/*
    *  Copyright 2012 Chris Pheby
    *
    *  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.jadira.scanner.file.locator;
  
  import java.io.File;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  
  import javax.servlet.ServletContext;
  
  import org.jadira.scanner.core.api.Locator;
  import org.jadira.scanner.core.exception.ClasspathAccessException;
  
  /**
   * Utilities for resolving urls against the classpath of a Web Archive
   */
  public class WebappClasspathUrlLocator implements Locator<URL> {
  
  	private final ServletContext servletContext;
  
  	public WebappClasspathUrlLocator(ServletContext servletContext) {
  		this.servletContext = servletContext;
  	}
  	
  	@Override
  	public List<URL> locate() {
  
          List<URL> list = new ArrayList<URL>();
          @SuppressWarnings("unchecked") Set<String> libJars = servletContext.getResourcePaths("/WEB-INF/lib");
          for (String jar : libJars) {
              try {
                  list.add(servletContext.getResource(jar));
              } catch (MalformedURLException e) {
                  throw new ClasspathAccessException(e);
              }
          }
          list.add(findWebInfClassesPath(servletContext));
          return list;
      }
  
      /**
       * Find the URL pointing to "/WEB-INF/classes" This method may not work in conjunction with
       * IteratorFactory if your servlet container does not extract the /WEB-INF/classes into a real
       * file-based directory
       * @param servletContext
       * @return null if cannot determin /WEB-INF/classes
       */
      private static URL findWebInfClassesPath(ServletContext servletContext) {
          String path = servletContext.getRealPath("/WEB-INF/classes");
          if (path == null) {
              return null;
          }
          File fp = new File(path);
          if (!fp.exists()) {
              return null;
          }
          try {
              return fp.toURI().toURL();
          } catch (MalformedURLException e) {
              throw new ClasspathAccessException(e);
          }
      }
  }