/*
 * 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: Page.java 1681384 2015-05-23 21:07:13Z adelmelle $ */

package org.apache.fop.area;

import java.awt.Rectangle;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;
import java.util.List;
import java.util.Map;

import org.apache.fop.datatypes.FODimension;
import org.apache.fop.datatypes.LengthBase;
import org.apache.fop.datatypes.SimplePercentBaseContext;
import org.apache.fop.fo.pagination.Region;
import org.apache.fop.fo.pagination.RegionBody;
import org.apache.fop.fo.pagination.SimplePageMaster;
import org.apache.fop.fo.properties.CommonMarginBlock;
import org.apache.fop.layoutmgr.TraitSetter;
import org.apache.fop.traits.WritingModeTraitsGetter;

import static org.apache.fop.fo.Constants.EN_ERROR_IF_OVERFLOW;
import static org.apache.fop.fo.Constants.EN_HIDDEN;
import static org.apache.fop.fo.Constants.FO_REGION_AFTER;
import static org.apache.fop.fo.Constants.FO_REGION_BEFORE;
import static org.apache.fop.fo.Constants.FO_REGION_BODY;
import static org.apache.fop.fo.Constants.FO_REGION_END;
import static org.apache.fop.fo.Constants.FO_REGION_START;

The page.
This holds the contents of the page. Each region is added.
The unresolved references area added so that if the page is
serialized then it will handle the resolving properly after
being reloaded.
This is serializable so it can be saved to cache to save
memory if there are forward references.
The page is cloneable so the page master can make copies of
the top level page and regions.
/**
 * The page.
 * This holds the contents of the page. Each region is added.
 * The unresolved references area added so that if the page is
 * serialized then it will handle the resolving properly after
 * being reloaded.
 * This is serializable so it can be saved to cache to save
 * memory if there are forward references.
 * The page is cloneable so the page master can make copies of
 * the top level page and regions.
 */
public class Page extends AreaTreeObject implements Serializable {

    private static final long serialVersionUID = 6272157047421543866L;

    // contains before, start, body, end and after regions
    private RegionViewport regionBefore;
    private RegionViewport regionStart;
    private RegionViewport regionBody;
    private RegionViewport regionEnd;
    private RegionViewport regionAfter;

    // temporary map of unresolved objects used when serializing the page
    private Map<String, List<Resolvable>> unresolved;

    
Set to true to make this page behave as if it were not empty. /** Set to true to make this page behave as if it were not empty. */
    private boolean fakeNonEmpty;

    
 Empty constructor
/**
     *  Empty constructor
     */
    public Page() { }

    
Constructor
Params:
spm – SimplePageMaster containing the dimensions for this
           page-reference-area/**
     * Constructor
     * @param spm SimplePageMaster containing the dimensions for this
     *            page-reference-area
     */
    public Page(SimplePageMaster spm) {
        // Width and Height of the page view port
        FODimension pageViewPortDims = new FODimension(spm.getPageWidth().getValue()
                            ,  spm.getPageHeight().getValue());

        // Get absolute margin properties (top, left, bottom, right)
        CommonMarginBlock mProps = spm.getCommonMarginBlock();

        /*
         * Create the page reference area rectangle (0,0 is at top left
         * of the "page media" and y increases
         * when moving towards the bottom of the page.
         * The media rectangle itself is (0,0,pageWidth,pageHeight).
         */
        /* Special rules apply to resolving margins in the page context.
         * Contrary to normal margins in this case top and bottom margin
         * are resolved relative to the height. In the property subsystem
         * all margin properties are configured to using BLOCK_WIDTH.
         * That's why we 'cheat' here and setup a context for the height but
         * use the LengthBase.BLOCK_WIDTH.
         */
        SimplePercentBaseContext pageWidthContext
            = new SimplePercentBaseContext(null, LengthBase.CONTAINING_BLOCK_WIDTH
                                            , pageViewPortDims.ipd);
        SimplePercentBaseContext pageHeightContext
            = new SimplePercentBaseContext(null, LengthBase.CONTAINING_BLOCK_WIDTH
                                            , pageViewPortDims.bpd);

