/*******************************************************************************
 * This file is part of logisim-evolution.
 *
 *   logisim-evolution is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   logisim-evolution is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with logisim-evolution.  If not, see <http://www.gnu.org/licenses/>.
 *
 *   Original code by Carl Burch (http://www.cburch.com), 2011.
 *   Subsequent modifications by :
 *     + Haute École Spécialisée Bernoise
 *       http://www.bfh.ch
 *     + Haute École du paysage, d'ingénierie et d'architecture de Genève
 *       http://hepia.hesge.ch/
 *     + Haute École d'Ingénierie et de Gestion du Canton de Vaud
 *       http://www.heig-vd.ch/
 *   The project is currently maintained by :
 *     + REDS Institute - HEIG-VD
 *       Yverdon-les-Bains, Switzerland
 *       http://reds.heig-vd.ch
 *******************************************************************************/

package com.cburch.logisim.gui.generic;

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JScrollPane;
import javax.swing.SwingConstants;

import com.cburch.logisim.util.MacCompatibility;

public class CanvasPane extends JScrollPane {
	private class Listener implements ComponentListener, PropertyChangeListener {

		public void componentHidden(ComponentEvent e) {
		}

		public void componentMoved(ComponentEvent e) {
		}

		//
		// ComponentListener methods
		//
		public void componentResized(ComponentEvent e) {
			contents.recomputeSize();
		}

		public void componentShown(ComponentEvent e) {
		}

		public void propertyChange(PropertyChangeEvent e) {
			String prop = e.getPropertyName();
			if (prop.equals(ZoomModel.ZOOM)) {
				double oldZoom = ((Double) e.getOldValue()).doubleValue();
				Rectangle r = getViewport().getViewRect();
				double cx = (r.x + r.width / 2) / oldZoom;
				double cy = (r.y + r.height / 2) / oldZoom;

				double newZoom = ((Double) e.getNewValue()).doubleValue();
				contents.recomputeSize();
				r = getViewport().getViewRect();
				int hv = (int) (cx * newZoom) - r.width / 2;
				int vv = (int) (cy * newZoom) - r.height / 2;
				getHorizontalScrollBar().setValue(hv);
				getVerticalScrollBar().setValue(vv);
			}
		}
	}

	private static final long serialVersionUID = 1L;

	private CanvasPaneContents contents;
	private Listener listener;
	private ZoomModel zoomModel;

	public CanvasPane(CanvasPaneContents contents) {
		super((Component) contents);
		this.contents = contents;
		this.listener = new Listener();
		this.zoomModel = null;
		if (MacCompatibility.mrjVersion >= 0.0) {
			setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
			setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
		}

		addComponentListener(listener);
		contents.setCanvasPane(this);
	}

	public Dimension getViewportSize() {
		Dimension size = new Dimension();
		getViewport().getSize(size);
		return size;
	}

	public double getZoomFactor() {
		ZoomModel model = zoomModel;
		return model == null ? 1.0 : model.getZoomFactor();
	}

	public void setZoomModel(ZoomModel model) {
		ZoomModel oldModel = zoomModel;
		if (oldModel != null) {
			oldModel.removePropertyChangeListener(ZoomModel.ZOOM, listener);
		}
		zoomModel = model;
		if (model != null) {
			model.addPropertyChangeListener(ZoomModel.ZOOM, listener);
		}
	}

	public Dimension supportPreferredSize(int width, int height) {
		double zoom = getZoomFactor();
		if (zoom != 1.0) {
			width = (int) Math.ceil(width * zoom);
			height = (int) Math.ceil(height * zoom);
		}
		Dimension minSize = getViewportSize();
		if (minSize.width > width)
			width = minSize.width;
		if (minSize.height > height)
			height = minSize.height;
		return new Dimension(width, height);
	}

	public int supportScrollableBlockIncrement(Rectangle visibleRect,
			int orientation, int direction) {
		int unit = supportScrollableUnitIncrement(visibleRect, orientation,
				direction);
		if (direction == SwingConstants.VERTICAL) {
			return visibleRect.height / unit * unit;
		} else {
			return visibleRect.width / unit * unit;
		}
	}

	public int supportScrollableUnitIncrement(Rectangle visibleRect,
			int orientation, int direction) {
		double zoom = getZoomFactor();
		return (int) Math.round(10 * zoom);
	}
}