// Copyright (c) 2013 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_KEYBOARD_KEYBOARD_CONTROLLER_OBSERVER_H_
#define UI_KEYBOARD_KEYBOARD_CONTROLLER_OBSERVER_H_

#include "ui/keyboard/keyboard_controller.h"
#include "ui/keyboard/keyboard_export.h"

namespace gfx {
class Rect;
}

namespace keyboard {

// Describes the various attributes of the keyboard's appearance and usability.
struct KeyboardStateDescriptor {
  bool is_visible;

  // The bounds of the keyboard window on the screen.
  gfx::Rect visual_bounds;

  // The bounds of the area on the screen that is considered "blocked" by the
  // keyboard. For example, the docked keyboard's occluded bounds is the same as
  // the visual bounds, but the floating keyboard has no occluded bounds (as the
  // window is small and moveable).
  gfx::Rect occluded_bounds;

  // The bounds of the area on the screen that is considered "unusable" because
  // it is blocked by the keyboard. This is used by the accessibility keyboard.
  gfx::Rect displaced_bounds;
};

// Observers to the KeyboardController are notified of significant events that
// occur with the keyboard, such as the bounds or visibility changing.
class KEYBOARD_EXPORT KeyboardControllerObserver {
 public:
  virtual ~KeyboardControllerObserver() {}

  // Called when the keyboard is shown or hidden (e.g. when user focuses and
  // unfocuses on a textfield).
  virtual void OnKeyboardVisibilityStateChanged(bool is_visible) {}

  // Called when the keyboard bounds are changing.
  virtual void OnKeyboardVisibleBoundsChanged(const gfx::Rect& new_bounds) {}

  // Called when the keyboard bounds have changed in a way that should affect
  // the usable region of the workspace. The user interface should respond to
  // this event by moving important elements away from |new_bounds| so that they
  // don't overlap. However, drastic visual changes should be avoided, as the
  // occluded bounds may change frequently.
  virtual void OnKeyboardWorkspaceOccludedBoundsChanged(
      const gfx::Rect& new_bounds) {}

  // Called when the keyboard bounds have changed in a way that affects how the
  // workspace should change to not take up the screen space occupied by the
  // keyboard. The user interface should respond to this event by moving all
  // elements away from |new_bounds| so that they don't overlap. Large visual
  // changes are okay, as the displacing bounds do not change frequently.
  virtual void OnKeyboardWorkspaceDisplacingBoundsChanged(
      const gfx::Rect& new_bounds) {}

  // Redundant with other various notification methods. Use this if the state of
  // multiple properties need to be conveyed simultaneously to observer
  // implementations without the need to track multiple stateful properties.
  virtual void OnKeyboardAppearanceChanged(
      const KeyboardStateDescriptor& state) {}

  // Called when an enable flag affecting the requested enabled state changes.
  virtual void OnKeyboardEnableFlagsChanged(
      std::set<mojom::KeyboardEnableFlag>& keyboard_enable_flags) {}

  // Called when the keyboard is enabled or disabled. NOTE: This is called
  // when Enabled() or Disabled() is called, not when the requested enabled
  // state (IsEnableRequested) changes.
  virtual void OnKeyboardEnabledChanged(bool is_enabled) {}

  // Called when the keyboard has been hidden and the hiding animation finished
  // successfully.
  // When |is_temporary_hide| is true, this hide is immediately followed by a
  // show (e.g. when changing to floating keyboard)
  virtual void OnKeyboardHidden(bool is_temporary_hide) {}

  // Called when the virtual keyboard IME config changed.
  virtual void OnKeyboardConfigChanged() {}
};

}  // namespace keyboard

#endif  // UI_KEYBOARD_KEYBOARD_CONTROLLER_OBSERVER_H_