/*
 * Copyright 2011 eBay Software Foundation
 *
 * 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.raptorjs.resources;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

public class OSGIAdapter {

    public static OSGIAdapter instance = new OSGIAdapter();

    public static OSGIAdapter getInstance() {
        return instance;
    }
    
    public void addSearchPathEntriesFromOSGIManifests(ResourceManager resourceManager) {
        Enumeration<URL> manifestUrls = null;
        
        ClassLoader cl = OSGIAdapter.class.getClassLoader();

        Set<String> foundBasePaths = new HashSet<String>();
        
        try {
            manifestUrls = cl.getResources("META-INF/MANIFEST.MF");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
      
	        if (manifestUrls != null) {
	            
	            while(manifestUrls.hasMoreElements()) {
	                URL manifestUrl = manifestUrls.nextElement();
	                InputStream in;
					try {
						in = manifestUrl.openStream();
					} catch (IOException e1) {
						throw new RuntimeException("Unable to open stream for manifest at path " + manifestUrl);
					}
	                
	                Manifest manifest = null;
	                try {
	                    manifest = new Manifest(in);
	                } catch (Exception e) {
	                    throw new RuntimeException("Unable to get input stream reader for manifest with URL \"" + manifestUrl + "\". Exception: " + e, e);
	                }
	                finally {
	                    if (in != null) {
	                        try {
								in.close();
							} catch (IOException e) {
								throw new RuntimeException();
							}
	                    }
	                }
	
	                if (manifest != null) {
	                    
	                    Attributes attributes = manifest.getMainAttributes();
	                    if (attributes != null) {
	                        String raptorSearchPath = attributes.getValue("X-Raptor-Resource-Search-Path");//manifest.getHeader("X-Raptor-Resource-Search-Path");
	                        if (raptorSearchPath != null) {
	                            String[] parts = raptorSearchPath.split("\\s*,\\s*");
	                            for (String basePath : parts) {
	                            	if (!foundBasePaths.contains(basePath)) {
	                            		foundBasePaths.add(basePath);
	                            		resourceManager.addClasspathSearchPathEntry(OSGIAdapter.class, basePath);
	                            	}
	                            }
	                        }
	                    }
	                }
	            }
	        }
        }
    
}