/*
    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, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA  02110-1301, USA.

    ---
    Copyright (C) 2010 Miha Čančula <miha.cancula@gmail.com>
 */

#ifndef CANTOR_DEFAULTVARIABLEMODEL_H
#define CANTOR_DEFAULTVARIABLEMODEL_H

#include <QAbstractTableModel>
#include "session.h"
#include "expression.h"

namespace Cantor {

class DefaultVariableModelPrivate;

/**
 * @brief
 * This DefaultVariableModel class is an implementation of QAbstractItemModel
 * that can be used with the Variable Manager plugin.
 *
 * For most uses the addVariable(), removeVariable() and clearVariables() methods are sufficient.
 * They can be used from session (directly or by connecting signals to them), or called from
 * a subclass.
 *
 * DefaultVariableModel uses the session to run expressions for changing variables, and it
 * gets the commands from the backend's VariableManagementExtension.
 * If you do not want this behavior, you can subclass it and reimplement data() and/or setData().
 *
 * @see Session::variableModel()
 */
class CANTOR_EXPORT DefaultVariableModel : public QAbstractTableModel
{
    Q_OBJECT
    Q_PROPERTY(Session* session READ session)

public:

    /**
     * A structure representing a variable.
     */
    struct Variable
    {
        /**
         * The variable's name
         */
        QString name;
        /**
         * The variable's value, represented as a string
         */
        QString value;
    };

    /**
     * Default constructor
     * If you are constructing a DefaultVariableModel without subclassing, the @p session must be valid
     * and its backends must support a VariableManagementExtension.
     *
     * This requirement can be avoided by reimplementing setData() in a subclass.
     *
     * @param session the session this Model belongs to, also becomes the Model's parent.
     */
    explicit DefaultVariableModel(Session* session);
    virtual ~DefaultVariableModel();

    /**
     * Get the session which created this Model and whose variables it contains
     * @return the session
     */
    Session* session() const;

public Q_SLOTS:
    /**
     * Adds a variable to the model.
     * If a variable with the same name already exists, it will be overwritten.
     * @param name the name of the variable
     * @param value the value of the variable
     */
    void addVariable(const QString& name, const QString& value);
    /**
     * Convenience method, equivalent to addVariable(variable.name, variable.value)
     * @param variable the variable to add
     */
    void addVariable(const Variable& variable);
    /**
     * Remove the variable @p name from the model.
     * If a variable with the specified @p name doesn't exists, this method does nothing.
     * @param name the name of the variable to remove
     */
    void removeVariable(const QString& name);
    /**
     * Convenience method, equivalent to removeVariable(variable.name)
     * @param variable the variable to remove
     */
    void removeVariable(const Variable& variable);
    /**
     * Clears all variables from the model
     */
    void clearVariables();


protected:
    virtual QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const;
    virtual bool setData(const QModelIndex& index, const QVariant& value, int role = Qt::EditRole);

    virtual int columnCount(const QModelIndex& parent = QModelIndex()) const;
    virtual int rowCount(const QModelIndex& parent = QModelIndex()) const;
    virtual QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const;
    virtual Qt::ItemFlags flags(const QModelIndex& index) const;

    enum Column
    {
        NameColumn = 0,
        ValueColumn = 1,
        ColumnCount = 2
    };

private:

    DefaultVariableModelPrivate* const d_ptr;
    Q_DECLARE_PRIVATE(DefaultVariableModel)
};

bool operator==(const Cantor::DefaultVariableModel::Variable& one, const Cantor::DefaultVariableModel::Variable& other);

}

#endif // CANTOR_DEFAULTVARIABLEMODEL_H