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

**

** 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 HbPlugins 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:

** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** 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.

**

** If you have questions regarding the use of this file, please contact

** Nokia at developer.feedback@nokia.com.

**

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

#include <QTextCharFormat>

#include <hbinputpredictionengine.h>

#include <hbinputsettingproxy.h>

#include <hbinputpredictionfactory.h>

#include <hbinputkeymap.h>

#include <hbinputkeymapfactory.h>

#include <hbinputdialog.h>

#include <hbaction.h>

#include <hbinputvkbhost.h>

#include <hbcolorscheme.h>

#include <hbinpututils.h>

#include <hbinputbutton.h>

#include "../touchinput/virtualqwerty.h"

#include "hbinputpredictionhandler_p.h"

#include "hbinputabstractbase.h"

static const qreal HbDeltaHeight = 3.0;

HbInputPredictionHandlerPrivate::HbInputPredictionHandlerPrivate()

    :mEngine(0),

    mCandidates(0),

    mBestGuessLocation(0),

    mShowTail(true),

    mAutoAddedSpace(true),

    mCanContinuePrediction(true),

    mShowTooltip(true),

    mSpellQueryDialog(0)

{

}

HbInputPredictionHandlerPrivate::~HbInputPredictionHandlerPrivate()

{

    if (mCandidates) {

        delete mCandidates;

        mCandidates = 0;

    }

}

void HbInputPredictionHandlerPrivate::deleteOneCharacter()

{

    if (!mEngine && !mInputMethod->focusObject()) {

        return;

    }

    mShowTail = true;

    mShowTooltip = true;

    // A backspace in predictive means updating the engine for the delete key press

    // and get the new candidate list from the engine.

    if ( mEngine->inputLength() >= 1 ) {

        int tailLength =  mInputMethod->focusObject()->preEditString().length() - mEngine->inputLength();

        //Only autocomplition part should be deleted when autocompliton part is shown and user pressed a delete key

        if(tailLength <= 0) { // no autocompletion part displayed

            mEngine->deleteKeyPress( this );

        }

        //To prevent showing autocompletion part while deleting the characters using backspace key

        mShowTail = false;

        mShowTooltip = false;

		bool unused = false;

        mEngine->updateCandidates(mBestGuessLocation, unused);

		//If Input length greater or equal to one then Append the current word to candidate 

		if (!mCandidates->count() && mEngine->inputLength() >= 1) {

			mCandidates->append(mEngine->currentWord());

        }

		mCanContinuePrediction = true;

		// update the editor with the new preedit text.

        updateEditor();

        return;

    } else {

        // we come here if their is no data in engine.

        // once the word is committed, we can not bring it back to inline edit.

        // so if the engine does not have any data, we just send backspace event to the editor.

        Q_Q(HbInputPredictionHandler);

        QKeyEvent event = QKeyEvent(QEvent::KeyPress, Qt::Key_Backspace, Qt::NoModifier);		

        q->sendAndUpdate(event);

        event = QKeyEvent(QEvent::KeyRelease, Qt::Key_Backspace, Qt::NoModifier);

        q->sendAndUpdate(event);

        return;

    }

}

void HbInputPredictionHandlerPrivate::commitAndAppendCharacter(QChar character)

{

    if (!mEngine) {

        return;

    }

    HbInputFocusObject* focusedObject = 0;

    focusedObject = mInputMethod->focusObject();

    if (!focusedObject) {

        return;

    }

    QString commitString;

    if (mEngine->inputLength() > 0 && mCandidates->count() > 0) {

        commitString = getCommitString();

        mEngine->addUsedWord(commitString);

        if (character == QChar(' ') || character == QChar('\n')) {

            mAutoAddedSpace = true;

        }

        commit(commitString);

    } else {

        mAutoAddedSpace = false;

    }

    commitString = character;

    commit(commitString);

}

/*!

Commits the candidate upon closing of the candidate list. Now can the closing key be anything other than

just selection. Need to evaluate this. When the candidate list is visible, the current implementation of the

candidate list does not allow the virtual keypad to be clicked.

*/

void HbInputPredictionHandlerPrivate::candidatePopupClosed(int closingKey, const QString& activatedText)

{

    if (!mEngine) {

        return;

    }

    HbInputFocusObject* focusedObject = 0;

    focusedObject = mInputMethod->focusObject();

    if (!focusedObject) {

        return;

    }

    QString commitString  = activatedText;

    if (closingKey == Qt::Key_0 || closingKey == HbInputButton::ButtonKeyCodeSpace) {

        commitString = activatedText+' ';

    } else if (closingKey == HbInputButton::ButtonKeyCodeEnter) {

        commitString = activatedText;

        commit(commitString);

        commitString = '\n';

    }

    commit(commitString,true);

}

/*!

