// 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_BASE_IME_CHROMEOS_INPUT_METHOD_MANAGER_H_
#define UI_BASE_IME_CHROMEOS_INPUT_METHOD_MANAGER_H_

#include <stddef.h>

#include <map>
#include <string>
#include <vector>

#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "ui/base/ime/chromeos/input_method_descriptor.h"
#include "ui/base/ime/ui_base_ime_export.h"

class Profile;

namespace ui {
class Accelerator;
class IMEEngineHandlerInterface;
}  // namespace ui

namespace user_manager {
class User;
}  // namespace user_manager

namespace chromeos {
class ComponentExtensionIMEManager;
namespace input_method {
class InputMethodUtil;
class ImeKeyboard;

// This class manages input methodshandles.  Classes can add themselves as
// observers. Clients can get an instance of this library class by:
// InputMethodManager::Get().
class UI_BASE_IME_EXPORT InputMethodManager {
 public:
  enum UISessionState {
    STATE_LOGIN_SCREEN = 0,
    STATE_BROWSER_SCREEN,
    STATE_LOCK_SCREEN,
    STATE_SECONDARY_LOGIN_SCREEN,
    STATE_TERMINATING,
  };

  enum MenuItemStyle {
    MENU_ITEM_STYLE_NONE,
    MENU_ITEM_STYLE_CHECK,
    MENU_ITEM_STYLE_RADIO,
    MENU_ITEM_STYLE_SEPARATOR,
  };

  struct MenuItem {
    MenuItem();
    virtual ~MenuItem();

    std::string id;
    std::string label;
    MenuItemStyle style;
    bool visible;
    bool enabled;
    bool checked;

    unsigned int modified;
    std::vector<MenuItem> children;
  };

  class Observer {
   public:
    virtual ~Observer() {}
    // Called when the current input method is changed.  |show_message|
    // indicates whether the user should be notified of this change.
    virtual void InputMethodChanged(InputMethodManager* manager,
                                    Profile* profile,
                                    bool show_message) = 0;
  };

  // CandidateWindowObserver is notified of events related to the candidate
  // window.  The "suggestion window" used by IMEs such as ibus-mozc does not
  // count as the candidate window (this may change if we later want suggestion
  // window events as well).  These events also won't occur when the virtual
  // keyboard is used, since it controls its own candidate window.
  class CandidateWindowObserver {
   public:
    virtual ~CandidateWindowObserver() {}
    // Called when the candidate window is opened.
    virtual void CandidateWindowOpened(InputMethodManager* manager) = 0;
    // Called when the candidate window is closed.
    virtual void CandidateWindowClosed(InputMethodManager* manager) = 0;
  };

  // ImeMenuObserver is notified of events related to the IME menu on the shelf
  // bar.
  class ImeMenuObserver {
   public:
    virtual ~ImeMenuObserver() {}

    // Called when the IME menu is activated or deactivated.
    virtual void ImeMenuActivationChanged(bool is_active) = 0;
    // Called when the current input method or the list of active input method
    // IDs is changed.
    virtual void ImeMenuListChanged() = 0;
    // Called when the input.ime.setMenuItems or input.ime.updateMenuItems API
    // is called.
    virtual void ImeMenuItemsChanged(const std::string& engine_id,
                                     const std::vector<MenuItem>& items) = 0;

    DISALLOW_ASSIGN(ImeMenuObserver);
  };

  class State : public base::RefCounted<InputMethodManager::State> {
   public:
    // Returns a copy of state.
    virtual scoped_refptr<State> Clone() const = 0;

    // Adds an input method extension. This function does not takes ownership of
    // |instance|.
    virtual void AddInputMethodExtension(
        const std::string& extension_id,
        const InputMethodDescriptors& descriptors,
        ui::IMEEngineHandlerInterface* instance) = 0;

    // Removes an input method extension.
    virtual void RemoveInputMethodExtension(
        const std::string& extension_id) = 0;

    // Changes the current input method to |input_method_id|. If
    // |input_method_id|
    // is not active, switch to the first one in the active input method list.
    virtual void ChangeInputMethod(const std::string& input_method_id,
                                   bool show_message) = 0;

    // Adds one entry to the list of active input method IDs, and then starts or
    // stops the system input method framework as needed.
    virtual bool EnableInputMethod(
        const std::string& new_active_input_method_id) = 0;

    // Enables "login" keyboard layouts (e.g. US Qwerty, US Dvorak, French
    // Azerty) that are necessary for the |language_code| and then switches to
    // |initial_layouts| if the given list is not empty. For example, if
    // |language_code| is "en-US", US Qwerty, US International, US Extended, US
    // Dvorak, and US Colemak layouts would be enabled. Likewise, for Germany
    // locale, US Qwerty which corresponds to the hardware keyboard layout and
    // several keyboard layouts for Germany would be enabled.
    // Only layouts suitable for login screen are enabled.
    virtual void EnableLoginLayouts(
        const std::string& language_code,
        const std::vector<std::string>& initial_layouts) = 0;

    // Filters current state layouts and leaves only suitable for lock screen.
    virtual void EnableLockScreenLayouts() = 0;

    // Returns a list of descriptors for all Input Method Extensions.
    virtual void GetInputMethodExtensions(InputMethodDescriptors* result) = 0;

    // Returns the list of input methods we can select (i.e. active) including
    // extension input methods.
    virtual scoped_ptr<InputMethodDescriptors> GetActiveInputMethods()
        const = 0;

    // Returns the list of input methods we can select (i.e. active) including
    // extension input methods.
    // The same as GetActiveInputMethods but returns reference to internal list.
    virtual const std::vector<std::string>& GetActiveInputMethodIds() const = 0;

