/**
    * This file Copyright (c) 2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.resourceloader.classpath;
  
  import info.magnolia.cms.util.ClasspathResourcesUtil;
  import info.magnolia.resourceloader.ResourceOriginFactory;
  import info.magnolia.resourceloader.ResourceVisitor;
  
  import java.net.URL;
  
  import com.google.auto.factory.AutoFactory;
  import com.google.common.base.Predicate;
  
  /**
   * A {@link ClasspathResourceOrigin} which exposes resources under the /mgnl-resources/ folder as if they were in the root.
   * See {@value #DOCU_LINK}.
   */
  @AutoFactory(implementing = ResourceOriginFactory.class)
  public class LegacyClasspathResourceOrigin extends ClasspathResourceOrigin {
      private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LegacyClasspathResourceOrigin.class);
  
      private static final String DOCU_LINK = "https://documentation.magnolia-cms.com/display/DOCS/Resources";
  
      private static final String PREFIX = "mgnl-resources";
      private static final String PREFIX_AND_SLASH = PREFIX + "/";
      private static final String PREFIX_AND_DOT = PREFIX + ".";
  
      LegacyClasspathResourceOrigin(String name) {
          super(null, name);
      }
  
      /**
       * {@link LegacyClasspathResourceOrigin} does not implement watching for resource changes, since there is nothing at all to observe there.
       * This will most likely ever contain only static web resources, and in particular no configuration file.
       */
      @Override
      public void watchForChanges(ResourceVisitor visitor) {
          log.debug("Watching resource changes is not supported in LegacyClasspathResourceOrigin.");
      }
  
      @Override
      protected Predicate<String> resourcesFilter() {
          return new StartsWith(PREFIX_AND_DOT);
      }
  
      @Override
      protected String validatePath(String resource) {
          if (!resource.startsWith(PREFIX_AND_SLASH)) {
              throw new IllegalStateException("Resources for " + getClass().getName() + " should be under /mgnl-resources/; got " + resource);
          }
          // Keep the slash after mgnl-resources:
          return resource.substring(PREFIX.length());
      }
  
      @Override
      protected URL getUrl(ClasspathResource resource) {
          final URL url = ClasspathResourcesUtil.getResource(PREFIX + resource.getRealPath());
          if (url == null) {
              throw new IllegalStateException("Can't open stream for " + resource);
          }
          log.warn("Using {} to load a resource off of mgnl-resources/ at {}. Please update your resources. See {}", getClass().getSimpleName(), url, DOCU_LINK);
          return url;
      }
  
      private static class StartsWith implements Predicate<String> {
          private final String prefix;
  
          public StartsWith(String prefix) {
             this.prefix = prefix;
         }
 
         @Override
         public boolean apply(String input) {
             return input.startsWith(prefix);
         }
     }
 }