/**
 * (The MIT License)
 *
 * Copyright (c) 2008 - 2011:
 *
 * * {Aaron Patterson}[http://tenderlovemaking.com]
 * * {Mike Dalessio}[http://mike.daless.io]
 * * {Charles Nutter}[http://blog.headius.com]
 * * {Sergio Arbeo}[http://www.serabe.com]
 * * {Patrick Mahoney}[http://polycrystal.org]
 * * {Yoko Harada}[http://yokolet.blogspot.com]
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * 'Software'), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package nokogiri;

import static nokogiri.internals.NokogiriHelpers.getNokogiriClass;
import static nokogiri.internals.NokogiriHelpers.stringOrBlank;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PipedReader;
import java.io.PipedWriter;
import java.io.StringReader;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
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.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.xalan.transformer.TransformerImpl;
import org.apache.xml.serializer.SerializationHandler;
import org.jruby.Ruby;
import org.jruby.RubyArray;
import org.jruby.RubyClass;
import org.jruby.RubyHash;
import org.jruby.RubyObject;
import org.jruby.RubyString;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.Helpers;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.w3c.dom.Document;

import nokogiri.internals.NokogiriXsltErrorListener;

/**
 * Class for Nokogiri::XSLT::Stylesheet
 *
 * @author sergio
 * @author Yoko Harada <yokolet@gmail.com>
 */
@JRubyClass(name="Nokogiri::XSLT::Stylesheet")
public class XsltStylesheet extends RubyObject {

    private TransformerFactory factory = null;
    private Templates sheet = null;
    private IRubyObject stylesheet = null;
    private boolean htmlish = false;

    public XsltStylesheet(Ruby ruby, RubyClass rubyClass) {
        super(ruby, rubyClass);
    }
    
    /**
     * Create and return a copy of this object.
     *
     * @return a clone of this object
     */
    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

    private void addParametersToTransformer(ThreadContext context, Transformer transf, IRubyObject parameters) {
        Ruby runtime = context.getRuntime();

        if (parameters instanceof RubyHash) {
            setHashParameters(transf, (RubyHash)parameters);
        } else if (parameters instanceof RubyArray) {
            setArrayParameters(transf, runtime, (RubyArray)parameters);
        } else {
            throw runtime.newTypeError("parameters should be given either Array or Hash");
        }
    }
    
    private void setHashParameters(Transformer transformer, RubyHash hash) {
        Set<String> keys = hash.keySet();
        for (String key : keys) {
            String value = (String)hash.get(key);
            transformer.setParameter(key, unparseValue(value));
        }
    }
    
    private void setArrayParameters(Transformer transformer, Ruby runtime, RubyArray params) {
        int limit = params.getLength();
        if(limit % 2 == 1) limit--;

        for(int i = 0; i < limit; i+=2) {
            String name = params.aref(runtime.newFixnum(i)).asJavaString();
            String value = params.aref(runtime.newFixnum(i+1)).asJavaString();
            transformer.setParameter(name, unparseValue(value));
        }
    }
    
    private static final Pattern QUOTED = Pattern.compile("'.{1,}'");

    private String unparseValue(String orig) {
        if ((orig.startsWith("\"") && orig.endsWith("\"")) || QUOTED.matcher(orig).matches()) {
            orig = orig.substring(1, orig.length() - 1);
        }

        return orig;
    }

    @JRubyMethod(meta = true, rest = true)
    public static IRubyObject parse_stylesheet_doc(ThreadContext context, IRubyObject klazz, IRubyObject[] args) {
        
        Ruby runtime = context.getRuntime();

        ensureFirstArgIsDocument(runtime, args[0]);

        XmlDocument xmlDoc = (XmlDocument) args[0];
        ensureDocumentHasNoError(context, xmlDoc);
        
        Document doc = ((XmlDocument) xmlDoc.dup_implementation(context, true)).getDocument();

