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

 * Copyright (c) 2000, 2004 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

 *     Lynne Kues (IBM Corp) - modified to reflect eSWT API subset

 *     Nokia Corporation - S60 implementation

 *     Nokia Corporation - Qt implementation

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

package org.eclipse.swt.widgets;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.ModifyListener;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.events.VerifyListener;

import org.eclipse.swt.graphics.Image;

import org.eclipse.swt.graphics.Internal_GfxPackageSupport;

import org.eclipse.swt.graphics.Point;

import org.eclipse.swt.graphics.Rectangle;

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

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

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

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

/**

 * Instances of this class are controls that allow the user to choose an item

 * from a list of items, or optionally enter a new value by typing it into an

 * editable text field. Often, <code>Combo</code>s are used in the same place

 * where a single selection <code>List</code> widget could be used but space is

 * limited. A <code>Combo</code> takes less space than a <code>List</code>

 * widget and shows similar information.

 * <p>

 * Note: Since <code>Combo</code>s can contain both a list and an editable text

 * field, it is possible to confuse methods which access one versus the other

 * (compare for example, <code>clearSelection()</code> and

 * <code>deselectAll()</code>). The API documentation is careful to indicate

 * either "the receiver's list" or the "the receiver's text field" to

 * distinguish between the two cases.

 * </p>

 * <p>

 * Note that although this class is a subclass of <code>Composite</code>, it

 * does not make sense to add children to it, or set a layout on it.

 * </p>

 * <dl>

 * <dt><b>Styles:</b></dt>

 * <dd>DROP_DOWN, READ_ONLY</dd>

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

 * <dd>DefaultSelection, Modify, Selection</dd>

 * </dl>

 * <p>

 * </p>

 * <p>

 * IMPORTANT: This class is <em>not</em> intended to be subclassed.

 * </p>

 * 

 * @see List

 */

public class Combo extends Composite {

    int comboTextHandle; // needed for mouse events and defaultSelection

    /**

     * the operating system limit for the number of characters that the text

     * field in an instance of this class can hold

     */

    public static final int LIMIT = 32767;

    /**

     * 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#DROP_DOWN

     * @see SWT#READ_ONLY

     * @see Widget#checkSubclass

     * @see Widget#getStyle

     */

    public Combo(Composite parent, int style) {

        super(parent, style);

    }

    void createHandle_pp(int index) {

        topHandle = handle = OS.QComboBox_new();

        // QComboBox to use text editor instead of button

        OS.QComboBox_setEditable(handle, true);

        OS.QComboBox_setSizeAdjustPolicy(handle,

                OS.QT_QComboBox_AdjustToMinimumContentsLength);

        // not to add edited text at the end

        OS.QComboBox_setInsertPolicy(handle, OS.QT_QComboBox_NoInsert);

        comboTextHandle = OS.QComboBox_lineEdit(handle);

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

            OS.QLineEdit_setReadOnly(comboTextHandle, true);

        }

        state |= WidgetState.HANDLE;

    }

    void register_pp() {

        super.register_pp();

        Display.addWidget(comboTextHandle, this);

    }

    void deregister_pp() {

        super.deregister_pp();

        Display.removeWidget(comboTextHandle);

    }

    void releaseHandle_pp() {

        comboTextHandle = 0;

        super.releaseHandle_pp();

    }

    /**

     * Adds the argument to the end of the receiver's list.

     * 

     * @param string

     *            the new item

     * 

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT - if the string 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 #add(String,int)

     */

    public void add(String string) {

        add(string, getItemCount());

    }

    /**

     * Adds the argument to the receiver's list at the given zero-relative

     * index.

     * <p>

     * Note: To add an item at the end of the list, use the result of calling

     * <code>getItemCount()</code> as the index or use <code>add(String)</code>.

