/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * Portion Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Nokia Corporation - Qt implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.qt.OS;
import org.eclipse.swt.internal.qt.WidgetState;
import org.eclipse.swt.events.*;

/**
 * Instances of this class represent a selectable user interface object
 * that issues notification when pressed and released. 
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>CHECK, CASCADE, PUSH, RADIO, SEPARATOR</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Arm, Selection</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles CHECK, CASCADE, PUSH, RADIO and SEPARATOR
 * may be specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 */
public class MenuItem extends Item {
    Menu parent, menu;
    int accelerator;
    
/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Menu</code>) and a style value
 * describing its behavior and appearance. The item is added
 * to the end of the items maintained by its parent.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a menu control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT#CHECK
 * @see SWT#CASCADE
 * @see SWT#PUSH
 * @see SWT#RADIO
 * @see SWT#SEPARATOR
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public MenuItem (Menu parent, int style) {
    super (parent, checkStyle (style));
    this.parent = parent;
    createWidget (parent.getItemCount ());
    parent.menuItemAdded();
}

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Menu</code>), a style value
 * describing its behavior and appearance, and the index
 * at which to place it in the items maintained by its parent.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a menu control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 * @param index the zero-relative index to store the receiver in its parent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT#CHECK
 * @see SWT#CASCADE
 * @see SWT#PUSH
 * @see SWT#RADIO
 * @see SWT#SEPARATOR
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public MenuItem (Menu parent, int style, int index) {
    super (parent, checkStyle (style));
    this.parent = parent;
    int count = parent.getItemCount ();
    if (!(0 <= index && index <= count)) {
        error (SWT.ERROR_INVALID_RANGE);
    }
    createWidget (index);
    parent.menuItemAdded();
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the menu item is selected by the user, by sending
 * it one of the messages defined in the <code>SelectionListener</code>
 * interface.
 * <p>
 * When <code>widgetSelected</code> is called, the stateMask field of the event object is valid.
 * <code>widgetDefaultSelected</code> is not called.
 * </p>
 *
 * @param listener the listener which should be notified when the menu item is selected by the user
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener (SelectionListener listener) {
    checkWidget();
    if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
    TypedListener typedListener = new TypedListener(listener);
    addListener (SWT.Selection,typedListener);
    addListener (SWT.DefaultSelection,typedListener);
}

static int checkStyle (int style) {
    return checkBits (style, SWT.PUSH, SWT.CHECK, SWT.RADIO, SWT.SEPARATOR, SWT.CASCADE, 0);
}

protected void checkSubclass () {
    if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
}

void createHandle_pp (int index) {
    topHandle = handle = OS.QAction_new( parent.handle );
    state |= WidgetState.HANDLE;
    
    if ((parent.style & SWT.BAR) != 0){
        OS.QMenuBar_addAction( parent.handle, handle );
    }
    else{
        int itemCount = parent.getItemCount();
        if( itemCount > 0 && index < itemCount ){
            int beforeHandle = parent.getItems()[index].handle;
            OS.QWidget_insertAction(parent.handle, beforeHandle, handle );
        }
        else{
            OS.QMenu_addAction(parent.handle, handle );
        }
    }
    int bits = SWT.CHECK | SWT.RADIO | SWT.PUSH | SWT.SEPARATOR ;
    switch (style & bits) {
        case SWT.SEPARATOR:
            OS.QAction_setSeparator( handle, true );
            break;
        case SWT.RADIO:
            if (parent.actionGroupHandle == 0){
                parent.actionGroupHandle = OS.QActionGroup_new( parent.handle );
                if ((parent.style & SWT.NO_RADIO_GROUP ) != 0 ){
                    OS.QActionGroup_setExclusive(parent.actionGroupHandle, false);
                }
            }
            OS.QAction_setCheckable( handle, true );
            OS.QActionGroup_addAction( parent.actionGroupHandle, handle );
            break;
        case SWT.CHECK:
            OS.QAction_setCheckable( handle, true );
            break;
        case SWT.PUSH:
        default:
            break;
    }
}

void fixMenus (Decorations newParent) {
//Commented for now. Needed for the reparenting of the Controls
//  if (menu != null) menu.fixMenus (newParent);
}

/**
 * Returns the widget accelerator.  An accelerator is the bit-wise
 * OR of zero or more modifier masks and a key. Examples:
 * <code>SWT.CONTROL | SWT.SHIFT | 'T', SWT.ALT | SWT.F2</code>.
 * The default value is zero, indicating that the menu item does
 * not have an accelerator.
 *
 * @return the accelerator or 0
 *
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getAccelerator () {
    checkWidget();
    return accelerator;
}

