/*
 * 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.
 */

/* $Id: BlockLayoutManager.java 1790795 2017-04-10 10:03:35Z cbowditch $ */

package org.apache.fop.layoutmgr;

import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Stack;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.fop.area.Area;
import org.apache.fop.area.Block;
import org.apache.fop.area.LineArea;
import org.apache.fop.datatypes.Length;
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
import org.apache.fop.fo.properties.KeepProperty;
import org.apache.fop.fonts.Font;
import org.apache.fop.fonts.FontInfo;
import org.apache.fop.fonts.FontTriplet;
import org.apache.fop.layoutmgr.inline.InlineLevelLayoutManager;
import org.apache.fop.layoutmgr.inline.LineLayoutManager;
import org.apache.fop.traits.MinOptMax;
import org.apache.fop.traits.SpaceVal;

LayoutManager for a block FO.
/**
 * LayoutManager for a block FO.
 */
public class BlockLayoutManager extends SpacedBorderedPaddedBlockLayoutManager
        implements BreakOpportunity {

    
logging instance /** logging instance */
    private static Log log = LogFactory.getLog(BlockLayoutManager.class);

    private Block curBlockArea;

    
Iterator over the child layout managers. /** Iterator over the child layout managers. */
    protected ListIterator<LayoutManager> proxyLMiter;

    private int lead = 12000;
    private Length lineHeight;
    private int follow = 2000;
    //private int middleShift = 0;

    
Creates a new BlockLayoutManager.
Params:
inBlock – the block FO object to create the layout manager for./**
     * Creates a new BlockLayoutManager.
     * @param inBlock the block FO object to create the layout manager for.
     */
    public BlockLayoutManager(org.apache.fop.fo.flow.Block inBlock) {
        super(inBlock);
        proxyLMiter = new ProxyLMiter();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public void initialize() {
        super.initialize();
        org.apache.fop.fo.flow.Block fo = getBlockFO();
        FontInfo fi = fo.getFOEventHandler().getFontInfo();
        FontTriplet[] fontkeys = fo.getCommonFont().getFontState(fi);
        Font initFont = fi.getFontInstance(fontkeys[0],
                getBlockFO().getCommonFont().fontSize.getValue(this));
        lead = initFont.getAscender();
        follow = -initFont.getDescender();
        //middleShift = -fs.getXHeight() / 2;
        lineHeight = fo.getLineHeight().getOptimum(this).getLength();
        startIndent = fo.getCommonMarginBlock().startIndent.getValue(this);
        endIndent = fo.getCommonMarginBlock().endIndent.getValue(this);
        foSpaceBefore = new SpaceVal(fo.getCommonMarginBlock().spaceBefore, this).getSpace();
        foSpaceAfter = new SpaceVal(fo.getCommonMarginBlock().spaceAfter, this).getSpace();
        // use optimum space values
        adjustedSpaceBefore = fo.getCommonMarginBlock().spaceBefore.getSpace()
                                    .getOptimum(this).getLength().getValue(this);
        adjustedSpaceAfter = fo.getCommonMarginBlock().spaceAfter.getSpace()
                                    .getOptimum(this).getLength().getValue(this);
    }

    @Override
    protected CommonBorderPaddingBackground getCommonBorderPaddingBackground() {
        return getBlockFO().getCommonBorderPaddingBackground();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public List getNextKnuthElements(LayoutContext context, int alignment) {
        return getNextKnuthElements(context, alignment, null, null, null);
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public List getNextKnuthElements(LayoutContext context, int alignment, Stack lmStack,
            Position restartPosition, LayoutManager restartAtLM) {
        resetSpaces();
        return super.getNextKnuthElements(
                context, alignment, lmStack, restartPosition, restartAtLM);
    }

