// 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_AURA_WINDOW_TREE_HOST_H_
#define UI_AURA_WINDOW_TREE_HOST_H_

#include <vector>

#include "base/event_types.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "ui/aura/aura_export.h"
#include "ui/base/cursor/cursor.h"
#include "ui/base/ime/input_method_delegate.h"
#include "ui/events/event_source.h"
#include "ui/gfx/geometry/insets.h"
#include "ui/gfx/native_widget_types.h"

namespace gfx {
class Insets;
class Point;
class Rect;
class Size;
class Transform;
}

namespace ui {
class Compositor;
class EventProcessor;
class InputMethod;
class ViewProp;
}

namespace aura {
namespace test {
class WindowTreeHostTestApi;
}

class WindowEventDispatcher;
class WindowTreeHostObserver;

// WindowTreeHost bridges between a native window and the embedded RootWindow.
// It provides the accelerated widget and maps events from the native os to
// aura.
class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
                                   public ui::EventSource {
 public:
  ~WindowTreeHost() override;

  // Creates a new WindowTreeHost. The caller owns the returned value.
  static WindowTreeHost* Create(const gfx::Rect& bounds);

  // Returns the WindowTreeHost for the specified accelerated widget, or NULL
  // if there is none associated.
  static WindowTreeHost* GetForAcceleratedWidget(gfx::AcceleratedWidget widget);

  void InitHost();

  void InitCompositor();

  void AddObserver(WindowTreeHostObserver* observer);
  void RemoveObserver(WindowTreeHostObserver* observer);

  Window* window() { return window_; }
  const Window* window() const { return window_; }

  ui::EventProcessor* event_processor();

  WindowEventDispatcher* dispatcher() {
    return const_cast<WindowEventDispatcher*>(
        const_cast<const WindowTreeHost*>(this)->dispatcher());
  }
  const WindowEventDispatcher* dispatcher() const { return dispatcher_.get(); }

  ui::Compositor* compositor() { return compositor_.get(); }

  // Gets/Sets the root window's transform.
  virtual gfx::Transform GetRootTransform() const;
  virtual void SetRootTransform(const gfx::Transform& transform);
  virtual gfx::Transform GetInverseRootTransform() const;

  // Sets padding applied to the output surface. The output surface is sized to
  // to the size of the host plus output surface padding. |window()| is offset
  // by |padding|, that is, |window|'s origin is set to padding.left(),
  // padding.top().
  // This does not impact the bounds as returned from GetBounds(), only the
  // output surface size and location of window(). Additionally window() is
  // sized to the size set by bounds (more specifically the size passed to
  // OnHostResized()), but the location of window() is set to that of
  // |padding|.
  void SetOutputSurfacePadding(const gfx::Insets& padding);

  // Updates the root window's size using |host_size|, current
  // transform and outsets.
  virtual void UpdateRootWindowSize(const gfx::Size& host_size);

  // Converts |point| from the root window's coordinate system to native
  // screen's.
  void ConvertPointToNativeScreen(gfx::Point* point) const;

  // Converts |point| from native screen coordinate system to the root window's.
  void ConvertPointFromNativeScreen(gfx::Point* point) const;

  // Converts |point| from the root window's coordinate system to the
  // host window's.
  void ConvertPointToHost(gfx::Point* point) const;

  // Converts |point| from the host window's coordinate system to the
  // root window's.
  void ConvertPointFromHost(gfx::Point* point) const;

  // Cursor.
  // Sets the currently-displayed cursor. If the cursor was previously hidden
  // via ShowCursor(false), it will remain hidden until ShowCursor(true) is
  // called, at which point the cursor that was last set via SetCursor() will be
  // used.
  void SetCursor(gfx::NativeCursor cursor);

  // Invoked when the cursor's visibility has changed.
  void OnCursorVisibilityChanged(bool visible);

  // Moves the cursor to the specified location relative to the root window.
  void MoveCursorTo(const gfx::Point& location);

  // Moves the cursor to the |host_location| given in host coordinates.
  void MoveCursorToHostLocation(const gfx::Point& host_location);

  gfx::NativeCursor last_cursor() const { return last_cursor_; }

  // Gets the InputMethod instance, if NULL, creates & owns it.
  ui::InputMethod* GetInputMethod();

