/*******************************************************************************
 * Copyright (c) 2004, 2008 Tasktop Technologies 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:
 *     Tasktop Technologies - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylyn.tasks.ui.editors;

/**
 * A layout hint for attribute editors.
 * 
 * @author Steffen Pingel
 * @since 3.0
 */
public class LayoutHint {

	/**
	 * @since 3.0
	 */
	public final static int DEFAULT_PRIORITY = 10;

	/**
	 * @since 3.0
	 */
	public enum ColumnSpan {
		MULTIPLE, SINGLE
	};

	/**
	 * @since 3.0
	 */
	public enum RowSpan {
		MULTIPLE, SINGLE
	};

	/**
	 * @since 3.0
	 */
	public RowSpan rowSpan;

	/**
	 * @since 3.0
	 */
	public ColumnSpan columnSpan;

	/**
	 * @since 3.0
	 */
	public LayoutHint(RowSpan rowHint, ColumnSpan columnHint) {
		this.rowSpan = rowHint;
		this.columnSpan = columnHint;
	}

	/**
	 * Clones <code>source</code>. Constructs a layout hint with a priority of {@link #DEFAULT_PRIORITY}, if
	 * <code>source</code> is null.
	 * 
	 * @param source
	 *            the layout hint to clone or <code>null</code>
	 * @since 3.1
	 */
	public LayoutHint(LayoutHint source) {
		if (source != null) {
			this.rowSpan = source.rowSpan;
			this.columnSpan = source.columnSpan;
		}
	}

	/**
	 * Constructs a layout hint with a priority of {@link #DEFAULT_PRIORITY}.
	 * 
	 * @since 3.1
	 */
	public LayoutHint() {
	}

	/**
	 * Returns a priority based on the size of the layout hint. The bigger the size the bigger the returned priority.
	 * <p>
	 * The priority is used to layout attribute editors.
	 * 
	 * @since 3.0
	 */
	public int getPriority() {
		if (columnSpan == null || columnSpan == ColumnSpan.SINGLE) {
			if (rowSpan == null || rowSpan == RowSpan.SINGLE) {
				return DEFAULT_PRIORITY;
			} else {
				return DEFAULT_PRIORITY * 2;
			}
		} else {
			if (rowSpan == null || rowSpan == RowSpan.SINGLE) {
				return DEFAULT_PRIORITY * 3;
			} else {
				return DEFAULT_PRIORITY * 4;
			}
		}
	}

}