/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package org.apache.jorphan.gui.layout;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;
import java.io.Serializable;

/**
 * A vertical layout manager similar to java.awt.FlowLayout. Like FlowLayout
 * components do not expand to fill available space except when the horizontal
 * alignment is <code>BOTH</code> in which case components are stretched
 * horizontally. Unlike FlowLayout, components will not wrap to form another
 * column if there isn't enough space vertically. VerticalLayout can optionally
 * anchor components to the top or bottom of the display area or center them
 * between the top and bottom. Revision date 04 April 1999
 * 
 * @author Colin Mummery e-mail:equitysoft@iname.com
 *         Homepage:www.kagi.com/equitysoft - Based on 'FlexLayout' in Java
 *         class libraries Vol 2 Chan/Lee Addison-Wesley 1998
 * @version $Revision: 493784 $
 */
public class VerticalLayout implements LayoutManager, Serializable {
	/**
	 * The horizontal alignment constant that designates centering. Also used to
	 * designate center anchoring.
	 */
	public final static int CENTER = 0;

	/**
	 * The horizontal alignment constant that designates right justification.
	 */
	public final static int RIGHT = 1;

	/**
	 * The horizontal alignment constant that designates left justification.
	 */
	public final static int LEFT = 2;

	/**
	 * The horizontal alignment constant that designates stretching the
	 * component horizontally.
	 */
	public final static int BOTH = 3;

	/**
	 * The anchoring constant that designates anchoring to the top of the
	 * display area.
	 */
	public final static int TOP = 1;

	/**
	 * The anchoring constant that designates anchoring to the bottom of the
	 * display area.
	 */
	public final static int BOTTOM = 2;

	/** The vertical vgap between components...defaults to 5. */
	private int vgap;

	/** LEFT, RIGHT, CENTER or BOTH...how the components are justified. */
	private int alignment;

	/**
	 * TOP, BOTTOM or CENTER ...where are the components positioned in an
	 * overlarge space.
	 */
	private int anchor;

	// Constructors
	/**
	 * Constructs an instance of VerticalLayout with a vertical vgap of 5
	 * pixels, horizontal centering and anchored to the top of the display area.
	 */
	public VerticalLayout() {
		this(5, CENTER, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance with horizontal centering, anchored
	 * to the top with the specified vgap.
	 * 
	 * @param vgap
	 *            an int value indicating the vertical seperation of the
	 *            components
	 */
	public VerticalLayout(int vgap) {
		this(vgap, CENTER, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance anchored to the top with the
	 * specified vgap and horizontal alignment.
	 * 
	 * @param vgap
	 *            an int value indicating the vertical seperation of the
	 *            components
	 * @param alignment
	 *            an int value which is one of <code>RIGHT, LEFT,
	 *                   CENTER, BOTH</code>
	 *            for the horizontal alignment.
	 */
	public VerticalLayout(int vgap, int alignment) {
		this(vgap, alignment, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance with the specified vgap, horizontal
	 * alignment and anchoring
	 * 
	 * @param vgap
	 *            an int value indicating the vertical seperation of the
	 *            components
	 * @param alignment
	 *            an int value which is one of <code>RIGHT, LEFT, CENTER,
	 *                  BOTH</code>
	 *            for the horizontal alignment.
	 * @param anchor
	 *            an int value which is one of <code>TOP, BOTTOM,
	 *                  CENTER</code>
	 *            indicating where the components are to appear if the display
	 *            area exceeds the minimum necessary.
	 */
	public VerticalLayout(int vgap, int alignment, int anchor) {
		this.vgap = vgap;
		this.alignment = alignment;
		this.anchor = anchor;
	}

	/**
	 * Lays out the container.
	 */
	public void layoutContainer(Container parent) {
		Insets insets = parent.getInsets();
		// NOTUSED Dimension dim = layoutSize(parent, false);
		synchronized (parent.getTreeLock()) {
			int n = parent.getComponentCount();
			Dimension pd = parent.getSize();
			int y = 0;
			// work out the total size
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				Dimension d = c.getPreferredSize();
				y += d.height + vgap;
			}
			y -= vgap; // otherwise there's a vgap too many
			// Work out the anchor paint
			if (anchor == TOP) {
				y = insets.top;
			} else if (anchor == CENTER) {
				y = (pd.height - y) / 2;
			} else {
				y = pd.height - y - insets.bottom;
			}
			// do layout
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				Dimension d = c.getPreferredSize();
				int x = insets.left;
				int wid = d.width;
				if (alignment == CENTER) {
					x = (pd.width - d.width) / 2;
				} else if (alignment == RIGHT) {
					x = pd.width - d.width - insets.right;
				} else if (alignment == BOTH) {
					wid = pd.width - insets.left - insets.right;
				}
				c.setBounds(x, y, wid, d.height);
				y += d.height + vgap;
			}
		}
	}

	public Dimension minimumLayoutSize(Container parent) {
		return layoutSize(parent, true);
	}

	public Dimension preferredLayoutSize(Container parent) {
		return layoutSize(parent, false);
	}

	/**
	 * Not used by this class.
	 */
	public void addLayoutComponent(String name, Component comp) {
	}

	/**
	 * Not used by this class.
	 */
	public void removeLayoutComponent(Component comp) {
	}

	public String toString() {
		return getClass().getName() + "[vgap=" + vgap + " align=" + alignment + " anchor=" + anchor + "]";
	}

	private Dimension layoutSize(Container parent, boolean minimum) {
		Dimension dim = new Dimension(0, 0);
		Dimension d;
		synchronized (parent.getTreeLock()) {
			int n = parent.getComponentCount();
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				if (c.isVisible()) {
					d = minimum ? c.getMinimumSize() : c.getPreferredSize();
					dim.width = Math.max(dim.width, d.width);
					dim.height += d.height;
					if (i > 0) {
						dim.height += vgap;
					}
				}
			}
		}
		Insets insets = parent.getInsets();
		dim.width += insets.left + insets.right;
		dim.height += insets.top + insets.bottom + vgap + vgap;
		return dim;
	}
}