        Rectangle pageRefRect
            =  new Rectangle(mProps.marginLeft.getValue(pageWidthContext)
                            , mProps.marginTop.getValue(pageHeightContext)
                            , pageViewPortDims.ipd
                                - mProps.marginLeft.getValue(pageWidthContext)
                                - mProps.marginRight.getValue(pageWidthContext)
                            , pageViewPortDims.bpd
                                - mProps.marginTop.getValue(pageHeightContext)
                                - mProps.marginBottom.getValue(pageHeightContext));

        // Set up the CTM on the page reference area based on writing-mode
        // and reference-orientation
        FODimension reldims = new FODimension(0, 0);
        CTM pageCTM = CTM.getCTMandRelDims(spm.getReferenceOrientation(),
            spm.getWritingMode(), pageRefRect, reldims);

        // Create a RegionViewport/ reference area pair for each page region
        RegionReference rr;
        for (Region r : spm.getRegions().values()) {
            RegionViewport rvp = makeRegionViewport(r, reldims, pageCTM);
            if (r.getNameId() == FO_REGION_BODY) {
                rr = new BodyRegion((RegionBody) r, rvp);
            } else {
                rr = new RegionReference(r, rvp);
            }
            // set borders and padding traits
            // (a little extensions wrt what prescribed by the specs at 6.4.14)
            TraitSetter.addBorders(rr, r.getCommonBorderPaddingBackground(),
                    false, false, false, false, null);
            TraitSetter.addPadding(rr, r.getCommonBorderPaddingBackground(),
                    false, false, false, false, null);
            setRegionReferencePosition(rr, r, rvp.getViewArea());
            rvp.setRegionReference(rr);
            setRegionViewport(r.getNameId(), rvp);
        }
    }

    
Call this method to force this page to pretend not to be empty.
/**
     * Call this method to force this page to pretend not to be empty.
     */
    public void fakeNonEmpty() {
        this.fakeNonEmpty = true;
    }

    
Creates a RegionViewport Area object for this pagination Region.
Params:
r – the region the viewport is to be created for
reldims – relative dimensions
pageCTM – page coordinate transformation matrix
Returns:
the new region viewport/**
     * Creates a RegionViewport Area object for this pagination Region.
     * @param r the region the viewport is to be created for
     * @param reldims relative dimensions
     * @param pageCTM page coordinate transformation matrix
     * @return the new region viewport
     */
    private static RegionViewport makeRegionViewport(Region r, FODimension reldims, CTM pageCTM) {
        Rectangle2D relRegionRect = r.getViewportRectangle(reldims);
        Rectangle2D absRegionRect = pageCTM.transform(relRegionRect);
        // Get the region viewport rectangle in absolute coords by
        // transforming it using the page CTM
        RegionViewport rv = new RegionViewport(absRegionRect);
        rv.setBPD((int)relRegionRect.getHeight());
        rv.setIPD((int)relRegionRect.getWidth());
        TraitSetter.addBackground(rv, r.getCommonBorderPaddingBackground(), null);
        rv.setClip(r.getOverflow() == EN_HIDDEN
                || r.getOverflow() == EN_ERROR_IF_OVERFLOW);
        return rv;
    }

    
Set the region reference position within the region viewport.
This sets the transform that is used to place the contents of
the region reference.
Params:
rr – the region reference area
r – the region-xxx formatting object
absRegVPRect – The region viewport rectangle in "absolute" coordinates
where x=distance from left, y=distance from bottom, width=right-left
height=top-bottom/**
     * Set the region reference position within the region viewport.
     * This sets the transform that is used to place the contents of
     * the region reference.
     *
     * @param rr the region reference area
     * @param r the region-xxx formatting object
     * @param absRegVPRect The region viewport rectangle in "absolute" coordinates
     * where x=distance from left, y=distance from bottom, width=right-left
     * height=top-bottom
     */
    private static void setRegionReferencePosition(RegionReference rr, Region r,
                                  Rectangle2D absRegVPRect) {
        FODimension reldims = new FODimension(0, 0);
        rr.setCTM(CTM.getCTMandRelDims(r.getReferenceOrientation(),
                r.getWritingMode(), absRegVPRect, reldims));
        rr.setIPD(reldims.ipd
                - rr.getBorderAndPaddingWidthStart()
                - rr.getBorderAndPaddingWidthEnd());
        rr.setBPD(reldims.bpd
                - rr.getBorderAndPaddingWidthBefore()
                - rr.getBorderAndPaddingWidthAfter());
    }

