/****************************************************************************

**

** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (developer.feedback@nokia.com)

**

** This file is part of the HbCore module of the UI Extensions for Mobile.

**

** GNU Lesser General Public License Usage

** This file may be used under the terms of the GNU Lesser General Public

** License version 2.1 as published by the Free Software Foundation and

** appearing in the file LICENSE.LGPL included in the packaging of this file.

** Please review the following information to ensure the GNU Lesser General

** Public License version 2.1 requirements will be met:

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**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

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#include "hbinputmethod.h"

#include "hbinputmethod_p.h"

#include <QInputMethodEvent>

#include <QGraphicsView>

#include <QGraphicsProxyWidget>

#include <QLocale>

#include "hbinputmodecache_p.h"

#include "hbinputsettingproxy.h"

#include "hbinputcontextproxy_p.h"

#include "hbinputfilter.h"

#include "hbinputmethodnull_p.h"

#include "hbinputpredictionfactory.h"

#include "hbinputextradictionaryfactory.h"

#include "hbinputstandardfilters.h"

#include "hbinpututils.h"

#include "hbinputvkbhost.h"

#include "hbinputvkbhostbridge.h"

/*!

@alpha

@hbcore

\class HbInputMethod

\brief A base class for input method implementations.

HbInputMethod is the base class for input method implementations. It inherits from QInputContext,

connects to the input framework behind the scenes and resolves correct input state handler when

an editor widget is focused.

An internal framework class called HbInputModeCache scans through the system and looks for

available HbInputMethod instances. It then forms a list of input methods based on language

and keyboard type. Input method plugin reports (as plugin meta-data) which languages,

keyboards and input modes that plugin instance implements. Input mode cache then activates matching

HbInputMethod depending on the editor properties. It switches the active input method on the fly

when the focus switches between editors if the previous input method is unable to

support newly focused editor.

Custom input methods are a special class of input methods. Once a custom input method is

activated from UI, input mode cache stops resolving input methods upon focus operations

and the custom input is active in all editors until it is deactivated.

\bold The input framework program flow

1. An editor gains input focus.<BR>

2. Editor sets requestSoftwareInputPanel event to active input context.<BR>

3. The input framework creates input state based on editor attributes and the input mode cache <BR>

   resolves correct mode handler and activates it.<BR>

4. A virtual function HbInputMethod::focusReceived is called. At this point the input method<BR>

   initializes whatever it needs to initialize in order to start the input operation (for example,<BR>

   opens the virtual keyboard by using HbVkbHost API) and waits for user actions.<BR>

5. Text is written. The input method delivers results to the editor buffer by using HbInputFocusObject API.<BR>

   It can access editor attributes via HbEditorInterface API.<BR>

6. The active editor loses focus. At this point the input method receives a call to virtual function<BR>

   HbInputMethod::focusLost and is expected to conclude any ongoing input operations and shut down active<BR>

   UI elements (such as the virtual keyboard).<BR>

7. The input method waits for next focusReceived() call. <BR>

\bold Input method resolving

The input framework resolves correct input state handler based on three attributes: input mode,

keyboard type and input language.

The framework recognizes three different input modes: default, numeric and custom.

Default and numeric input modes are something that the framework resolves for active

input language and keyboard type. Custom input mode is something that the framework never

activates automatically, but it is activated from UI or directly from application

(or input method) code.

Numeric input mode is something that can handle those editors that are configured to only accept

numeric data (for example those that have Qt::ImhDigitsOnly hints on).

Language attribute is matched either as a direct match or as a language range. Language range

means the input method is capable of handling all the languages that

HbKeymapFactory::availableLanguages() returns. Direct match always wins so it is possible

to override language range for specific languages.

The keyboard attribute is always matched directly. Note that event though the constant

has term "keyboard" in it, it covers all input devices such as hand writing recognition widgets

that don't utilize traditional keys. it is up the the input method what that constant

really means.

