/*
    This file is part of the Okteta Core library, made within the KDE community.

    Copyright 2005,2008-2009 Friedrich W. H. Kossebau <kossebau@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) version 3, or any
    later version accepted by the membership of KDE e.V. (or its
    successor approved by the membership of KDE e.V.), which shall
    act as a proxy defined in Section 6 of version 3 of the license.

    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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/

#include "wordbytearrayservice.h"

// lib
#include "abstractbytearraymodel.h"
#include "character.h"
#include "charcodec.h"

namespace Okteta {

WordByteArrayService::WordByteArrayService(const AbstractByteArrayModel* byteArrayModel, const CharCodec* charCodec)
    : mByteArrayModel(byteArrayModel)
    , mCharCodec(charCodec)
{}

WordByteArrayService::~WordByteArrayService() = default;

AddressRange WordByteArrayService::wordSection(Address index) const
{
    return isWordChar(index) ?
           AddressRange(indexOfWordStart(index), indexOfWordEnd(index)) :
           AddressRange();
}

bool WordByteArrayService::isWordChar(Address index) const
{
    const Character decodedChar = mCharCodec->decode(mByteArrayModel->byte(index));
    return !decodedChar.isUndefined() && decodedChar.isLetterOrNumber();
}

Address WordByteArrayService::indexOfPreviousWordStart(Address index) const
{
    const Size size = mByteArrayModel->size();
    // already at the start or can the result only be 0?
    if (index == 0 || size < 3) {
        return 0;
    }

    // search in two rounds: first for the next char, than for the next nonchar
    // after that return the index of the one before
    bool lookingForFirstWordChar = false;
    for (; index > 0; --index) {
        if (!isWordChar(index - 1)) {
            if (!lookingForFirstWordChar) {
                continue;
            }
            return(index);
        } else if (!lookingForFirstWordChar) {
            lookingForFirstWordChar = true;
        }
    }

    return 0;
}

Address WordByteArrayService::indexOfNextWordStart(Address index) const
{
    const Size size = mByteArrayModel->size();
    bool lookingForFirstWordChar = false;
    for (; index < size; ++index) {
        if (isWordChar(index)) {
            if (!lookingForFirstWordChar) {
                continue;
            }
            return index;
        } else if (!lookingForFirstWordChar) {
            lookingForFirstWordChar = true;
        }
    }

    // if no more word found, go to the end
    return size;
}

Address WordByteArrayService::indexOfBeforeNextWordStart(Address index) const
{
    const Size size = mByteArrayModel->size();
    bool lookingForFirstWordChar = false;
    for (; index < size; ++index) {
        if (isWordChar(index)) {
            if (!lookingForFirstWordChar) {
                continue;
            }
            return index - 1;
        } else if (!lookingForFirstWordChar) {
            lookingForFirstWordChar = true;
        }
    }

    // if no more word found, go to the end
    return size - 1;
}

Address WordByteArrayService::indexOfWordStart(Address index) const
{
    for (; index > 0; --index) {
        if (!isWordChar(index - 1)) {
            return(index);
        }
    }

    return 0;
}

Address WordByteArrayService::indexOfWordEnd(Address index) const
{
    const Size size = mByteArrayModel->size();
    for (++index; index < size; ++index) {
        if (!isWordChar(index)) {
            return index - 1;
        }
    }

    // word reaches the end
    return size - 1;
}

Address WordByteArrayService::indexOfLeftWordSelect(Address index) const
{
    // word at index?
    if (isWordChar(index)) {
        // search for word start to the left
        for (; index > 0; --index) {
            if (!isWordChar(index - 1)) {
                return index;
            }
        }

        // reached start, so return it
        return 0;
    } else {
        const Size size = mByteArrayModel->size();
        // search for word start to the right
        for (++index; index < size; ++index) {
            if (isWordChar(index)) {
                return index;
            }
        }

        // word reaches the end, so step behind
        return size;
    }
}

Address WordByteArrayService::indexOfRightWordSelect(Address index) const
{
    // TODO: should this check be here or with the caller?
    // the later would need another function to search the previous word end
    const Size size = mByteArrayModel->size();
    bool searchToLeft;
    if (index >= size) {
        index = size;
        searchToLeft = true;
    } else {
        searchToLeft = !isWordChar(index);
    }
    // no word at index?
    if (searchToLeft) {
        // search for word end to the left
        for (; index > 0; --index) {
            if (isWordChar(index - 1)) {
                return index;
            }
        }

        // reached start, so return it
        return 0;
    } else {
        for (++index; index < size; ++index) {
            // search for word end to the right
            if (!isWordChar(index)) {
                return index;
            }
        }

        // word reaches the end, so step behind
        return size;
    }
}

/*
Address WordByteArrayService::indexOfBehindWordEnd( Address index ) const
{
   // no word at index?
   return !::isWordChar(byte(index)) ? indexOfBehindLeftWordEnd(index) : indexOfBehindRightWordEnd(index+1)
}


Address WordByteArrayService::indexOfBehindRightWordEnd( Address index ) const
{
   for( ; index<size(); ++index )
   {
        if( !::isWordChar(byte(index)) )
            return index;
   }
   // word reaches the end, so step behind
   return size();
}


Address WordByteArrayService::indexOfBehindLeftWordEnd( Address index ) const
{
   for( --index; index>=0; --index )
   {
        if( ::isWordChar(byte(index)) )
            return index+1;
   }
   // word reaches the end, so step behind
   return 0;
}
*/

// TODO: rename WordByteArrayService to TextByteArrayService or TextByteArrayAnalyser
QString WordByteArrayService::text(Address index, Address lastIndex) const
{
    QString result;

    const Address lastValidIndex = mByteArrayModel->size() - 1;
    const Address behindLastIndex =
        ((lastIndex <0 || lastIndex> lastValidIndex) ? lastValidIndex : lastIndex) + 1;

    const Size maxTextLength = behindLastIndex - index;
    result.reserve(maxTextLength);

    for (; index < behindLastIndex; ++index) {
        const Character decodedChar = mCharCodec->decode(mByteArrayModel->byte(index));
        // TODO: handle line breaks, separators and spacing, controlled by flags given as parameter
        const bool isTextChar = (!decodedChar.isUndefined() &&
                                 (decodedChar.isLetterOrNumber() || decodedChar.isSpace() || decodedChar.isPunct()));

        if (!isTextChar) {
            break;
        }

        result.append(decodedChar);
    }

    result.squeeze();

    return result;
}

}
