/*  This file is part of the Kate project.
 *
 *  Copyright (C) 2013 Christoph Cullmann <cullmann@kde.org>
 *
 *  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 "katetextfolding.h"
#include "katetextbuffer.h"
#include "katetextrange.h"
#include "documentcursor.h"

#include <QJsonObject>

namespace Kate
{

TextFolding::FoldingRange::FoldingRange(TextBuffer &buffer, const KTextEditor::Range &range, FoldingRangeFlags _flags)
    : start(new TextCursor(buffer, range.start(), KTextEditor::MovingCursor::MoveOnInsert))
    , end(new TextCursor(buffer, range.end(), KTextEditor::MovingCursor::MoveOnInsert))
    , parent(nullptr)
    , flags(_flags)
    , id(-1)
{
}

TextFolding::FoldingRange::~FoldingRange()
{
    /**
     * kill all our data!
     * this will recurse all sub-structures!
     */
    delete start;
    delete end;
    qDeleteAll(nestedRanges);
}

TextFolding::TextFolding(TextBuffer &buffer)
    : QObject()
    , m_buffer(buffer)
    , m_idCounter(-1)
{
    /**
     * connect needed signals from buffer
     */
    connect(&m_buffer, SIGNAL(cleared()), SLOT(clear()));
}

TextFolding::~TextFolding()
{
    /**
     * only delete the folding ranges, the folded ranges and mapped ranges are the same objects
     */
    qDeleteAll(m_foldingRanges);
}

void TextFolding::clear()
{
    /**
     * reset counter
     */
    m_idCounter = -1;

    /**
     * no ranges, no work
     */
    if (m_foldingRanges.isEmpty()) {
        /**
         * assert all stuff is consistent and return!
         */
        Q_ASSERT(m_idToFoldingRange.isEmpty());
        Q_ASSERT(m_foldedFoldingRanges.isEmpty());
        return;
    }

    /**
     * cleanup
     */
    m_idToFoldingRange.clear();
    m_foldedFoldingRanges.clear();
    qDeleteAll(m_foldingRanges);
    m_foldingRanges.clear();

    /**
     * folding changed!
     */
    emit foldingRangesChanged();
}

qint64 TextFolding::newFoldingRange(const KTextEditor::Range &range, FoldingRangeFlags flags)
{
    /**
     * sort out invalid and empty ranges
     * that makes no sense, they will never grow again!
     */
    if (!range.isValid() || range.isEmpty()) {
        return -1;
    }

    /**
     * create new folding region that we want to insert
     * this will internally create moving cursors!
     */
    FoldingRange *newRange = new FoldingRange(m_buffer, range, flags);

    /**
     * the construction of the text cursors might have invalidated this
     * check and bail out if that happens
     * bail out, too, if it can't be inserted!
     */
    if (!newRange->start->isValid()
            || !newRange->end->isValid()
            || !insertNewFoldingRange(nullptr /* no parent here */, m_foldingRanges, newRange)) {
        /**
         * cleanup and be done
         */
        delete newRange;
        return -1;
    }

    /**
     * set id, catch overflows, even if they shall not happen
     */
    newRange->id = ++m_idCounter;
    if (newRange->id < 0) {
        newRange->id = m_idCounter = 0;
    }

    /**
     * remember the range
     */
    m_idToFoldingRange.insert(newRange->id, newRange);

    /**
     * update our folded ranges vector!
     */
    bool updated = updateFoldedRangesForNewRange(newRange);

    /**
     * emit that something may have changed
     * do that only, if updateFoldedRangesForNewRange did not already do the job!
     */
    if (!updated) {
        emit foldingRangesChanged();
    }

    /**
     * all went fine, newRange is now registered internally!
     */
    return newRange->id;
}

KTextEditor::Range TextFolding::foldingRange(qint64 id) const
{
    FoldingRange *range = m_idToFoldingRange.value(id);
    if (!range) {
        return KTextEditor::Range::invalid();
    }

    return KTextEditor::Range(range->start->toCursor(), range->end->toCursor());
}

bool TextFolding::foldRange(qint64 id)
{
    /**
     * try to find the range, else bail out
     */
    FoldingRange *range = m_idToFoldingRange.value(id);
    if (!range) {
        return false;
    }

    /**
     * already folded? nothing to do
     */
    if (range->flags & Folded) {
        return true;
    }

