/*
 * 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: RenderPagesModel.java 1479969 2013-05-07 16:23:13Z vhennebert $ */

package org.apache.fop.area;

// Java
import java.io.IOException;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;

import org.xml.sax.SAXException;

import org.apache.fop.apps.FOPException;
import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.fonts.FontInfo;
import org.apache.fop.render.Renderer;
import org.apache.fop.render.RendererEventProducer;

This uses the AreaTreeModel to store the pages
Each page is either rendered if ready or prepared
for later rendering.
Once a page is rendered it is cleared to release the
contents but the PageViewport is retained. So even
though the pages are stored the contents are discarded.
/**
 * This uses the AreaTreeModel to store the pages
 * Each page is either rendered if ready or prepared
 * for later rendering.
 * Once a page is rendered it is cleared to release the
 * contents but the PageViewport is retained. So even
 * though the pages are stored the contents are discarded.
 */
public class RenderPagesModel extends AreaTreeModel {
    
The renderer that will render the pages.
/**
     * The renderer that will render the pages.
     */
    protected Renderer renderer;

    
Pages that have been prepared but not rendered yet.
/**
     * Pages that have been prepared but not rendered yet.
     */
    protected List<PageViewport> prepared = new java.util.ArrayList<PageViewport>();

    private List<OffDocumentItem> pendingODI = new java.util.ArrayList<OffDocumentItem>();
    private List<OffDocumentItem> endDocODI = new java.util.ArrayList<OffDocumentItem>();

    
Create a new render pages model with the given renderer.
Params:
userAgent – FOUserAgent object for process
outputFormat – the MIME type of the output format to use (ex. "application/pdf").
fontInfo – FontInfo object
stream – OutputStream
Throws:
FOPException – if the renderer cannot be properly initialized/**
     * Create a new render pages model with the given renderer.
     * @param userAgent FOUserAgent object for process
     * @param outputFormat the MIME type of the output format to use (ex. "application/pdf").
     * @param fontInfo FontInfo object
     * @param stream OutputStream
     * @throws FOPException if the renderer cannot be properly initialized
     */
    public RenderPagesModel(FOUserAgent userAgent, String outputFormat,
        FontInfo fontInfo, OutputStream stream) throws FOPException {

        super();
        this.renderer = userAgent.getRendererFactory().createRenderer(
                userAgent, outputFormat);

        try {
            renderer.setupFontInfo(fontInfo);
            // check that the "any,normal,400" font exists
            if (!fontInfo.isSetupValid()) {
                throw new FOPException(
                    "No default font defined by OutputConverter");
            }
            renderer.startRenderer(stream);
        } catch (IOException e) {
            throw new FOPException(e);
        }
    }

    @Override
    public void setDocumentLocale(Locale locale) {
        renderer.setDocumentLocale(locale);
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public void startPageSequence(PageSequence pageSequence) {
        super.startPageSequence(pageSequence);
        if (renderer.supportsOutOfOrder()) {
            renderer.startPageSequence(getCurrentPageSequence());
        }
    }

    
Add a page to the render page model.
If the page is finished it can be rendered immediately.
If the page needs resolving then if the renderer supports
out of order rendering it can prepare the page. Otherwise
the page is added to a queue.
Params:
page – the page to add to the model/**
     * Add a page to the render page model.
     * If the page is finished it can be rendered immediately.
     * If the page needs resolving then if the renderer supports
     * out of order rendering it can prepare the page. Otherwise
     * the page is added to a queue.
     * @param page the page to add to the model
     */
    @Override
    public void addPage(PageViewport page) {
        super.addPage(page);

        // for links the renderer needs to prepare the page
        // it is more appropriate to do this after queued pages but
        // it will mean that the renderer has not prepared a page that
        // could be referenced
        boolean ready = renderer.supportsOutOfOrder() && page.isResolved();
        if (ready) {
            if (!renderer.supportsOutOfOrder() && page.getPageSequence().isFirstPage(page)) {
                renderer.startPageSequence(getCurrentPageSequence());
            }
            try {
                renderer.renderPage(page);
            } catch (RuntimeException re) {
                String err = "Error while rendering page " + page.getPageNumberString();
                log.error(err, re);
                throw re;
            } catch (IOException ioe) {
                RendererEventProducer eventProducer = RendererEventProducer.Provider.get(
                        renderer.getUserAgent().getEventBroadcaster());
                eventProducer.ioError(this, ioe);
            } catch (FOPException e) {
                //TODO use error handler to handle this FOPException or propagate exception
                String err = "Error while rendering page " + page.getPageNumberString();
                log.error(err, e);
                throw new IllegalStateException("Fatal error occurred. Cannot continue. "
                        + e.getClass().getName() + ": " + err);
            }
            page.clear();
        } else {
            preparePage(page);
        }