The input method resolving parameters are part of input plugin meta data and they are returned

by QInputContextPlugin::languages() method. A single entry in the returned string list

is formed by packing resolving parameters into HbInputModeProperties structure and calling

HbInputModeProperties::asString() method.

Following code snippet shows how the input context plugin returns resolving parameters

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,1}

\bold Input method resolving example

Say that we have implemented touch input methods for 12 key portrait mode and qwerty landscape mode.

Then we have Chinese touch input method for both portrait and landscape orientations and also

Chinese handwriting recognition input mode for portrait mode.

Touch input methods resolve to language range, which means that they will handle all

the other languages, except Chinese, which has its own designated input method.

Touch input methods also implement support for numeric mode. Because Chinese language uses

same numeric system as "latin" based languages, we only want to implement numeric mode

handling in one input method and arrange resolving parameters so that the numeric mode

is handled by default touch input method even when the global input language is Chinese.

Chinese handwriting input method is something that is a custom mode, and will be activated

from UI.

Following example shows how the resolving attributes are set up to achieve above configuration.

Portait touch input method returns following attributes

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,2}

Landscape touch input method returns following attributes

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,3}

Chinese portrait input method returns following attributes

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,4}

Chinese landscape input method returns following attributes

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,5}

Chinese handwriting recognition input method returns following attributes

(note use of HbInputModeCustom, in this example HWR is something that we

want to active from UI separately).

\snippet{unittest_hbinputmethod/unittest_hbinputmethod.cpp,6}

\sa QInputContext

\sa HbInputFocusObject

\sa HbEditorInterface

\sa HbVkbHost

*/

/*!

Constructs the object

*/

HbInputMethod::HbInputMethod() : d_ptr(new HbInputMethodPrivate(this))

{

    HbInputSettingProxy::instance()->connectObservingObject(this);

}

/*!

Destructs the object

*/

HbInputMethod::~HbInputMethod()

{

    HbInputSettingProxy::instance()->disconnectObservingObject(this);

    delete d_ptr;

}

/*!

Initializes the input framework.

*/

bool HbInputMethod::initializeFramework(QApplication &app)

{

    // Activate singleton shutdown.

    connect(&app, SIGNAL(aboutToQuit()), HbInputModeCache::instance(), SLOT(shutdown()));

    connect(&app, SIGNAL(aboutToQuit()), HbInputSettingProxy::instance(), SLOT(shutdown()));

    connect(&app, SIGNAL(aboutToQuit()), HbPredictionFactory::instance(), SLOT(shutDown()));

    connect(&app, SIGNAL(aboutToQuit()), HbExtraDictionaryFactory::instance(), SLOT(shutdown()));

    HbInputMethod *master = HbInputMethodNull::Instance();

    if (!master) {

        return false;

    }

    master->d_ptr->mIsActive = true;

    // Finally set application input context.

    QInputContext *proxy = master->d_ptr->proxy();

    // A check required so that Qt does not delete inputcontext

    // which we are passing.

    if (proxy != app.inputContext()) {

        app.setInputContext(proxy);

    }

    return true;

}

/*!

Returns the active instance of HbInputMethod. There is always active HbInputMethod instance after

InitializeFramework method has been called, even when there is no focused editor (in some cases it may

be so called null input method).

*/

HbInputMethod *HbInputMethod::activeInputMethod()

{

    // First try, try app input context directly. It is possible that it is an instance

    // of HbInputMethod that is installed directly there without framework knowing about it

    // (that shouldn't be done, but it is possible). That's why we rely on app input context as

    // a primary source instead of mode cache.

    QInputContext *context = qApp->inputContext();

    if (context && context->inherits("HbInputMethod")) {

        HbInputMethod *active = static_cast<HbInputMethod *>(context);

        return active;

    }

    // Then check if the 'null' is active.

    HbInputMethod *nullInstance = HbInputMethodNull::Instance();

    if (nullInstance && nullInstance->isActiveMethod()) {

        return nullInstance;

    }

    // No it wasn't, then go through the methods in the cache and see which one is

    // active.

    return HbInputModeCache::instance()->activeMethod();

}

/*!

