/***************************************************************************
    qgspythonrunner.h
    ---------------------
    begin                : May 2011
    copyright            : (C) 2011 by Martin Dobias
    email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
#ifndef QGSPYTHONRUNNER_H
#define QGSPYTHONRUNNER_H

#include "qgis_core.h"
#include "qgis_sip.h"

#include <QString>

/**
 * \ingroup core
 * \brief Utility class for running Python commands from various parts of QGIS.
 *
 * There is no direct Python support in the core library, so it is expected
 * that application with Python support creates a subclass that implements
 * pure virtual function(s) during the initialization. The static methods
 * will then work as expected.
 */
class CORE_EXPORT QgsPythonRunner
{
  public:
    /**
     * Returns TRUE if the runner has an instance
     * (and thus is able to run commands)
    */
    static bool isValid();

    //! Execute a Python statement
    static bool run( const QString &command, const QString &messageOnError = QString() );

    /**
     * Execute a Python \a filename, showing an error message if one occurred.
     * \returns true if no error occurred
     */
    static bool runFile( const QString &filename, const QString &messageOnError = QString() );

    //! Eval a Python statement
    static bool eval( const QString &command, QString &result SIP_OUT );

    //! Set sys.argv
    static bool setArgv( const QStringList &arguments, const QString &messageOnError = QString() );

    /**
     * Assign an instance of Python runner so that run() can be used.
     * This method should be called during app initialization.
     * Takes ownership of the object, deletes previous instance.
    */
    static void setInstance( QgsPythonRunner *runner SIP_TRANSFER );

  protected:
    //! Protected constructor: can be instantiated only from children
    QgsPythonRunner() = default;
    virtual ~QgsPythonRunner() = default;

    //! Runs the given statement.
    virtual bool runCommand( QString command, QString messageOnError = QString() ) = 0;

    //! Runs the code from the given file.
    virtual bool runFileCommand( const QString &filename, const QString &messageOnError = QString() ) = 0;

    //! Evaluates the given expression, producing a result.
    virtual bool evalCommand( QString command, QString &result ) = 0;

    //! Sets sys.argv to the given arguments.
    virtual bool setArgvCommand( const QStringList &arguments, const QString &messageOnError = QString() ) = 0;

    static QgsPythonRunner *sInstance;
};

#endif // QGSPYTHONRUNNER_H
