/**
 * \file QSelectionManager.h
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Richard Heck
 * \author Et Alia
 *
 * Full author contact details are available in file CREDITS.
 */

#ifndef QSELECTIONMANAGER_H
#define QSELECTIONMANAGER_H

#include "Dialog.h"
#include <QObject>
#include <QKeyEvent>
#include <QStringList>
#include <QStringListModel>
#include <QListView>
#include <QPushButton>

namespace lyx {
namespace frontend {

/** Class to manage a collection of widgets that allows selection
 *  of items from a list of available items. Adapted from code originally
 *  written for QCitationDialog. 
 *  Note that this is a not a QWidget, though it could be converted to
 *  one. Rather, the managed widgets---see constructor for descripton 
 *  of them---should be created independently, and then passed to the
 *  constructor.
 */
class QSelectionManager: public QObject {
	Q_OBJECT

	public:
		///
		QSelectionManager(
			QListView * availableLV, 
			QListView * selectedLV,
			QPushButton * addPB, 
			QPushButton * delPB, 
			QPushButton * upPB, 
			QPushButton * downPB,
			QStringListModel * availableModel,
			QStringListModel * selectedModel);
		/// Sets the state of the various push buttons, depending upon the
		/// state of the widgets. (E.g., "delete" is enabled only if the
		/// selection is non-empty.)
		virtual void update();
		
		/// Not strictly a matter of focus, which may be elsewhere, but
		/// whether selectedLV is `more focused' than availableLV. Intended
		/// to be used, for example, in displaying information about a
		/// highlighted item: should it be the highlighted available item
		/// or the highlighted selected item that is displayed?
		bool selectedFocused() { return selectedHasFocus_; };

	Q_SIGNALS:
		///Emitted when the list of selected items has changed. 
		void selectionChanged();
		///Emitted when something has changed that might lead the containing 
		///dialog to want to update---the focused subwidget or selected item.
		///(Specifically, it is emitted by *_PB_clicked() and *_LV_clicked.)
		///NOTE: No automatic update of the button state is done here. If you
		///just want to do that, connect updateHook() to update(). Much of the
		///time, though, you will want to do a bit more processing first, so
		///you can connect to some other function that itself calls update().
		void updateHook();
		///Emitted on Ctrl-Enter in the availableLV. Intended to be connected 
		///to an "OK" event in the parent dialog.
		void okHook();

	
	protected:
		///Given a QModelIndex from availableLV, determines whether it has
		///been selected (i.e., is also in selectedLV).
		bool isSelected(const QModelIndex & idx);

	protected Q_SLOTS:
		///
		void availableChanged(const QModelIndex & idx, const QModelIndex &);
		///
		void selectedChanged(const QModelIndex & idx, const QModelIndex &);
		///
		void addPB_clicked();
		///
		void deletePB_clicked();
		///
		void upPB_clicked();
		///
		void downPB_clicked();
		///
		void availableLV_clicked(const QModelIndex &);
		///
		void availableLV_doubleClicked(const QModelIndex &);
		///
		void selectedLV_clicked(const QModelIndex &);
		///
		bool eventFilter(QObject *, QEvent *);

	private:
		QListView * availableLV;
		QListView * selectedLV;
		QPushButton * addPB;
		QPushButton * deletePB; 
		QPushButton * upPB;
		QPushButton * downPB;
		QStringListModel * availableModel;
		QStringListModel * selectedModel;
		Dialog::View * dialog;
		
		bool selectedHasFocus_;
};
}//namespace frontend
}//namespace lyx
#endif