This function shows the exact popup if needed.

*/

void HbInputPredictionHandlerPrivate::showExactWordPopupIfNeeded()

{

}

QList<HbKeyPressProbability> HbInputPredictionHandlerPrivate::probableKeypresses()

{

    if(HbInputUtils::isQwertyKeyboard(mInputMethod->inputState().keyboard())) {

        //Useof the concrete input method implementations make the modehandlersin flexible.

        //Later an intermediate abstract class needsto be introduced.

        HbVirtualQwerty * qwertyInputMethod = qobject_cast<HbVirtualQwerty*>(mInputMethod);

        if(qwertyInputMethod) {

            return qwertyInputMethod->probableKeypresses();

        }

    }

    return QList<HbKeyPressProbability>();

}

/*!

This method updates the editor contents based on the candidates available in the candidate list.

*/

void HbInputPredictionHandlerPrivate::updateEditor()

{

    Q_Q(HbInputPredictionHandler);

    if (!mEngine) {

        return;

    }

    QList<QInputMethodEvent::Attribute> list;

    QTextCharFormat underlined;

    HbInputFocusObject *focusedObject = 0;

    underlined.setFontUnderline(true);

    QInputMethodEvent::Attribute textstyle(QInputMethodEvent::TextFormat, 0, mEngine->inputLength(), underlined);

    list.append(textstyle);

    focusedObject = mInputMethod->focusObject();

    Q_ASSERT(focusedObject);

    if (mEngine->inputLength() == 0) {

        QInputMethodEvent event(QString(), list);

        q->sendAndUpdate(event);

    } else {

        if (mCandidates->count() > mBestGuessLocation) {

            int taillength = mCandidates->at(mBestGuessLocation).length() - mEngine->inputLength();

            if (taillength > 0 && mShowTail) {

                // TODO: Color from skin should be used

				QColor col = HbColorScheme::color("qtc_input_hint_normal");

                QBrush brush(col);

                QTextCharFormat gray;

                gray.setForeground(brush);

                if((focusedObject->object())->inherits("QGraphicsWebView") || (focusedObject->object())->inherits("QWebView")) {

                    //QGraphicsWebView does not handle partial input length formatting well. Causes crash, a temporary fix provided,

                    //This makes the whole text field grey insted of just the auto-completion part. Anyways, it does not cause crash.

                    //This should be treated as a work around till QGraphicsWebView is fixed.

                    list.append(QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, 0, QInputMethodEvent::TextFormat, gray));

                } else {

                    list.append(QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, mEngine->inputLength(), taillength, gray));

                }

				list.append(QInputMethodEvent::Attribute(QInputMethodEvent::Cursor, mEngine->inputLength(), 0, 0));

                QInputMethodEvent event(mCandidates->at(mBestGuessLocation), list);

                focusedObject->sendEvent(event);

            } else {

				list.append(QInputMethodEvent::Attribute(QInputMethodEvent::Cursor, mCandidates->at(mBestGuessLocation).length(), 0, 0));

                QInputMethodEvent event(mCandidates->at(mBestGuessLocation).left(mEngine->inputLength()), list);

                focusedObject->sendEvent(event);

            }

            if (mShowTooltip && mBestGuessLocation > 0 && mCandidates->at(0).mid(0, mEngine->inputLength()) \

                != mCandidates->at(mBestGuessLocation).mid(0, mEngine->inputLength())) {                

                    q->processExactWord(mCandidates->at(0));

            } else {

                QString empty;

                q->processExactWord(empty);

            }

        } else {

            QInputMethodEvent event(QString(""), list);

            focusedObject->sendEvent(event);

        }

    }

}

bool HbInputPredictionHandlerPrivate::filterEvent(const QKeyEvent * event)

{

    HbInputFocusObject* focusObject = 0;

    focusObject = mInputMethod->focusObject();

    //If the focused object is NULL or the key event is improper, can not continue

    if(!focusObject || event->key() < 0 ||

        event->key() == HbInputButton::ButtonKeyCodeCustom) {

        return false;

    }

    Q_Q(HbInputPredictionHandler);

    if (!mEngine) {

        return false;