Lists all custom input methods.

*/

QList<HbInputMethodDescriptor> HbInputMethod::listCustomInputMethods()

{

    return HbInputModeCache::instance()->listCustomInputMethods();

}

/*!

Lists custom input methods for given parameters.

*/

QList<HbInputMethodDescriptor> HbInputMethod::listCustomInputMethods(Qt::Orientation orientation, const HbInputLanguage &language)

{

    return HbInputModeCache::instance()->listCustomInputMethods(orientation, language);

}

/*!

Returns default input method for given orientation.

*/

HbInputMethodDescriptor HbInputMethod::defaultInputMethod(Qt::Orientation orientation)

{

    return HbInputModeCache::instance()->defaultInputMethod(orientation);

}

/*!

Activates given input method. Returns false if input method was not found

or the framework was not able to activate it.

*/

bool HbInputMethod::activateInputMethod(const HbInputMethodDescriptor &inputMethod)

{

    Q_D(HbInputMethod);

    if (!inputMethod.isEmpty()) {

        if (inputMethod.isDefault()) {

            d->setFocusCommon();

            return true;

        } else {

            HbInputMethod *customMethod = HbInputModeCache::instance()->loadInputMethod(inputMethod);

            if (customMethod && HbInputModeCache::instance()->acceptsState(customMethod, d->mInputState)) {

                d->contextSwitch(customMethod);

                return true;

            }

        }

    }

    return false;

}

/*!

This slot is called when the input language changes. The framework connects it

to the input setting proxy. When the signal is received, the input method implementation

is notified by calling inputLanguageChanged.

\sa inputLanguageChanged

\sa HbInputSettingProxy

*/

void HbInputMethod::globalInputLanguageChanged(const HbInputLanguage &newLanguage)

{

    Q_D(HbInputMethod);

    inputLanguageChanged(newLanguage);

    if (!isActiveMethod()) {

        // Notify non-active input methods of language change, but check

        // if the method has promised to handle the new language only

        // in the active method

        return;

    }

    // Just behave as if this was the first focus operation

    // to this editor.

    if (d->mFocusObject) {

        HbInputState state;

        editorRootState(state);

        activateState(state);

    }

}

/*!

This slot is called when the secondary input language changes. The framework connects it

to the input setting proxy. When the signal is received, the input method implementation

is notified by calling secondaryInputLanguageChanged.

\sa secondaryInputLanguageChanged

\sa HbInputSettingProxy

*/

void HbInputMethod::globalSecondaryInputLanguageChanged(const HbInputLanguage &newLanguage)

{

    secondaryInputLanguageChanged(newLanguage);

}

/*!

This slot is connected to the setting proxy activeKeyboard attribute. It will

activate proper state when the signal is received.

*/

void HbInputMethod::activeKeyboardChanged(HbKeyboardType newKeyboard)

{

    if (!isActiveMethod() || !HbInputSettingProxy::instance()->orientationChangeCompleted()) {

        return;

    }

    Q_D(HbInputMethod);

    d->mInputState.setKeyboard(newKeyboard);

    HbInputMethod *stateHandler = d->findStateHandler(d->mInputState);

    if (stateHandler) {

        d->inputStateToEditor(d->mInputState);

        if (stateHandler != this) {

            // Context switch needed.

            d->contextSwitch(stateHandler);

        } else {

            // Same method handles new state, just report the state change.

            inputStateActivated(d->mInputState);

        }

    }

}

/*!

The framework calls this method when an input capable widget receives UI focus. This is empty

default implementation and the inheriting class should override it.

\sa focusLost

*/

void HbInputMethod::focusReceived()

{

    // Empty default implementation, do nothing.

}

/*!

The framework calls this method when an active editor loses focus. The parameter focusSwitch

is true if the focus is moving from one editor to another and false if the input focus

going to be lost completely.

