package org.erlide.ui.util;

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 final 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(final Shell parent, final String title,
			final String message, final PartInitException exception) {
		// Check for a nested CoreException
		CoreException nestedException = null;
		final 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
			MessageDialog.openError(parent, title, message);
		}
	}

	/**
	 * Removes the '&' accelerator indicator from a label, if any. Also removes
	 * the () accelerators which are used in Asian languages.
	 */
	public static String removeAccel(String label) {

		final int startBracket = label.indexOf("(&"); //$NON-NLS-1$
		// Non latin accelerator?
		if (startBracket >= 0) {
			final int endBracket = label.indexOf(')');

			// If there is more than one character it is not an accelerator
			if ((endBracket - startBracket) == 3) {
				return label.substring(0, startBracket)
						+ label.substring(endBracket + 1);
			}
		}

		final int i = label.indexOf('&');
		if (i >= 0) {
			label = label.substring(0, i) + label.substring(i + 1);
		}

		return label;
	}

	/**
	 * 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(final Composite parent) {

		final int fontHeight = (parent.getFont().getFontData())[0].getHeight();
		final 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(final Composite parent) {

		return availableRows(parent) > 50;
	}
}
