/* This file is part of the KDE project
   Copyright (C) 2002 Anders Lund <anders.lund@lund.tdcadsl.dk>

   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., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#ifndef _KACTION_SELECTOR_H_
#define _KACTION_SELECTOR_H_

#include <qwidget.h>

#include <kdelibs_export.h>

class QListBox;
class QListBoxItem;
class QKeyEvent;
class QEvent;
class QIconSet;

class KActionSelectorPrivate;

/**
    @short A widget for selecting and arranging actions/objects

    This widget allows the user to select from a set of objects and arrange
    the order of the selected ones using two list boxes labeled "Available"
    and "Used" with horizontal arrows in between to move selected objects between
    the two, and vertical arrows on the right to arrange the order of the selected
    objects.

    The widget moves objects to the other listbox when doubleclicked if
    the property moveOnDoubleClick is set to true (default). See moveOnDoubleClick()
    and setMoveOnDoubleClick().

    The user control the widget using the keyboard if enabled (default),
    see keyboardEnabled.

    Note that this may conflist with keyboard selection in the selected list box,
    if you set that to anything else than QListBox::Single (which is the default).

    To use it, simply construct an instance and then add items to the two listboxes,
    available through lbAvailable() and lbSelected(). Whenever you want, you can retrieve
    the selected options using QListBox methods on lbSelected().

    This way, you can use your own QListBoxItem class, allowing you to easily
    store object data in those.

    When an item is moved to a listbox, it is placed below the current item
    of that listbox.

    Standard arrow icons are used, but you can use icons of your own choice if desired,
    see setButtonIcon(). It is also possible to set tooltips and whatsthis help
    for the buttons. See setButtonTooltip() and setButtonWhatsThis().

    To set whatsthis or tooltips for the listboxes, access them through
    availableListbox() and selectedListBox().

    All the moving buttons are automatically set enabled as expected.

    Signals are sent each time an item is moved, allowing you to follow the
    users actions if you need to. See addedToSelection(), removedFromSelection(),
    movedUp() and movedDown()

    @author Anders Lund <anders@alweb.dk>
*/

class KDEUI_EXPORT KActionSelector : public QWidget {
  Q_OBJECT
  Q_ENUMS( ButtonIconSize InsertionPolicy )
  Q_PROPERTY( bool moveOnDoubleClick READ moveOnDoubleClick WRITE setMoveOnDoubleClick )
  Q_PROPERTY( bool keyboardEnabled READ keyboardEnabled WRITE setKeyboardEnabled )
  Q_PROPERTY( QString availableLabel READ availableLabel WRITE setAvailableLabel )
  Q_PROPERTY( QString selectedLabel READ selectedLabel WRITE setSelectedLabel )
  Q_PROPERTY( ButtonIconSize buttonIconSize READ buttonIconSize WRITE setButtonIconSize )
  Q_PROPERTY( InsertionPolicy availableInsertionPolicy READ availableInsertionPolicy WRITE setAvailableInsertionPolicy )
  Q_PROPERTY( InsertionPolicy selectedInsertionPolicy READ selectedInsertionPolicy WRITE setSelectedInsertionPolicy )
  Q_PROPERTY( bool showUpDownButtons READ showUpDownButtons WRITE setShowUpDownButtons )

public:
  KActionSelector( QWidget *parent=0, const char *name=0 );
  ~KActionSelector();

  /**
     @return The QListBox holding the available actions
  */
  QListBox *availableListBox() const;

  /**
     @return The QListBox holding the selected actions
  */
  QListBox *selectedListBox() const;

  /**
    This enum indentifies the moving buttons
  */
  enum MoveButton {
    ButtonAdd,
    ButtonRemove,
    ButtonUp,
    ButtonDown
  };

  /**
    This enum identifies the icon sizes, used for the move buttons.
    The values correspond to the following pixel sizes:
    @li SmallIcon - the return value of IconSize( KIcon::Small ), the user defined size
                of a small icon in KDE. This is the default setting.
    @li Small - 16px
    @li Medium - 22px
    @li Large - 32px
    @li XLarge - 48px
  */
  enum ButtonIconSize {
    SmallIcon,
    Small,
    Medium,
    Large,
    XLarge
  };

  /**
    This enum defines policies for where to insert moved items in a listbox.
    The following policies are currently defined:
    @li BelowCurrent - The item is inserted below the listbox'
        currentItem() or at the end if there is no curent item.
    @li Sorted - The listbox is sort()ed after one or more items are inserted.
    @li AtTop - The item is inserted at index 0 in the listbox.
    @li AtBottom - The item is inserted at the end of the listbox.

    @sa availableInsertionPolicy(), setAvailableInsertionPolicy(),
    selectedInsertionPolicy(), setSelectedInsertionPolicy().
  */
  enum InsertionPolicy {
    BelowCurrent,
    Sorted,
    AtTop,
    AtBottom
  };

  /**
    @return Wheather moveOnDoubleClcik is enabled.

    If enabled, an item in any listbox will be moved to the other one whenever
    doubleclicked.
    @sa setMoveOnDoubleClick()
  */
  bool moveOnDoubleClick() const;

  /**
    Sets moveOnDoubleClick to @p enable
    @sa moveOnDoubleClick()
  */
  void setMoveOnDoubleClick( bool enable );

  /**
    @return Weather keyboard control is enabled.

    When Keyboard control is enabled, the widget will react to
    the following keyboard actions:
    @li CTRL + Right - simulate clicking the add button
    @li CTRL + Left - simulate clicking the remove button
    @li CTRL + Up - simulate clicking the up button
    @li CTRL + Down - simulate clicking the down button

    Additionally, pressing RETURN or ENTER on one of the list boxes
    will cause the current item of that listbox to be moved to the other
    listbox.

