/**
 * 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.cxf.jca.core.classloader;


import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.ProtectionDomain;
import java.security.SecureClassLoader;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.logging.Logger;

import org.apache.cxf.common.logging.LogUtils;


public class PlugInClassLoader extends SecureClassLoader {
    private static final Logger LOG =  LogUtils.getL7dLogger(PlugInClassLoader.class);
    private static final String FILE_COLON = "file:";
    private static final String ZIP_COLON = "zip:";
    private static final String URL_SCHEME_COLON = "classloader:";
    private static final String JARS_PROPS_FILE = "jars.properties";
    private static final String FILTERS_PROPS_FILE = "filters.properties";
    private static final String NEFILTERS_PROPS_FILE = "negativefilters.properties";
    private String jarUrls[] = new String[0];
    private final ProtectionDomain protectionDomain;
    
    private final ClassLoader ploader;

    public PlugInClassLoader(final ClassLoader p) throws IOException {        
        super(new FireWallClassLoader(p, 
                                      getFilterList(p, FILTERS_PROPS_FILE),
                                      getFilterList(p, NEFILTERS_PROPS_FILE)));
        ploader = p;
        protectionDomain = getClass().getProtectionDomain();
        jarUrls = loadUrls(p);
        processJarUrls(jarUrls);
    }

    private void processJarUrls(String urls[]) {
        for (int i = 0; i < urls.length; i++) {
            if (urls[i].startsWith(ZIP_COLON)) {
                urls[i] = FILE_COLON + urls[i].substring(ZIP_COLON.length());                              
            }
        }
    }

    private static String[] getFilterList(ClassLoader parent, String propFile) throws IOException {
        Properties filtersProps = getProperties(parent, propFile);
        Iterator<Object> i = filtersProps.keySet().iterator();
        while (i.hasNext()) {            
            LOG.config("get Filter " + propFile + "::" + (String)i.next());            
        }    
        return filtersProps.keySet().toArray(new String[filtersProps.keySet().size()]);
    }

    private static Properties getProperties(ClassLoader parent, String propsFileName) throws IOException {
        InputStream in = parent.getResourceAsStream(propsFileName);

        if (null == in) {
            in = PlugInClassLoader.class.getResourceAsStream(propsFileName);

            if (null == in) {
                String msg = "Internal rar classloader failed to locate configuration resource: "
                        + propsFileName;
                IOException ioe = new IOException(msg);

                LOG.warning(ioe.toString());
                throw ioe;
            }
        }

        Properties props = new Properties();

        props.load(in);
        LOG.fine("Contents: " + propsFileName + props);

        return props;
    }

    private String[] loadUrls(ClassLoader parent) throws IOException {
        List<String> urlList = new ArrayList<String>();

        Properties props = getProperties(parent, JARS_PROPS_FILE);

        LOG.fine(props.toString());

        Enumeration<Object> keys = props.keys();

        while (keys.hasMoreElements()) {
            String key = (String)keys.nextElement();
            URL url = parent.getResource(key);

            if (url != null) {
                LOG.config(url.toString());
                urlList.add(url.toString());
            }
        }

        return urlList.toArray(new String[urlList.size()]);
    }

    protected Class<?> findClass(String name) throws ClassNotFoundException {
        String path = name.replace('.', '/').concat(".class");
        LOG.fine("findClass " + path);
        byte bytes[] = null;

        for (int i = 0; i < jarUrls.length; i++) {
            String fullpath = jarUrls[i] + "!/" + path;           
            try {
                bytes = PlugInClassLoaderHelper.getResourceAsBytes(fullpath);

                if (bytes != null) {
                    break;
                }
            } catch (IOException ex) {
                // we should find everything we look for but if we don't our
                // parent can when we throw cnf below
                LOG.fine("findClass: " + name + ": " + ex.toString());
            }
        }

        if (bytes != null) {
            return defineClass(name, bytes, 0, bytes.length, protectionDomain);
        } else {
            LOG.config("can't find name " + name + " , try to using the ploader");
            Class<?> result = ploader.loadClass(name);
            if (null == result) {
                throw new ClassNotFoundException(name);
            } else {
                return result;
            }                
        }
    }
    
   
    protected URL findResource(String name) {
        LOG.fine("findResource: " + name);
        for (int i = 0; i < jarUrls.length; i++) {
            String fullpath = jarUrls[i] + "!/" + name;         
              
            if (PlugInClassLoaderHelper.hasResource(fullpath)) {                
                return genURL(fullpath);
            }
        }
        
        return null;
    }

    protected URL genURL(String path) {
        URL url = null;
        String urlString = URL_SCHEME_COLON + path;

        try {
            url = new URL(null, urlString, new Handler());
        } catch (MalformedURLException mue) {
            LOG.warning(mue.toString());
        }

        return url;
    }
}
