window is spread over two displays,
  // the location of the view within that window won't influence the result).
  virtual Display GetDisplayNearestView(gfx::NativeView view) const;

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

  // Returns the display that most closely intersects the provided bounds.
  virtual Display GetDisplayMatching(const gfx::Rect& match_rect) const = 0;

  // Returns the primary display. It is guaranteed that this will return a
  // display with a valid display ID even if there is no display connected.
  // A real display will be reported via DisplayObserver when it is connected.
  virtual Display GetPrimaryDisplay() const = 0;

  // Returns a suggested display to use when creating a new window. On most
  // platforms just returns the primary display.
  Display GetDisplayForNewWindows() const;

  // Sets the suggested display to use when creating a new window.
  void SetDisplayForNewWindows(int64_t display_id);

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

  // Converts |screen_rect| to DIP coordinates in the context of |window|
  // clamping to the enclosing rect if the coordinates do not fall on pixel
  // boundaries. If |window| is null, the primary display is used as the
  // context.
  virtual gfx::Rect ScreenToDIPRectInWindow(gfx::NativeWindow window,
                                            const gfx::Rect& screen_rect) const;

  // Converts |dip_rect| to screen coordinates in the context of |window|
  // clamping to the enclosing rect if the coordinates do not fall on pixel
  // boundaries. If |window| is null, the primary display is used as the
  // context.
  virtual gfx::Rect DIPToScreenRectInWindow(gfx::NativeWindow window,
                                            const gfx::Rect& dip_rect) const;

  // Returns true if the display with |display_id| is found and returns that
  // display in |display|. Otherwise returns false and |display| remains
  // untouched.
  bool GetDisplayWithDisplayId(int64_t display_id, Display* display) const;

  virtual void SetPanelRotationForTesting(int64_t display_id,
                                          Display::Rotation rotation);

  // Depending on a platform, a client can listen to global workspace changes
  // by implementing and setting self as a DisplayObserver. It is also possible
  // to get current workspace through the GetCurrentWorkspace method.
  virtual std::string GetCurrentWorkspace();

 private:
  friend class ScopedDisplayForNewWindows;

  // Used to temporarily override the value from SetDisplayForNewWindows() by
  // creating an instance of ScopedDisplayForNewWindows. Call with
  // |kInvalidDisplayId| to unset.
  void SetScopedDisplayForNewWindows(int64_t display_id);

  static gfx::NativeWindow GetWindowForView(gfx::NativeView view);

  int64_t display_id_for_new_windows_;
  int64_t scoped_display_id_for_new_windows_ = display::kInvalidDisplayId;

  DISALLOW_COPY_AND_ASSIGN(Screen);
};

Screen* CreateNativeScreen();

}  // namespace display

#endif  // UI_DISPLAY_SCREEN_H_