/*
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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.
 */
package org.apache.qetest.xslwrapper;

import java.util.Properties;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import static jaxp.library.JAXPTestUtilities.filenameToURL;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;

/**
 * Implementation of TransformWrapper that uses the TrAX API and uses DOMs for
 * it's sources.
 *
 * This implementation records separate times for xslRead (time to parse the xsl
 * and build a DOM) and xslBuild (time to take the DOMSource object until it's
 * built the templates); xmlRead (time to parse the xml and build a DOM). Note
 * xmlBuild is not timed since it's not easily measureable in TrAX. The
 * transform time is just the time to create the DOMResult object; the
 * resultsWrite is the separate time it takes to serialize that to disk.
 *
 * <b>Important!</b> The underlying System property of
 * javax.xml.transform.TransformerFactory will determine the actual TrAX
 * implementation used. This value will be reported out in our
 * getProcessorInfo() method.
 *
 */
public class TraxDOMWrapper extends TransformWrapperHelper {

    /**
     * TransformerFactory to use; constructed in newProcessor().
     */
    private  TransformerFactory factory;

    /**
     * Templates to use for buildStylesheet().
     */
    private Templates builtTemplates;

    /**
     * Cached copy of newProcessor() properties.
     */
    private Properties newProcessorOpts;

    /**
     * Get a general description of this wrapper itself.
     *
     * @return Uses TrAX to perform transforms from DOMSource(node)
     */
    public String getDescription() {
        return "Uses TrAX to perform transforms from DOMSource(node)";
    }

    /**
     * Get a specific description of the wrappered processor.
     *
     * @return specific description of the underlying processor or transformer
     * implementation: this should include both the general product name, as
     * well as specific version info. If possible, should be implemented without
     * actively creating an underlying processor.
     */
    @Override
    public Properties getProcessorInfo() {
        Properties p = TraxWrapperUtils.getTraxInfo();
        p.put("traxwrapper.method", "dom");
        p.put("traxwrapper.desc", getDescription());
        return p;
    }

    /**
     * Actually create/initialize an underlying processor or factory.
     *
     * For TrAX/javax.xml.transform implementations, this creates a new
     * TransformerFactory. For Xalan-J 1.x this creates an XSLTProcessor. Other
     * implementations may or may not actually do any work in this method.
     *
     * @param options Properties of options, unused.
     *
     * @return (Object)getProcessor() as a side-effect, this will be null if
     * there was any problem creating the processor OR if the underlying
     * implementation doesn't use this
     * @throws javax.xml.transform.TransformerConfigurationException when 
     * actual implementation doesn't support StreamSource or StreamResult.
     */
    @Override
    public TransformerFactory newProcessor(Properties options) throws TransformerConfigurationException {
        newProcessorOpts = options;
        reset(false);
        factory = TransformerFactory.newInstance();
        // Verify the factory supports DOM!
        if (!(factory.getFeature(DOMSource.FEATURE)
                && factory.getFeature(DOMResult.FEATURE))) {
            throw new TransformerConfigurationException("TraxDOMWrapper.newProcessor: factory does not support DOM!");
        }
        // Set any of our options as Attributes on the factory
        TraxWrapperUtils.setAttributes(factory, options);
        return factory;
    }

    /**
     * Transform supplied xmlName file with the stylesheet in the xslName file
     * into a resultName file.
     *
     * Names are assumed to be local path\filename references, and will be
     * converted to URLs as needed for any underlying processor implementation.
     *
     * @param xmlName local path\filename of XML file to transform
     * @param xslName local path\filename of XSL stylesheet to use
     * @param resultName local path\filename to put result in
     *
     * @throws Exception any underlying exceptions from the wrapped processor
     * are simply allowed to propagate; throws a RuntimeException if any other
     * problems prevent us from actually completing the operation
     */
    @Override
    public void transform(String xmlName, String xslName, String resultName)
            throws Exception {
        preventFootShooting();
        DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
        dfactory.setNamespaceAware(true);
        DocumentBuilder docBuilder = dfactory.newDocumentBuilder();

        // Timed: read xsl into a DOM
        Node xslNode = docBuilder.parse(new InputSource(filenameToURL(xslName)));

        // Untimed: create DOMSource and setSystemId
        DOMSource xslSource = new DOMSource(xslNode);
        xslSource.setSystemId(filenameToURL(xslName));

        // Timed: build Transformer from DOMSource
        Transformer transformer = factory.newTransformer(xslSource);

