/*******************************************************************************

 * 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.SWT;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.graphics.Image;

import org.eclipse.swt.graphics.Internal_GfxPackageSupport;

import org.eclipse.swt.graphics.Rectangle;

import org.eclipse.swt.internal.qt.OS;

import org.eclipse.swt.internal.qt.WidgetState;

/**

 * 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, PUSH, RADIO, TOGGLE, FLAT</dd>

 * <dd>UP, DOWN, LEFT, RIGHT, CENTER</dd>

 * <dt><b>Events:</b></dt>

 * <dd>Selection</dd>

 * </dl>

 * <p>

 * Note: Only one of the styles CHECK, PUSH, RADIO, and TOGGLE 

 * may be specified.

 * </p><p>

 * Note: Only one of the styles LEFT, RIGHT, and CENTER may be specified.

 * </p><p>

 * Note: Only one of the styles UP, DOWN, LEFT, and RIGHT may be specified

 * </p><p>

 * IMPORTANT: This class is intended to be subclassed <em>only</em>

 * within the SWT implementation.

 * </p>

 */

public class Button extends Control {

    int alignment;

    Image image;

    /**

     * Constructs a new instance of this class given its parent

     * and a style value describing its behavior and appearance.

     * <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 composite 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#PUSH

     * @see SWT#RADIO

     * @see SWT#TOGGLE

     * @see SWT#FLAT

     * @see SWT#LEFT

     * @see SWT#RIGHT

     * @see SWT#CENTER

     * @see Widget#checkSubclass

     * @see Widget#getStyle

     */

    public Button (Composite parent, int style) {

        super (parent, checkStyle (style));

    }

    static int checkStyle (int style) {

        style = checkBits (style, SWT.PUSH, SWT.CHECK, SWT.RADIO, SWT.TOGGLE, 0, 0);

        if ((style & (SWT.PUSH | SWT.TOGGLE)) != 0) {

            return checkBits (style, SWT.CENTER, SWT.LEFT, SWT.RIGHT, 0, 0, 0);

        }

        if ((style & (SWT.CHECK | SWT.RADIO)) != 0) {

            return checkBits (style, SWT.LEFT, SWT.RIGHT, SWT.CENTER, 0, 0, 0);

        }

        return style;

    }

    /**

     * Adds the listener to the collection of listeners who will

     * be notified when the control is selected by the user, by sending

     * it one of the messages defined in the <code>SelectionListener</code>

     * interface.

     * <p>

     * <code>widgetSelected</code> is called when the control is selected by the user.

     * <code>widgetDefaultSelected</code> is not called.

     * </p>

     *

     * @param listener the listener which should 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 #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);

    }

    void createHandle_pp (int index) {

        int bits = SWT.TOGGLE | SWT.CHECK | SWT.RADIO | SWT.PUSH;

        switch (style & bits) {

        case SWT.CHECK:

            handle = OS.QCheckBox_new();

            break;

        case SWT.RADIO:

            handle = OS.QRadioButton_new();

            if((getParent().style & SWT.NO_RADIO_GROUP) != 0) {

                OS.QAbstractButton_setAutoExclusive(handle, false);

            }

            break;

        case SWT.TOGGLE:

            // fall through

        case SWT.PUSH:

            // fall through

        default:

            handle = OS.QPushButton_new();

            if((style & SWT.TOGGLE) != 0) {

                OS.QAbstractButton_setCheckable(handle, true);      

            }

            if((style & SWT.FLAT) != 0) {

                OS.QPushButton_setFlat(handle, true);

            }

            break;

        }

        topHandle = handle;

        state |= WidgetState.HANDLE;

    }

    void hookEvents_pp () {

        int signalProxy = OS.SignalHandler_new(handle, OS.QSIGNAL_CLICKED);

        OS.QObject_connectOrThrow(handle, "clicked()", signalProxy, "widgetSignal()", OS.QT_AUTOCONNECTION);

    }

    /**

     * Returns a value which describes the position of the

     * text or image in the receiver. The value will be one of

     * <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code>

     *

     * @return the alignment 

     *

     * @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 getAlignment () {

        checkWidget ();

        if ((alignment & SWT.LEFT) != 0) return SWT.LEFT;

        if ((alignment & SWT.CENTER) != 0) return SWT.CENTER;

        if ((alignment & SWT.RIGHT) != 0) return SWT.RIGHT;

        return SWT.LEFT;

    }

    /**

     * Returns the receiver's image if it has one, or null

     * if it does not.

