/***********************************************************************
 * Copyright (c) 2004 Actuate Corporation.
 * 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:
 * Actuate Corporation - initial API and implementation
 ***********************************************************************/

package org.eclipse.birt.report.engine.layout.pdf;

import java.util.Iterator;
import java.util.LinkedList;

import org.eclipse.birt.report.engine.content.IContent;
import org.eclipse.birt.report.engine.content.IStyle;
import org.eclipse.birt.report.engine.css.engine.StyleConstants;
import org.eclipse.birt.report.engine.extension.IReportItemExecutor;
import org.eclipse.birt.report.engine.layout.IBlockStackingLayoutManager;
import org.eclipse.birt.report.engine.layout.area.IArea;
import org.eclipse.birt.report.engine.layout.area.impl.AbstractArea;
import org.eclipse.birt.report.engine.layout.content.BlockStackingExecutor;
import org.eclipse.birt.report.engine.layout.pdf.util.PropertyUtil;
import org.w3c.dom.css.CSSValue;

/**
 * represents block stacking layout manager
 * 
 */
public abstract class PDFBlockStackingLM extends PDFStackingLM
		implements
			IBlockStackingLayoutManager
{
	
	protected IReportItemExecutor blockExecutor = null;

	protected CompositeArea keepWithCache = new CompositeArea();
	
	protected boolean keepWith = false;
	
		
	public int getCurrentMaxContentHeight()
	{
		return maxAvaHeight - currentBP - keepWithCache.getHeight( );
	}
	
	protected void addChild( PDFAbstractLM child )
	{
		this.child = child;
	}

	public PDFBlockStackingLM( PDFLayoutEngineContext context,
			PDFStackingLM parent, IContent content, IReportItemExecutor executor )
	{
		super( context, parent, content, executor );
	}

	protected boolean traverseChildren( )
	{
		boolean hasNextPage = false;
		if ( child != null )
		{
			hasNextPage = child.layout( );
			if ( hasNextPage )
			{
				if ( child.isFinished( ) )
				{
					child = null;
				}
				return true;
			}

		}
		if ( blockExecutor == null )
		{
			// get first child of this container
			blockExecutor = createExecutor( );
		}
		while ( blockExecutor.hasNextChild( ) )
		{
			IReportItemExecutor childExecutor = blockExecutor.getNextChild( );
			if(childExecutor!=null)
			{
				if ( layoutChildNode( childExecutor ) )
				{
					return true;
				}
			}
		}
		return false;
	}

	protected IReportItemExecutor createExecutor( )
	{
		return new BlockStackingExecutor( content, executor );
	}

	private boolean layoutChildNode( IReportItemExecutor childExecutor )
	{
		boolean hasNextPage = false;
		IContent childContent = childExecutor.execute( );
		PDFAbstractLM childLM = getFactory( ).createLayoutManager( this,
				childContent, childExecutor );
		hasNextPage = childLM.layout( );
		if ( hasNextPage && !childLM.isFinished( ) )
		{
			child = childLM;
		}
		else
		{
			child = null;
		}
		return hasNextPage;
	}

	protected void initialize( )
	{
		if(root==null)
		{
			createRoot( );
			validateBoxProperty( root.getStyle( ), parent.getCurrentMaxContentWidth( ),
					context.getMaxHeight( ) );
			calculateSpecifiedWidth( );
			//initialize offsetX and offsetY
			setOffsetX( root.getContentX( ) );
			setOffsetY( isFirst ? root.getContentY( ) : 0 );
			//initialize current position
			setCurrentBP( 0 );
			setCurrentIP( 0 );
		}
		// support user defined width
		int maxW = parent.getCurrentMaxContentWidth( );
		if ( specifiedWidth > 0 )
		{
			maxW = Math.min( maxW, specifiedWidth );
		}
		root.setAllocatedWidth( maxW );
		maxAvaWidth = root.getContentWidth( );
		
		root.setAllocatedHeight( parent.getCurrentMaxContentHeight( ));
		maxAvaHeight = root.getContentHeight( );
		
	}
	
	protected void closeLayout( )
	{
		if ( root == null )
		{
			return;
		}
		IStyle areaStyle = root.getStyle( );
		if ( !isLast )
		{
			// set dimension property for root
			// TODO support user defined height
			areaStyle.setProperty( IStyle.STYLE_BORDER_BOTTOM_WIDTH,
					IStyle.NUMBER_0 );
			areaStyle.setProperty( IStyle.STYLE_PADDING_BOTTOM,
					IStyle.NUMBER_0 );
			areaStyle.setProperty( IStyle.STYLE_MARGIN_BOTTOM, IStyle.NUMBER_0 );
		}
		
