/*
 * This file is part of the DOM implementation for KDE.
 *
 * Copyright (C) 2006 Lars Knoll <lars@trolltech.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "TextBreakIterator.h"

#if QT_VERSION >= 0x040400
#include <QtCore/qtextboundaryfinder.h>
#include <qdebug.h>

// #define DEBUG_TEXT_ITERATORS
#ifdef DEBUG_TEXT_ITERATORS
#define DEBUG qDebug
#else
#define DEBUG if (1) {} else qDebug
#endif

namespace WebCore {

    class TextBreakIterator : public QTextBoundaryFinder {
    };
    static QTextBoundaryFinder* iterator = 0;
    static unsigned char buffer[1024];

    TextBreakIterator* wordBreakIterator(const UChar* string, int length)
    {
        if (!string)
            return 0;
        if (!iterator)
            iterator = new QTextBoundaryFinder;

        *iterator = QTextBoundaryFinder(QTextBoundaryFinder::Word, (const QChar *)string, length, buffer, sizeof(buffer));
        return static_cast<TextBreakIterator*>(iterator);
    }

    TextBreakIterator* characterBreakIterator(const UChar* string, int length)
    {
        if (!string)
            return 0;
        if (!iterator)
            iterator = new QTextBoundaryFinder;

        *iterator = QTextBoundaryFinder(QTextBoundaryFinder::Grapheme, (const QChar *)string, length, buffer, sizeof(buffer));
        return static_cast<TextBreakIterator*>(iterator);
    }

    TextBreakIterator* cursorMovementIterator(const UChar* string, int length)
    {
        return characterBreakIterator(string, length);
    }

    TextBreakIterator* lineBreakIterator(const UChar* string, int length)
    {
        static QTextBoundaryFinder *iterator = 0;
        if (!string)
            return 0;
        if (!iterator)
            iterator = new QTextBoundaryFinder;

        *iterator = QTextBoundaryFinder(QTextBoundaryFinder::Line, (const QChar *)string, length, buffer, sizeof(buffer));
        return static_cast<TextBreakIterator*>(iterator);
    }

    TextBreakIterator* sentenceBreakIterator(const UChar* string, int length)
    {
        if (!string)
            return 0;
        if (!iterator)
            iterator = new QTextBoundaryFinder;

        *iterator = QTextBoundaryFinder(QTextBoundaryFinder::Sentence, (const QChar *)string, length, buffer, sizeof(buffer));
        return static_cast<TextBreakIterator*>(iterator);
    }

    int textBreakFirst(TextBreakIterator* bi)
    {
        bi->toStart();
        DEBUG() << "textBreakFirst" << bi->position();
        return bi->position();
    }

    int textBreakNext(TextBreakIterator* bi)
    {
        int pos = bi->toNextBoundary();
        DEBUG() << "textBreakNext" << pos;
        return pos;
    }

    int textBreakPreceding(TextBreakIterator* bi, int pos)
    {
        bi->setPosition(pos);
        int newpos = bi->toPreviousBoundary();
        DEBUG() << "textBreakPreceding" << pos << newpos;
        return newpos;
    }

    int textBreakFollowing(TextBreakIterator* bi, int pos)
    {
        bi->setPosition(pos);
        int newpos = bi->toNextBoundary();
        DEBUG() << "textBreakFollowing" << pos << newpos;
        return newpos;
    }

    int textBreakCurrent(TextBreakIterator* bi)
    {
        return bi->position();
    }

    bool isTextBreak(TextBreakIterator*, int)
    {
        return true;
    }

}
#else
#include <qtextlayout.h>

namespace WebCore {

    class TextBreakIterator {
    public:
        virtual int first() = 0;
        virtual int next() = 0;
        virtual int previous() = 0;
        inline int following(int pos)
        {
            currentPos = pos;
            return next();
        }
        inline int preceding(int pos)
        {
            currentPos = pos;
            return previous();
        }
        int currentPos;
        const UChar *string;
        int length;
    };

    class WordBreakIteratorQt : public TextBreakIterator {
    public:
        virtual int first();
        virtual int next();
        virtual int previous();
    };

    class CharBreakIteratorQt : public TextBreakIterator {
    public:
        virtual int first();
        virtual int next();
        virtual int previous();
        QTextLayout layout;
    };

    int WordBreakIteratorQt::first()
    {
        currentPos = 0;
        return currentPos;
    }

    int WordBreakIteratorQt::next()
    {
        if (currentPos >= length) {
            currentPos = -1;
            return currentPos;
        }
        bool haveSpace = false;
        while (currentPos < length) {
            if (haveSpace && !QChar(string[currentPos]).isSpace())
                break;
            if (QChar(string[currentPos]).isSpace())
                haveSpace = true;
            ++currentPos;
        }
        return currentPos;
    }

    int WordBreakIteratorQt::previous()
    {
        if (currentPos <= 0) {
            currentPos = -1;
            return currentPos;
        }
        bool haveSpace = false;
        while (currentPos > 0) {
            if (haveSpace && !QChar(string[currentPos]).isSpace())
                break;
            if (QChar(string[currentPos]).isSpace())
                haveSpace = true;
            --currentPos;
        }
        return currentPos;
    }

    int CharBreakIteratorQt::first()
    {
        currentPos = 0;
        return currentPos;
    }

    int CharBreakIteratorQt::next()
    {
        if (currentPos >= length)
            return -1;
        currentPos = layout.nextCursorPosition(currentPos);
        return currentPos;
    }

    int CharBreakIteratorQt::previous()
    {
        if (currentPos <= 0)
            return -1;
        currentPos = layout.previousCursorPosition(currentPos);
        return currentPos;
    }


TextBreakIterator* wordBreakIterator(const UChar* string, int length)
{
    static WordBreakIteratorQt *iterator = 0;
    if (!iterator)
        iterator = new WordBreakIteratorQt;

    iterator->string = string;
    iterator->length = length;
    iterator->currentPos = 0;

    return iterator;
}

TextBreakIterator* characterBreakIterator(const UChar* string, int length)
{
    static CharBreakIteratorQt *iterator = 0;
    if (!iterator)
        iterator = new CharBreakIteratorQt;

    iterator->string = string;
    iterator->length = length;
    iterator->currentPos = 0;
    iterator->layout.setText(QString(reinterpret_cast<const QChar*>(string), length));

    return iterator;
}

TextBreakIterator* cursorMovementIterator(const UChar* string, int length)
{
    return characterBreakIterator(string, length);
}

TextBreakIterator* lineBreakIterator(const UChar*, int)
{
    // not yet implemented
    return 0;
}

TextBreakIterator* sentenceBreakIterator(const UChar*, int)
{
    // not yet implemented
    return 0;
}

int textBreakFirst(TextBreakIterator* bi)
{
    return bi->first();
}

int textBreakNext(TextBreakIterator* bi)
{
    return bi->next();
}

int textBreakPreceding(TextBreakIterator* bi, int pos)
{
    return bi->preceding(pos);
}

int textBreakFollowing(TextBreakIterator* bi, int pos)
{
    return bi->following(pos);
}

int textBreakCurrent(TextBreakIterator* bi)
{
    return bi->currentPos;
}

bool isTextBreak(TextBreakIterator*, int)
{
    return true;
}

}

#endif