    // Returns the number of active input methods including extension input
    // methods.
    virtual size_t GetNumActiveInputMethods() const = 0;

    // Returns the input method descriptor from the given input method id
    // string.
    // If the given input method id is invalid, returns NULL.
    virtual const InputMethodDescriptor* GetInputMethodFromId(
        const std::string& input_method_id) const = 0;

    // Sets the list of extension IME ids which should be enabled.
    virtual void SetEnabledExtensionImes(std::vector<std::string>* ids) = 0;

    // Sets current input method to login default (first owners, then hardware).
    virtual void SetInputMethodLoginDefault() = 0;

    // Sets current input method to login default with the given locale and
    // layout info from VPD.
    virtual void SetInputMethodLoginDefaultFromVPD(
        const std::string& locale,
        const std::string& layout) = 0;

    // Returns whether the input method (or keyboard layout) can be switched
    // to the next or previous one. Returns false if only one input method is
    // enabled.
    virtual bool CanCycleInputMethod() = 0;

    // Switches the current input method (or keyboard layout) to the next one.
    virtual void SwitchToNextInputMethod() = 0;

    // Switches the current input method (or keyboard layout) to the previous
    // one.
    virtual void SwitchToPreviousInputMethod() = 0;

    // Returns true if the input method can be switched to the input method
    // associated with |accelerator|.
    virtual bool CanSwitchInputMethod(const ui::Accelerator& accelerator) = 0;

    // Switches to an input method (or keyboard layout) which is associated with
    // the |accelerator|.
    virtual void SwitchInputMethod(const ui::Accelerator& accelerator) = 0;

    // Gets the descriptor of the input method which is currently selected.
    virtual InputMethodDescriptor GetCurrentInputMethod() const = 0;

    // Updates the list of active input method IDs, and then starts or stops the
    // system input method framework as needed.
    virtual bool ReplaceEnabledInputMethods(
        const std::vector<std::string>& new_active_input_method_ids) = 0;

   protected:
    friend base::RefCounted<InputMethodManager::State>;

    virtual ~State();
  };

  virtual ~InputMethodManager() {}

  // Gets the global instance of InputMethodManager. Initialize() must be called
  // first.
  static UI_BASE_IME_EXPORT InputMethodManager* Get();

  // Sets the global instance. |instance| will be owned by the internal pointer
  // and deleted by Shutdown().
  // TODO(nona): Instanciate InputMethodManagerImpl inside of this function once
  //             crbug.com/164375 is fixed.
  static UI_BASE_IME_EXPORT void Initialize(InputMethodManager* instance);

  // Destroy the global instance.
  static UI_BASE_IME_EXPORT void Shutdown();

  // Get the current UI session state (e.g. login screen, lock screen, etc.).
  virtual UISessionState GetUISessionState() = 0;

  // Adds an observer to receive notifications of input method related
  // changes as desribed in the Observer class above.
  virtual void AddObserver(Observer* observer) = 0;
  virtual void AddCandidateWindowObserver(
      CandidateWindowObserver* observer) = 0;
  virtual void AddImeMenuObserver(ImeMenuObserver* observer) = 0;
  virtual void RemoveObserver(Observer* observer) = 0;
  virtual void RemoveCandidateWindowObserver(
      CandidateWindowObserver* observer) = 0;
  virtual void RemoveImeMenuObserver(ImeMenuObserver* observer) = 0;

  // Returns all input methods that are supported, including ones not active.
  // This function never returns NULL. Note that input method extensions are NOT
  // included in the result.
  virtual scoped_ptr<InputMethodDescriptors>
      GetSupportedInputMethods() const = 0;

  // Activates the input method property specified by the |key|.
  virtual void ActivateInputMethodMenuItem(const std::string& key) = 0;

  virtual bool IsISOLevel5ShiftUsedByCurrentInputMethod() const = 0;

  virtual bool IsAltGrUsedByCurrentInputMethod() const = 0;

  // Returns an X keyboard object which could be used to change the current XKB
  // layout, change the caps lock status, and set the auto repeat rate/interval.
  virtual ImeKeyboard* GetImeKeyboard() = 0;

  // Returns an InputMethodUtil object.
  virtual InputMethodUtil* GetInputMethodUtil() = 0;

  // Returns a ComponentExtentionIMEManager object.
  virtual ComponentExtensionIMEManager* GetComponentExtensionIMEManager() = 0;

  // If keyboard layout can be uset at login screen
  virtual bool IsLoginKeyboard(const std::string& layout) const = 0;

  // Migrates the input method id to extension-based input method id.
  virtual bool MigrateInputMethods(
      std::vector<std::string>* input_method_ids) = 0;

  // Returns new empty state for the |profile|.
  virtual scoped_refptr<State> CreateNewState(Profile* profile) = 0;

  // Returns active state.
  virtual scoped_refptr<InputMethodManager::State> GetActiveIMEState() = 0;

  // Replaces active state.
  virtual void SetState(scoped_refptr<State> state) = 0;

  // Activates or deactivates the IME Menu.
  virtual void ImeMenuActivationChanged(bool is_active) = 0;

  // Notifies the input.ime.setMenuItems or input.ime.updateMenuItems API is
  // called to update the IME menu items.
  virtual void NotifyImeMenuItemsChanged(
      const std::string& engine_id,
      const std::vector<MenuItem>& items) = 0;
};

}  // namespace input_method
}  // namespace chromeos

#endif  // UI_BASE_IME_CHROMEOS_INPUT_METHOD_MANAGER_H_