/**
 * @file Plugins/pluginmanager_p.h
 * @brief Private implementation of the plugin manager
 *
 * 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_P_H
#define __PLUGINS_PLUGINMANAGER_P_H

#include <QObject>
#include <QSharedData>
#include <QExplicitlySharedDataPointer>
#include <QScopedPointer>
#include <QPluginLoader>

namespace eVaf {
namespace Plugins {

class iPlugin;
class iPluginFactory;

namespace Internal {

class Plugin;
class Module;

/**
 * Internal implementation of the plugin manager
 */
class PluginManagerPrivate : public QObject
{
    Q_OBJECT

public:

    /// Ctr.
    PluginManagerPrivate();

    /// Dtr.
    virtual ~PluginManagerPrivate();

    /**
     * Initializes the private plugin manager object
     * @return True; false if failed
     */
    bool init();

    /**
     * Finalizes the private plugin manager object
     */
    void done();

    /**
     * Loads and initializes plugins
     * @return True; false if failed
     */
    bool loadPlugins();

    /**
     * Finalizes and unloads plugins
     */
    void unloadPlugins();


private: // Members

    /// List of all the modules
    QList<QExplicitlySharedDataPointer<Module> > mModules;

    /// List of all the plugins
    QList<QExplicitlySharedDataPointer<Plugin> > mPlugins;


private: // Methods

    /**
     * Returns the module object by its name
     * @param name Name of the module
     * @return Module object or 0 if not found
     */
    Module * moduleByName(QString const & name) const;

};

/**
 * One external module implementing the iPluginFactory or the iPlugin interfaces.
 *
 * This class is a wrapper around the external module.
 */
class Module : public QSharedData
{
public:

    /**
     * Ctr.
     * @param name Name of the module
     */
    Module(QString const & name);

    /// Dtr.
    ~Module();

    /// Returns true if the module is loaded
    bool isLoaded() const { return mLoader != 0; }

    /// The name of the module
    QString const & name() const { return mName; }

    /**
     * Loads the module
     * @return True; false if failed
     */
    bool load();

    /// Unloads the module
    void unload();

    /**
     * Creates the requested iPlugin interface object
     * @param name Name of the interface
     * @return The iPlugin interface object or 0 if failed
     */
    iPlugin * create(QString const & name);


private: // Members

    /// Name of the module
    QString mName;

    /// Plugin loader
    QScopedPointer<QPluginLoader> mLoader;

    /// Plugin's root component
    QObject * mRoot;

    /// The iPlugin interface object if the module implements only one iPlugin interface
    iPlugin * mPlugin;

    /// The iPluginFactory interface object if the module implements more than one iPluginFactory interface
    iPluginFactory * mPluginFactory;

};

/**
 * One iPlugin interface object.
 *
 * This class is a wrapper around the plugin.
 */
class Plugin : public QSharedData
{
public:

    /**
     * Ctr.
     * @param module The Module implementing this iPlugin interface
     * @param name Name of the plugin
     * @param args Arguments for the plugin initialization
     */
    Plugin(Module * module, QString const & name, QString const & args);

    /// Dtr.
    ~Plugin();

    /// The iPlugin interface
    iPlugin * plugin() const { return mPlugin; }

    /// The name of the plugin
    QString const & name() const { return mName; }

    /**
     * Loads the plugin
     * @return True; false if failed
     */
    bool load();

    /// Unloads the plugin
    void unload();

    /**
     * Initializes the plugin
     * @return True; false if failed
     */
    bool init();

    /// Uninitializes the plugin
    void done();


private: // Members

    /// Module implementing this iPlugin interface
    Module * mModule;

    /// Name of the plugin
    QString mName;

    /// Arguments for the initialization
    QString mArgs;

    /// The iPlugin interface object
    iPlugin * mPlugin;

};

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

#endif // pluginmanager_p.h