/*
 * 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.cloudstack.framework.serializer;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;


//
// Finding classes in a given package code is taken and modified from 
// Credit: http://internna.blogspot.com/2007/11/java-5-retrieving-all-classes-from.html
//
public class OnwireClassRegistry {
	
	private List<String> packages = new ArrayList<String>();
	private Map<String, Class<?>> registry =  new HashMap<String, Class<?>>();

	public OnwireClassRegistry() {
		registry.put("Object", Object.class);
	}
	
	public OnwireClassRegistry(String packageName) {
		addPackage(packageName);
	}
	
	public OnwireClassRegistry(List<String> packages) {
		packages.addAll(packages);
	}
	
	public List<String> getPackages() {
		return packages;
	}
	
	public void setPackages(List<String> packages) {
		this.packages = packages;
	}
	
	public void addPackage(String packageName) {
		packages.add(packageName);
	}
	
	public void scan() {
		Set<Class<?>> classes = new HashSet<Class<?>>();
		for(String pkg : packages) {
			classes.addAll(getClasses(pkg));
		}
		
		for(Class<?> clz : classes) {
			OnwireName onwire = clz.getAnnotation(OnwireName.class);
			if(onwire != null) {
				assert(onwire.name() != null);
				
				registry.put(onwire.name(), clz);
			}
		}
	}
	
	public Class<?> getOnwireClass(String onwireName) {
		return registry.get(onwireName);
	}
	
	static Set<Class<?>> getClasses(String packageName) {
	   ClassLoader loader = Thread.currentThread().getContextClassLoader();
	   return getClasses(loader, packageName);
	}

	//
	// Following helper methods can be put in a separated helper class,
	// will do that later
	//
	static Set<Class<?>> getClasses(ClassLoader loader, String packageName) {
	   Set<Class<?>> classes = new HashSet<Class<?>>();
	   String path = packageName.replace('.', '/');
	   try {
		   Enumeration<URL> resources = loader.getResources(path);
		   if (resources != null) {
		      while (resources.hasMoreElements()) {
		         String filePath = resources.nextElement().getFile();
		         // WINDOWS HACK
		         if(filePath.indexOf("%20") > 0)
		            filePath = filePath.replaceAll("%20", " ");
		         if (filePath != null) {
		            if ((filePath.indexOf("!") > 0) && (filePath.indexOf(".jar") > 0)) {
		               String jarPath = filePath.substring(0, filePath.indexOf("!"))
		                  .substring(filePath.indexOf(":") + 1);
		               // WINDOWS HACK
		               if (jarPath.indexOf(":") >= 0) jarPath = jarPath.substring(1); 
		               classes.addAll(getFromJARFile(jarPath, path));
		            } else {
		               classes.addAll(getFromDirectory(new File(filePath), packageName));
		            }
		         }
		      }
		   }
	   } catch(IOException e) {
	   } catch(ClassNotFoundException e) {
	   }
	   return classes;
	}	
	
	static Set<Class<?>> getFromDirectory(File directory, String packageName) throws ClassNotFoundException {
		   Set<Class<?>> classes = new HashSet<Class<?>>();
		   if (directory.exists()) {
		      for (String file : directory.list()) {
		         if (file.endsWith(".class")) {
		            String name = packageName + '.' + stripFilenameExtension(file);
		            try {
			            Class<?> clazz = Class.forName(name);
			            classes.add(clazz);
		            } catch(ClassNotFoundException e) {
		            } catch(Exception e) {
	            	}
		         } else {
		        	 File f = new File(directory.getPath() + "/" + file);
		        	 if(f.isDirectory()) {
		        		 classes.addAll(getFromDirectory(f, packageName + "." + file));
		        	 }
		         }
		      }
		   }
		   return classes;
		}
	
	static Set<Class<?>> getFromJARFile(String jar, String packageName) throws IOException, ClassNotFoundException {
	   Set<Class<?>> classes = new HashSet<Class<?>>();
	   JarInputStream jarFile = new JarInputStream(new FileInputStream(jar));
	   JarEntry jarEntry;
	   do {
	      jarEntry = jarFile.getNextJarEntry();
	      if (jarEntry != null) {
	         String className = jarEntry.getName();
	         if (className.endsWith(".class")) {
	            className = stripFilenameExtension(className);
	            if (className.startsWith(packageName)) {
	            	try {
	            		Class<?> clz = Class.forName(className.replace('/', '.'));
	            		classes.add(clz);
	            	} catch(ClassNotFoundException e) {
	            	} catch(NoClassDefFoundError e) {
	            	}
	            }
	         }
	      }
	   } while (jarEntry != null);
	   
	   return classes;
	}
	
	static String stripFilenameExtension(String file) {
		return file.substring(0, file.lastIndexOf('.'));
	}
}