    /**
     * fold and be done
     */
    range->flags |= Folded;
    updateFoldedRangesForNewRange(range);
    return true;
}

bool TextFolding::unfoldRange(qint64 id, bool remove)
{
    /**
     * try to find the range, else bail out
     */
    FoldingRange *range = m_idToFoldingRange.value(id);
    if (!range) {
        return false;
    }

    /**
     * nothing to do?
     * range is already unfolded and we need not to remove it!
     */
    if (!remove && !(range->flags & Folded)) {
        return true;
    }

    /**
     * do we need to delete the range?
     */
    const bool deleteRange = remove || !(range->flags & Persistent);

    /**
     * first: remove the range, if forced or non-persistent!
     */
    if (deleteRange) {
        /**
         * remove from outside visible mapping!
         */
        m_idToFoldingRange.remove(id);

        /**
         * remove from folding vectors!
         * FIXME: OPTIMIZE
         */
        FoldingRange::Vector &parentVector = range->parent ? range->parent->nestedRanges : m_foldingRanges;
        FoldingRange::Vector newParentVector;
        Q_FOREACH (FoldingRange *curRange, parentVector) {
            /**
             * insert our nested ranges and reparent them
             */
            if (curRange == range) {
                Q_FOREACH (FoldingRange *newRange, range->nestedRanges) {
                    newRange->parent = range->parent;
                    newParentVector.push_back(newRange);
                }

                continue;
            }

            /**
             * else just transfer elements
             */
            newParentVector.push_back(curRange);
        }
        parentVector = newParentVector;
    }

    /**
     * second: unfold the range, if needed!
     */
    bool updated = false;
    if (range->flags & Folded) {
        range->flags &= ~Folded;
        updated = updateFoldedRangesForRemovedRange(range);
    }

    /**
     * emit that something may have changed
     * do that only, if updateFoldedRangesForRemoveRange did not already do the job!
     */
    if (!updated) {
        emit foldingRangesChanged();
    }

    /**
     * really delete the range, if needed!
     */
    if (deleteRange) {
        /**
         * clear ranges first, they got moved!
         */
        range->nestedRanges.clear();
        delete range;
    }

    /**
     * be done ;)
     */
    return true;
}

bool TextFolding::isLineVisible(int line, qint64 *foldedRangeId) const
{
    /**
     * skip if nothing folded
     */
    if (m_foldedFoldingRanges.isEmpty()) {
        return true;
    }

    /**
     * search upper bound, index to item with start line higher than our one
     */
    FoldingRange::Vector::const_iterator upperBound = qUpperBound(m_foldedFoldingRanges.begin(), m_foldedFoldingRanges.end(), line, compareRangeByStartWithLine);
    if (upperBound != m_foldedFoldingRanges.begin()) {
        --upperBound;
    }

    /**
     * check if we overlap with the range in front of us
     */
    const bool hidden = (((*upperBound)->end->line() >= line) && (line > (*upperBound)->start->line()));

    /**
     * fill in folded range id, if needed
     */
    if (foldedRangeId) {
        (*foldedRangeId) = hidden ? (*upperBound)->id : -1;
    }

    /**
     * visible == !hidden
     */
    return !hidden;
}

void TextFolding::ensureLineIsVisible(int line)
{
    /**
     * skip if nothing folded
     */
    if (m_foldedFoldingRanges.isEmpty()) {
        return;
    }

    /**
     * while not visible, unfold
     */
    qint64 foldedRangeId = -1;
    while (!isLineVisible(line, &foldedRangeId)) {
        /**
         * id should be valid!
         */
        Q_ASSERT(foldedRangeId >= 0);

        /**
         * unfold shall work!
         */
        const bool unfolded = unfoldRange(foldedRangeId);
        (void) unfolded;
        Q_ASSERT(unfolded);
    }
}

int TextFolding::visibleLines() const
{
    /**
     * start with all lines we have
     */
    int visibleLines = m_buffer.lines();

    /**
     * skip if nothing folded
     */
    if (m_foldedFoldingRanges.isEmpty()) {
        return visibleLines;
    }

    /**
     * count all folded lines and subtract them from visible lines
     */
    Q_FOREACH (FoldingRange *range, m_foldedFoldingRanges) {
        visibleLines -= (range->end->line() - range->start->line());
    }

    /**
     * be done, assert we did no trash
     */
    Q_ASSERT(visibleLines > 0);
    return visibleLines;
}

int TextFolding::lineToVisibleLine(int line) const
{
    /**
     * valid input needed!
     */
    Q_ASSERT(line >= 0);