    
Overridden to take into account that the childLM may be the block's LineLayoutManager. {@inheritDoc} /**
     * Overridden to take into account that the childLM may be the block's
     * {@link LineLayoutManager}.
     * {@inheritDoc}
     */
    @Override
    protected List<ListElement> getNextChildElements(LayoutManager childLM, LayoutContext context,
           LayoutContext childLC, int alignment, Stack lmStack, Position restartPosition,
           LayoutManager restartAtLM) {

        childLC.copyPendingMarksFrom(context);

        if (childLM instanceof LineLayoutManager) {
            childLC.setRefIPD(getContentAreaIPD());
        } else {
            // nop; will have been properly set by makeChildLayoutContext()
        }

        if (childLM == this.childLMs.get(0)) {
            childLC.setFlags(LayoutContext.SUPPRESS_BREAK_BEFORE);
            //Handled already by the parent (break collapsing, see above)
        }

        if (lmStack == null) {
            return childLM.getNextKnuthElements(childLC, alignment);
        } else {
            if (childLM instanceof LineLayoutManager) {
                assert (restartPosition instanceof LeafPosition);
                return ((LineLayoutManager) childLM).getNextKnuthElements(childLC, alignment,
                        (LeafPosition) restartPosition);
            } else {
                return childLM.getNextKnuthElements(childLC, alignment,
                        lmStack, restartPosition, restartAtLM);
            }
        }
    }

    private void resetSpaces() {
        this.discardBorderBefore = false;
        this.discardBorderAfter = false;
        this.discardPaddingBefore = false;
        this.discardPaddingAfter = false;
        this.effSpaceBefore = null;
        this.effSpaceAfter = null;
    }

    
Proxy iterator for Block LM.
This iterator creates and holds the complete list
of child LMs.
It uses fobjIter as its base iterator.
Block LM's createNextChildLMs uses this iterator
as its base iterator.
/**
     * Proxy iterator for Block LM.
     * This iterator creates and holds the complete list
     * of child LMs.
     * It uses fobjIter as its base iterator.
     * Block LM's createNextChildLMs uses this iterator
     * as its base iterator.
     */
    protected class ProxyLMiter extends LMiter {

        
Constructs a proxy iterator for Block LM.
/**
         * Constructs a proxy iterator for Block LM.
         */
        public ProxyLMiter() {
            super(BlockLayoutManager.this);
            listLMs = new java.util.ArrayList<LayoutManager>(10);
        }

        
Returns:
true if there are more child lms/**
         * @return true if there are more child lms
         */
        public boolean hasNext() {
            return (curPos < listLMs.size()) || createNextChildLMs(curPos);
        }

        
Params:
pos – ...
Returns:
true if new child lms were added/**
         * @param pos ...
         * @return true if new child lms were added
         */
        protected boolean createNextChildLMs(int pos) {
            List<LayoutManager> newLMs = createChildLMs(pos + 1 - listLMs.size());
            if (newLMs != null) {
                listLMs.addAll(newLMs);
            }
            return pos < listLMs.size();
        }
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public boolean createNextChildLMs(int pos) {

        while (proxyLMiter.hasNext()) {
            LayoutManager lm = proxyLMiter.next();
            if (lm instanceof InlineLevelLayoutManager) {
                LineLayoutManager lineLM = createLineManager(lm);
                addChildLM(lineLM);
            } else {
                addChildLM(lm);
            }
            if (pos < childLMs.size()) {
                return true;
            }
        }
        return false;
    }