     * </p>

     * 

     * @param string

     *            the new item

     * @param index

     *            the index for the item

     * 

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT - if the string is null</li>

     *                <li>ERROR_INVALID_RANGE - if the index is not between 0

     *                and the number of elements in the list (inclusive)</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 #add(String)

     */

    public void add(String string, int index) {

        checkWidget();

        if (string == null)

            error(SWT.ERROR_NULL_ARGUMENT);

        int count = getItemCount();

        if (!(index <= count && index >= 0))

            error(SWT.ERROR_INVALID_RANGE);

        OS.QComboBox_insertItem(topHandle, string, index);

    }

    /**

     * Adds the listener to the collection of listeners who will be notified

     * when the receiver's text is modified, by sending it one of the messages

     * defined in the <code>ModifyListener</code> interface.

     * 

     * @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 ModifyListener

     * @see #removeModifyListener

     */

    public void addModifyListener(ModifyListener listener) {

        checkWidget();

        if (listener == null)

            error(SWT.ERROR_NULL_ARGUMENT);

        TypedListener typedListener = new TypedListener(listener);

        addListener(SWT.Modify, typedListener);

    }

    /**

     * Adds the listener to the collection of listeners who will be notified

     * when the receiver's text is verified, by sending it one of the messages

     * defined in the <code>VerifyListener</code> interface.

     * 

     * @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 VerifyListener

     * @see #removeVerifyListener

     */

    public void addVerifyListener(VerifyListener listener) {

        checkWidget();

        if (listener == null)

            error(SWT.ERROR_NULL_ARGUMENT);

        TypedListener typedListener = new TypedListener(listener);

        addListener(SWT.Verify, typedListener);

    }

    /**

     * Adds the listener to the collection of listeners who will be notified

     * when the receiver's selection changes, by sending it one of the messages

     * defined in the <code>SelectionListener</code> interface.

     * <p>

     * <code>widgetSelected</code> is called when the combo's list selection

     * changes. <code>widgetDefaultSelected</code> is typically called when

     * ENTER is pressed the combo's text area.

     * </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);

        addListener(SWT.DefaultSelection, typedListener);

    }

    void hookEvents_pp() {

        super.hookEvents_pp();

        int selectionSignalProxy = OS.SignalHandler_new(topHandle,

                OS.QSIGNAL_SELECTIONCHANGED);

        OS.QObject_connectOrThrow(topHandle,

                "currentIndexChanged(const QString&)", selectionSignalProxy,

                "widgetSignal(const QString&)", OS.QT_AUTOCONNECTION);

        int returnPressedProxy = OS.SignalHandler_new(comboTextHandle, 

                OS.QSIGNAL_RETURN_PRESSED);

        OS.QObject_connectOrThrow(comboTextHandle, "returnPressed()",

                returnPressedProxy, "widgetSignal()", OS.QT_AUTOCONNECTION);

        int modifySignalProxy = OS.SignalHandler_new(topHandle,

                OS.QSIGNAL_TEXT_CHANGED);

        OS.QObject_connectOrThrow(topHandle,

                "editTextChanged(const QString&)", modifySignalProxy,

                "widgetSignal(const QString&)", OS.QT_AUTOCONNECTION);

    }

    void qt_signal_text_changed_pp(String text) {

        sendEvent(SWT.Modify);

    }

    void qt_signal_selectionChanged_pp(int selectionHandle,

            int deSelectionHandle) {

        // this is hack to select text in combo editor when changes the current

        // item in combo

        setSelection(new Point(0, OS.QLineEdit_text(comboTextHandle).length()));

        sendEvent(SWT.Selection);

    }

    void qt_signal_return_pressed_pp() {

        sendEvent(SWT.DefaultSelection);

    }

    boolean qt_event_keypress_pp(int widgetHandle, int key,

            int modifier, int character, int nativeScanCode) {

        if (super.qt_event_keypress_pp(widgetHandle, key, modifier, character, nativeScanCode))

            return true;

        if (!(hooks(SWT.Verify) || filters(SWT.Verify)) && getTextLimit() <= 0) {

            return false;