        XsltStylesheet xslt =
            (XsltStylesheet) NokogiriService.XSLT_STYLESHEET_ALLOCATOR.allocate(runtime, (RubyClass)klazz);

        try {
            xslt.init(args[1], doc);
        } catch (TransformerConfigurationException ex) {
            throw runtime.newRuntimeError("could not parse xslt stylesheet");
        }

        return xslt;
    }
    
    private void init(IRubyObject stylesheet, Document document) throws TransformerConfigurationException {
        this.stylesheet = stylesheet;  // either RubyString or RubyFile
        if (factory == null) factory = TransformerFactory.newInstance();
        NokogiriXsltErrorListener elistener = new NokogiriXsltErrorListener();
        factory.setErrorListener(elistener);
        sheet = factory.newTemplates(new DOMSource(document));
    }
    
    private static void ensureFirstArgIsDocument(Ruby runtime, IRubyObject arg) {
        if (arg instanceof XmlDocument) return;
        throw runtime.newArgumentError("doc must be a Nokogiri::XML::Document instance");
    }
    
    private static void ensureDocumentHasNoError(ThreadContext context, XmlDocument xmlDoc) {
        Ruby runtime = context.getRuntime();
        RubyArray errors_of_xmlDoc = (RubyArray) xmlDoc.getInstanceVariable("@errors");
        if (!errors_of_xmlDoc.isEmpty()) {
            throw runtime.newRuntimeError(errors_of_xmlDoc.first().asString().asJavaString());
        }
    }

    @JRubyMethod
    public IRubyObject serialize(ThreadContext context, IRubyObject doc) throws IOException, TransformerException {
    	XmlDocument xmlDoc = (XmlDocument) doc;
    	TransformerImpl transformer = (TransformerImpl) this.sheet.newTransformer();
    	ByteArrayOutputStream writer = new ByteArrayOutputStream();
    	StreamResult streamResult = new StreamResult(writer);
    	SerializationHandler serializationHandler = transformer.createSerializationHandler(streamResult);
    	serializationHandler.serialize(xmlDoc.getNode());
    	return context.getRuntime().newString(writer.toString());
    }

    @JRubyMethod(rest = true, required=1, optional=2)
    public IRubyObject transform(ThreadContext context, IRubyObject[] args) {
        Ruby runtime = context.getRuntime();

        argumentTypeCheck(runtime, args[0]);

        NokogiriXsltErrorListener elistener = new NokogiriXsltErrorListener();
        DOMSource domSource = new DOMSource(((XmlDocument) args[0]).getDocument());
        final DOMResult result; String stringResult = null;
        try{
            result = tryXsltTransformation(context, args, domSource, elistener); // DOMResult
            if (result.getNode().getFirstChild() == null) {
                stringResult = retryXsltTransformation(context, args, domSource, elistener); // StreamResult
            }
        } catch(TransformerConfigurationException ex) {
            throw runtime.newRuntimeError(ex.getMessage());
        } catch(TransformerException ex) {
            throw runtime.newRuntimeError(ex.getMessage());
        } catch (IOException ex) {
            throw runtime.newRuntimeError(ex.getMessage());
        }

        switch (elistener.getErrorType()) {
            case ERROR:
            case FATAL:
                throw runtime.newRuntimeError(elistener.getErrorMessage());
            case WARNING:
            default:
                // no-op
        }

        if (stringResult == null) {
            return createDocumentFromDomResult(context, runtime, result);
        } else {
            return createDocumentFromString(context, runtime, stringResult);
        }
    }
    
    private DOMResult tryXsltTransformation(ThreadContext context, IRubyObject[] args, DOMSource domSource, NokogiriXsltErrorListener elistener) throws TransformerException {
        Transformer transf = sheet.newTransformer();
        transf.reset();
        transf.setErrorListener(elistener);
        if (args.length > 1) {
            addParametersToTransformer(context, transf, args[1]);
        }

