// Copyright 2014 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_IME_BRIDGE_H_
#define UI_BASE_IME_CHROMEOS_IME_BRIDGE_H_

#include <string>
#include "base/basictypes.h"
#include "base/callback.h"
#include "base/strings/string16.h"
#include "ui/base/ime/text_input_mode.h"
#include "ui/base/ime/text_input_type.h"
#include "ui/base/ui_base_export.h"

namespace gfx {
class Rect;
}  // namespace gfx

namespace ui {
class CandidateWindow;
class KeyEvent;
}  // namespace ui

namespace chromeos {

class CompositionText;

class UI_BASE_EXPORT IMEInputContextHandlerInterface {
 public:
  // Called when the engine commit a text.
  virtual void CommitText(const std::string& text) = 0;

  // Called when the engine updates composition text.
  virtual void UpdateCompositionText(const CompositionText& text,
                                     uint32 cursor_pos,
                                     bool visible) = 0;

  // Called when the engine request deleting surrounding string.
  virtual void DeleteSurroundingText(int32 offset, uint32 length) = 0;
};


// A interface to handle the engine handler method call.
class UI_BASE_EXPORT IMEEngineHandlerInterface {
 public:
  typedef base::Callback<void (bool consumed)> KeyEventDoneCallback;

  // A information about a focused text input field.
  // A type of each member is based on the html spec, but InputContext can be
  // used to specify about a non html text field like Omnibox.
  struct InputContext {
    InputContext(ui::TextInputType type_, ui::TextInputMode mode_) :
      type(type_), mode(mode_) {}

    // An attribute of the field defined at
    // http://www.w3.org/TR/html401/interact/forms.html#input-control-types.
    ui::TextInputType type;
    // An attribute of the field defined at
    // http://www.whatwg.org/specs/web-apps/current-work/multipage/
    //  association-of-controls-and-forms.html#input-modalities
    //  :-the-inputmode-attribute.
    ui::TextInputMode mode;
  };

  virtual ~IMEEngineHandlerInterface() {}

  // Called when the Chrome input field get the focus.
  virtual void FocusIn(const InputContext& input_context) = 0;

  // Called when the Chrome input field lose the focus.
  virtual void FocusOut() = 0;

  // Called when the IME is enabled.
  virtual void Enable() = 0;

  // Called when the IME is disabled.
  virtual void Disable() = 0;

  // Called when a property is activated or changed.
  virtual void PropertyActivate(const std::string& property_name) = 0;

  // Called when the IME is reset.
  virtual void Reset() = 0;

  // Called when the key event is received.
  // Actual implementation must call |callback| after key event handling.
  virtual void ProcessKeyEvent(const ui::KeyEvent& key_event,
                               const KeyEventDoneCallback& callback) = 0;

  // Called when the candidate in lookup table is clicked. The |index| is 0
  // based candidate index in lookup table.
  virtual void CandidateClicked(uint32 index) = 0;

  // Called when a new surrounding text is set. The |text| is surrounding text
  // and |cursor_pos| is 0 based index of cursor position in |text|. If there is
  // selection range, |anchor_pos| represents opposite index from |cursor_pos|.
  // Otherwise |anchor_pos| is equal to |cursor_pos|.
  virtual void SetSurroundingText(const std::string& text, uint32 cursor_pos,
                                  uint32 anchor_pos) = 0;

 protected:
  IMEEngineHandlerInterface() {}
};

// A interface to handle the candidate window related method call.
class UI_BASE_EXPORT IMECandidateWindowHandlerInterface {
 public:
  virtual ~IMECandidateWindowHandlerInterface() {}

  // Called when the IME updates the lookup table.
  virtual void UpdateLookupTable(const ui::CandidateWindow& candidate_window,
                                 bool visible) = 0;

  // Called when the IME updates the preedit text. The |text| is given in
  // UTF-16 encoding.
  virtual void UpdatePreeditText(const base::string16& text,
                                 uint32 cursor_pos,
                                 bool visible) = 0;

  // Called when the application changes its caret bounds.
  virtual void SetCursorBounds(const gfx::Rect& cursor_bounds,
                               const gfx::Rect& composition_head) = 0;

  // Called when the text field's focus state is changed.
  // |is_focused| is true when the text field gains the focus.
  virtual void FocusStateChanged(bool is_focused) {}

 protected:
  IMECandidateWindowHandlerInterface() {}
};


// IMEBridge provides access of each IME related handler. This class
// is used for IME implementation.
class UI_BASE_EXPORT IMEBridge {
 public:
  virtual ~IMEBridge();

  // Allocates the global instance. Must be called before any calls to Get().
  static void Initialize();

  // Releases the global instance.
  static void Shutdown();

  // Returns IMEBridge global instance. Initialize() must be called first.
  static IMEBridge* Get();

  // Returns current InputContextHandler. This function returns NULL if input
  // context is not ready to use.
  virtual IMEInputContextHandlerInterface* GetInputContextHandler() const = 0;

  // Updates current InputContextHandler. If there is no active input context,
  // pass NULL for |handler|. Caller must release |handler|.
  virtual void SetInputContextHandler(
      IMEInputContextHandlerInterface* handler) = 0;

  // Updates current EngineHandler. If there is no active engine service, pass
  // NULL for |handler|. Caller must release |handler|.
  virtual void SetCurrentEngineHandler(IMEEngineHandlerInterface* handler) = 0;

  // Returns current EngineHandler. This function returns NULL if current engine
  // is not ready to use.
  virtual IMEEngineHandlerInterface* GetCurrentEngineHandler() const = 0;

  // Returns current CandidateWindowHandler. This function returns NULL if
  // current candidate window is not ready to use.
  virtual IMECandidateWindowHandlerInterface* GetCandidateWindowHandler()
      const = 0;

  // Updates current CandidatWindowHandler. If there is no active candidate
  // window service, pass NULL for |handler|. Caller must release |handler|.
  virtual void SetCandidateWindowHandler(
      IMECandidateWindowHandlerInterface* handler) = 0;

  // Updates current text input type.
  virtual void SetCurrentTextInputType(ui::TextInputType input_type) = 0;

  // Returns the current text input type.
  virtual ui::TextInputType GetCurrentTextInputType() const = 0;

 protected:
  IMEBridge();

 private:
  DISALLOW_COPY_AND_ASSIGN(IMEBridge);
};

}  // namespace chromeos

#endif  // UI_BASE_IME_CHROMEOS_IME_BRIDGE_H_