/*  This file is part of the KDE project
    Copyright (C) 2003 Matthias Kretz <kretz@kde.org>
    Copyright (C) 2004 Frans Englich <frans.englich@telia.com>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License version 2 as published by the Free Software Foundation.

    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., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.

*/

#ifndef KCMODULEPROXY_H
#define KCMODULEPROXY_H

#include <qwidget.h>
#include <qstringlist.h>

#include <kservice.h>
#include <kdelibs_export.h>

class KAboutData;
class KCModule;
class KCModuleInfo;
class KInstance;
class KProcess;

/**
 *
 * @brief Encapsulates a @ref KCModule for embedding.
 *
 * @ref KCModuleProxy is a wrapper for KCModule intended for cases where 
 * modules are to be displayed. It ensures layout is consistent, handles 
 * root/administrator modules and in general takes care of the details 
 * needed for making a module available in an interface. A KCModuleProxy 
 * can be treated as a QWidget, without worrying about the details specific 
 * for modules such as library loading. KCModuleProxy is not a sub class of KCModule 
 * but its API closely resembles KCModule's.\n
 * Usually, an instance is created by passing one of the constructors a @ref KService::Ptr, 
 * @ref KCModuleInfo or simply the name of the module and then added to the layout as any 
 * other widget. \n
 * When the user have changed the module, @ref changed( bool ) as well as @ref changed ( KCModuleProxy * )
 * is emitted. KCModuleProxy does not take care of prompting for saving - if the object is deleted while 
 * changes is not saved the changes will be lost. @ref changed() returns true if changes are unsaved. \n
 * \n
 * KCModuleProxy does not take care of authorization of KCModules. \n
 * KCModuleProxy do lazy loading, meaning the library will not be loaded or 
 * any other initialization done before its show() function is called. This means 
 * modules will only be loaded when they are actually needed as well as it is possible to 
 * load many KCModuleProxy without any speed penalty.
 *
 * KCModuleProxy should be used in all cases where modules are embedded in order to 
 * promote code efficiency and usability consistency.
 * 
 * @author Frans Englich <frans.englich@telia.com>
 * @author Matthias Kretz <kretz@kde.org>
 *
 */
class KUTILS_EXPORT KCModuleProxy : public QWidget
{
Q_OBJECT

	friend class KCModuleProxyRootCommunicatorImpl;

public:

	/**
	 * Constructs a KCModuleProxy from a KCModuleInfo class.
	 *
	 * @param info The KCModuleInfo to construct the module from.
	 *
	 * @param withFallback If set to true and loading of the module fails, 
	 * a alternative will be tried, resulting in the module appearing in its 
	 * own window, if at all.
	 * The embedded module will be load()ed.
	 *
	 * @param args This is used in the implementation and is internal. Use the 
	 * default.
	 */
	KCModuleProxy( const KCModuleInfo & info, bool withFallback = true,
			QWidget * parent = 0, const char * name = 0,
			const QStringList & args = QStringList() );

	/**
	 * Constructs a KCModuleProxy from a module's service name, which is 
	 * equivalent to the desktop file for the kcm without the ".desktop" part. 
	 * Otherwise equal to the one above.
	 *
	 * @param serviceName The module's service name to construct from.
	 */
	KCModuleProxy( const QString& serviceName, bool withFallback = true, 
			QWidget * parent = 0, const char * name = 0,
			const QStringList & args = QStringList() );
			
	/**
	 * Constructs a KCModuleProxy from KService. Otherwise equal to the one above.
	 *
	 * @param service The KService to construct from.
	 */
	KCModuleProxy( const KService::Ptr& service, bool withFallback = true, 
			QWidget  * parent = 0, const char * name = 0,
			const QStringList & args = QStringList() );

	/**
	 * Default destructor
	 */
	~KCModuleProxy();

	/**
	 * Calling it will cause the contained module to 
	 * run its load() routine.
	 */
	void load();

	/**
	 * Calling it will cause the contained module to 
	 * run its save() routine.
	 *
	 * If the module was not modified, it will not be asked
	 * to save.
	 */
	void save();

	/**
	 * @return the module's quickHelp();
	 */
	QString quickHelp() const;

	/**
	 * @return the module's aboutData()
	 */
	const KAboutData * aboutData() const;

	/**
	 * @return what buttons the module
	 * needs
	 */
	int buttons() const;