    
Set the region on this page.
Params:
areaclass – the area class of the region to set
port – the region viewport to set/**
     * Set the region on this page.
     *
     * @param areaclass the area class of the region to set
     * @param port the region viewport to set
     */
    public void setRegionViewport(int areaclass, RegionViewport port) {
        if (areaclass == FO_REGION_BEFORE) {
            regionBefore = port;
        } else if (areaclass == FO_REGION_START) {
            regionStart = port;
        } else if (areaclass == FO_REGION_BODY) {
            regionBody = port;
        } else if (areaclass == FO_REGION_END) {
            regionEnd = port;
        } else if (areaclass == FO_REGION_AFTER) {
            regionAfter = port;
        }
    }

    
Get the region from this page.
Params:
areaClass – the region area class
Returns:
the region viewport or null if none/**
     * Get the region from this page.
     *
     * @param areaClass the region area class
     * @return the region viewport or null if none
     */
    public RegionViewport getRegionViewport(int areaClass) {
        switch (areaClass) {
        case FO_REGION_BEFORE:
            return regionBefore;
        case FO_REGION_START:
            return regionStart;
        case FO_REGION_BODY:
            return regionBody;
        case FO_REGION_END:
            return regionEnd;
        case FO_REGION_AFTER:
            return regionAfter;
        default:
            throw new IllegalArgumentException("No such area class with ID = " + areaClass);
        }
    }

    
Indicates whether any FOs have been added to the body region
Returns:
whether any FOs have been added to the body region/**
     * Indicates whether any FOs have been added to the body region
     *
     * @return whether any FOs have been added to the body region
     */
    public boolean isEmpty() {
        if (fakeNonEmpty) {
            return false;
        } else if (regionBody == null) {
            return true;
        } else {
            return regionBody.getRegionReference().isEmpty();
        }
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public Object clone() throws CloneNotSupportedException {
        Page p = (Page) super.clone();
        if (regionBefore != null) {
            p.regionBefore = (RegionViewport)regionBefore.clone();
        }
        if (regionStart != null) {
            p.regionStart = (RegionViewport)regionStart.clone();
        }
        if (regionBody != null) {
            p.regionBody = (RegionViewport)regionBody.clone();
        }
        if (regionEnd != null) {
            p.regionEnd = (RegionViewport)regionEnd.clone();
        }
        if (regionAfter != null) {
            p.regionAfter = (RegionViewport)regionAfter.clone();
        }

        return p;
    }

    
Set the unresolved references on this page for serializing.
Params:
unres – the Map of unresolved objects/**
     * Set the unresolved references on this page for serializing.
     *
     * @param unres the Map of unresolved objects
     */
    public void setUnresolvedReferences(Map<String, List<Resolvable>> unres) {
        unresolved = unres;
    }

    
Get the map unresolved references from this page.
This should be called after deserializing to retrieve
the map of unresolved references that were serialized.
Returns:
the de-serialized HashMap of unresolved objects/**
     * Get the map unresolved references from this page.
     * This should be called after deserializing to retrieve
     * the map of unresolved references that were serialized.
     *
     * @return the de-serialized HashMap of unresolved objects
     */
    public Map<String, List<Resolvable>> getUnresolvedReferences() {
        return unresolved;
    }

    
Sets the writing mode traits for the region viewports of
this page.
Params:
wmtg – a WM traits getter/**
     * Sets the writing mode traits for the region viewports of
     * this page.
     * @param wmtg a WM traits getter
     */
    public void setWritingModeTraits(WritingModeTraitsGetter wmtg) {
        if (regionBefore != null) {
            regionBefore.setWritingModeTraits(wmtg);
        }
        if (regionStart != null) {
            regionStart.setWritingModeTraits(wmtg);
        }
        if (regionBody != null) {
            regionBody.setWritingModeTraits(wmtg);
        }
        if (regionEnd != null) {
            regionEnd.setWritingModeTraits(wmtg);
        }
        if (regionAfter != null) {
            regionAfter.setWritingModeTraits(wmtg);
        }
    }

}