    /**
     * start with identity
     */
    int visibleLine = line;

    /**
     * skip if nothing folded or first line
     */
    if (m_foldedFoldingRanges.isEmpty() || (line == 0)) {
        return visibleLine;
    }

    /**
     * walk over all folded ranges until we reach the line
     * keep track of seen visible lines, for the case we want to convert a hidden line!
     */
    int seenVisibleLines = 0;
    int lastLine = 0;
    Q_FOREACH (FoldingRange *range, m_foldedFoldingRanges) {
        /**
         * abort if we reach our line!
         */
        if (range->start->line() >= line) {
            break;
        }

        /**
         * count visible lines
         */
        seenVisibleLines += (range->start->line() - lastLine);
        lastLine = range->end->line();

        /**
         * we might be contained in the region, then we return last visible line
         */
        if (line <= range->end->line()) {
            return seenVisibleLines;
        }

        /**
         * subtrace folded lines
         */
        visibleLine -= (range->end->line() - range->start->line());
    }

    /**
     * be done, assert we did no trash
     */
    Q_ASSERT(visibleLine >= 0);
    return visibleLine;
}

int TextFolding::visibleLineToLine(int visibleLine) const
{
    /**
     * valid input needed!
     */
    Q_ASSERT(visibleLine >= 0);

    /**
     * start with identity
     */
    int line = visibleLine;

    /**
     * skip if nothing folded or first line
     */
    if (m_foldedFoldingRanges.isEmpty() || (visibleLine == 0)) {
        return line;
    }

    /**
     * last visible line seen, as line in buffer
     */
    int seenVisibleLines = 0;
    int lastLine = 0;
    int lastLineVisibleLines = 0;
    Q_FOREACH (FoldingRange *range, m_foldedFoldingRanges) {
        /**
         * else compute visible lines and move last seen
         */
        lastLineVisibleLines = seenVisibleLines;
        seenVisibleLines += (range->start->line() - lastLine);

        /**
         * bail out if enough seen
         */
        if (seenVisibleLines >= visibleLine) {
            break;
        }

        lastLine = range->end->line();
    }

    /**
     * check if still no enough visible!
     */
    if (seenVisibleLines < visibleLine) {
        lastLineVisibleLines = seenVisibleLines;
    }

    /**
     * compute visible line
     */
    line = (lastLine + (visibleLine - lastLineVisibleLines));
    Q_ASSERT(line >= 0);
    return line;
}

QVector<QPair<qint64, TextFolding::FoldingRangeFlags> > TextFolding::foldingRangesStartingOnLine(int line) const
{
    /**
     * results vector
     */
    QVector<QPair<qint64, TextFolding::FoldingRangeFlags> > results;

    /**
     * recursively do binary search
     */
    foldingRangesStartingOnLine(results, m_foldingRanges, line);

    /**
     * return found results
     */
    return results;
}

void TextFolding::foldingRangesStartingOnLine(QVector<QPair<qint64, FoldingRangeFlags> > &results, const TextFolding::FoldingRange::Vector &ranges, int line) const
{
    /**
     * early out for no folds
     */
    if (ranges.isEmpty()) {
        return;
    }

    /**
     * first: lower bound of start
     */
    FoldingRange::Vector::const_iterator lowerBound = qLowerBound(ranges.begin(), ranges.end(), line, compareRangeByLineWithStart);

    /**
     * second: upper bound of end
     */
    FoldingRange::Vector::const_iterator upperBound = qUpperBound(ranges.begin(), ranges.end(), line, compareRangeByStartWithLine);

    /**
     * we may need to go one to the left, if not already at the begin, as we might overlap with the one in front of us!
     */
    if ((lowerBound != ranges.begin()) && ((*(lowerBound - 1))->end->line() >= line)) {
        --lowerBound;
    }

    /**
     * for all of them, check if we start at right line and recurse
     */
    for (FoldingRange::Vector::const_iterator it = lowerBound; it != upperBound; ++it) {
        /**
         * this range already ok? add it to results
         */
        if ((*it)->start->line() == line) {
            results.push_back(qMakePair((*it)->id, (*it)->flags));
        }

        /**
         * recurse anyway
         */
        foldingRangesStartingOnLine(results, (*it)->nestedRanges, line);
    }
}