        // Timed: read xml into a DOM
        Node xmlNode = docBuilder.parse(new InputSource(filenameToURL(xmlName)));

        // Untimed: create DOMSource and setSystemId
        DOMSource xmlSource = new DOMSource(xmlNode);
        xmlSource.setSystemId(filenameToURL(xmlName));

        // Untimed: create DOMResult
        Document outDoc = docBuilder.newDocument();
        DocumentFragment outNode = outDoc.createDocumentFragment();
        DOMResult domResult = new DOMResult(outNode);

        // Untimed: Set any of our options as Attributes on the transformer
        TraxWrapperUtils.setAttributes(transformer, newProcessorOpts);

        // Untimed: Apply any parameters needed
        applyParameters(transformer);

        // Timed: build xml (so to speak) and transform
        transformer.transform(xmlSource, domResult);

        // Untimed: prepare serializer with outputProperties
        //  from the stylesheet
        Transformer resultSerializer = factory.newTransformer();
        Properties serializationProps = transformer.getOutputProperties();
        resultSerializer.setOutputProperties(serializationProps);

        // Timed: writeResults from the DOMResult
        resultSerializer.transform(new DOMSource(outNode),
                new StreamResult(resultName));
    }

    /**
     * Pre-build/pre-compile a stylesheet.
     *
     * Although the actual mechanics are implementation-dependent, most
     * processors have some method of pre-setting up the data needed by the
     * stylesheet itself for later use in transforms. In
     * TrAX/javax.xml.transform, this equates to creating a Templates object.
     *
     * Sets isStylesheetReady() to true if it succeeds. Users can then call
     * transformWithStylesheet(xmlName, resultName) to actually perform a
     * transformation with this pre-built stylesheet.
     *
     * @param xslName local path\filename of XSL stylesheet to use
     *
     * @throws Exception any underlying exceptions from the wrapped processor
     * are simply allowed to propagate; throws a RuntimeException if any other
     * problems prevent us from actually completing the operation
     *
     * @see #transformWithStylesheet(String xmlName, String resultName)
     */
    @Override
    public void buildStylesheet(String xslName) throws Exception {
        preventFootShooting();
        DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
        dfactory.setNamespaceAware(true);
        DocumentBuilder docBuilder = dfactory.newDocumentBuilder();

        // Read xsl into a DOM
        Node xslNode = docBuilder.parse(new InputSource(filenameToURL(xslName)));
        // Untimed: create DOMSource and setSystemId
        DOMSource xslSource = new DOMSource(xslNode);
        xslSource.setSystemId(filenameToURL(xslName));

        // Build Templates from DOMSource
        builtTemplates = factory.newTemplates(xslSource);

        m_stylesheetReady = true;
    }

    /**
     * Transform supplied xmlName file with a pre-built/pre-compiled stylesheet
     * into a resultName file.
     *
     * User must have called buildStylesheet(xslName) beforehand, obviously.
     * Names are assumed to be local path\filename references, and will be
     * converted to URLs as needed.
     *
     * @param xmlName local path\filename of XML file to transform
     * @param resultName local path\filename to put result in
     *
     * @throws Exception any underlying exceptions from the wrappered processor
     * are simply allowed to propagate; throws a RuntimeException if any other
     * problems prevent us from actually completing the operation; throws an
     * IllegalStateException if isStylesheetReady() == false.
     *
     * @see #buildStylesheet(String xslName)
     */
    @Override
    public void transformWithStylesheet(String xmlName, String resultName)
            throws Exception {
        if (!isStylesheetReady()) {
            throw new IllegalStateException("transformWithStylesheet() when isStylesheetReady() == false");
        }

        preventFootShooting();

        // Get Transformer from Templates
        Transformer transformer = builtTemplates.newTransformer();

        DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
        dfactory.setNamespaceAware(true);
        DocumentBuilder docBuilder = dfactory.newDocumentBuilder();

        // Read xml into a DOM
        Node xmlNode = docBuilder.parse(new InputSource(filenameToURL(xmlName)));

        // Create DOMSource and setSystemId
        DOMSource xmlSource = new DOMSource(xmlNode);
        xmlSource.setSystemId(filenameToURL(xmlName));

        // Create DOMResult
        Document outNode = docBuilder.newDocument();
        DOMResult domResult = new DOMResult(outNode);

        // Set any of our options as Attributes on the transformer
        TraxWrapperUtils.setAttributes(transformer, newProcessorOpts);