    }

    bool ret = false;

    mModifiers = Qt::NoModifier;   

    mCanContinuePrediction = true;

    switch (event->key()) {

    case Qt::Key_Backspace:

    case HbInputButton::ButtonKeyCodeDelete:

        {

            QString currentSelection = focusObject->inputMethodQuery(Qt::ImCurrentSelection).toString();

            if(currentSelection.length()) {

                QKeyEvent event = QKeyEvent(QEvent::KeyPress, Qt::Key_Backspace, Qt::NoModifier);		

                q->sendAndUpdate(event);

                event = QKeyEvent(QEvent::KeyRelease, Qt::Key_Backspace, Qt::NoModifier);

                q->sendAndUpdate(event);

            } else {

                deleteOneCharacter();

            }

		}

        ret = true;

        break;

    case HbInputButton::ButtonKeyCodeEnter:

    case HbInputButton::ButtonKeyCodeSpace:

        {

            // A space means we have to commit the candidates when we are in predictive mode.

            QChar qc(event->key());

            if (qc == Qt::Key_Enter) {

                qc = QChar('\n');  // Editor expects normal line feed.

            } 

            commitAndAppendCharacter(qc);

            // if exact word popup functionality is on then we should inform exact word popup

            // about the space.//++TODO

            QString empty;

            q->processExactWord(empty);

            ret = true;

        }

        break;

    default: {

            mShowTail = true;

            mShowTooltip = true;

            mAutoAddedSpace = false;

            if (q->HbInputModeHandler::filterEvent(event)) {

                return true;

            }

            if (mEngine) {

                int currentTextCase = focusObject->editorInterface().textCase();

                if ( HbTextCaseUpper == currentTextCase || HbTextCaseAutomatic == currentTextCase ) {

                    mModifiers |= Qt::ShiftModifier;

                }

                if (event->text().isEmpty()) {

                    mEngine->appendKeyPress(event->key(), mModifiers, mInputMethod->inputState().textCase(), this);

                } else {

                    mEngine->appendCharacter(event->text().at(0), mInputMethod->inputState().textCase(), this);

                }

                bool isCustomWord = false;

                mEngine->updateCandidates(mBestGuessLocation, isCustomWord);

                //The engine can not predict the word, it is a custom word. Now engine returns a

                //single candidate entry which is actually the previous properly predicted character.

                //TODO: In such a scenario, the prediction should stop and there needs to be some way for

                //the user to tell the correct word which he wants (Some query editor). But, such a thing is

                //not in place and hence the current implementation just appends a "?" and displays the

                //previous word itself.

                if (isCustomWord && mCandidates->count()) {

                    QString replacementText = mCandidates->at(0);//+"?";

                    mCandidates->clear();

                    mCandidates->append(replacementText);

                    //Since there is only one candidate, that's the best prediction.

                    mBestGuessLocation = 0;

                }

                //We need to check and carry out necessary steps if the engine fails to predict any candidate,

                //for the give input sequence.

                handleEmptyCandidateList();

                updateEditor();

                mInputMethod->updateState();

                ret = true;

            }

        }

    }

    return ret;

}

void HbInputPredictionHandlerPrivate::keyHandlerUnicode(const QChar& character)

{

    if (!mEngine) {

        return;

    }

    mEngine->appendCharacter(character, mInputMethod->inputState().textCase(), this);

    bool unused = false;

    mEngine->updateCandidates(mBestGuessLocation, unused);

    //Check if the candidate list is empty and take necessary steps if so.

    handleEmptyCandidateList();

    updateEditor();

}

void HbInputPredictionHandlerPrivate::mouseHandler(int cursorPosition, QMouseEvent* mouseEvent)

{

    Q_Q(HbInputPredictionHandler);

    // we are missing something we must get out.

    if (!mEngine && !mInputMethod->focusObject()) {

        return;

    }

    // mouse move / hover events needs to be ignored.

    if (mouseEvent->type() != QEvent::MouseButtonPress) {

        return;

    }

    //The mouse has been clicked outside of the pre-editing word and hence need to commit the word.

    if ( cursorPosition < 0 || cursorPosition >= mInputMethod->focusObject()->preEditString().length()) {

        commit();

    } else if (mCandidates->size() > 0) {

        if(!mCanContinuePrediction && (*mCandidates)[mBestGuessLocation].endsWith('?')) {

            // mouse has been clicked on the pre-editing string ends with "?"