QVector<QPair<qint64, TextFolding::FoldingRangeFlags> > TextFolding::foldingRangesForParentRange(qint64 parentRangeId) const
{
    /**
     * toplevel ranges requested or real parent?
     */
    const FoldingRange::Vector *ranges = nullptr;
    if (parentRangeId == -1) {
        ranges = &m_foldingRanges;
    } else if (FoldingRange *range = m_idToFoldingRange.value(parentRangeId)) {
        ranges = &range->nestedRanges;
    }

    /**
     * no ranges => nothing to do
     */
    QVector<QPair<qint64, FoldingRangeFlags> > results;
    if (!ranges)
        return results;

    /**
     * else convert ranges to id + flags and pass that back
     */
    for (FoldingRange::Vector::const_iterator it = ranges->begin(); it != ranges->end(); ++it) {
        results.append(qMakePair((*it)->id, (*it)->flags));
    }
    return results;
}

QString TextFolding::debugDump() const
{
    /**
     * dump toplevel ranges recursively
     */
    return QStringLiteral("tree %1 - folded %2").arg(debugDump(m_foldingRanges, true), debugDump(m_foldedFoldingRanges, false));
}

void TextFolding::debugPrint(const QString &title) const
{
    // print title + content
    printf("%s\n    %s\n", qPrintable(title), qPrintable(debugDump()));
}

QString TextFolding::debugDump(const TextFolding::FoldingRange::Vector &ranges, bool recurse)
{
    /**
     * dump all ranges recursively
     */
    QString dump;
    Q_FOREACH (FoldingRange *range, ranges) {
        if (!dump.isEmpty()) {
            dump += QLatin1Char(' ');
        }

        const QString persistent = (range->flags & Persistent) ? QStringLiteral("p") : QString();
        const QString folded = (range->flags & Folded) ? QStringLiteral("f") : QString();
        dump += QString::fromLatin1("[%1:%2 %3%4 ").arg(range->start->line()).arg(range->start->column()).arg(persistent, folded);

        /**
         * recurse
         */
        if (recurse) {
            QString inner = debugDump(range->nestedRanges, recurse);
            if (!inner.isEmpty()) {
                dump += inner + QLatin1Char(' ');
            }
        }

        dump += QString::fromLatin1("%1:%2]").arg(range->end->line()).arg(range->end->column());
    }
    return dump;
}

bool TextFolding::insertNewFoldingRange(FoldingRange *parent, FoldingRange::Vector &existingRanges, FoldingRange *newRange)
{
    /**
     * existing ranges are non-overlapping and sorted
     * that means, we can search for lower bound of start of range and upper bound of end of range to find all "overlapping" ranges.
     */

    /**
     * first: lower bound of start
     */
    FoldingRange::Vector::iterator lowerBound = qLowerBound(existingRanges.begin(), existingRanges.end(), newRange, compareRangeByStart);

    /**
     * second: upper bound of end
     */
    FoldingRange::Vector::iterator upperBound = qUpperBound(existingRanges.begin(), existingRanges.end(), newRange, compareRangeByEnd);

    /**
     * we may need to go one to the left, if not already at the begin, as we might overlap with the one in front of us!
     */
    if ((lowerBound != existingRanges.begin()) && ((*(lowerBound - 1))->end->toCursor() > newRange->start->toCursor())) {
        --lowerBound;
    }

    /**
     * now: first case, we overlap with nothing or hit exactly one range!
     */
    if (lowerBound == upperBound) {
        /**
         * nothing we overlap with?
         * then just insert and be done!
         */
        if ((lowerBound == existingRanges.end()) || (newRange->start->toCursor() >= (*lowerBound)->end->toCursor()) || (newRange->end->toCursor() <= (*lowerBound)->start->toCursor())) {
            /**
             * insert + fix parent
             */
            existingRanges.insert(lowerBound, newRange);
            newRange->parent = parent;

            /**
             * all done
             */
            return true;
        }

        /**
         * we are contained in this one range?
         * then recurse!
         */
        if ((newRange->start->toCursor() >= (*lowerBound)->start->toCursor()) && (newRange->end->toCursor() <= (*lowerBound)->end->toCursor())) {
            return insertNewFoldingRange((*lowerBound), (*lowerBound)->nestedRanges, newRange);
        }

        /**
         * else: we might contain at least this fold, or many more, if this if block is not taken at all
         * use the general code that checks for "we contain stuff" below!
         */
    }

