/***************************************************************************
 *   Copyright (c) 2015 Eivind Kvedalen <eivind@kvedalen.name>             *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   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                              *
 *                                                                         *
 ***************************************************************************/

#ifndef EXPRESSIONBINDING_H
#define EXPRESSIONBINDING_H

#include <memory>
#include <string>
#include <App/ObjectIdentifier.h>
#include <QPalette>
#include <boost/signals2.hpp>


namespace App
{
class Expression;
}

class ExpressionLabel;
class QLineEdit;

namespace Gui
{

class GuiExport ExpressionBinding
{
public:
    ExpressionBinding();
    virtual ~ExpressionBinding();

    virtual void bind(const App::ObjectIdentifier& _path);
    virtual void bind(const App::Property& prop);
    bool isBound() const;
    void unbind();
    virtual bool apply(const std::string& propName);
    virtual bool apply();
    bool hasExpression() const;

    // auto apply means that the python code is issued not only on apply() but
    // also on setExpression
    bool autoApply() const
    {
        return m_autoApply;
    }
    void setAutoApply(bool value)
    {
        m_autoApply = value;
    }

protected:
    const App::ObjectIdentifier& getPath() const
    {
        return path;
    }
    std::shared_ptr<App::Expression> getExpression() const;
    std::string getExpressionString(bool no_throw = true) const;
    std::string getEscapedExpressionString() const;
    bool assignToProperty(const std::string& propName, double);
    virtual void setExpression(std::shared_ptr<App::Expression> expr);

    // gets called when the bound expression is changed, either by this binding or any external action
    virtual void onChange()
    {}

private:
    App::ObjectIdentifier path;
    std::shared_ptr<App::Expression> lastExpression;

protected:
    void expressionChange(const App::ObjectIdentifier& id);
    void objectDeleted(const App::DocumentObject&);
    void onDocumentDeleted(const App::Document&);
    boost::signals2::scoped_connection expressionchanged;
    boost::signals2::scoped_connection objectdeleted;
    boost::signals2::scoped_connection documentdeleted;
    bool m_autoApply {false};
};

class GuiExport ExpressionWidget: public ExpressionBinding
{
public:
    ExpressionWidget();
    QPixmap getIcon(const char* name, const QSize& size) const;

protected:
    void makeLabel(QLineEdit* parent);

protected:
    ExpressionLabel* iconLabel {nullptr};
    QPalette defaultPalette;
    int iconHeight {-1};
};

}  // namespace Gui

#endif  // EXPRESSIONBINDING_H