// Copyright 2012 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_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_
#define UI_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_

#include "ui/base/mojom/window_show_state.mojom-forward.h"
#include "ui/events/event_constants.h"
#include "ui/gfx/native_ui_types.h"
#include "ui/views/views_export.h"

class SkPath;

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

namespace ui {
class GestureEvent;
class KeyEvent;
class Layer;
class MouseEvent;
class PaintContext;
class ScrollEvent;
}  // namespace ui

namespace views {
class Widget;

namespace internal {

////////////////////////////////////////////////////////////////////////////////
// NativeWidgetDelegate
//
//  An interface implemented by the object that handles events sent by a
//  NativeWidget implementation.
//
class VIEWS_EXPORT NativeWidgetDelegate {
 public:
  virtual ~NativeWidgetDelegate() = default;

  // Returns true if the window is modal.
  virtual bool IsModal() const = 0;

  // Returns true if the window is a dialog box.
  virtual bool IsDialogBox() const = 0;

  // Returns true if the window can be activated.
  virtual bool CanActivate() const = 0;

  // Returns true if the native widget has been initialized.
  virtual bool IsNativeWidgetInitialized() const = 0;

  // Called when the activation state of a window has changed.
  // Returns true if this event was handled.
  virtual bool OnNativeWidgetActivationChanged(bool active) = 0;

  // Returns true if the window's activation change event should be handled.
  virtual bool ShouldHandleNativeWidgetActivationChanged(bool active) = 0;

  // Called when native focus moves from one native view to another.
  virtual void OnNativeFocus() = 0;
  virtual void OnNativeBlur() = 0;

  // Called when the window is shown/hidden. A visible widget might be
  // physically invisible on screen, for example, if it is shown on an hidden
  // virtual desktop.
  virtual void OnNativeWidgetVisibilityChanged(bool visible) = 0;

  // Called when the window's visibility on screen changes.
  virtual void OnNativeWidgetVisibilityOnScreenChanged(bool visible) = 0;

  // Called when the native widget is created.
  virtual void OnNativeWidgetCreated() = 0;

  // Called just before the native widget is destroyed. This is the delegate's
  // last chance to do anything with the native widget handle.
  virtual void OnNativeWidgetDestroying() = 0;

  // Called just after the native widget is destroyed.
  virtual void OnNativeWidgetDestroyed() = 0;

  // Called after the native widget's parent has changed.
  virtual void OnNativeWidgetParentChanged(gfx::NativeView parent) = 0;

  // Returns the smallest size the window can be resized to by the user.
  virtual gfx::Size GetMinimumSize() const = 0;

  // Returns the largest size the window can be resized to by the user.
  virtual gfx::Size GetMaximumSize() const = 0;

  // Called when the NativeWidget changed position.
  virtual void OnNativeWidgetMove() = 0;

  // Called when the NativeWidget changed size to |new_size|.
  // This may happen at the same time as OnNativeWidgetWindowShowStateChanged,
  // e.g. maximize.
  virtual void OnNativeWidgetSizeChanged(const gfx::Size& new_size) = 0;

  // Called when the user begins/ends to resizing the window.
  virtual void OnNativeWidgetUserResizeStarted() = 0;
  virtual void OnNativeWidgetUserResizeEnded() = 0;

  // Called when NativeWidget changed workspaces or its visible on all
  // workspaces state changes.
  virtual void OnNativeWidgetWorkspaceChanged() = 0;

  // Called when the NativeWidget changes its window state.
  // This may happen at the same time as OnNativeWidgetSizeChanged, e.g.
  // maximize.
  virtual void OnNativeWidgetWindowShowStateChanged() = 0;

  // Called when the user begins/ends to change the bounds of the window.
  virtual void OnNativeWidgetBeginUserBoundsChange() = 0;
  virtual void OnNativeWidgetEndUserBoundsChange() = 0;

  // Called when the NativeWidget is added and/or being removed from a
  // Compositor. On some platforms the Compositor never changes, and these
  // functions are never called.
  virtual void OnNativeWidgetAddedToCompositor() = 0;
  virtual void OnNativeWidgetRemovingFromCompositor() = 0;

  // Returns true if the delegate has a FocusManager.
  virtual bool HasFocusManager() const = 0;

  // Paints the rootview in the context. This will also refresh the compositor
  // tree if necessary.
  virtual void OnNativeWidgetPaint(const ui::PaintContext& context) = 0;

  // Returns the non-client component (see ui/base/hit_test.h) containing
  // |point|, in client coordinates.
  virtual int GetNonClientComponent(const gfx::Point& point) = 0;

  // Event handlers.
  virtual void OnKeyEvent(ui::KeyEvent* event) = 0;
  virtual void OnMouseEvent(ui::MouseEvent* event) = 0;
  virtual void OnMouseCaptureLost() = 0;
  virtual void OnScrollEvent(ui::ScrollEvent* event) = 0;
  virtual void OnGestureEvent(ui::GestureEvent* event) = 0;

  // Runs the specified native command. Returns true if the command is handled.
  virtual bool ExecuteCommand(int command_id) = 0;

  // Returns true if window has a hit-test mask.
  virtual bool HasHitTestMask() const = 0;

  // Provides the hit-test mask if HasHitTestMask above returns true.
  virtual void GetHitTestMask(SkPath* mask) const = 0;

  virtual Widget* AsWidget() = 0;
  virtual const Widget* AsWidget() const = 0;

  // Sets-up the focus manager with the view that should have focus when the
  // window is shown the first time.  It takes the intended |show_state| of the
  // window in order to decide whether the window should be focused now or
  // later.  Returns true if the initial focus has been set or the window should
  // not set the initial focus, or false if the caller should set the initial
  // focus (if any).
  virtual bool SetInitialFocus(ui::mojom::WindowShowState show_state) = 0;

  // Returns true if event handling should descend into |child|. |root_layer| is
  // the layer associated with the root Window and |child_layer| the layer
  // associated with |child|. |location| is in terms of the Window.
  virtual bool ShouldDescendIntoChildForEventHandling(
      ui::Layer* root_layer,
      gfx::NativeView child,
      ui::Layer* child_layer,
      const gfx::Point& location) = 0;

  // Called to process a previous call to ScheduleLayout().
  virtual void LayoutRootViewIfNecessary() = 0;
};

}  // namespace internal
}  // namespace views

#endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_