/**
 * Returns <code>true</code> if the receiver is enabled, and
 * <code>false</code> otherwise. A disabled menu item is typically
 * not selectable from the user interface and draws with an
 * inactive or "grayed" look.
 *
 * @return the receiver's enabled state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @see #isEnabled
 */
public boolean getEnabled () {
    checkWidget();
    return OS.QAction_isEnabled( handle );
}

/**
 * Returns the receiver's cascade menu if it has one or null
 * if it does not. Only <code>CASCADE</code> menu items can have
 * a pull down menu. The sequence of key strokes, button presses 
 * and/or button releases that are used to request a pull down
 * menu is platform specific.
 *
 * @return the receiver's menu
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Menu getMenu () {
    checkWidget();
    return menu;
}

String getNameText () {
    if ((style & SWT.SEPARATOR) != 0) return "|";
    return super.getNameText ();
}

/**
 * Returns the receiver's parent, which must be a <code>Menu</code>.
 *
 * @return the receiver's parent
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Menu getParent () {
    checkWidget();
    return parent;
}

/**
 * Returns <code>true</code> if the receiver is selected,
 * and false otherwise.
 * <p>
 * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,
 * it is selected when it is checked.
 *
 * @return the selection state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public boolean getSelection () {
    checkWidget();
    if ((style & (SWT.CHECK | SWT.RADIO)) == 0) return false;
    return OS.QAction_isChecked( handle );
}

void qt_signal_triggered_pp( boolean checked ) {
    Event event = new Event ();
    sendEvent (SWT.Selection, event);
}

void qt_signal_hover() {
    sendEvent (SWT.Arm);
}

void hookEvents_pp () {
    super.hookEvents_pp ();
    if ((style & SWT.CASCADE) == 0 ){
        int triggeredProxy = OS.SignalHandler_new(handle, OS.QSIGNAL_TRIGGERED);
        OS.QObject_connectOrThrow(handle, "triggered(bool)", triggeredProxy, "widgetSignal(bool)", OS.QT_AUTOCONNECTION);
    }
    int hoveredProxy = OS.SignalHandler_new(handle, OS.QSIGNAL_HOVER );
    OS.QObject_connectOrThrow(handle, "hovered()", hoveredProxy, "widgetSignal()", OS.QT_AUTOCONNECTION);
}

/**
 * Returns <code>true</code> if the receiver is enabled and all
 * of the receiver's ancestors are enabled, and <code>false</code>
 * otherwise. A disabled menu item is typically not selectable from the
 * user interface and draws with an inactive or "grayed" look.
 *
 * @return the receiver's enabled state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @see #getEnabled
 */
public boolean isEnabled () {
    return getEnabled () && parent.isEnabled ();
}

void releaseChildren_pp (boolean destroy) {
    if (menu != null) {
        menu.release (false);
        menu = null;
    }
    super.releaseChildren_pp (destroy);
}

void releaseParent_pp () {
    super.releaseParent_pp ();
    if (menu != null) {
        menu.dispose ();
    }
    menu = null;
    parent.menuItemRemoved();
}

void releaseWidget_pp () {
    if( (style & SWT.RADIO) != 0 ){
        if (parent.actionGroupHandle != 0){
            OS.QActionGroup_removeAction(parent.actionGroupHandle, handle);
        }
    }
    OS.QWidget_removeAction( parent.handle, handle );
    super.releaseWidget_pp ();
    accelerator = 0;
    parent = null;
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the control is selected by the user.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener (SelectionListener listener) {
    checkWidget();
    if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
    if (eventTable == null) return;
    eventTable.unhook (SWT.Selection, listener);
    eventTable.unhook (SWT.DefaultSelection,listener);  
}

/**
 * Sets the widget accelerator.  An accelerator is the bit-wise
 * OR of zero or more modifier masks and a key. Examples:
 * <code>SWT.MOD1 | SWT.MOD2 | 'T', SWT.MOD3 | SWT.F2</code>.
 * <code>SWT.CONTROL | SWT.SHIFT | 'T', SWT.ALT | SWT.F2</code>.
 * The default value is zero, indicating that the menu item does
 * not have an accelerator.
 *
 * @param accelerator an integer that is the bit-wise OR of masks and a key
 *
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setAccelerator (int accelerator) {
    checkWidget();
    if (this.accelerator == accelerator) return;
    int mask = 0;
    if ((accelerator & SWT.ALT) != 0) mask |= OS.QT_ALTMODIFIER;
    if ((accelerator & SWT.SHIFT) != 0) mask |= OS.QT_SHIFTMODIFIER;
    if ((accelerator & SWT.CONTROL) != 0) mask |= OS.QT_CONTROLMODIFIER;
    int keysym = accelerator & SWT.KEY_MASK;
    int newKey = Display.untranslateKey (keysym);
    if (newKey != 0) {
        keysym = newKey;
    }
    int keySequenceHandle = OS.QKeySequence_new( mask + keysym );
    OS.QAction_setShortcut( handle, keySequenceHandle );
    this.accelerator = accelerator;
    OS.QKeySequence_delete( keySequenceHandle );
}