		// FIXME currently do not consider a special case...
		int height = getCurrentBP( )
				+ getOffsetY( )
				+ getDimensionValue( areaStyle
						.getProperty( StyleConstants.STYLE_PADDING_BOTTOM ) )
				+ getDimensionValue( areaStyle
						.getProperty( StyleConstants.STYLE_BORDER_BOTTOM_WIDTH ) );
		if ( isFirst && isLast )
		{
			calculateSpecifiedHeight( );
			if ( specifiedHeight > height )
			{
				CSSValue verticalAlign = areaStyle
						.getProperty( IStyle.STYLE_VERTICAL_ALIGN );
				if ( IStyle.BOTTOM_VALUE.equals( verticalAlign )
						|| IStyle.MIDDLE_VALUE.equals( verticalAlign ) )
				{
					int offset = specifiedHeight - height;
					if ( IStyle.BOTTOM_VALUE.equals( verticalAlign ) )
					{
						Iterator iter = root.getChildren( );
						while ( iter.hasNext( ) )
						{
							AbstractArea child = (AbstractArea) iter.next( );
							child.setAllocatedPosition( child.getAllocatedX( ),
									child.getAllocatedY( ) + offset );
						}
					}
					else if ( IStyle.MIDDLE_VALUE.equals( verticalAlign ) )
					{
						Iterator iter = root.getChildren( );
						while ( iter.hasNext( ) )
						{
							AbstractArea child = (AbstractArea) iter.next( );
							child.setAllocatedPosition( child.getAllocatedX( ),
									child.getAllocatedY( ) + offset / 2 );
						}
					}
				}
				height = specifiedHeight;
			}
		}
		root.setHeight( height );
	}

	public boolean addArea( IArea area, boolean keepWithPrevious, boolean keepWithNext )
	{
		// ignore empty area
		if ( area == null )
		{
			return true;
		}
		
		keepWith = keepWith || keepWithNext || pageBreakAvoid;
		
		if(!keepWith && !keepWithPrevious)
		{
			clearCache( );
		}

		AbstractArea aArea = (AbstractArea)area;
		if(keepWithCache.getHeight( ) + aArea.getAllocatedHeight( ) + getCurrentBP() > getMaxAvaHeight())
		{
			if(isPageEmpty())
			{
				addToRoot(aArea);
			}
			else
			{
				context.setAutoPageBreak( true );
				return false;
			}	
		}
		else
		{
			if(keepWithPrevious || keepWith)
			{
				keepWithCache.add( area );
			}
			else
			{
				addToRoot(aArea);
			}
		}
		keepWith = keepWithNext;
		if(!keepWith )
		{
			clearCache( );
		}
		return true;
	}

	public String getTextAlign( )
	{
		if ( content != null )
		{
			IStyle contentStyle = content.getComputedStyle( );
			return contentStyle.getTextAlign( );
		}
		return null;
	}

	protected void cancelChildren( )
	{
		if ( child != null )
		{
			child.cancel( );
		}
	}
	protected boolean hasNextChild()
	{
		if(child==null && (blockExecutor!=null && !blockExecutor.hasNextChild( )))
		{
			return false;
		}
		return true;
				
	}
	public void setKeepWithNext(boolean keepWithNext)
	{
		if(keepWithNext)
		{
			keepWith = true;
		}
		
		if(!keepWith && !pageBreakAvoid)
		{
			clearCache( );
		}
	}
	
	protected boolean clearCache()
	{
		while(!keepWithCache.isEmpty( ))
		{
			AbstractArea area = (AbstractArea)keepWithCache.getFirst( );
			boolean succeed = addToRoot(area);
			if(!succeed)
			{
				//autoPageBreak();
				return false;
			}
			else
			{
				keepWithCache.removeFirst( );
			}
		}
		return true;
		
	}
	
	protected boolean addToRoot(AbstractArea area)
	{	
		root.addChild( area );
		area.setAllocatedPosition( currentIP + offsetX, currentBP + offsetY );
		currentBP += area.getAllocatedHeight( );
		if ( currentIP + area.getAllocatedWidth( ) > root.getContentWidth( ))
		{
			root.setNeedClip( true );
		}
		
		if( currentBP > maxAvaHeight )
		{
			root.setNeedClip( true );
		}
		return true;
	}
	
	
	protected static class CompositeArea
	{
		protected LinkedList cache = new LinkedList();
		
		protected int height = 0;
		
		public CompositeArea()
		{
		}
		
		public int size()
		{
			return cache.size( );
		}
		public void add(IArea area)
		{
			AbstractArea aArea = (AbstractArea)area;
			cache.addLast( area );
			height += aArea.getAllocatedHeight( );
		}
		
