/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2016 TIBCO Software Inc. All rights reserved.
 * http://www.jaspersoft.com
 *
 * Unless you have purchased a commercial license agreement from Jaspersoft,
 * the following license terms apply:
 *
 * This program is part of JasperReports.
 *
 * JasperReports is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JasperReports 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with JasperReports. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.jasperreports.engine.fill;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import net.sf.jasperreports.engine.JRPrintElement;
import net.sf.jasperreports.engine.JRPrintElementContainer;


/**
 * @author Teodor Danciu (teodord@users.sourceforge.net)
 */
public class JRPrintBand implements JRPrintElementContainer
{
	

	/**
	 *
	 */
	private int height;
	// adding both elements and OffsetElements to this list
	private List<Object> elements = new ArrayList<Object>();
	private boolean iterated = false;

	
	@Override
	public int getHeight()
	{
		return this.height;
	}
		
	@Override
	public void setHeight(int height)
	{
		this.height = height;
	}

	@Override
	public List<JRPrintElement> getElements()
	{
		// should not be called
		throw new UnsupportedOperationException();
	}
	
	public Iterator<JRPrintElement> iterateElements()
	{
		// we only allow one iteration of the elements because we apply 
		// the offsets during iteration
		if (iterated)
		{
			// this should not happen
			throw new IllegalStateException("Elements already iterated");
		}
		
		iterated = true;
		return new ElementsIterator(elements);
	}
	
	@Override
	public void addElement(JRPrintElement element)
	{
		this.elements.add(element);
	}
	
	public void addOffsetElements(Collection<? extends JRPrintElement> elements, int offsetX, int offsetY)
	{
		if (elements == null || elements.isEmpty())
		{
			// nothing to do
			return;
		}
		
		OffsetElements offsetElements = new OffsetElements(elements, offsetX, offsetY);
		this.elements.add(offsetElements);
	}
		
	protected static class OffsetElements
	{
		private final Collection<? extends JRPrintElement> elements;
		private final int offsetX;
		private final int offsetY;
		
		public OffsetElements(Collection<? extends JRPrintElement> elements,
				int offsetX, int offsetY)
		{
			this.elements = elements;
			this.offsetX = offsetX;
			this.offsetY = offsetY;
		}
	}
	
	protected static class ElementsIterator implements Iterator<JRPrintElement>
	{
		private final Iterator<Object> iterator;
		
		private OffsetElements subElements;
		private Iterator<? extends JRPrintElement> subIterator;

		public ElementsIterator(List<Object> elements)
		{
			this.iterator = elements.iterator();
		}

		@Override
		public boolean hasNext()
		{
			return (subIterator != null && subIterator.hasNext()) || iterator.hasNext();
		}

		@Override
		public JRPrintElement next()
		{
			JRPrintElement element = null;
			// try to get the element from the sublist
			if (subIterator != null)
			{
				if (subIterator.hasNext())
				{
					element = subIterator.next();
					// remove the element from the sublist.  this helps with virtualized subreport pages 
					// by releasing the external data and allowing the master page to reuse the storage.
					subIterator.remove();
					
					// apply the offsets
					setSubOffsets(element);
				}
				else
				{
					subIterator = null;
					subElements = null;
				}
			}
			
			// if no sublist element, get from the main list
			if (element == null)
			{
				Object next = iterator.next();
				if (next instanceof JRPrintElement)
				{
					element = (JRPrintElement) next;
				}
				else
				{
					subElements = (OffsetElements) next;
					subIterator = subElements.elements.iterator();

					// we're only adding non empty sublists, hence not checking hasNext()
					element = subIterator.next();
					subIterator.remove();
					
					// apply the offsets
					setSubOffsets(element);
				}
			}
			
			return element;
		}

		protected void setSubOffsets(JRPrintElement element)
		{
			element.setX(subElements.offsetX + element.getX());
			element.setY(subElements.offsetY + element.getY());
		}

		@Override
		public void remove()
		{
			throw new UnsupportedOperationException();
		}
	}
}
