/**
 * \file GuiSelectionManager.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 GUISELECTIONMANAGER_H
#define GUISELECTIONMANAGER_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 GuiCitationDialog. 
 *  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 GuiSelectionManager : public QObject
{
Q_OBJECT

public:
	///
	GuiSelectionManager(
		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 updateView();
	
	/// 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 updateView(). 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 updateView().
	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  // GUISELECTIONMANAGER