// 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_H_
#define UI_KEYBOARD_KEYBOARD_CONTROLLER_H_

#include <memory>

#include "base/macros.h"
#include "base/observer_list.h"
#include "ui/aura/window_observer.h"
#include "ui/base/ime/input_method_observer.h"
#include "ui/base/ime/text_input_type.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/keyboard/keyboard_event_filter.h"
#include "ui/keyboard/keyboard_export.h"
#include "ui/keyboard/keyboard_layout_delegate.h"

namespace aura {
class Window;
}
namespace ui {
class InputMethod;
class TextInputClient;
}

namespace keyboard {

class CallbackAnimationObserver;
class KeyboardControllerObserver;
class KeyboardUI;

// Relative distance from the parent window, from which show animation starts
// or hide animation finishes.
constexpr int kAnimationDistance = 30;

// Represents the current state of the keyboard managed by the controller.
// Don't change the numeric value of the members because they are used in UMA
// - VirtualKeyboard.ControllerStateTransition.
// - VirtualKeyboard.LingeringIntermediateState
enum class KeyboardControllerState {
  UNKNOWN = 0,
  // Keyboard has never been shown.
  INITIAL = 1,
  // Waiting for an extension to be loaded. Will move to HIDDEN if this is
  // loading pre-emptively, otherwise will move to SHOWING.
  LOADING_EXTENSION = 2,
  // Keyboard is being shown via animation.
  SHOWING = 3,
  // Keyboard is shown.
  SHOWN = 4,
  // Keyboard is still shown, but will move to HIDING in a short period, or if
  // an input element gets focused again, will move to SHOWN.
  WILL_HIDE = 5,
  // Keyboard is being hidden via animation.
  HIDING = 6,
  // Keyboard is hidden, but has shown at least once.
  HIDDEN = 7,
  COUNT,
};

// Provides control of the virtual keyboard, including providing a container
// and controlling visibility.
class KEYBOARD_EXPORT KeyboardController : public ui::InputMethodObserver,
                                           public aura::WindowObserver {
 public:
  // Different ways to hide the keyboard.
  enum HideReason {
    // System initiated.
    HIDE_REASON_AUTOMATIC,
    // User initiated.
    HIDE_REASON_MANUAL,
  };

  KeyboardController(std::unique_ptr<KeyboardUI> ui,
                     KeyboardLayoutDelegate* delegate);
  ~KeyboardController() override;

  // Returns the container for the keyboard, which is owned by
  // KeyboardController. Creates the container if it's not already created.
  aura::Window* GetContainerWindow();

  // Same as GetContainerWindow except that this function doesn't create the
  // window.
  aura::Window* GetContainerWindowWithoutCreationForTest();

  // Whether the container window for the keyboard has been initialized.
  bool keyboard_container_initialized() const { return container_ != nullptr; }

  // Reloads the content of the keyboard. No-op if the keyboard content is not
  // loaded yet.
  void Reload();

  // Notifies the observer for contents bounds changed.
  void NotifyContentsBoundsChanging(const gfx::Rect& new_bounds);

  // Management of the observer list.
  void AddObserver(KeyboardControllerObserver* observer);
  bool HasObserver(KeyboardControllerObserver* observer) const;
  void RemoveObserver(KeyboardControllerObserver* observer);

  KeyboardUI* ui() { return ui_.get(); }

  void set_keyboard_locked(bool lock) { keyboard_locked_ = lock; }

  bool keyboard_locked() const { return keyboard_locked_; }

  // Immediately starts hiding animation of virtual keyboard and notifies
  // observers bounds change. This method forcibly sets keyboard_locked_
  // false while closing the keyboard.
  void HideKeyboard(HideReason reason);

  // Force the keyboard to show up if not showing and lock the keyboard if
  // |lock| is true.
  void ShowKeyboard(bool lock);

  // Loads the keyboard UI contents in the background, but does not display
  // the keyboard.
  void LoadKeyboardUiInBackground();

  // Force the keyboard to show up in the specific display if not showing and
  // lock the keyboard
  void ShowKeyboardInDisplay(const int64_t display_id);

