/***************************************************************************
    KwaveFilterPlugin.h  -  generic class for filter plugins with setup
                             -------------------
    begin                : Sat Jun 07 2003
    copyright            : (C) 2003 by Thomas Eschenbacher
    email                : Thomas.Eschenbacher@gmx.de
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 _KWAVE_FILTER_PLUGIN_H_
#define _KWAVE_FILTER_PLUGIN_H_

#include "config.h"

#include <qobject.h>
#include <qstring.h>
#include "mt/SignalProxy.h"
#include "libkwave/KwavePlugin.h"
#include "libkwave/KwavePluginSetupDialog.h"

class ConfirmCancelProxy;
class QProgressDialog;
class QStringList;
class QWidget;

namespace Kwave {

    class SampleSource;
    class SampleSink;

    class FilterPlugin: public KwavePlugin
    {
	Q_OBJECT
    public:

	/** Constructor */
	FilterPlugin(const PluginContext &context);

	/** Destructor */
	virtual ~FilterPlugin();

	/** Reads values from the parameter list */
	virtual int interpreteParameters(QStringList & /* params */) = 0;

	/**
	* Creates a setup dialog an returns a pointer to it.
	*/
	virtual KwavePluginSetupDialog *createDialog(QWidget * /*parent*/) = 0;

	/**
	* Creates a multi-track filter with the given number of tracks
	* @param tracks number of tracks that the filter should have
	* @return pointer to the filter or null if failed
	*/
	virtual Kwave::SampleSource *createFilter(unsigned int tracks) = 0;

	/**
	* Shows a dialog for setting up the filter plugin
	* @see KwavePlugin::setup
	*/
	virtual QStringList *setup(QStringList &previous_params);

	/** Does the filter operation and/or pre-listen */
	virtual void run(QStringList);

	/** Aborts the process (if running). */
	virtual int stop();

	/**
	* Returns true if the parameters have changed during pre-listen.
	* @note this default implementation always returns false.
	*/
	virtual bool paramsChanged();

	/**
	* Update the filter with new parameters if it has changed
	* changed during the pre-listen.
	* @param filter the Kwave::SampleSource to be updated, should be the
	*               same one as created with createFilter()
	* @param force if true, even update if no settings have changed
	*/
	virtual void updateFilter(Kwave::SampleSource *filter, bool force=0);

	/**
	* Returns a verbose name of the performed action. Used for giving
	* the undo action a readable name.
	* The name must already be localized !
	*/
	virtual QString actionName() = 0;

    signals:

	/**
	* emitted when the user pressed the cancel button
	* of the progress dialog
	* @internal
	*/
	void sigCancelPressed();

    protected slots:

	/** Start the pre-listening */
	void startPreListen();

	/** Stop the pre-listening */
	void stopPreListen();

	/** forward changes of the progress dialog to a signal proxy */
	void forwardProgress(unsigned int progress);

	/** forward press of the cancel button int the progress dialog */
	void forwardCancel();

	/** update the progress dialog */
	void updateProgress();

	/**
	* called when the user has pressed "Cancel" in the progress
	* dialog and also has confirmed the cancel confirmation
	* message box.
	*/
	void cancel();

    private:
	/** List of parameters */
	QStringList m_params;

	/** flag for stopping the process */
	bool m_stop;

	/** flag for indicating pre-listen mode */
	bool m_listen;

	/** a progress dialog, if the audio processing takes longer... */
	QProgressDialog *m_progress;

	/** signal proxy for the progress / dialog */
	SignalProxy1< unsigned int > *m_spx_progress;

	/**
	* proxy dialog that asks for configmation if the user
	* pressed cancel in the progress dialog
	*/
	ConfirmCancelProxy *m_confirm_cancel;

	/** flag for pausing the process */
	bool m_pause;

	/**
	 * a sample sink, used either for pre-listen
	 * or for normal processing
	 */
	Kwave::SampleSink *m_sink;

    };
}

#endif /* _KWAVE_FILTER_PLUGIN_H_ */
