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

 * 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:

 *      Nokia Corporation - Qt implementation

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

package org.eclipse.swt.widgets;

import org.eclipse.swt.SWT;

import org.eclipse.swt.SWTException;

import org.eclipse.swt.events.DisposeEvent;

import org.eclipse.swt.events.DisposeListener;

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

/**

 * Instances of this class are used to inform or warn the user.

 * <dl>

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

 * <dd>ICON_ERROR, ICON_INFORMATION, ICON_QUESTION, ICON_WARNING, ICON_WORKING</dd>

 * <dd>OK, OK | CANCEL</dd>

 * <dd>YES | NO, YES | NO | CANCEL</dd>

 * <dd>RETRY | CANCEL</dd>

 * <dd>ABORT | RETRY | IGNORE</dd>

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

 * <dd>(none)</dd>

 * </dl>

 * <p>

 * Note: Only one of the styles ICON_ERROR, ICON_INFORMATION, ICON_QUESTION,

 * ICON_WARNING and ICON_WORKING may be specified.

 * </p><p>

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

 * within the SWT implementation.

 * </p>

 */

public class MessageBox extends Dialog {

    private String message = "";

    private String dialogID;

    static int dialogCount;

    /**

     * Constructs a new instance of this class given only its parent.

     *

     * @param parent a shell which will be the parent of the new instance

     *

     * @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>

     */

    public MessageBox(Shell parent) {

        this(parent, SWT.OK | SWT.ICON_INFORMATION | SWT.APPLICATION_MODAL);

    }

    /**

     * 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.

     *

     * @param parent a shell which will be the parent of the new instance

     * @param style the style of dialog 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>

     */

    public MessageBox(Shell parent, int style) {

        super(parent, parent == null ? checkStyle(style) : checkStyle(parent, style));

        checkSubclass();

        checkDialog();

        dialogCount++;

        dialogID = toString() + String.valueOf(dialogCount);

    }

    /**

     * Returns the dialog's message, or an empty string if it does not have one.

     * The message is a description of the purpose for which the dialog was opened.

     * This message will be visible in the dialog while it is open.

     *

     * @return the message

     */

    public String getMessage() {

        return message;

    }

    /**

     * Sets the dialog's message, which is a description of

     * the purpose for which it was opened. This message will be

     * visible on the dialog while it is open.

     *

     * @param string the message

     * 

     * @exception IllegalArgumentException <ul>

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

     * </ul>

     */

    public void setMessage(String string) {

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

        message = string;

    }

    /**

     * Makes the dialog visible and brings it to the front

     * of the display.

     *

     * @return the ID of the button that was selected to dismiss the

     *         message box (e.g. SWT.OK, SWT.CANCEL, etc.)

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the dialog has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the dialog</li>

     * </ul>

     */

    public int open() {

        checkDialog();

        DisposeListener listener = new DisposeListener() {

            public void widgetDisposed(DisposeEvent e) {

                if (e.widget == parent) {

                    // close dialogs which are opened on top of parent

                    OS.QDialog_swt_closeDialogs(parent.handle, dialogID);

                }

            }

        };

        parent.addDisposeListener(listener);

        int icon = OS.QMESSAGEBOX_NOICON;

        if ((style & (SWT.ICON_INFORMATION)) != 0)  icon = OS.QMESSAGEBOX_INFORMATION;

        if ((style & (SWT.ICON_WARNING)) != 0)  icon = OS.QMESSAGEBOX_WARNING;

        if ((style & (SWT.ICON_QUESTION)) != 0) icon = OS.QMESSAGEBOX_QUESTION;

        if ((style & (SWT.ICON_ERROR)) != 0)    icon = OS.QMESSAGEBOX_CRITICAL;

        int buttons = 0;

        if ((style & SWT.OK) != 0) buttons |= OS.QMESSAGEBOX_OK;

        if ((style & SWT.CANCEL) != 0) buttons |= OS.QMESSAGEBOX_CANCEL;

        if ((style & SWT.YES) != 0) buttons |= OS.QMESSAGEBOX_YES;

        if ((style & SWT.NO) != 0) buttons |= OS.QMESSAGEBOX_NO;

        if ((style & SWT.ABORT) != 0) buttons |= OS.QMESSAGEBOX_ABORT;

        if ((style & SWT.RETRY) != 0) buttons |= OS.QMESSAGEBOX_RETRY; 

        if ((style & SWT.IGNORE) != 0) buttons |= OS.QMESSAGEBOX_IGNORE;

        int modality = OS.QT_WINDOWMODALITY_WINDOWMODAL; 

        if ((style & (SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL)) != 0) {

            modality = OS.QT_WINDOWMODALITY_APPLICATIONMODAL;

        }

        int qtLayoutDirection = (style & SWT.RIGHT_TO_LEFT) != 0 ? OS.QT_RIGHTTOLEFT : OS.QT_LEFTTORIGHT;

        int ret = OS.QMessageBox_swt_exec(icon, title, message, buttons, 

                parent.handle, modality, dialogID, qtLayoutDirection);

        if (parent != null && !parent.isDisposed()) {

            parent.removeDisposeListener(listener);

        }

        return translateToSwtButton(ret);

    }

    private int translateToSwtButton(int nativeButton) {

        int button = 0;

        switch (nativeButton) {

        case OS.QMESSAGEBOX_OK: 

            button = SWT.OK;

            break;

        case OS.QMESSAGEBOX_CANCEL:

            button = SWT.CANCEL;

            break;

        case OS.QMESSAGEBOX_YES:

            button = SWT.YES;

            break;

        case OS.QMESSAGEBOX_NO:

            button = SWT.NO;

            break;

        case OS.QMESSAGEBOX_ABORT:

            button = SWT.ABORT;

            break;

        case OS.QMESSAGEBOX_RETRY:

            button = SWT.RETRY;

            break;

        case OS.QMESSAGEBOX_IGNORE:

            button = SWT.IGNORE;

            break;

        default:

            break;

        }

        return button;

    }

    void checkDialog() {

        if (parent == null) error(SWT.ERROR_WIDGET_DISPOSED);

        if (parent.isDisposed()) error(SWT.ERROR_WIDGET_DISPOSED);

        Display display = parent.display;

        if (display == null) error(SWT.ERROR_WIDGET_DISPOSED);

        if (display.thread != Thread.currentThread()) error(SWT.ERROR_THREAD_INVALID_ACCESS);

    }

    static private int checkStyle(int style) {

        int mask = (SWT.YES | SWT.NO | SWT.OK | SWT.CANCEL | SWT.ABORT | SWT.RETRY | SWT.IGNORE);

        int bits = style & mask;

        if (bits == SWT.OK || bits == SWT.CANCEL || bits == (SWT.OK | SWT.CANCEL)) return style;

        if (bits == SWT.YES || bits == SWT.NO || bits == (SWT.YES | SWT.NO) || bits == (SWT.YES | SWT.NO | SWT.CANCEL)) return style;

        if (bits == (SWT.RETRY | SWT.CANCEL) || bits == (SWT.ABORT | SWT.RETRY | SWT.IGNORE)) return style;

        style = (style & ~mask) | SWT.OK;

        return style;

    }

    static int checkStyle(Shell parent, int style) {

        return checkStyle(Dialog.checkStyle(parent, style));

    }

}