    /**
     * check if we contain other folds!
     */
    FoldingRange::Vector::iterator it = lowerBound;
    bool includeUpperBound = false;
    FoldingRange::Vector nestedRanges;
    while (it != existingRanges.end()) {
        /**
         * do we need to take look at upper bound, too?
         * if not break
         */
        if (it == upperBound) {
            if (newRange->end->toCursor() <= (*upperBound)->start->toCursor()) {
                break;
            } else {
                includeUpperBound = true;
            }
        }

        /**
         * if one region is not contained in the new one, abort!
         * then this is not well nested!
         */
        if (!((newRange->start->toCursor() <= (*it)->start->toCursor()) && (newRange->end->toCursor() >= (*it)->end->toCursor()))) {
            return false;
        }

        /**
         * include into new nested ranges
         */
        nestedRanges.push_back((*it));

        /**
         * end reached
         */
        if (it == upperBound) {
            break;
        }

        /**
         * else increment
         */
        ++it;
    }

    /**
     * if we arrive here, all is nicely nested into our new range
     * remove the contained ones here, insert new range with new nested ranges we already constructed
     */
    it = existingRanges.erase(lowerBound, includeUpperBound ? (upperBound + 1) : upperBound);
    existingRanges.insert(it, newRange);
    newRange->nestedRanges = nestedRanges;

    /**
     * correct parent mapping!
     */
    newRange->parent = parent;
    Q_FOREACH (FoldingRange *range, newRange->nestedRanges) {
        range->parent = newRange;
    }

    /**
     * all nice
     */
    return true;
}

bool TextFolding::compareRangeByStart(FoldingRange *a, FoldingRange *b)
{
    return a->start->toCursor() < b->start->toCursor();
}

bool TextFolding::compareRangeByEnd(FoldingRange *a, FoldingRange *b)
{
    return a->end->toCursor() < b->end->toCursor();
}

bool TextFolding::compareRangeByStartWithLine(int line, FoldingRange *range)
{
    return (line < range->start->line());
}

bool TextFolding::compareRangeByLineWithStart(FoldingRange *range, int line)
{
    return (range->start->line() < line);
}

bool TextFolding::updateFoldedRangesForNewRange(TextFolding::FoldingRange *newRange)
{
    /**
     * not folded? not interesting! we don't need to touch our m_foldedFoldingRanges vector
     */
    if (!(newRange->flags & Folded)) {
        return false;
    }

    /**
     * any of the parents folded? not interesting, too!
     */
    TextFolding::FoldingRange *parent = newRange->parent;
    while (parent) {
        /**
         * parent folded => be done
         */
        if (parent->flags & Folded) {
            return false;
        }

        /**
         * walk up
         */
        parent = parent->parent;
    }

    /**
     * ok, if we arrive here, we are a folded range and we have no folded parent
     * we now want to add this range to the m_foldedFoldingRanges vector, just removing any ranges that is included in it!
     * TODO: OPTIMIZE
     */
    FoldingRange::Vector newFoldedFoldingRanges;
    bool newRangeInserted = false;
    Q_FOREACH (FoldingRange *range, m_foldedFoldingRanges) {
        /**
         * contained? kill
         */
        if ((newRange->start->toCursor() <= range->start->toCursor()) && (newRange->end->toCursor() >= range->end->toCursor())) {
            continue;
        }

        /**
         * range is behind newRange?
         * insert newRange if not already done
         */
        if (!newRangeInserted && (range->start->toCursor() >= newRange->end->toCursor())) {
            newFoldedFoldingRanges.push_back(newRange);
            newRangeInserted = true;
        }

        /**
         * just transfer range
         */
        newFoldedFoldingRanges.push_back(range);
    }

    /**
     * last: insert new range, if not done
     */
    if (!newRangeInserted) {
        newFoldedFoldingRanges.push_back(newRange);
    }

    /**
     * fixup folded ranges
     */
    m_foldedFoldingRanges = newFoldedFoldingRanges;

    /**
     * folding changed!
     */
    emit foldingRangesChanged();

    /**
     * all fine, stuff done, signal emitted
     */
    return true;
}

bool TextFolding::updateFoldedRangesForRemovedRange(TextFolding::FoldingRange *oldRange)
{
    /**
     * folded? not interesting! we don't need to touch our m_foldedFoldingRanges vector
     */
    if (oldRange->flags & Folded) {
        return false;
    }