		public int getHeight()
		{
			return this.height;
		}
		
		public boolean isEmpty()
		{
			return cache.isEmpty( );
		}
		
		public Iterator getChildren()
		{
			return cache.iterator( );
		}
		
		public IArea getFirst()
		{
			if(!cache.isEmpty( ))
			{
				return (IArea)cache.getFirst( );
			}
			return null;
		}
		
		public IArea removeFirst()
		{
			if(!cache.isEmpty( ))
			{
				AbstractArea area = ((AbstractArea)cache.removeFirst( )); 
				height -= area.getAllocatedHeight( );
				return area;
			}
			return null;
		}
		
		public void addAll(CompositeArea areas)
		{
			Iterator iter = areas.getChildren( );
			while(iter.hasNext( ))
			{
				add((IArea)iter.next( ));
			}
		}
		
		public CompositeArea getLastN(int count)
		{
			CompositeArea areas = new CompositeArea();
			for(int i=0; i<count; i++)
			{
				AbstractArea area = (AbstractArea)this.getFirst( );
				if(area!=null)
				{
					areas.add( area );
				}
				else
				{
					return areas;
				}
			}
			return areas;
		}
		
		public CompositeArea getFirstN(int count)
		{
			CompositeArea areas = new CompositeArea();
			for(int i=0; i<count; i++)
			{
				AbstractArea area = (AbstractArea)this.getFirst( );
				if(area!=null)
				{
					areas.add( area );
				}
				else
				{
					return areas;
				}
			}
			return areas;
		}
		
		public CompositeArea getAreas(int height, boolean force)
		{
			if(height>=this.height)
			{
				return this;
			}
			else
			{
				CompositeArea areas = new CompositeArea();
				int current = 0;
				while(current<height )
				{
					AbstractArea area = (AbstractArea)this.getFirst( );
					if(area!=null)
					{
						current += area.getAllocatedHeight( );
						if(current<=height)
						{
							areas.add( area );
							removeFirst( );
						}
						else
						{
							if(current==0 && force)
							{
								areas.add( area );
								removeFirst( );
							}
							return areas;
						}
					}
				}
					
				
			}
			return null;
		}

	}
	
	protected class KeepWithMgr
	{
		protected CompositeArea cache = new CompositeArea();
		
		protected int maxHeight = 0;
		
		public KeepWithMgr()
		{
			
		}
		
		public KeepWithMgr(int maxHeight)
		{
			this.maxHeight = maxHeight;
		}
		
		public void setMaxHeight(int maxHeight)
		{
			this.maxHeight = maxHeight;
		}
		
		public void addLast(IArea area)
		{
			cache.add( area );
		}
		
		public boolean isOverFlow()
		{
			return cache.getHeight( )>maxHeight;
		}
		
		public int getHeight()
		{
			return cache.getHeight( );
		}
		
		public boolean isEmpty()
		{
			return cache.isEmpty( );
		}
		
		public IArea getFirst()
		{
			if(!cache.isEmpty( ))
			{
				return (IArea)cache.getFirst( );
			}
			return null;
		}
		
		public void removeFirst()
		{
			if(!cache.isEmpty( ))
			{
				cache.removeFirst( );
			}
		}
	
	}
	
	public void autoPageBreak()
	{
		if(!isRootEmpty( ))
		{
			closeLayout();
			submitRoot();
			return;
		}
		else if(!keepWithCache.isEmpty( ))
		{
			clearCache( );
			if(!isRootEmpty( ))
			{
				closeLayout();
				submitRoot();
				return;
			}
		}
		if(child!=null)
		{
			child.autoPageBreak();
			closeLayout();
			submitRoot();
		}
		
	}
	
	public void submit(AbstractArea area)
	{
		root.addChild( area );
		area.setAllocatedPosition( currentIP + offsetX, currentBP + offsetY );
		currentBP += area.getAllocatedHeight( );
	}
	
	
	protected boolean submitRoot( )
	{
		if(root==null)
		{
			return true;
		}
		boolean success = true;
		if ( parent != null )
		{
			if(isLast)
			{
				//FIXME to support keepWithPrevious
				success = parent.addArea( root, false, isKeepWithNext() );
			}
			else if(context.isAutoPageBreak( ) && isFirst)
			{
				success = parent.addArea( root, false, false );
			}
			else
			{
				parent.submit( root );
			}
			if ( success )
			{
				isFirst = false;
				root = null;
			}
		}
		else
		{
			if ( content != null )
			{
				content.setExtension( IContent.LAYOUT_EXTENSION, root );
				//root = null;
			}
		}
		return success;
	}
	
	
	
}