	/**
	 * @return The module's custom root 
	 * message, if it has one
	 * @deprecated
	 */
	QString rootOnlyMsg() const;
	//KDE4 remove. There's a limit for convenience functions, 
	// this one's available via moduleInfo()-> and realModule()->

	/**
	 * @return If the module is a root module.
	 * @deprecated
	 */
	bool useRootOnlyMsg() const;
	//KDE4 remove. There's a limit for convenience functions, 
	// this one's available via moduleInfo()-> and realModule()->

	/**
	 * Returns the embedded KCModule's KInstance.
	 * @return The module's KInstance.
	 * @deprecated
	 */
	KInstance * instance() const;
	//KDE4 remove. There's a limit for convenience functions, 
	// this one's available via realModule()

	/**
	 * @return true if the module is modified 
	 * and needs to be saved.
	 */
	bool changed() const;

	/**
	 * Returns whether the module is running in root mode. A module is in root mode
	 * when @ref runAsRoot() has been called. A session under root user will never reach 
	 * root mode.
	 *
	 * @note realModule() will return null when the module is running in root mode.
	 *
	 * @return true if the module is running with root privileges
	 * @since 3.4
	 */
	bool rootMode() const;

	/**
	 * Access to the actual module. However, if the module is 
	 * running in root mode, see @ref rootMode(), this function returns 
	 * a NULL pointer, since the module is in another process. It may also 
	 * return NULL if anything goes wrong.
	 *
	 * @return the encapsulated module. 
	 */
	KCModule* realModule() const;

	/**
	 * @return a KCModuleInfo for the encapsulated
	 * module
	 */
	const KCModuleInfo& moduleInfo() const;

	/**
	 * Returns the DCOP the module's @ref DCOPClient 
	 * and @ref DCOPObject has(they are identical).
	 *
	 * @since 3.4
	 */
	QCString dcopName() const;

public slots:
	
	/**
	 * Calling this will cause the module to be run in 
	 * "administrator mode".
	 *
	 * @since 3.4
	 */
	void runAsRoot();

	/**
	 * Calling it will cause the contained module to 
	 * load its default values.
	 */
	void defaults();
	
	/**
	 * Calling this, results in deleting the contained 
	 * module, and unregistering from DCOP. A similar result is achieved
	 * by deleting the KCModuleProxy itself.
	 *
	 * @since 3.4
	 */
	void deleteClient();

signals:

	/*
	 * This signal is emitted when the contained module is changed.
	 */
	void changed( bool state );
	
	/**
	 * This is emitted in the same situations as in the one above. Practical 
	 * when several KCModuleProxys are loaded.
	 *
	 * @since 3.4
	 */
	void changed( KCModuleProxy* mod );

	/**
	 * When a module running with root privileges and exits, returns to normal mode, the 
	 * childClosed() signal is emitted.
	 *
	 * @since 3.4
	 */
	void childClosed();

	/*
	 * This signal is relayed from the encapsulated module, and 
	 * is equivalent to the module's own quickHelpChanged() signal.
	 *
	 * @since 3.4
	 */
	void quickHelpChanged();

protected:

	/**
	 * Reimplemented for internal purposes. Makes sure the encapsulated 
	 * module is loaded before the show event is taken care of.
	 */
	void showEvent( QShowEvent * );

	/**
	 * Internal intialization function, called by the constructors.
	 *
	 * @internal
	 * @since 3.4
	 */
	void init( const KCModuleInfo& info );


	/**
	 * Emits the quickHelpChanged signal.
	 * @since 3.4
	 */
	void emitQuickHelpChanged();

private slots:

   /**
	* Calls the function @p function of the root module's KCModuleProxy 
	* DCOP interface.
	* 
	* @param function the function signature of the function to call.
	* @since 3.4
	*/
	void callRootModule( const QCString& function );

	/**
	 * This is called when the module exits from root mode. It zeroes 
	 * pointers, deletes the embed window, and so forth.
	 *
	 * @since 3.4
	 */
	void rootExited();

	/**
	 * Makes sure the proper variables is set and signals are emitted.
	 */
	void moduleChanged( bool );

	/**
	 * Zeroes d->kcm
	 */
	void moduleDestroyed();

	/**
	 * Gets called by DCOP when an application closes.
	 * Is used to (try to) reload a KCM which previously 
	 * was loaded.
	 *
	 * @since 3.4
	 */
	void applicationRemoved( const QCString& app );

private:
	
	class KCModuleProxyPrivate;
	KCModuleProxyPrivate * d;
};

#endif // KCMODULEPROXY_H
// vim: sw=4 ts=4 noet