    
Create a new LineLM, and collect all consecutive
inline generating LMs as its child LMs.
Params:
firstlm – First LM in new LineLM
Returns:
the newly created LineLM/**
     * Create a new LineLM, and collect all consecutive
     * inline generating LMs as its child LMs.
     * @param firstlm First LM in new LineLM
     * @return the newly created LineLM
     */
    private LineLayoutManager createLineManager(LayoutManager firstlm) {
        LineLayoutManager llm;
        llm = new LineLayoutManager(getBlockFO(), lineHeight, lead, follow);
        List<LayoutManager> inlines = new java.util.ArrayList<LayoutManager>();
        inlines.add(firstlm);
        while (proxyLMiter.hasNext()) {
            LayoutManager lm = proxyLMiter.next();
            if (lm instanceof InlineLevelLayoutManager) {
                inlines.add(lm);
            } else {
                proxyLMiter.previous();
                break;
            }
        }
        llm.addChildLMs(inlines);
        return llm;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public KeepProperty getKeepTogetherProperty() {
        return getBlockFO().getKeepTogether();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public KeepProperty getKeepWithPreviousProperty() {
        return getBlockFO().getKeepWithPrevious();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public KeepProperty getKeepWithNextProperty() {
        return getBlockFO().getKeepWithNext();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public void addAreas(PositionIterator parentIter, LayoutContext layoutContext) {
        getParentArea(null);

        // if this will create the first block area in a page
        // and display-align is after or center, add space before
        if (layoutContext.getSpaceBefore() > 0) {
            addBlockSpacing(0.0, MinOptMax.getInstance(layoutContext.getSpaceBefore()));
        }

        LayoutManager childLM;
        LayoutManager lastLM = null;
        LayoutContext lc = LayoutContext.offspringOf(layoutContext);
        lc.setSpaceAdjust(layoutContext.getSpaceAdjust());
        // set space after in the LayoutContext for children
        if (layoutContext.getSpaceAfter() > 0) {
            lc.setSpaceAfter(layoutContext.getSpaceAfter());
        }
        PositionIterator childPosIter;

        // "unwrap" the NonLeafPositions stored in parentIter
        // and put them in a new list;
        LinkedList<Position> positionList = new LinkedList<Position>();
        Position pos;
        Position firstPos = null;
        Position lastPos = null;
        while (parentIter.hasNext()) {
            pos = parentIter.next();
            //log.trace("pos = " + pos.getClass().getName() + "; " + pos);
            if (pos.getIndex() >= 0) {
                if (firstPos == null) {
                    firstPos = pos;
                }
                lastPos = pos;
            }
            Position innerPosition = pos;
            if (pos instanceof NonLeafPosition) {
                //Not all elements are wrapped
                innerPosition = pos.getPosition();
            }

            if (innerPosition != null
                    && (innerPosition.getLM() != this
                        || innerPosition instanceof MappingPosition)) {
                // innerPosition was created by another LM
                positionList.add(innerPosition);
                lastLM = innerPosition.getLM();
            }
        }

        addId();

        registerMarkers(true, isFirst(firstPos), isLast(lastPos));

        // the Positions in positionList were inside the elements
        // created by the LineLM
        childPosIter = new PositionIterator(positionList.listIterator());

        while ((childLM = childPosIter.getNextChildLM()) != null) {
            // set last area flag
            lc.setFlags(LayoutContext.LAST_AREA,
                    (layoutContext.isLastArea() && childLM == lastLM));
            lc.setStackLimitBP(layoutContext.getStackLimitBP());
            // Add the line areas to Area
            childLM.addAreas(childPosIter, lc);
        }

        registerMarkers(false, isFirst(firstPos), isLast(lastPos));

        TraitSetter.addSpaceBeforeAfter(curBlockArea, layoutContext.getSpaceAdjust(),
                effSpaceBefore, effSpaceAfter);
        TraitSetter.setVisibility(curBlockArea, getBlockFO().getVisibility());
        flush();

        curBlockArea = null;
        resetSpaces();

        //Notify end of block layout manager to the PSLM
        checkEndOfLayout(lastPos);
    }

