/*******************************************************************************
 * Copyright (c) 2000, 2009 IBM Corporation and others.
 * 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
 *******************************************************************************/
package org.eclipse.ui.internal.ide;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.dialogs.ErrorDialog;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PartInitException;

/**
 * Utility class to help with dialogs.
 * <p>
 * Note that a copy of this class exists in the
 * org.eclipse.ui.internal package.
 * </p>
 */
public class DialogUtil {

    /**
     * Prevent instantiation.
     */
    private DialogUtil() {
    }

    /**
     * Open an error style dialog for PartInitException by
     * including any extra information from the nested
     * CoreException if present.
     */
    public static void openError(Shell parent, String title, String message,
            PartInitException exception) {
        // Check for a nested CoreException
        CoreException nestedException = null;
        IStatus status = exception.getStatus();
        if (status != null && status.getException() instanceof CoreException) {
			nestedException = (CoreException) status.getException();
		}

        if (nestedException != null) {
            // Open an error dialog and include the extra
            // status information from the nested CoreException
            ErrorDialog.openError(parent, title, message, nestedException
                    .getStatus());
        } else {
            // Open a regular error dialog since there is no
            // extra information to display. Don't use SWT.SHEET because
        	// we don't know if the title contains important information.
            MessageDialog.openError(parent, title, message);
        }
    }

    /**
     * Return the number of rows available in the current display using the
     * current font.
     * @param parent The Composite whose Font will be queried.
     * @return int The result of the display size divided by the font size.
     */
    public static int availableRows(Composite parent) {

        int fontHeight = (parent.getFont().getFontData())[0].getHeight();
        int displayHeight = parent.getDisplay().getClientArea().height;

        return displayHeight / fontHeight;
    }

    /**
     * Return whether or not the font in the parent is the size of a regular
     * font.  Typically used to know if a font is smaller than the High Contrast
     * Font. This method is used to make layout decisions based on screen space.
     *
     * @param parent The Composite whose Font will be queried.
     * @return boolean. True if there are more than 50 lines of possible
     * text in the display.
     */
    public static boolean inRegularFontMode(Composite parent) {

        return availableRows(parent) > 50;
    }
}