/*
 * 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.
 */

/* $Id$ */

package org.apache.fop.layoutmgr.table;

import org.apache.fop.area.Area;
import org.apache.fop.area.Block;
import org.apache.fop.fo.flow.table.TableAndCaption;
import org.apache.fop.layoutmgr.BlockStackingLayoutManager;
import org.apache.fop.layoutmgr.Keep;
import org.apache.fop.layoutmgr.LayoutContext;
import org.apache.fop.layoutmgr.PositionIterator;

/**
 * LayoutManager for a table-and-caption FO.
 * A table and caption consists of a table and a caption.
 * The caption contains blocks that are positioned next to the
 * table on the caption side.
 * The caption blocks have an implicit keep with the table.
 * TODO Implement getNextKnuthElements()
 */
public class TableAndCaptionLayoutManager extends BlockStackingLayoutManager {

    private Block curBlockArea;

    /**
     * Create a new table and caption layout manager.
     * @param node table-and-caption FO
     */
    public TableAndCaptionLayoutManager(TableAndCaption node) {
        super(node);
    }

    /**
     * Returns the table-and-caption formatting object.
     * @return the table-and-caption formatting object
     */
    public TableAndCaption getTableAndCaptionFO() {
        return (TableAndCaption)this.fobj;
    }

    /**
     * Get the next break possibility.
     *
     * @param context the layout context for getting breaks
     * @return the next break possibility
     */
    /*
    public BreakPoss getNextBreakPoss(LayoutContext context) {
        LayoutManager curLM; // currently active LM

        MinOptMax stackSize = new MinOptMax();
        // if starting add space before
        // stackSize.add(spaceBefore);
        BreakPoss lastPos = null;

        // if there is a caption then get the side and work out when
        // to handle it

        while ((curLM = getChildLM()) != null) {
            // Make break positions and return blocks!
            // Set up a LayoutContext
            int ipd = context.getRefIPD();
            BreakPoss bp;

            LayoutContext childLC = LayoutContext.newInstance();
            // if line layout manager then set stack limit to ipd
            // line LM actually generates a LineArea which is a block
            childLC.setStackLimit(
                  MinOptMax.subtract(context.getStackLimit(),
                                     stackSize));
            childLC.setRefIPD(ipd);

            boolean over = false;
            while (!curLM.isFinished()) {
                if ((bp = curLM.getNextBreakPoss(childLC)) != null) {
                    if (stackSize.opt + bp.getStackingSize().opt > context.getStackLimit().max) {
                        // reset to last break
                        if (lastPos != null) {
                            LayoutManager lm = lastPos.getLayoutManager();
                            lm.resetPosition(lastPos.getPosition());
                            if (lm != curLM) {
                                curLM.resetPosition(null);
                            }
                        } else {
                            curLM.resetPosition(null);
                        }
                        over = true;
                        break;
                    }
                    stackSize.add(bp.getStackingSize());
                    lastPos = bp;
                    childBreaks.add(bp);

                    if (bp.nextBreakOverflows()) {
                        over = true;
                        break;
                    }

                    childLC.setStackLimit(MinOptMax.subtract(
                                             context.getStackLimit(), stackSize));
                }
            }
            BreakPoss breakPoss = new BreakPoss(
                                    new LeafPosition(this, childBreaks.size() - 1));
            if (over) {
                breakPoss.setFlag(BreakPoss.NEXT_OVERFLOWS, true);
            }
            breakPoss.setStackingSize(stackSize);
            return breakPoss;
        }
        setFinished(true);
        return null;
    }*/

    /**
     * Add the areas.
     *
     * @param parentIter the position iterator
     * @param layoutContext the layout context for adding areas
     */
    public void addAreas(PositionIterator parentIter,
                         LayoutContext layoutContext) {
        getParentArea(null);
        addId();

        /* TODO: Reimplement using Knuth approach
        LayoutManager childLM;
        int iStartPos = 0;
        LayoutContext lc = LayoutContext.newInstance();
        while (parentIter.hasNext()) {
            LeafPosition lfp = (LeafPosition) parentIter.next();
            // Add the block areas to Area
            PositionIterator breakPosIter = new BreakPossPosIter(
                    childBreaks, iStartPos, lfp.getLeafPos() + 1);
            iStartPos = lfp.getLeafPos() + 1;
            while ((childLM = breakPosIter.getNextChildLM()) != null) {
                childLM.addAreas(breakPosIter, lc);
            }
        }*/

        flush();

        //childBreaks.clear();
        curBlockArea = null;
    }

    /**
     * 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 the child area to locate the parent
     * @return the area for this table and caption
     */
    public Area getParentArea(Area childArea) {
        if (curBlockArea == null) {
            curBlockArea = new Block();
            curBlockArea.setChangeBarList(getChangeBarList());

            // Set up dimensions
            // Must get dimensions from parent area
            Area parentArea = parentLayoutManager.getParentArea(curBlockArea);
            int referenceIPD = parentArea.getIPD();
            curBlockArea.setIPD(referenceIPD);
            curBlockArea.setBidiLevel(getTableAndCaptionFO().getBidiLevel());
            // Get reference IPD from parentArea
            setCurrentArea(curBlockArea); // ??? for generic operations
        }
        return curBlockArea;
    }

    /**
     * Add the child to the current area.
     *
     * @param childArea the area to add
     */
    public void addChildArea(Area childArea) {
        if (curBlockArea != null) {
            curBlockArea.addBlock((Block) childArea);
        }
    }

    /** {@inheritDoc} */
    public Keep getKeepWithNext() {
        return Keep.KEEP_AUTO;
        /* TODO Complete me!
        return KeepUtil.getCombinedBlockLevelKeepStrength(
                getTableAndCaptionFO().getKeepWithNext());
        */
    }

    /** {@inheritDoc} */
    public Keep getKeepWithPrevious() {
        return Keep.KEEP_AUTO;
        /* TODO Complete me!
        return KeepUtil.getCombinedBlockLevelKeepStrength(
                getTableAndCaptionFO().getKeepWithPrevious());
        */
    }

}