    
Return an Area which can contain the passed childArea. The childArea
may not yet have any content, but it has essential traits set.
In general, if the LayoutManager already has an Area it simply returns
it. Otherwise, it makes a new Area of the appropriate class.
It gets a parent area for its area by calling its parent LM.
Finally, based on the dimensions of the parent area, it initializes
its own area. This includes setting the content IPD and the maximum
BPD.
Params:
childArea – area to get the parent area for
Returns:
the parent area/**
     * Return an Area which can contain the passed childArea. The childArea
     * may not yet have any content, but it has essential traits set.
     * In general, if the LayoutManager already has an Area it simply returns
     * it. Otherwise, it makes a new Area of the appropriate class.
     * It gets a parent area for its area by calling its parent LM.
     * Finally, based on the dimensions of the parent area, it initializes
     * its own area. This includes setting the content IPD and the maximum
     * BPD.
     * @param childArea area to get the parent area for
     * @return the parent area
     */
    @Override
    public Area getParentArea(Area childArea) {
        if (curBlockArea == null) {
            curBlockArea = new Block();

            curBlockArea.setIPD(super.getContentAreaIPD());

            curBlockArea.setBidiLevel(getBlockFO().getBidiLevelRecursive());

            TraitSetter.addBreaks(curBlockArea,
                    getBlockFO().getBreakBefore(), getBlockFO().getBreakAfter());

            // Must get dimensions from parent area
            //Don't optimize this line away. It can have ugly side-effects.
            /*Area parentArea =*/ parentLayoutManager.getParentArea(curBlockArea);

            // set traits
            TraitSetter.setProducerID(curBlockArea, getBlockFO().getId());
            TraitSetter.addBorders(curBlockArea,
                    getBlockFO().getCommonBorderPaddingBackground(),
                    discardBorderBefore, discardBorderAfter, false, false, this);
            TraitSetter.addPadding(curBlockArea,
                    getBlockFO().getCommonBorderPaddingBackground(),
                    discardPaddingBefore, discardPaddingAfter, false, false, this);
            TraitSetter.addMargins(curBlockArea,
                    getBlockFO().getCommonBorderPaddingBackground(),
                    startIndent, endIndent,
                    this);
            TraitSetter.setLayer(curBlockArea, getBlockFO().getLayer());

            curBlockArea.setLocale(getBlockFO().getCommonHyphenation().getLocale());
            curBlockArea.setLocation(FONode.getLocatorString(getBlockFO().getLocator()));
            setCurrentArea(curBlockArea); // ??? for generic operations
        }
        return curBlockArea;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public void addChildArea(Area childArea) {
        if (curBlockArea != null) {
            if (childArea instanceof LineArea) {
                curBlockArea.addLineArea((LineArea) childArea);
            } else {
                curBlockArea.addBlock((Block) childArea);
            }
        }
    }

    
Force current area to be added to parent area.
{@inheritDoc}
/**
     * Force current area to be added to parent area.
     * {@inheritDoc}
     */
    @Override
    protected void flush() {
        if (curBlockArea != null) {
            TraitSetter.addBackground(curBlockArea,
                    getBlockFO().getCommonBorderPaddingBackground(),
                    this);
            super.flush();
        }
    }

    
convenience method that returns the Block node
Returns:
the block node/**
     * convenience method that returns the Block node
     * @return the block node
     */
    protected org.apache.fop.fo.flow.Block getBlockFO() {
        return (org.apache.fop.fo.flow.Block) fobj;
    }

    // --------- Property Resolution related functions --------- //

    
Returns the IPD of the content area
Returns:
the IPD of the content area/**
     * Returns the IPD of the content area
     * @return the IPD of the content area
     */
    @Override
    public int getContentAreaIPD() {
        if (curBlockArea != null) {
            return curBlockArea.getIPD();
        }
        return super.getContentAreaIPD();
    }


    
Returns the BPD of the content area
Returns:
the BPD of the content area/**
     * Returns the BPD of the content area
     * @return the BPD of the content area
     */
    @Override
    public int getContentAreaBPD() {
        if (curBlockArea != null) {
            return curBlockArea.getBPD();
        }
        return -1;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public boolean getGeneratesBlockArea() {
        return true;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public boolean isRestartable() {
        return true;
    }

}