        }

        Event keyEv = makeKeyEvent(key, modifier, character, nativeScanCode);

        return TextUtils.handle_keypress(TextUtils.LINE_EDIT, comboTextHandle, 

            key, modifier, character, keyEv, getTextLimit(), this);

    }

    int getTraversalTypeForKey(int key, int modifier, int character) {

        int type = 0;

        switch (key) {

        case OS.QT_KEY_ENTER:

        case OS.QT_KEY_RETURN:

            type = SWT.TRAVERSE_NONE;

            break;

        default:

            type = super.getTraversalTypeForKey(key, modifier, character);

            break;

        }

        return type;

    }

    void setTraversalFlags_pp(int type, int key, int modifier,

            int character) {

        traverseDoit = false;

        traverseCancel = false;

        // If the system is about to traverse out of the Text because mnemonic

        // shortcut of some widget was pressed then it is allowed.

        // Note that if keys used to launch shortcuts overlap the keys that are

        // used

        // by Text then shortcut has priority over text with this

        // implementation.

        // However, platforms usually define the shortucts in such a way that

        // they

        // don't overlap. E.g. in X11 Alt+something.

        if (type == SWT.TRAVERSE_MNEMONIC) {

            traverseDoit = true;

            return;

        }

        switch (key) {

        case OS.QT_KEY_ENTER:

        case OS.QT_KEY_RETURN:

            traverseDoit = false;

            break;

        case OS.QT_KEY_TAB:

            traverseDoit = true;

            break;

        case OS.QT_KEY_LEFT:

        case OS.QT_KEY_RIGHT:

            traverseDoit = false;

            break;

        case OS.QT_KEY_UP:

        case OS.QT_KEY_DOWN:

            traverseDoit = true;

            break;

        default:

            break;

        }

    }

    /**

     * Sets the selection in the receiver's text field to an empty selection

     * starting just before the first character. If the text field is editable,

     * this has the effect of placing the i-beam at the start of the text.

     * <p>

     * Note: To clear the selected items in the receiver's list, use

     * <code>deselectAll()</code>.

     * </p>

     * 

     * @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 #deselectAll

     */

    public void clearSelection() {

        checkWidget();

        OS.QLineEdit_setCursorPosition(comboTextHandle, 0);

    }

    /**

     * Copies the selected text.

     * <p>

     * The current selection is copied to the clipboard.

     * </p>

     * 

     * @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>

     * 

     * @since 2.1

     */

    public void copy() {

        checkWidget();

        TextUtils.copy(TextUtils.LINE_EDIT, comboTextHandle);

    }

    /**

     * Cuts the selected text.

     * <p>

     * The current selection is first copied to the clipboard and then deleted

     * from the widget.

     * </p>

     * 

     * @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>

     * 

     * @since 2.1

     */

    public void cut() {

        checkWidget();

        TextUtils.cut(TextUtils.LINE_EDIT, comboTextHandle, this);

    }

    /**

     * Deselects the item at the given zero-relative index in the receiver's

     * list. If the item at the index was already deselected, it remains

     * deselected. Indices that are out of range are ignored.

     * 

     * @param index

     *            the index of the item to deselect

     * 

     * @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 deselect(int index) {

        checkWidget();

        if (getSelectionIndex() == index)

            deselectAll();

    }

    /**

     * Deselects all selected items in the receiver's list.

     * <p>

     * Note: To clear the selection in the receiver's text field, use

     * <code>clearSelection()</code>.

     * </p>

     * 

     * @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 #clearSelection

     */

    public void deselectAll() {

        checkWidget();

        OS.QComboBox_swt_deselect(topHandle);

    }

    /**

     * Returns the item at the given, zero-relative index in the receiver's

     * list. Throws an exception if the index is out of range.

     *