    The keyboard actions are enabled by default.

    @sa setKeyboardEnabled()
  */
  bool keyboardEnabled() const;

  /**
    Sets the keyboard enabled depending on @p enable.
    @sa keyboardEnabled()
  */
  void setKeyboardEnabled( bool enable );

  /**
    @return The text of the label for the available items listbox.
  */
  QString availableLabel() const;

  /**
    Sets the label for the available items listbox to @p text.
    Note that this label has the listbox as its @e buddy, so that
    if you have a single ampersand in the text, the following character
    will become the accellerator to focus te listbox.
  */
  void setAvailableLabel( const QString & text );

  /**
    @return the label of the selected items listbox.
  */
  QString selectedLabel() const;

  /**
    Sets the label for the selected items listbox to @p text.
    Note that this label has the listbox as its @e buddy, so that
    if you have a single ampersand in the text, the following character
    will become the accellerator to focus te listbox.
  */
  void setSelectedLabel( const QString & text );

  /**
    @return the current ButtonIconSize.
  */
  ButtonIconSize buttonIconSize() const;

  /**
    Sets the button icon size.
    See ButtonIconSize for the possible values and their pixel meaning.
  */
  void setButtonIconSize( ButtonIconSize size );

  /**
    @return The current insertion policy for the available listbox.
    The default policy for the available listbox is Sorted.
    See also InsertionPolicy, setAvailableInsertionPolicy().
  */
  InsertionPolicy availableInsertionPolicy() const;

  /**
    Sets the insertion policy for the available listbox.
    See also InsertionPolicy, availableInsertionPolicy().
  */
  void setAvailableInsertionPolicy( InsertionPolicy policy );

  /**
    @return The current insertion policy for the selected listbox.
    The default policy for the selected listbox is BelowCurrent.
    See also InsertionPolicy, setSelectedInsertionPolicy().
  */
  InsertionPolicy selectedInsertionPolicy() const;

  /**
    Sets the insertion policy for the selected listbox.
    See also InsertionPolicy, selectedInsertionPolicy().
  */
  void setSelectedInsertionPolicy( InsertionPolicy policy );

  /**
    @return wheather the Up and Down buttons should be displayed.
  */
  bool showUpDownButtons() const;

  /**
    Sets wheather the Up and Down buttons should be displayed
    according to @p show
  */
  void setShowUpDownButtons( bool show );

  /**
    Sets the pixmap of the button @p button to @p icon.
    It calls SmallIconSet(pm) to generate the icon set.
  */
  void setButtonIcon( const QString &icon, MoveButton button );

  /**
    Sets the iconset for button @p button to @p iconset.
    You can use this method to et a costum icon set. Either
    created by QIconSet, or use the application instance of
    KIconLoader (recommended).
  */
  void setButtonIconSet( const QIconSet &iconset, MoveButton button );

  /**
    Sets the tooltip for the button @p button to @p tip.
  */
  void setButtonTooltip( const QString &tip, MoveButton button );

  /**
    Sets the whatsthis help for button @p button to @p text.
  */
  void setButtonWhatsThis( const QString &text, MoveButton button );

  /**
     Sets the enabled state of all moving buttons to reflect the current
     options.

     Be sure to call this if you add or removes items to either listbox after the
     widget is show()n
  */
  void setButtonsEnabled();

signals:
  /**
    Emitted when an item is moved to the "selected" listbox.
  */
  void added( QListBoxItem *item );

  /**
    Emitted when an item is moved out of the "selected" listbox.
  */
  void removed( QListBoxItem *item );

  /**
    Emitted when an item is moved upwards in the "selected" listbox.
  */
  void movedUp( QListBoxItem *item );

  /**
    Emitted when an item is moved downwards in the "selected" listbox.
  */
  void movedDown( QListBoxItem *item );

  /**
    Emitted when an item is moved to the "selected" listbox.
  */
//  void addedToSelection( QListBoxItem *item );

public slots:
  /**
    Reimplemented for internal reasons.
    (calls setButtonsEnabled())
  */
  void polish();

protected:
  /**
    Reimplamented for internal reasons.
  */
  void keyPressEvent( QKeyEvent * );

  /**
    Reimplemented for internal reasons.
  */
  bool eventFilter( QObject *, QEvent * );

private slots:
  /**
    Move selected item from available box to the selected box
  */
  void buttonAddClicked();

  /**
    Move selected item from selected box to available box
  */
  void buttonRemoveClicked();

  /**
    Move selected item in selected box upwards
  */
  void buttonUpClicked();

  /**
    Move seleted item in selected box downwards
  */
  void buttonDownClicked();

  /**
    Moves the item @p item to the other listbox if moveOnDoubleClick is enabled.
  */
  void  itemDoubleClicked( QListBoxItem *item );

  /**
    connected to both list boxes to set the buttons enabled
  */
  void slotCurrentChanged( QListBoxItem * ) { setButtonsEnabled(); }

private:

  /**
    Move item @p item to the other listbox
  */
  void moveItem( QListBoxItem *item );

  /**
    loads the icons for the move buttons.
  */
  void loadIcons();

  /**
    @return the index to insert an item into listbox @p lb,
    given InsertionPolicy @p policy.

    Note that if policy is Sorted, this will return -1.
    Sort the listbox after inserting the item in that case.
  */
  int insertionIndex( QListBox *lb, InsertionPolicy policy );

  /** @private
    Private data storage
  */
  KActionSelectorPrivate *d;
};

#endif // _KACTION_SELECTOR_H_