        // Apply any parameters needed
        applyParameters(transformer);

        // Build xml (so to speak) and transform
        transformer.transform(xmlSource, domResult);

        // Prepare serializer with outputProperties from the stylesheet
        Transformer resultSerializer = factory.newTransformer();
        Properties serializationProps = transformer.getOutputProperties();
        resultSerializer.setOutputProperties(serializationProps);

        // writeResults from the DOMResult
        resultSerializer.transform(new DOMSource(outNode),
                new StreamResult(resultName));
    }

    /**
     * Transform supplied xmlName file with a stylesheet found in an
     * xml-stylesheet PI into a resultName file.
     *
     * Names are assumed to be local path\filename references, and will be
     * converted to URLs as needed. Implementations will use whatever facilities
     * exist in their wrapped processor to fetch and build the stylesheet to
     * use for the transform.
     *
     * @param xmlName local path\filename of XML file to transform
     * @param resultName local path\filename to put result in
     *
     * @throws Exception any underlying exceptions from the wrapped processor
     * are simply allowed to propagate; throws a RuntimeException if any other
     * problems prevent us from actually completing the operation
     */
    @Override
    public void transformEmbedded(String xmlName, String resultName)
            throws Exception {
        DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
        dfactory.setNamespaceAware(true);
        DocumentBuilder docBuilder = dfactory.newDocumentBuilder();

        // read xml into a DOM
        Node xmlNode = docBuilder.parse(new InputSource(filenameToURL(xmlName)));

        // create DOMSource and setSystemId
        DOMSource xmlSource = new DOMSource(xmlNode);
        xmlSource.setSystemId(filenameToURL(xmlName));

        // readxsl from the xml document
        Source xslSource = factory.getAssociatedStylesheet(xmlSource,
                null, null, null);

        // build Transformer from Source
        Transformer transformer = factory.newTransformer(xslSource);

        // create DOMResult
        Document outNode = docBuilder.newDocument();
        DOMResult domResult = new DOMResult(outNode);

        // Set any of our options as Attributes on the transformer
        TraxWrapperUtils.setAttributes(transformer, newProcessorOpts);

        // Apply any parameters needed
        applyParameters(transformer);

        // Build xml (so to speak) and transform
        transformer.transform(xmlSource, domResult);

        // Prepare serializer with outputProperties from the stylesheet
        Transformer resultSerializer = factory.newTransformer();
        Properties serializationProps = transformer.getOutputProperties();
        resultSerializer.setOutputProperties(serializationProps);

        // writeResults from the DOMResult
        resultSerializer.transform(new DOMSource(outNode),
                new StreamResult(resultName));
    }

    /**
     * Reset our parameters and wrapper state, and optionally force creation of
     * a new underlying processor implementation.
     *
     * This always clears our built stylesheet and any parameters that have been
     * set. If newProcessor is true, also forces a re-creation of our underlying
     * processor as if by calling newProcessor().
     *
     * @param newProcessor if we should reset our underlying processor
     * implementation as well
     */
    @Override
    public void reset(boolean newProcessor) {
        super.reset(newProcessor); // clears indent and parameters
        m_stylesheetReady = false;
        builtTemplates = null;
        if (newProcessor) {
            try {
                newProcessor(newProcessorOpts);
            } catch (TransformerConfigurationException ignore) {}
        }
    }

    /**
     * Apply a single parameter to a Transformer.
     *
     * Overridden to take a Transformer and call setParameter().
     *
     * @param transformer a Transformer object.
     * @param namespace for the parameter, may be null
     * @param name for the parameter, should not be null
     * @param value for the parameter, may be null
     */
    @Override
    protected void applyParameter(Transformer transformer, String namespace,
            String name, String value) {
        try {
            // Munge the namespace into the name per
            //  javax.xml.transform.Transformer.setParameter()
            if (null != namespace) {
                name = "{" + namespace + "}" + name;
            }
            transformer.setParameter(name, value);
        } catch (Exception e) {
            throw new IllegalArgumentException("applyParameter threw: " + e.toString());
        }
    }

    /**
     * Ensure newProcessor has been called when needed.
     *
     * Prevent users from shooting themselves in the foot by calling a
     * transform* API before newProcessor().
     *
     * @throws java.lang.Exception
     */
    public void preventFootShooting() throws Exception {
        if (null == factory) {
            newProcessor(newProcessorOpts);
        }
    }
}