     *

     * @return the receiver's image

     *

     * @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 Image getImage () {

        checkWidget ();

        return image;

    }

    String getNameText () {

        return getText ();

    }

    /**

     * 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. When it is of type <code>TOGGLE</code>,

     * it is selected when it is pushed in. If the receiver is of any other type,

     * this method returns false.

     *

     * @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 | SWT.TOGGLE)) == 0) return false;

        return OS.QAbstractButton_isChecked(handle);

    }

    /**

     * Returns the receiver's text, which will be an empty

     * string if it has never been set 

     *

     * @return the receiver's text

     *

     * @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 String getText () {

        checkWidget();

        return OS.QAbstractButton_text(handle);

    }

    void qt_swt_event_focusWasGained() {

        super.qt_swt_event_focusWasGained();

        if(display == null || display.isDisposed()) return;

        // This button overrides the default button when focused

        if ((style & SWT.PUSH) != 0) {

            menuShell ().setDefaultButton (this, false);

        }

    }

    void qt_swt_event_focusWasLost() {

        super.qt_swt_event_focusWasLost();

        if(display == null || display.isDisposed()) return;

        // Restore the original default button if this button was overriding it

        if ((style & SWT.PUSH) != 0 && OS.QPushButton_isDefault(handle)) {

            menuShell ().setDefaultButton (null, false);

        }

    }

    void qt_signal_clicked() {

        sendEvent (SWT.Selection);

    }

    void releaseWidget_pp () {

        super.releaseWidget_pp ();

        image = 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);

    }

    /**

     * Controls how text, images will be displayed

     * in the receiver. The argument should be one of

     * <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code>

     *

     * @param alignment the new alignment 

     *

     * @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 setAlignment (int alignment) {

        checkWidget ();

        this.alignment = alignment;

    }

    /**

     * Sets the receiver's image to the argument, which may be

     * <code>null</code> indicating that no image should be displayed.

     * 

     * @param image the image to display on the receiver (may be <code>null</code>)

     *

     * @exception IllegalArgumentException <ul>

     *    <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</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 setImage (Image image) {

        checkWidget ();

        if (image != null && image.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);

        this.image = image;

        if (image != null ) {

            Rectangle iconRect = image.getBounds();

            OS.QAbstractButton_setIconSize(handle, iconRect.width, iconRect.height);

            OS.QAbstractButton_setIcon(handle, Internal_GfxPackageSupport.getIconHandle(image));

        } else {

            OS.QAbstractButton_setIcon(handle, Internal_GfxPackageSupport.getNullIconHandle());

        }

    }

    /**

     * Sets the selection state of the receiver, if it is of type <code>CHECK</code>, 

     * <code>RADIO</code>, or <code>TOGGLE</code>.

     *

     * <p>

     * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,

     * it is selected when it is checked. When it is of type <code>TOGGLE</code>,

     * it is selected when it is pushed in.

     *

     * @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 | SWT.TOGGLE)) == 0) return;

        OS.QAbstractButton_setChecked(handle, selected);

    }

    /**

     * Sets the receiver's text.

     * <p>

     * This method sets the button label.  The label may include

     * the mnemonic character but must not contain line delimiters.

     * </p>

     * <p>

     * Mnemonics are indicated by an '&' 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 emphasized in a platform specific

     * manner.  The mnemonic indicator character '&' can be

     * escaped by doubling it in the string, causing a single

     * '&' to be displayed.

     * </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>

     */

    public void setText (String string) {

        checkWidget ();

        if (string == null) error (SWT.ERROR_NULL_ARGUMENT);

        OS.QAbstractButton_setText(handle, string);

    }

    boolean setRadioFocus (boolean tabbing) {

        if ((style & SWT.RADIO) == 0 || !getSelection ()) return false;

        return tabbing ? setTabItemFocus () : setFocus (tabbing ? OS.QT_TABFOCUSREASON : OS.QT_OTHERFOCUSREASON);

    }

    boolean isTabGroup () {

        // The default behavior is to traverse to a Control which accepts focus

        // by tabbing. In the case of a radio button group only the radio button

        // which is selected accepts focus by tabbing. Mobile devices often

        // don't have more than arrow keys for traversing which are used for tab

        // group traversal. It must be possible to traverse to any of the radio

        // buttons within the group. Therefore, this behavior is overridden so

        // that all buttons accept focus from tab group traversal.

        if((style & SWT.RADIO) != 0) {

            return true;

        }

        else {

            return super.isTabGroup();

        }

    }

    Control getShortcutHandler() {

        // Button shortcut events are just let through to the native Button. 

        // This will happen if we don't return any handler. 

        return null;

    }

    void setDefault (boolean value) {

        if ((style & SWT.PUSH) == 0) return;

        OS.QPushButton_setDefault(handle, value);

    }

}