/**
 * @file Plugins/pluginmanager.h
 * @brief Manager for loadable modules (plugins)
 *
 * Copyright (c) 2011-2019 Enar Vaikene
 *
 * This file is part of the eVaf C++ cross-platform application development framework.
 *
 * This file can be used under the terms of the GNU General Public License
 * version 3.0 as published by the Free Software Foundation and appearing in
 * the file LICENSE included in the packaging of this file. Please review the
 * the following information to ensure the GNU General Public License version
 * 3.0 requirements will be met: http://www.gnu.org/copyleft/gpl.html.
 *
 * Alternatively, this file may be used in accordance with the Commercial License
 * Agreement provided with the Software.
 */

#ifndef __PLUGINS_PLUGINMANAGER_H
#define __PLUGINS_PLUGINMANAGER_H

#include "libplugins.h"

#include <version_rc.h>

#include <QObject>
#include <QString>
#include <QScopedPointer>

namespace eVaf {

/**
 * Library for managing loadable modules (plugins).
 *
 * The Plugins library adds loadable modules (plugins) support to the eVaf application. A module is one
 * external library (.so or .dll file) that implements one or more plugins. A plugin is an individual object
 * that is created and initialized as one entirety.
 *
 * Modules are loaded and plugins created by the plugin manager. Plugin manager uses the application's
 * XML file to define which modules should be loaded and which plugins to be created.
 */
namespace Plugins {

/**
 * Internal implementation of the plugin manager library.
 */
namespace Internal {
    class PluginManagerPrivate;
}

/**
 * Expands plugin names for the selected platform.
 * @param name Name of the plugin
 * @return Expanded plugin name
 *
 * This function expands the plugin name so that it becomes valid for the selected platform.
 * For example, on Linux it adds the prefix "lib" to the beginning and extension ".so" to the end.
 */
inline QString expandPluginName(QString const & name)
{
#ifdef Q_OS_WIN32
#  ifdef Q_CC_MINGW
    return "lib" + name + ".dll";
#  else
    return name + ".dll";
#  endif
#elif defined Q_OS_LINUX
    return "lib" + name + ".so";
#elif defined Q_OS_CYGWIN
    return "cyg" + name + ".dll";
#elif defined Q_OS_MACOS
    return "lib" + name + ".dylib";
#else
    return name;
#endif
}

/**
 * Plugin manager for eVaf applications.
 */
class PLUGINS_EXPORT PluginManager : public QObject
{
    Q_OBJECT

public:

    /// Ctr.
    PluginManager();

    /// Dtr.
    virtual ~PluginManager();

    /**
     * Returns the plugin manager's instance
     */
    static PluginManager * instance();

    /**
     * Initializes the plugin manager.
     * @return True if ok; false if initialization failed.
     *
     * This function initializes the plugin manager. External modules are loaded and plugin objects
     * created in this function.
     */
    bool init();

    /**
     * Finalizes the plugin manager.
     *
     * This function finalizes the plugin manager. Plugin objects are destroyed and external modules
     * unloaded in this function.
     */
    void done();


signals:

    /**
     * Plugins loaded signal.
     *
     * This signal is emitted when all the modules are loaded and plugin objects created.
     */
    void pluginsLoaded();

    /**
     * Plugins unloaded signal.
     *
     * This signal is emitted when all the plugin objects are destroyed and modules unloaded.
     */
    void pluginsUnloaded();


private:

    QScopedPointer<Internal::PluginManagerPrivate> d;

};

} // namespace eVaf::Plugins
} // namespace eVaf

#endif // pluginmanager.h