/*
 * 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.layoutengine;

import java.io.File;
import java.io.IOException;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.TransformerHandler;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.fop.apps.FormattingResults;
import org.apache.fop.area.AreaTreeModel;
import org.apache.fop.area.AreaTreeParser;
import org.apache.fop.area.RenderPagesModel;
import org.apache.fop.events.model.EventSeverity;
import org.apache.fop.fonts.FontInfo;
import org.apache.fop.intermediate.IFTester;
import org.apache.fop.intermediate.TestAssistant;
import org.apache.fop.layoutmgr.ElementListObserver;
import org.apache.fop.render.intermediate.IFContext;
import org.apache.fop.render.intermediate.IFRenderer;
import org.apache.fop.render.intermediate.IFSerializer;
import org.apache.fop.render.xml.XMLRenderer;
import org.apache.fop.util.ConsoleEventListenerForTests;
import org.apache.fop.util.DelegatingContentHandler;

/**
 * Class for testing the FOP's layout engine using testcases specified in XML
 * files.
 */
public class LayoutEngineTester {

    private TestAssistant testAssistant = new TestAssistant();

    private LayoutEngineChecksFactory layoutEngineChecksFactory = new LayoutEngineChecksFactory();
    private File areaTreeBackupDir;
    private IFTester ifTester;

    private TransformerFactory tfactory = TransformerFactory.newInstance();

    /**
     * Constructs a new instance.
     * @param areaTreeBackupDir Optional directory that receives the generated
     *     area tree XML files. May be null.
     */
    public LayoutEngineTester(File areaTreeBackupDir) {
        this.areaTreeBackupDir = areaTreeBackupDir;
        this.ifTester = new IFTester(tfactory, areaTreeBackupDir);
    }

    /**
     * Runs a single layout engine test case.
     * @param testFile Test case to run
     * @throws TransformerException In case of an XSLT/JAXP problem
     * @throws IOException In case of an I/O problem
     * @throws SAXException In case of a problem during SAX processing
     * @throws ParserConfigurationException In case of a problem with the XML parser setup
     */
    public void runTest(File testFile)
            throws TransformerException, SAXException, IOException, ParserConfigurationException {

        DOMResult domres = new DOMResult();

        ElementListCollector elCollector = new ElementListCollector();
        ElementListObserver.addObserver(elCollector);

        Fop fop;
        FopFactory effFactory;
        try {
            Document testDoc = testAssistant.loadTestCase(testFile);
            effFactory = testAssistant.getFopFactory(testDoc);

            //Setup Transformer to convert the testcase XML to XSL-FO
            Transformer transformer = testAssistant.getTestcase2FOStylesheet().newTransformer();
            Source src = new DOMSource(testDoc);

            //Setup Transformer to convert the area tree to a DOM
            TransformerHandler athandler;
            athandler = testAssistant.getTransformerFactory().newTransformerHandler();
            athandler.setResult(domres);

            //Setup FOP for area tree rendering
            FOUserAgent ua = effFactory.newFOUserAgent();
            ua.setBaseURL(testFile.getParentFile().toURI().toURL().toString());
            ua.getEventBroadcaster().addEventListener(
                    new ConsoleEventListenerForTests(testFile.getName(), EventSeverity.WARN));

            XMLRenderer atrenderer = new XMLRenderer();
            atrenderer.setUserAgent(ua);
            atrenderer.setContentHandler(athandler);
            ua.setRendererOverride(atrenderer);
            fop = effFactory.newFop(ua);

            SAXResult fores = new SAXResult(fop.getDefaultHandler());
            transformer.transform(src, fores);
        } finally {
            ElementListObserver.removeObserver(elCollector);
        }

        Document doc = (Document)domres.getNode();
        if (this.areaTreeBackupDir != null) {
            testAssistant.saveDOM(doc,
                    new File(this.areaTreeBackupDir, testFile.getName() + ".at.xml"));
        }
        FormattingResults results = fop.getResults();
        LayoutResult result = new LayoutResult(doc, elCollector, results);
        checkAll(effFactory, testFile, result);
    }

    /**
     * Perform all checks on the area tree and, optionally, on the intermediate format.
     * @param testFile Test case XML file
     * @param result The layout results
     * @throws TransformerException if a problem occurs in XSLT/JAXP
     */
    protected void checkAll(FopFactory fopFactory, File testFile, LayoutResult result)
            throws TransformerException {
        Element testRoot = testAssistant.getTestRoot(testFile);

        NodeList nodes;
        //AT tests only when checks are available
        nodes = testRoot.getElementsByTagName("at-checks");
        if (nodes.getLength() > 0) {
            Element atChecks = (Element)nodes.item(0);
            doATChecks(atChecks, result);
        }

        //IF tests only when checks are available
        nodes = testRoot.getElementsByTagName("if-checks");
        if (nodes.getLength() > 0) {
            Element ifChecks = (Element)nodes.item(0);
            Document ifDocument = createIF(fopFactory, testFile, result.getAreaTree());
            ifTester.doIFChecks(testFile.getName(), ifChecks, ifDocument);
        }
    }

    private Document createIF(FopFactory fopFactory, File testFile, Document areaTreeXML)
            throws TransformerException {
        try {
            FOUserAgent ua = fopFactory.newFOUserAgent();
            ua.setBaseURL(testFile.getParentFile().toURI().toURL().toExternalForm());
            ua.getEventBroadcaster().addEventListener(
                    new ConsoleEventListenerForTests(testFile.getName(), EventSeverity.WARN));

            IFRenderer ifRenderer = new IFRenderer();
            ifRenderer.setUserAgent(ua);

            IFSerializer serializer = new IFSerializer();
            serializer.setContext(new IFContext(ua));
            DOMResult result = new DOMResult();
            serializer.setResult(result);
            ifRenderer.setDocumentHandler(serializer);

            ua.setRendererOverride(ifRenderer);
            FontInfo fontInfo = new FontInfo();
            //Construct the AreaTreeModel that will received the individual pages
            final AreaTreeModel treeModel = new RenderPagesModel(ua,
                    null, fontInfo, null);

            //Iterate over all intermediate files
            AreaTreeParser parser = new AreaTreeParser();
            ContentHandler handler = parser.getContentHandler(treeModel, ua);

            DelegatingContentHandler proxy = new DelegatingContentHandler() {

                public void endDocument() throws SAXException {
                    super.endDocument();
                    //Signal the end of the processing.
                    //The renderer can finalize the target document.
                    treeModel.endDocument();
                }

            };
            proxy.setDelegateContentHandler(handler);

            Transformer transformer = tfactory.newTransformer();
            transformer.transform(new DOMSource(areaTreeXML), new SAXResult(proxy));

            return (Document)result.getNode();
        } catch (Exception e) {
            throw new TransformerException(
                    "Error while generating intermediate format file: " + e.getMessage(), e);
        }
    }

    private void doATChecks(Element checksRoot, LayoutResult result) {
        List<LayoutEngineCheck> checks = layoutEngineChecksFactory.createCheckList(checksRoot);
        if (checks.size() == 0) {
            throw new RuntimeException("No available area tree check");
        }
        for (LayoutEngineCheck check : checks) {
            check.check(result);
        }
    }

}