        // check prepared pages
        boolean cont = checkPreparedPages(page, false);

        if (cont) {
            processOffDocumentItems(pendingODI);
            pendingODI.clear();
        }
    }

    
Check prepared pages
Params:
newPageViewport – the new page being added
renderUnresolved – render pages with unresolved idref's
         (done at end-of-document processing)
Returns:
true if the current page should be rendered
        false if the renderer doesn't support out of order
        rendering and there are pending pages/**
     * Check prepared pages
     *
     * @param newPageViewport the new page being added
     * @param renderUnresolved render pages with unresolved idref's
     *          (done at end-of-document processing)
     * @return true if the current page should be rendered
     *         false if the renderer doesn't support out of order
     *         rendering and there are pending pages
     */
    protected boolean checkPreparedPages(PageViewport newPageViewport,
                                         boolean renderUnresolved) {

        for (Iterator iter = prepared.iterator(); iter.hasNext();) {
            PageViewport pageViewport = (PageViewport)iter.next();
            if (pageViewport.isResolved() || renderUnresolved) {
                if (!renderer.supportsOutOfOrder()
                        && pageViewport.getPageSequence().isFirstPage(pageViewport)) {
                    renderer.startPageSequence(pageViewport.getPageSequence());
                }
                renderPage(pageViewport);
                pageViewport.clear();
                iter.remove();
            } else {
                // if keeping order then stop at first page not resolved
                if (!renderer.supportsOutOfOrder()) {
                    break;
                }
            }
        }
        return renderer.supportsOutOfOrder() || prepared.isEmpty();
    }

    
Renders the given page and notified about unresolved IDs if any.
Params:
pageViewport – the page to be rendered./**
     * Renders the given page and notified about unresolved IDs if any.
     * @param pageViewport the page to be rendered.
     */
    protected void renderPage(PageViewport pageViewport) {
        try {
            renderer.renderPage(pageViewport);
            if (!pageViewport.isResolved()) {
                String[] idrefs = pageViewport.getIDRefs();
                for (String idref : idrefs) {
                    AreaEventProducer eventProducer = AreaEventProducer.Provider.get(
                            renderer.getUserAgent().getEventBroadcaster());
                    eventProducer.unresolvedIDReferenceOnPage(this,
                            pageViewport.getPageNumberString(), idref);
                }
            }
        } catch (Exception e) {
            AreaEventProducer eventProducer = AreaEventProducer.Provider.get(
                    renderer.getUserAgent().getEventBroadcaster());
            eventProducer.pageRenderingError(this,
                    pageViewport.getPageNumberString(), e);
            if (e instanceof RuntimeException) {
                throw (RuntimeException)e;
            }
        }
    }

    
Prepare a page.
An unresolved page can be prepared if the renderer supports
it and the page will be rendered later.
Params:
page – the page to prepare/**
     * Prepare a page.
     * An unresolved page can be prepared if the renderer supports
     * it and the page will be rendered later.
     * @param page the page to prepare
     */
    protected void preparePage(PageViewport page) {
        if (renderer.supportsOutOfOrder()) {
            renderer.preparePage(page);
        }
        prepared.add(page);
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public void handleOffDocumentItem(OffDocumentItem oDI) {
        switch(oDI.getWhenToProcess()) {
            case OffDocumentItem.IMMEDIATELY:
                renderer.processOffDocumentItem(oDI);
                break;
            case OffDocumentItem.AFTER_PAGE:
                pendingODI.add(oDI);
                break;
            case OffDocumentItem.END_OF_DOC:
                endDocODI.add(oDI);
                break;
            default:
                throw new RuntimeException();
        }
    }

    private void processOffDocumentItems(List<OffDocumentItem> list) {
        for (OffDocumentItem oDI : list) {
            renderer.processOffDocumentItem(oDI);
        }
    }

    
End the document. Render any end document OffDocumentItems
{@inheritDoc}
/**
     * End the document. Render any end document OffDocumentItems
     * {@inheritDoc}
     */
    @Override
    public void endDocument() throws SAXException {
        // render any pages that had unresolved ids
        checkPreparedPages(null, true);

        processOffDocumentItems(pendingODI);
        pendingODI.clear();
        processOffDocumentItems(endDocODI);

        try {
            renderer.stopRenderer();
        } catch (IOException ex) {
            throw new SAXException(ex);
        }
    }
}