/**
 * Enables the receiver if the argument is <code>true</code>,
 * and disables it otherwise. A disabled menu item is typically
 * not selectable from the user interface and draws with an
 * inactive or "grayed" look.
 *
 * @param enabled the new enabled state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setEnabled (boolean enabled) {
    checkWidget();
    OS.QAction_setEnabled(handle, enabled);

}

/**
 * Sets the image the receiver will display to the argument.
 * <p>
 * Note: This operation is a hint and is not supported on
 * platforms that do not have this concept (for example, Windows NT).
 * </p>
 *
 * @param image the image to display
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setImage (Image image) {
    checkWidget();
    if ((style & SWT.SEPARATOR) != 0) return;
    super.setImage (image);
    if (image != null ) {
        OS.QAction_setIcon(handle, Internal_GfxPackageSupport.getIconHandle(image));
    } else {
        OS.QAction_setIcon(handle, Internal_GfxPackageSupport.getNullIconHandle());
    }
}

/**
 * Sets the receiver's pull down menu to the argument.
 * Only <code>CASCADE</code> menu items can have a
 * pull down menu. The sequence of key strokes, button presses
 * and/or button releases that are used to request a pull down
 * menu is platform specific.
 * <p>
 * Note: Disposing of a menu item that has a pull down menu
 * will dispose of the menu.  To avoid this behavior, set the
 * menu to null before the menu item is disposed.
 * </p>
 *
 * @param menu the new pull down menu
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_MENU_NOT_DROP_DOWN - if the menu is not a drop down menu</li>
 *    <li>ERROR_MENUITEM_NOT_CASCADE - if the menu item is not a <code>CASCADE</code></li>
 *    <li>ERROR_INVALID_ARGUMENT - if the menu has been disposed</li>
 *    <li>ERROR_INVALID_PARENT - if the menu is not in the same widget tree</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setMenu (Menu menu) {
    checkWidget ();

    /* Check to make sure the new menu is valid */
    if ((style & SWT.CASCADE) == 0) {
        error (SWT.ERROR_MENUITEM_NOT_CASCADE);
    }
    int menuHandle = 0;
    if (menu != null) {
        if ((menu.style & SWT.DROP_DOWN) == 0) {
            error (SWT.ERROR_MENU_NOT_DROP_DOWN);
        }
        if (menu.parent != parent.parent) {
            error (SWT.ERROR_INVALID_PARENT);
        }
        menuHandle = menu.handle;
    }
    /* Assign the new menu */
    Menu oldMenu = this.menu;
    if (oldMenu == menu) return;
    if (oldMenu != null) oldMenu.cascade = null;
    OS.QAction_setMenu( handle, menuHandle );
    this.menu = menu;
    if( this.menu != null )this.menu.cascade = this;
}


/**
 * Sets the selection state of the receiver.
 * <p>
 * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,
 * it is selected when it is checked.
 *
 * @param selected the new selection state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (boolean selected) {
    checkWidget();
    if ((style & (SWT.CHECK | SWT.RADIO)) == 0) return;
    OS.QAction_setChecked( handle, selected );
}

/**
 * Sets the receiver's text. The string may include
 * the mnemonic character and accelerator text.
 * <p>
 * Mnemonics are indicated by an '&amp;' that causes the next
 * character to be the mnemonic.  When the user presses a
 * key sequence that matches the mnemonic, a selection
 * event occurs. On most platforms, the mnemonic appears
 * underlined but may be emphasised in a platform specific
 * manner.  The mnemonic indicator character '&amp;' can be
 * escaped by doubling it in the string, causing a single
 * '&amp;' to be displayed.
 * </p>
 * <p>
 * Accelerator text is indicated by the '\t' character.
 * On platforms that support accelerator text, the text
 * that follows the '\t' character is displayed to the user,
 * typically indicating the key stroke that will cause
 * the item to become selected.  On most platforms, the
 * accelerator text appears right aligned in the menu.
 * Setting the accelerator text does not install the
 * accelerator key sequence. The accelerator key sequence
 * is installed using #setAccelerator.
 * </p>
 * 
 * @param string the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @see #setAccelerator
 */
public void setText (String string) {
    checkWidget();
    if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
    if ((style & SWT.SEPARATOR) != 0) return;
    if (text.equals (string)) return;
    OS.QAction_setText(handle, string);
    text = string;
}

}