  // Sets the active keyboard controller. KeyboardController takes ownership of
  // the instance. Calling ResetIntance with a new instance destroys the
  // previous one. May be called with NULL to clear the instance.
  static void ResetInstance(KeyboardController* controller);

  // Retrieve the active keyboard controller.
  static KeyboardController* GetInstance();

  // Returns true if keyboard is in SHOWN or SHOWING state.
  bool keyboard_visible() const;

  // Returns true if keyboard window has been created.
  bool IsKeyboardWindowCreated();

  // Returns the current keyboard bounds. An empty rectangle will get returned
  // when the keyboard is not shown or in FLOATING mode.
  const gfx::Rect& current_keyboard_bounds() const {
    return current_keyboard_bounds_;
  }

  KeyboardControllerState GetStateForTest() const { return state_; }

 private:
  // For access to Observer methods for simulation.
  friend class KeyboardControllerTest;

  // For access to SetContainerBounds.
  friend class KeyboardLayoutManager;

  bool show_on_resize() const { return show_on_resize_; }

  // aura::WindowObserver overrides
  void OnWindowHierarchyChanged(const HierarchyChangeParams& params) override;
  void OnWindowAddedToRootWindow(aura::Window* window) override;
  void OnWindowRemovingFromRootWindow(aura::Window* window,
                                      aura::Window* new_root) override;
  void OnWindowBoundsChanged(aura::Window* window,
                             const gfx::Rect& old_bounds,
                             const gfx::Rect& new_bounds) override;

  // InputMethodObserver overrides
  void OnBlur() override {}
  void OnCaretBoundsChanged(const ui::TextInputClient* client) override {}
  void OnFocus() override {}
  void OnInputMethodDestroyed(const ui::InputMethod* input_method) override {}
  void OnTextInputStateChanged(const ui::TextInputClient* client) override;
  void OnShowImeIfNeeded() override;

  // Sets the bounds of the container window. Shows the keyboard if contents
  // is first loaded and show_on_resize() is true. Called by
  // KayboardLayoutManager.
  void SetContainerBounds(const gfx::Rect& new_bounds,
                          const bool contents_loaded);

  // Show virtual keyboard immediately with animation.
  void ShowKeyboardInternal(int64_t display_id);
  void PopulateKeyboardContent(int64_t display_id, bool show_keyboard);

  // Returns true if keyboard is scheduled to hide.
  bool WillHideKeyboard() const;

  // Called when show and hide animation finished successfully. If the animation
  // is aborted, it won't be called.
  void ShowAnimationFinished();
  void HideAnimationFinished();

  void NotifyKeyboardBoundsChangingAndEnsrueCaretInWorkArea();

  // Called when the keyboard mode is set or the keyboard is moved to another
  // display.
  void AdjustKeyboardBounds();

  // Validates the state transition. Called from ChangeState.
  void CheckStateTransition(KeyboardControllerState prev,
                            KeyboardControllerState next);

  // Changes the current state with validating the transition.
  void ChangeState(KeyboardControllerState state);

  // Reports error histogram in case lingering in an intermediate state.
  void ReportLingeringState();

  std::unique_ptr<KeyboardUI> ui_;
  KeyboardLayoutDelegate* layout_delegate_;
  std::unique_ptr<aura::Window> container_;
  // CallbackAnimationObserver should destructed before container_ because it
  // uses container_'s animator.
  std::unique_ptr<CallbackAnimationObserver> animation_observer_;

  bool show_on_resize_;
  // If true, the keyboard is always visible even if no window has input focus.
  bool keyboard_locked_;
  KeyboardEventFilter event_filter_;

  base::ObserverList<KeyboardControllerObserver> observer_list_;

  // The currently used keyboard position.
  // If the contents window is visible, this should be the same size as the
  // contents window. If not, this should be empty.
  gfx::Rect current_keyboard_bounds_;

  KeyboardControllerState state_;

  static KeyboardController* instance_;

  base::WeakPtrFactory<KeyboardController> weak_factory_report_lingering_state_;
  base::WeakPtrFactory<KeyboardController> weak_factory_will_hide_;

  DISALLOW_COPY_AND_ASSIGN(KeyboardController);
};

}  // namespace keyboard

#endif  // UI_KEYBOARD_KEYBOARD_CONTROLLER_H_