        DOMResult result = new DOMResult();
        transf.transform(domSource, result);
        return result;
    }
    
    private String retryXsltTransformation(ThreadContext context,
                                           IRubyObject[] args,
                                           DOMSource domSource,
                                           NokogiriXsltErrorListener elistener)
            throws TransformerException, IOException {
        Templates templates = getTemplatesFromStreamSource();
        Transformer transf = templates.newTransformer();
        transf.setErrorListener(elistener);
        if (args.length > 1) {
            addParametersToTransformer(context, transf, args[1]);
        }
        PipedWriter pwriter = new PipedWriter();
        PipedReader preader = new PipedReader();
        pwriter.connect(preader);
        StreamResult result = new StreamResult(pwriter);
        transf.transform(domSource, result);

        char[] cbuf = new char[1024];
        int len = preader.read(cbuf, 0, 1024);
        StringBuilder builder = new StringBuilder(len);
        builder.append(cbuf, 0, len);
        htmlish = isHtml(builder); // judge from the first chunk
        
        while (len == 1024) {
            len = preader.read(cbuf, 0, 1024);
            if (len > 0) {
                builder.append(cbuf, 0, len);
            }
        }
        
        preader.close();
        pwriter.close();
        
        return builder.toString();
    }
    
    private IRubyObject createDocumentFromDomResult(ThreadContext context, Ruby runtime, DOMResult domResult) {
        if ("html".equals(domResult.getNode().getFirstChild().getNodeName())) {
            return new HtmlDocument(context.runtime, (Document) domResult.getNode());
        } else {
            return new XmlDocument(context.runtime, (Document) domResult.getNode());
        }
    }
    
    private Templates getTemplatesFromStreamSource() throws TransformerConfigurationException {
        if (stylesheet instanceof RubyString) {
            StringReader reader = new StringReader(stylesheet.asJavaString());
            StreamSource xsltStreamSource = new StreamSource(reader);
            return factory.newTemplates(xsltStreamSource);
        }
        return null;
    }
    
    private static final Pattern HTML_TAG = Pattern.compile("<(%s)*html", Pattern.CASE_INSENSITIVE);
    
    private static boolean isHtml(CharSequence chunk) {
        Matcher match = HTML_TAG.matcher(chunk);
        return match.find();
    }
    
    private IRubyObject createDocumentFromString(ThreadContext context, Ruby runtime, String stringResult) {
        IRubyObject[] args = new IRubyObject[4];
        args[0] = stringOrBlank(runtime, stringResult);
        args[1] = runtime.getNil();  // url
        args[2] = runtime.getNil();  // encoding
        RubyClass parse_options = (RubyClass)runtime.getClassFromPath("Nokogiri::XML::ParseOptions");
        if (htmlish) {
            args[3] = parse_options.getConstant("DEFAULT_HTML");
            RubyClass htmlDocumentClass = getNokogiriClass(runtime, "Nokogiri::HTML::Document");
            return Helpers.invoke(context, htmlDocumentClass, "parse", args);
        } else {
            args[3] = parse_options.getConstant("DEFAULT_XML");
            RubyClass xmlDocumentClass = getNokogiriClass(runtime, "Nokogiri::XML::Document");            
            XmlDocument xmlDocument = (XmlDocument) Helpers.invoke(context, xmlDocumentClass, "parse", args);
            if (((Document)xmlDocument.getNode()).getDocumentElement() == null) {
                RubyArray errors = (RubyArray) xmlDocument.getInstanceVariable("@errors");
                Helpers.invoke(context, errors, "<<", args[0]);
            }
            return xmlDocument;
        }
    }
    
    private static void argumentTypeCheck(Ruby runtime, IRubyObject arg) {
        if (arg instanceof XmlDocument) return;
        throw runtime.newArgumentError("argument must be a Nokogiri::XML::Document");
    }
    
    @JRubyMethod(name = {"registr", "register"}, meta = true)
    public static IRubyObject register(ThreadContext context, IRubyObject cls, IRubyObject uri, IRubyObject receiver) {
        throw context.getRuntime().newNotImplementedError("Nokogiri::XSLT.register method is not implemented");
        /* When API conflict is solved, this method should be below:
        // ThreadContext is used while executing xslt extension function
        registry.put("context", context);
        registry.put("receiver", receiver);
        return context.getRuntime().getNil();
        */
    }
}