            //Remove the "?" mark

            (*mCandidates)[mBestGuessLocation].chop(1);

            updateEditor();

            q->launchSpellQueryDialog();

        } else {

        //The mouse has been clicked on the pre-editing word, launch candidate list

        mInputMethod->launchCandidatePopup(*mCandidates);

        }	

    }

}

void HbInputPredictionHandlerPrivate::init()

{

    mEngine = 0;

    HbInputLanguage language = HbInputSettingProxy::instance()->globalInputLanguage();

    mEngine = HbPredictionFactory::instance()->predictionEngineForLanguage(language.language());

    if (mEngine && !mCandidates) {

        mCandidates = new QStringList();

    }

}

void HbInputPredictionHandlerPrivate::reset()

{

    if (mEngine) {

        mEngine->clear();

    }

    if (mCandidates) {

        mCandidates->clear();

    }

}

void HbInputPredictionHandlerPrivate::commit()

{

    if (mEngine && mEngine->inputLength() > 0 && mCandidates->count() > 0) {

		// Close exact word pop up in qwerty when the word is committed

		if(HbInputUtils::isQwertyKeyboard(mInputMethod->inputState().keyboard())) {

			mInputMethod->closeExactWordPopup();

		}

        QString commitString = getCommitString();

        // need to update the freq information

        mEngine->commit(commitString);

        commit(commitString,false);

    }

}

QString HbInputPredictionHandlerPrivate::getCommitString()

{

    QString commitString;

    if(mCandidates->count()) {

        if(!mCanContinuePrediction) {

           //Remove the "?" mark

           (*mCandidates)[mBestGuessLocation].chop(1);

        }

        if(mCandidates->count() <= mBestGuessLocation) {

            commitString = mCandidates->at(0);

        } else if (mShowTail == false) {

            commitString = mCandidates->at(mBestGuessLocation).left(mEngine->inputLength());

        } else {

            commitString = mCandidates->at(mBestGuessLocation);

        }

    }

    return commitString;

}

/*!

This function accepts a Qstring and commits the string to editor. This also clears all the key presses and

candidates from prediction engine

*/

void HbInputPredictionHandlerPrivate::commit(const QString& string, bool addToUsedWordDict, bool isAsync)

{

    Q_Q(HbInputPredictionHandler);

    // Close exact word pop up in qwerty when the word is committed

	if(HbInputUtils::isQwertyKeyboard(mInputMethod->inputState().keyboard())) {

		mInputMethod->closeExactWordPopup();

	}

    q->commitAndUpdate(string, 0, 0, isAsync);

    if(mEngine) {

        if(addToUsedWordDict && !string.isEmpty()) {

            QChar spaceChar(' ');

            QStringList stringList = string.split(spaceChar, QString::SkipEmptyParts);

            foreach (const QString str, stringList) {

                mEngine->addUsedWord(str);

            }

        }

        mEngine->clear();

    }

    //Enable the flag after commit

    mCanContinuePrediction = true;

}

/*!

This function accepts a QInputMethodEvent and commits the event to editor. This also clears all the key presses and

candidates from prediction engine

Warning: Use this only when you want to commit some string to editor. If you want to send some formating information 

to editor, use sendAndUpdate(QInputMethodEvent & event); The reason is that, this commit function cleans prediction

engine state also.

*/

void HbInputPredictionHandlerPrivate::commit(QInputMethodEvent & event,bool addToUsedWordDict)

{

    Q_Q(HbInputPredictionHandler);

	// Close exact word pop up in qwerty when the word is committed

	if(HbInputUtils::isQwertyKeyboard(mInputMethod->inputState().keyboard())) {

		mInputMethod->closeExactWordPopup();

	}

    q->sendAndUpdate(event);

    if(mEngine) {

        if(addToUsedWordDict && !event.commitString().isEmpty())

            mEngine->addUsedWord(event.commitString());

        mEngine->clear();

    }

    //Enable the flag after commit

    mCanContinuePrediction = true;

}

void HbInputPredictionHandlerPrivate::commitExactWord()

{

    if (mEngine && mEngine->inputLength() /*> 0 && mCandidates->count() > 0*/) {

        commit(mCandidates->at(0), true);

    }

}

/*!

This function checks if the constructed candidate list is empty and if so, then 

appends a "?" mark to the best guessed candidate with put the current key input.

*/

void HbInputPredictionHandlerPrivate::handleEmptyCandidateList()

{

    if (!mCandidates->count()) {

        QString existingWord(mEngine->currentWord());

        int lastKeyCode = 0;

        int lastCharacterCode = 0;

        bool isCustomWord = false;