//  UndoRedoModel.hpp
//
//  Copyright (C) 2016  Jaye Evins <evins@snaught.com>
//
//  This file is part of gLabels-qt.
//
//  gLabels-qt 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 3 of the License, or
//  (at your option) any later version.
//
//  gLabels-qt 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 gLabels-qt.  If not, see <http://www.gnu.org/licenses/>.
//

#ifndef UndoRedoModel_hpp
#define UndoRedoModel_hpp


#include "model/Model.hpp"

#include <QList>
#include <QObject>
#include <QString>


namespace glabels
{

        ///
        /// UndoRedoModel
        ///
        class UndoRedoModel : public QObject
        {
                Q_OBJECT


                /////////////////////////////////
                // Life Cycle
                /////////////////////////////////
        public:
                UndoRedoModel( model::Model* model );
                virtual ~UndoRedoModel() = default;


                /////////////////////////////////
                // Public Methods
                /////////////////////////////////
        public:
                void checkpoint( const QString& description );
                void undo();
                void redo();
                bool canUndo() const;
                bool canRedo() const;
                QString undoDescription() const;
                QString redoDescription() const;


                /////////////////////////////////
                // Slots
                /////////////////////////////////
        private slots:
                void onSelectionChanged();


                /////////////////////////////////
                // Signals
                /////////////////////////////////
        signals:
                void changed();


                /////////////////////////////////
                // Private types
                /////////////////////////////////
        private:
                class State
                {
                public:
                        State( model::Model* model, const QString& description );
                        ~State();

                        model::Model* model;
                        QString       description;
                };

                class Stack
                {
                public:
                        Stack();
                        ~Stack();

                        void push( State* state );
                        State* pop();
                        const State* topState() const;
                        bool isEmpty() const;
                        void clear();

                private:
                        QList<State*> list;
                };


                /////////////////////////////////
                // Private data
                /////////////////////////////////
        private:
                model::Model*  mModel;

                Stack          mUndoStack;
                Stack          mRedoStack;

                bool           mNewSelection;
                QString        mLastDescription;

        };

}


#endif // UndoRedoModel_hpp