    /**
     * any of the parents folded? not interesting, too!
     */
    TextFolding::FoldingRange *parent = oldRange->parent;
    while (parent) {
        /**
         * parent folded => be done
         */
        if (parent->flags & Folded) {
            return false;
        }

        /**
         * walk up
         */
        parent = parent->parent;
    }

    /**
    * ok, if we arrive here, we are a unfolded range and we have no folded parent
    * we now want to remove this range from the m_foldedFoldingRanges vector and include our nested folded ranges!
    * TODO: OPTIMIZE
    */
    FoldingRange::Vector newFoldedFoldingRanges;
    Q_FOREACH (FoldingRange *range, m_foldedFoldingRanges) {
        /**
         * right range? insert folded nested ranges
         */
        if (range == oldRange) {
            appendFoldedRanges(newFoldedFoldingRanges, oldRange->nestedRanges);
            continue;
        }

        /**
         * just transfer range
         */
        newFoldedFoldingRanges.push_back(range);
    }

    /**
     * fixup folded ranges
     */
    m_foldedFoldingRanges = newFoldedFoldingRanges;

    /**
     * folding changed!
     */
    emit foldingRangesChanged();

    /**
     * all fine, stuff done, signal emitted
     */
    return true;
}

void TextFolding::appendFoldedRanges(TextFolding::FoldingRange::Vector &newFoldedFoldingRanges, const TextFolding::FoldingRange::Vector &ranges) const
{
    /**
     * search for folded ranges and append them
     */
    Q_FOREACH (FoldingRange *range, ranges) {
        /**
         * itself folded? append
         */
        if (range->flags & Folded) {
            newFoldedFoldingRanges.push_back(range);
            continue;
        }

        /**
         * else: recurse!
         */
        appendFoldedRanges(newFoldedFoldingRanges, range->nestedRanges);
    }
}

QJsonDocument TextFolding::exportFoldingRanges() const
{
    QJsonArray array;
    exportFoldingRanges(m_foldingRanges, array);
    QJsonDocument folds;
    folds.setArray(array);
    return folds;
}

void TextFolding::exportFoldingRanges(const TextFolding::FoldingRange::Vector &ranges, QJsonArray &folds)
{
    /**
     * dump all ranges recursively
     */
    Q_FOREACH (FoldingRange *range, ranges) {
        /**
         * construct one range and dump to folds
         */
        QJsonObject rangeMap;
        rangeMap[QStringLiteral("startLine")] = range->start->line();
        rangeMap[QStringLiteral("startColumn")] = range->start->column();
        rangeMap[QStringLiteral("endLine")] = range->end->line();
        rangeMap[QStringLiteral("endColumn")] = range->end->column();
        rangeMap[QStringLiteral("flags")] = (int)range->flags;
        folds.append(rangeMap);

        /**
         * recurse
         */
        exportFoldingRanges(range->nestedRanges, folds);
    }
}

void TextFolding::importFoldingRanges(const QJsonDocument &folds)
{
    Q_FOREACH (FoldingRange *range, m_foldingRanges) {
        unfoldRange(range->id);
    }
    /**
     * try to create all folding ranges
     */
    Q_FOREACH (const QJsonValue &rangeVariant, folds.array()) {
        /**
         * get map
         */
        QJsonObject rangeMap = rangeVariant.toObject();

        /**
         * construct range start/end
         */
        const KTextEditor::Cursor start(rangeMap[QStringLiteral("startLine")].toInt(), rangeMap[QStringLiteral("startColumn")].toInt());
        const KTextEditor::Cursor end(rangeMap[QStringLiteral("endLine")].toInt(), rangeMap[QStringLiteral("endColumn")].toInt());

        /**
         * check validity (required when loading a possibly broken folding state from disk)
         */
        if (start >= end ||
            (m_buffer.document() && // <-- unit test katetextbuffertest does not have a KTE::Document assigned
               (!KTextEditor::DocumentCursor(m_buffer.document(), start).isValidTextPosition() ||
                !KTextEditor::DocumentCursor(m_buffer.document(), end).isValidTextPosition()))
           )
        {
            continue;
        }

        /**
         * get flags
         */
        const int rawFlags = rangeMap[QStringLiteral("flags")].toInt();
        FoldingRangeFlags flags;
        if (rawFlags & Persistent) {
            flags = Persistent;
        }
        if (rawFlags & Folded) {
            flags = Folded;
        }

        /**
         * create folding range
         */
        newFoldingRange(KTextEditor::Range(start, end), flags);
    }
}

}
