/*
 * 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.fo.pagination;

// Java
import java.util.Map;

import org.xml.sax.Locator;

import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.FObj;
import org.apache.fop.fo.PropertyList;
import org.apache.fop.fo.ValidationException;

/**
 * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_layout-master-set">
 * <code>fo:layout-master-set</code></a> object.
 *
 * This class maintains the set of simple page master and
 * page sequence masters.
 * The masters are stored so that the page sequence can obtain
 * the required page master to create a page.
 * The page sequence masters can be reset as they hold state
 * information for a page sequence.
 */
public class LayoutMasterSet extends FObj {

    private Map<String, SimplePageMaster> simplePageMasters;
    private Map<String, PageSequenceMaster> pageSequenceMasters;

    /**
     * Create a LayoutMasterSet instance that is a child of the given
     * parent {@link FONode}.
     *
     * @param parent {@link FONode} that is the parent of this object
     */
    public LayoutMasterSet(FONode parent) {
        super(parent);
    }

    /** {@inheritDoc} */
    public void bind(PropertyList pList) throws FOPException {
        // No properties in layout-master-set.
    }

    /** {@inheritDoc} */
    public void startOfNode() throws FOPException {
        getRoot().setLayoutMasterSet(this);
        simplePageMasters = new java.util.HashMap<String, SimplePageMaster>();
        pageSequenceMasters = new java.util.HashMap<String, PageSequenceMaster>();
    }

    /** {@inheritDoc} */
    public void endOfNode() throws FOPException {
        if (firstChild == null) {
            missingChildElementError("(simple-page-master|page-sequence-master)+");
        }
        checkRegionNames();
        resolveSubSequenceReferences();
    }

    /**
     * {@inheritDoc}
     * <br>XSL/FOP: (simple-page-master|page-sequence-master)+
     */
    protected void validateChildNode(Locator loc, String nsURI, String localName)
            throws ValidationException {
        if (FO_URI.equals(nsURI)) {
            if (!localName.equals("simple-page-master")
                && !localName.equals("page-sequence-master")) {
                    invalidChildError(loc, nsURI, localName);
            }
        }
    }

    /**
     * Section 7.25.7: check to see that if a region-name is a
     * duplicate, that it maps to the same fo region-class.
     * @throws ValidationException if there's a name duplication
     */
    private void checkRegionNames() throws ValidationException {
        // (user-entered) region-name to default region map.
        Map<String, String> allRegions = new java.util.HashMap<String, String>();
        for (SimplePageMaster simplePageMaster : simplePageMasters.values()) {
            Map<String, Region> spmRegions = simplePageMaster.getRegions();
            for (Region region : spmRegions.values()) {
                if (allRegions.containsKey(region.getRegionName())) {
                    String defaultRegionName
                        =  allRegions.get(region.getRegionName());
                    if (!defaultRegionName.equals(region.getDefaultRegionName())) {
                        getFOValidationEventProducer().regionNameMappedToMultipleRegionClasses(this,
                                region.getRegionName(),
                                defaultRegionName,
                                region.getDefaultRegionName(), getLocator());
                    }
                }
                allRegions.put(region.getRegionName(),
                        region.getDefaultRegionName());
            }
        }
    }

    private void resolveSubSequenceReferences() throws ValidationException {
        for (PageSequenceMaster psm : pageSequenceMasters.values()) {
            for (SubSequenceSpecifier subSequenceSpecifier : psm.getSubSequenceSpecifier()) {
                subSequenceSpecifier.resolveReferences(this);
            }
        }
    }

    /**
     * Add a simple page master.
     * The name is checked to throw an error if already added.
     * @param sPM simple-page-master to add
     * @throws ValidationException if there's a problem with name uniqueness
     */
    protected void addSimplePageMaster(SimplePageMaster sPM)
                throws ValidationException {

        // check for duplication of master-name
        String masterName = sPM.getMasterName();
        if (existsName(masterName)) {
            getFOValidationEventProducer().masterNameNotUnique(this,
                    getName(),
                    masterName, sPM.getLocator());
        }
        this.simplePageMasters.put(masterName, sPM);
    }

    private boolean existsName(String masterName) {
        return (simplePageMasters.containsKey(masterName)
                || pageSequenceMasters.containsKey(masterName));
    }

    /**
     * Get a simple page master by name.
     * This is used by the page sequence to get a page master for
     * creating pages.
     * @param masterName the name of the page master
     * @return the requested simple-page-master
     */
    public SimplePageMaster getSimplePageMaster(String masterName) {
        return simplePageMasters.get(masterName);
    }

    /**
     * Add a page sequence master.
     * The name is checked to throw an error if already added.
     * @param masterName name for the master
     * @param pSM PageSequenceMaster instance
     * @throws ValidationException if there's a problem with name uniqueness
     */
    protected void addPageSequenceMaster(String masterName,
                                        PageSequenceMaster pSM)
                throws ValidationException {
        // check against duplication of master-name
        if (existsName(masterName)) {
            getFOValidationEventProducer().masterNameNotUnique(this,
                    getName(),
                    masterName, pSM.getLocator());
        }
        this.pageSequenceMasters.put(masterName, pSM);
    }

    /**
     * Get a page sequence master by name.
     * This is used by the page sequence to get a page master for
     * creating pages.
     * @param masterName name of the master
     * @return the requested PageSequenceMaster instance
     */
    public PageSequenceMaster getPageSequenceMaster(String masterName) {
        return this.pageSequenceMasters.get(masterName);
    }

    /**
     * Checks whether or not a region name exists in this master set.
     * @param regionName name of the region
     * @return true when the region name specified has a region in this LayoutMasterSet
     */
    public boolean regionNameExists(String regionName) {
        for (SimplePageMaster spm : simplePageMasters.values()) {
            if (spm.regionNameExists(regionName)) {
                return true;
            }
        }
        return false;
    }

    /** {@inheritDoc} */
    public String getLocalName() {
        return "layout-master-set";
    }

    /**
     * {@inheritDoc}
     * @return {@link org.apache.fop.fo.Constants#FO_LAYOUT_MASTER_SET}
     */
    public int getNameId() {
        return FO_LAYOUT_MASTER_SET;
    }

    /**
     * Returns the default name of the region to which the flow or static-content having
     * the given flow-name is assigned.
     *
     * @param flowName the value of the flow-name property
     * @return the default region name ("xsl-region-body", "xsl-region-before", etc.)
     */
    public String getDefaultRegionNameFor(String flowName) {
        for (SimplePageMaster spm : simplePageMasters.values()) {
            for (Region region : spm.getRegions().values()) {
                if (region.getRegionName().equals(flowName)) {
                    return region.getDefaultRegionName();
                }
            }
        }
        assert flowName.equals("xsl-before-float-separator") || flowName.equals("xsl-footnote-separator");
        return flowName;
    }
}