/*
 * Copyright (C) 2001-2008 Justin Karneges, Martin Hostettler
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

// Generic tab completion support code.

#ifndef TABCOMPLETION_H
#define TABCOMPLETION_H

#include "msgmle.h"

#include <QObject>

class TabCompletion : public QObject {
    Q_OBJECT
public:
    TabCompletion(QObject *parent = nullptr);
    ~TabCompletion() = default;

    void       setTextEdit(QTextEdit *mle);
    QTextEdit *getTextEdit();

    virtual void reset();
    void         tryComplete();

protected:
    QString toComplete_;
    bool    atStart_;

    virtual void        setup(QString str, int pos, int &start, int &end);
    virtual QStringList possibleCompletions()      = 0;
    virtual QStringList allChoices(QString &guess) = 0;

    virtual void highlight(bool set);
    QColor       highlight_;

private:
    QString longestCommonPrefix(QStringList list);
    QString suggestCompletion(bool *replaced);

    void moveCursorToOffset(QTextCursor &cur, int offset, QTextCursor::MoveMode mode = QTextCursor::MoveAnchor);

    enum class TypingStatus : char {
        Normal,
        TabPressed,         // initial completion
        TabbingCompletions, // switch to tab through multiple
        MultipleSuggestions
    };

    QTextCursor  replacementCursor_;
    TypingStatus typingStatus_;
    QStringList  suggestedCompletion_;
    int          suggestedIndex_;

    QTextEdit *textEdit_;
};

#endif // TABCOMPLETION_H
