/*
 * Copyright 1999-2005 The Apache Software Foundation.
 * 
 * Licensed 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.List;

import org.xml.sax.Locator;

import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.FOEventHandler;
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.FObj;
import org.apache.fop.fo.PropertyList;
import org.apache.fop.fo.ValidationException;
import org.apache.fop.fo.pagination.bookmarks.BookmarkTree;

/**
 * The fo:root formatting object. Contains page masters, page-sequences.
 */
public class Root extends FObj {
    // The value of properties relevant for fo:root.
    private int mediaUsage;
    // End of property values

    private LayoutMasterSet layoutMasterSet;
    private Declarations declarations;
    private BookmarkTree bookmarkTree = null;
    private List pageSequences;

    // temporary until above list populated
    private boolean pageSequenceFound = false;

    /**
     * Keeps count of page number from over PageSequence instances
     */
    private int endingPageNumberOfPreviousSequence = 0;
    private int totalPagesGenerated = 0;

    /**
     * FOEventHandler object for this FO Tree
     */
    private FOEventHandler foEventHandler = null;
     
     /**
     * @see org.apache.fop.fo.FONode#FONode(FONode)
     */
    public Root(FONode parent) {
        super(parent);
        pageSequences = new java.util.ArrayList();
        if (parent != null) {
            //throw new FOPException("root must be root element");
        }
    }

    /**
     * @see org.apache.fop.fo.FObj#bind(PropertyList)
     */
    public void bind(PropertyList pList) throws FOPException {
        mediaUsage = pList.get(PR_MEDIA_USAGE).getEnum();
    }

    /**
     * Signal end of this xml element.
     */
    protected void endOfNode() throws FOPException {
        if (!pageSequenceFound || layoutMasterSet == null) {
            missingChildElementError("(layout-master-set, declarations?, " + 
                "bookmark-tree?, page-sequence+)");
        }
    }

    /**
     * @see org.apache.fop.fo.FONode#validateChildNode(Locator, String, String)
        XSL 1.0 Spec: (layout-master-set,declarations?,page-sequence+)
        FOP: (layout-master-set, declarations?, fox:bookmarks?, page-sequence+)
     */
    protected void validateChildNode(Locator loc, String nsURI, String localName) 
        throws ValidationException {
        if (FO_URI.equals(nsURI)) {
            if (localName.equals("layout-master-set")) {   
                if (layoutMasterSet != null) {
                    tooManyNodesError(loc, "fo:layout-master-set");
                }
            } else if (localName.equals("declarations")) { 
                if (layoutMasterSet == null) {
                    nodesOutOfOrderError(loc, "fo:layout-master-set", "fo:declarations");
                } else if (declarations != null) {
                    tooManyNodesError(loc, "fo:declarations");
                } else if (bookmarkTree != null) {
                    nodesOutOfOrderError(loc, "fo:declarations", "fo:bookmark-tree");
                } else if (pageSequenceFound) {
                    nodesOutOfOrderError(loc, "fo:declarations", "fo:page-sequence");
                }
            } else if (localName.equals("bookmark-tree")) {
                if (layoutMasterSet == null) {
                    nodesOutOfOrderError(loc, "fo:layout-master-set", "fo:bookmark-tree");
                } else if (bookmarkTree != null) {
                    tooManyNodesError(loc, "fo:bookmark-tree");
                } else if (pageSequenceFound) {
                    nodesOutOfOrderError(loc, "fo:bookmark-tree", "fo:page-sequence");
                }
            } else if (localName.equals("page-sequence")) { 
                if (layoutMasterSet == null) {
                    nodesOutOfOrderError(loc, "fo:layout-master-set", "fo:page-sequence");
                } else {
                    pageSequenceFound = true;
                }
            } else {
                invalidChildError(loc, nsURI, localName);
            }
        } else {
            invalidChildError(loc, nsURI, localName);
        }
    }

    /**
     * Sets the FOEventHandler object that this Root is attached to
     * @param foEventHandler the FOEventHandler object
     */
    public void setFOEventHandler(FOEventHandler foEventHandler) {
        this.foEventHandler = foEventHandler;
    }

