/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
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** use the contact form at http://www.qt.io/contact-us.
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** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
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** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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****************************************************************************/

#ifndef DIFFER_H
#define DIFFER_H

#include "diffeditor_global.h"
#include <QString>

QT_BEGIN_NAMESPACE
template <class K, class T>
class QMap;
QT_END_NAMESPACE

namespace DiffEditor {

class DIFFEDITOR_EXPORT Diff
{
public:
    enum Command {
        Delete,
        Insert,
        Equal
    };
    Command command;
    QString text;
    Diff(Command com, const QString &txt = QString());
    Diff();
    bool operator==(const Diff &other) const;
    bool operator!=(const Diff &other) const;
    QString toString() const;
    static QString commandString(Command com);
};

class DIFFEDITOR_EXPORT Differ
{
public:
    enum DiffMode
    {
        CharMode,
        WordMode,
        LineMode
    };
    Differ();
    QList<Diff> diff(const QString &text1, const QString &text2);
    QList<Diff> unifiedDiff(const QString &text1, const QString &text2);
    void setDiffMode(DiffMode mode);
    DiffMode diffMode() const;
    static QList<Diff> merge(const QList<Diff> &diffList);
    static QList<Diff> cleanupSemantics(const QList<Diff> &diffList);
    static QList<Diff> cleanupSemanticsLossless(const QList<Diff> &diffList);

    static void splitDiffList(const QList<Diff> &diffList,
                              QList<Diff> *leftDiffList,
                              QList<Diff> *rightDiffList);
    static QList<Diff> moveWhitespaceIntoEqualities(const QList<Diff> &input);
    static void diffWithWhitespaceReduced(const QString &leftInput,
                                          const QString &rightInput,
                                          QList<Diff> *leftOutput,
                                          QList<Diff> *rightOutput);
    static void unifiedDiffWithWhitespaceReduced(const QString &leftInput,
                                          const QString &rightInput,
                                          QList<Diff> *leftOutput,
                                          QList<Diff> *rightOutput);
    static void ignoreWhitespaceBetweenEqualities(const QList<Diff> &leftInput,
                                      const QList<Diff> &rightInput,
                                      QList<Diff> *leftOutput,
                                      QList<Diff> *rightOutput);
    static void diffBetweenEqualities(const QList<Diff> &leftInput,
                                      const QList<Diff> &rightInput,
                                      QList<Diff> *leftOutput,
                                      QList<Diff> *rightOutput);

private:
    QList<Diff> preprocess1AndDiff(const QString &text1, const QString &text2);
    QList<Diff> preprocess2AndDiff(const QString &text1, const QString &text2);
    QList<Diff> diffMyers(const QString &text1, const QString &text2);
    QList<Diff> diffMyersSplit(const QString &text1, int x,
                               const QString &text2, int y);
    QList<Diff> diffNonCharMode(const QString &text1, const QString &text2);
    QStringList encode(const QString &text1,
                       const QString &text2,
                       QString *encodedText1,
                       QString *encodedText2);
    QString encode(const QString &text,
                   QStringList *lines,
                   QMap<QString, int> *lineToCode);
    int findSubtextEnd(const QString &text,
                       int subTextStart);
    DiffMode m_diffMode;
    DiffMode m_currentDiffMode;
};

} // namespace DiffEditor

#endif // DIFF_H