/* 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.
 */
package org.flowable.osgi;

import static org.flowable.osgi.Constants.BUNDLE_FLOWABLE_HEADER;
import static org.osgi.framework.Constants.BUNDLE_MANIFESTVERSION;
import static org.osgi.framework.Constants.BUNDLE_SYMBOLICNAME;
import static org.osgi.framework.Constants.BUNDLE_VERSION;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.Properties;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.ZipEntry;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

/**
 * Helper class to actually transform the BPMN xml file into a bundle.
 * 
 * @author <a href="gnodet@gmail.com">Guillaume Nodet</a>
 */
public class BpmnTransformer {

    static DocumentBuilderFactory dbf;
    static TransformerFactory tf;

    @SuppressWarnings({ "rawtypes" })
    public static void transform(URL url, OutputStream os) throws Exception {
        // Build dom document
        Document doc = parse(url);
        // Heuristicly retrieve name and version
        String name = url.getPath();
        int idx = name.lastIndexOf('/');
        if (idx >= 0) {
            name = name.substring(idx + 1);
        }
        String[] str = extractNameVersionType(name);
        // Create manifest
        Manifest m = new Manifest();
        m.getMainAttributes().putValue("Manifest-Version", "2");
        m.getMainAttributes().putValue(BUNDLE_MANIFESTVERSION, "2");
        m.getMainAttributes().putValue(BUNDLE_SYMBOLICNAME, str[0]);
        m.getMainAttributes().putValue(BUNDLE_VERSION, str[1]);
        m.getMainAttributes().putValue(BUNDLE_FLOWABLE_HEADER, "OSGI-INF/flowable/");
        // Extract manifest entries from the DOM
        NodeList l = doc.getElementsByTagName("manifest");
        if (l != null) {
            for (int i = 0; i < l.getLength(); i++) {
                Element e = (Element) l.item(i);
                String text = e.getTextContent();
                Properties props = new Properties();
                props.load(new ByteArrayInputStream(text.trim().getBytes()));
                Enumeration en = props.propertyNames();
                while (en.hasMoreElements()) {
                    String k = (String) en.nextElement();
                    String v = props.getProperty(k);
                    m.getMainAttributes().putValue(k, v);
                }
                e.getParentNode().removeChild(e);
            }
        }

        JarOutputStream out = new JarOutputStream(os);
        ZipEntry e = new ZipEntry(JarFile.MANIFEST_NAME);
        out.putNextEntry(e);
        m.write(out);
        out.closeEntry();
        e = new ZipEntry("OSGI-INF/");
        out.putNextEntry(e);
        e = new ZipEntry("OSGI-INF/flowable/");
        out.putNextEntry(e);
        out.closeEntry();
        e = new ZipEntry("OSGI-INF/flowable/" + name);
        out.putNextEntry(e);
        // Copy the new DOM
        if (tf == null) {
            tf = TransformerFactory.newInstance();
        }
        tf.newTransformer().transform(new DOMSource(doc), new StreamResult(out));
        out.closeEntry();
        out.close();
    }

    private static final String DEFAULT_VERSION = "0.0.0";

    private static final Pattern ARTIFACT_MATCHER = Pattern.compile("(.+)(?:-(\\d+)(?:\\.(\\d+)(?:\\.(\\d+))?)?(?:[^a-zA-Z0-9](.*))?)(?:\\.([^\\.]+))", Pattern.DOTALL);
    private static final Pattern FUZZY_MODIFIDER = Pattern.compile("(?:\\d+[.-])*(.*)", Pattern.DOTALL);

    public static String[] extractNameVersionType(String url) {
        Matcher m = ARTIFACT_MATCHER.matcher(url);
        if (!m.matches()) {
            return new String[] { url, DEFAULT_VERSION };
        } else {
            // System.err.println(m.groupCount());
            // for (int i = 1; i <= m.groupCount(); i++) {
            // System.err.println("Group " + i + ": " + m.group(i));
            // }

            StringBuffer v = new StringBuffer();
            String d1 = m.group(1);
            String d2 = m.group(2);
            String d3 = m.group(3);
            String d4 = m.group(4);
            String d5 = m.group(5);
            String d6 = m.group(6);
            if (d2 != null) {
                v.append(d2);
                if (d3 != null) {
                    v.append('.');
                    v.append(d3);
                    if (d4 != null) {
                        v.append('.');
                        v.append(d4);
                        if (d5 != null) {
                            v.append(".");
                            cleanupModifier(v, d5);
                        }
                    } else if (d5 != null) {
                        v.append(".0.");
                        cleanupModifier(v, d5);
                    }
                } else if (d5 != null) {
                    v.append(".0.0.");
                    cleanupModifier(v, d5);
                }
            }
            return new String[] { d1, v.toString(), d6 };
        }
    }

    private static void cleanupModifier(StringBuffer result, String modifier) {
        Matcher m = FUZZY_MODIFIDER.matcher(modifier);
        if (m.matches()) {
            modifier = m.group(1);
        }
        for (int i = 0; i < modifier.length(); i++) {
            char c = modifier.charAt(i);
            if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == '-') {
                result.append(c);
            }
        }
    }

    protected static Document parse(URL url) throws Exception {
        if (dbf == null) {
            dbf = DocumentBuilderFactory.newInstance();
            dbf.setNamespaceAware(true);
        }
        DocumentBuilder db = dbf.newDocumentBuilder();
        return db.parse(url.toString());
    }

    protected static void copyInputStream(InputStream in, OutputStream out) throws Exception {
        byte[] buffer = new byte[4096];
        int len = in.read(buffer);
        while (len >= 0) {
            out.write(buffer, 0, len);
            len = in.read(buffer);
        }
    }

}