    /**      
     * This method overrides the FONode version. The FONode version calls the    
     * method by the same name for the parent object. Since Root is at the top   
     * of the tree, it returns the actual FOEventHandler object. Thus, any FONode    
     * can use this chain to find which FOEventHandler it is being built for.    
     * @return the FOEventHandler implementation that this Root is attached to   
     */      
    public FOEventHandler getFOEventHandler() {      
        return foEventHandler;   
    }

     /**
     * Gets the last page number generated by the previous page-sequence
     * @return the last page number, 0 if no page sequences yet generated
     */
    public int getEndingPageNumberOfPreviousSequence() {
        return endingPageNumberOfPreviousSequence;
    }

    /**
     * Returns the total number of pages generated by FOP
     * (May not equal endingPageNumberOfPreviousSequence due to
     * initial-page-number property on fo:page-sequences.)
     * @return the last page number, 0 if no page sequences yet generated
     */
    public int getTotalPagesGenerated() {
        return totalPagesGenerated;
    }

    /**
     * Notify additional pages generated to increase the totalPagesGenerated counter
     * @param lastPageNumber the last page number generated by the sequence
     * @param additionalPages the total pages generated by the sequence (for statistics)
     * @throws IllegalArgumentException for negative additional page counts
     */
    public void notifyPageSequenceFinished(int lastPageNumber, int additionalPages) {    
        
        if (additionalPages >= 0) {
            totalPagesGenerated += additionalPages;
            endingPageNumberOfPreviousSequence = lastPageNumber;           
        } else {
            throw new IllegalArgumentException(
                "Number of additional pages must be zero or greater.");
        }       
    }

    /**
     * Returns the number of PageSequence instances.
     * @return the number of PageSequence instances
     */
    public int getPageSequenceCount() {
        return pageSequences.size();
    }

    /**
     * Some properties, such as 'force-page-count', require a
     * page-sequence to know about some properties of the next.
     * @param current the current PageSequence
     * @return succeeding PageSequence; null if none
     */
    public PageSequence getSucceedingPageSequence(PageSequence current) {
        int currentIndex = pageSequences.indexOf(current);
        if (currentIndex == -1) {
            return null;
        }
        if (currentIndex < (pageSequences.size() - 1)) {
            return (PageSequence)pageSequences.get(currentIndex + 1);
        } else {
            return null;
        }
    }

    /**
     * Returns the associated LayoutMasterSet.
     * @return the LayoutMasterSet instance
     */
    public LayoutMasterSet getLayoutMasterSet() {
        return this.layoutMasterSet;
    }

    /**
     * Sets the associated LayoutMasterSet.
     * @param layoutMasterSet the LayoutMasterSet to use
     */
    public void setLayoutMasterSet(LayoutMasterSet layoutMasterSet) {
        this.layoutMasterSet = layoutMasterSet;
    }

    /**
     * Returns the associated Declarations.
     * @return the Declarations instance
     */
    public Declarations getDeclarations() {
        return this.declarations;
    }

    /**
     * Sets the associated Declarations.
     * @param declarations the Declarations to use
     */
    public void setDeclarations(Declarations declarations) {
        this.declarations = declarations;
    }

    /**
     * Set the BookmarkTree object for this FO
     * @param bookmarkTree the BookmarkTree object
     */
    public void setBookmarkTree(BookmarkTree bookmarkTree) {
        this.bookmarkTree = bookmarkTree;
    }

    /**
     * Public accessor for the BookmarkTree object for this FO
     * @return the BookmarkTree object
     */
    public BookmarkTree getBookmarkTree() {
        return bookmarkTree;
    }

    /**
     * @see org.apache.fop.fo.FONode#getRoot()
     */
    public Root getRoot() {
        return this;
    }

    /** @see org.apache.fop.fo.FONode#getLocalName() */
    public String getLocalName() {
        return "root";
    }

    /**
     * @see org.apache.fop.fo.FObj#getNameId()
     */
    public int getNameId() {
        return FO_ROOT;
    }

}