\sa focusReceived

*/

void HbInputMethod::focusLost(bool focusSwitch)

{

    Q_UNUSED(focusSwitch);

    // Empty default implementation, do nothing.

}

/*!

Returns pointer to active focus object.

*/

HbInputFocusObject *HbInputMethod::focusObject() const

{

    Q_D(const HbInputMethod);

    return d->mFocusObject;

}

/*!

QWidget based editors notify focus changes through this method. This is the

default focus handling mechanism for QInputContext system. Input method

implementation should never override this method unless it knows what it is doing.

\sa setFocusObject

*/

void HbInputMethod::setFocusWidget(QWidget *widget)

{

    Q_D(HbInputMethod);

    if (d->mFocusLocked) {

        return;

    }

    if (!widget) {

        bool unfocus = true;

        if (d->mFocusObject) {

            // If the input focus is inside HbGraphicsScene then do not unfocus automatically.

            if (d->ignoreFrameworkFocusRelease(d->mFocusObject->object())) {

                unfocus = false;

            }

        }

        // Losing focus.

        if (d->mFocusObject && unfocus) {

            focusLost(false);

            d->hideMainWindow();

            delete d->mFocusObject;

            d->mFocusObject = 0;

        }

        return;

    }

    // attach focuswidget to prxoy inputcontext as proxy is 

    // the only inputcotext known to qt framework.

    d->proxy()->QInputContext::setFocusWidget(widget);

    QGraphicsView *gView = qobject_cast<QGraphicsView *>(widget);

    if (gView) {

        // We don't want to focus to graphics view but the items inside the scene, so just return

        return;

    }

    // Check whether the editor has read-only constraint and reject focus

    // if so.

    bool readOnly = false;

    if (HbEditorInterface::isConnected(widget)) {

        HbEditorInterface eInt(widget);

        if (eInt.inputConstraints() & HbEditorConstraintIgnoreFocus) {

            readOnly = true;

        }

    }

    // Focusing widget doesn't have input capabilities

    // or it is read-only.

    if (readOnly && HbInputFocusObject::isReadOnlyWidget(widget)) {

        if (d->mFocusObject) {

            focusLost();

            d->hideMainWindow();

        }

        return;

    }

    if (d->mFocusObject) {

        if (d->mFocusObject->object() == widget) {

            // Focus remains in same widget, do nothing.

            return;

        } else {

            // Lose editor focus unless we are focusing back to the editor from e.g. a vkb

            focusLost();

        }

    }

    bool refreshHost = false;

    // Delete previous focus object.

    if (d->mFocusObject) {

        refreshHost = true;

        disconnect(d->mFocusObject, SIGNAL(editorDeleted()), this, SLOT(editorDeleted()));

    }

    delete d->mFocusObject;

    d->mFocusObject = 0;

    // Attach focus.

    d->mFocusObject = new HbInputFocusObject(widget);

    connect(widget, SIGNAL(destroyed(QObject *)), this, SLOT(editorDeleted(QObject *)));

    d->setFocusCommon();

    // The focus jumped from one editor to another. Make sure that vkb host

    // updates the situation correctly.

    if (refreshHost && d->mFocusObject) {

        HbVkbHost *vkbHost = d->mFocusObject->editorInterface().vkbHost();

        if (vkbHost) {

            vkbHost->refresh();

        }

    }

}

/*!

Checks if the destroyed widget is currently focused and clears the focus

if needed. This method should not be overridden.

*/

void HbInputMethod::widgetDestroyed(QWidget *widget)

{

    Q_D(HbInputMethod);

    if (d->mFocusObject && d->mFocusObject->object() == widget) {

        delete d->mFocusObject;

        d->mFocusObject = 0;

        // passing to actual QInputContext which is attached to Qt framework.

        // which will internally set QInputContext::focusWidget to Null.

        d->proxy()->QInputContext::widgetDestroyed(widget);

        d->proxy()->QInputContext::setFocusWidget(0);

    }

}