  // Sets a shared unowned InputMethod. This is used when there is a singleton
  // InputMethod shared between multiple WindowTreeHost instances.
  //
  // This is used for Ash only. There are 2 reasons:
  // 1) ChromeOS virtual keyboard needs to receive ShowImeIfNeeded notification
  // from InputMethod. Multiple InputMethod instances makes it hard to
  // register/unregister the observer for that notification.
  // 2) For Ozone, there is no native focus state for the root window and
  // WindowTreeHost. See DrmWindowHost::CanDispatchEvent, the key events always
  // goes to the primary WindowTreeHost. And after InputMethod processed the key
  // event and continue dispatching it, WindowTargeter::FindTargetForEvent may
  // re-dispatch it to a different WindowTreeHost. So the singleton InputMethod
  // can make sure the correct InputMethod instance processes the key event no
  // matter which WindowTreeHost is the target for event. Please refer to the
  // test: ExtendedDesktopTest.KeyEventsOnLockScreen.
  //
  // TODO(shuchen): remove this method after above reasons become invalid.
  // A possible solution is to make sure DrmWindowHost can find the correct
  // WindowTreeHost to dispatch events.
  void SetSharedInputMethod(ui::InputMethod* input_method);

  // Overridden from ui::internal::InputMethodDelegate:
  ui::EventDispatchDetails DispatchKeyEventPostIME(
      ui::KeyEvent* event) override;

  // Returns the EventSource responsible for dispatching events to the window
  // tree.
  virtual ui::EventSource* GetEventSource() = 0;

  // Returns the accelerated widget.
  virtual gfx::AcceleratedWidget GetAcceleratedWidget() = 0;

  // Shows the WindowTreeHost.
  void Show();

  // Hides the WindowTreeHost.
  void Hide();

  // Gets/Sets the size of the WindowTreeHost (in pixels).
  virtual gfx::Rect GetBounds() const = 0;
  virtual void SetBounds(const gfx::Rect& bounds_in_pixels) = 0;

  // Sets the OS capture to the root window.
  virtual void SetCapture() = 0;

  // Releases OS capture of the root window.
  virtual void ReleaseCapture() = 0;

 protected:
  friend class TestScreen;  // TODO(beng): see if we can remove/consolidate.

  WindowTreeHost();
  void DestroyCompositor();
  void DestroyDispatcher();

  void CreateCompositor();
  void OnAcceleratedWidgetAvailable();

  // Returns the location of the RootWindow on native screen.
  virtual gfx::Point GetLocationOnNativeScreen() const = 0;

  void OnHostMoved(const gfx::Point& new_location);
  void OnHostResized(const gfx::Size& new_size);
  void OnHostWorkspaceChanged();
  void OnHostCloseRequested();
  void OnHostActivated();
  void OnHostLostWindowCapture();

  // Sets the currently displayed cursor.
  virtual void SetCursorNative(gfx::NativeCursor cursor) = 0;

  // Moves the cursor to the specified location relative to the root window.
  virtual void MoveCursorToNative(const gfx::Point& location) = 0;

  // kCalled when the cursor visibility has changed.
  virtual void OnCursorVisibilityChangedNative(bool show) = 0;

  // Shows the WindowTreeHost.
  virtual void ShowImpl() = 0;

  // Hides the WindowTreeHost.
  virtual void HideImpl() = 0;

  // Overridden from ui::EventSource:
  ui::EventProcessor* GetEventProcessor() override;

 private:
  friend class test::WindowTreeHostTestApi;

  // Moves the cursor to the specified location. This method is internally used
  // by MoveCursorTo() and MoveCursorToHostLocation().
  void MoveCursorToInternal(const gfx::Point& root_location,
                            const gfx::Point& host_location);

  // We don't use a std::unique_ptr for |window_| since we need this ptr to be
  // valid during its deletion. (Window's dtor notifies observers that may
  // attempt to reach back up to access this object which will be valid until
  // the end of the dtor).
  Window* window_;  // Owning.

  base::ObserverList<WindowTreeHostObserver> observers_;

  std::unique_ptr<WindowEventDispatcher> dispatcher_;

  std::unique_ptr<ui::Compositor> compositor_;

  // Last cursor set.  Used for testing.
  gfx::NativeCursor last_cursor_;
  gfx::Point last_cursor_request_position_in_host_;

  std::unique_ptr<ui::ViewProp> prop_;

  // The InputMethod instance used to process key events.
  // If owned it, it is created in GetInputMethod() method;
  // If not owned it, it is passed in through SetSharedInputMethod() method.
  ui::InputMethod* input_method_;

  // Whether the InputMethod instance is owned by this WindowTreeHost.
  bool owned_input_method_;

  gfx::Insets output_surface_padding_;

  DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
};

}  // namespace aura

#endif  // UI_AURA_WINDOW_TREE_HOST_H_