/**
    * This file Copyright (c) 2015-2016 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 static info.magnolia.resourceloader.classpath.service.ClasspathService.ClasspathEntryNotFoundException;
  
  import info.magnolia.resourceloader.AbstractResourceOrigin;
  import info.magnolia.resourceloader.ResourceOriginFactory;
  import info.magnolia.resourceloader.ResourceStub;
  import info.magnolia.resourceloader.ResourceVisitor;
  import info.magnolia.resourceloader.classpath.hierarchy.ClasspathDirectory;
  import info.magnolia.resourceloader.classpath.hierarchy.ClasspathEntry;
  import info.magnolia.resourceloader.classpath.hierarchy.ClasspathFile;
  import info.magnolia.resourceloader.classpath.service.ClasspathService;
  import info.magnolia.resourceloader.classpath.service.MonitoredClasspathService;
  import info.magnolia.resourceloader.util.VoidFunction;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.charset.Charset;
  import java.util.List;
  
  import com.google.auto.factory.AutoFactory;
  import com.google.auto.factory.Provided;
  import com.google.common.base.Function;
  import com.google.common.collect.Lists;
  
  /**
   * A {@link info.magnolia.resourceloader.ResourceOrigin} which serves resources collected from the web application classpath.
   * Classpath file/folder hierarchy is provided by the {@link ClasspathService classpath service} which also acts as a delegate
   * for most of this origin's calls.
   *
   * @see ClasspathService
   * @see ClasspathResource
   */
  @AutoFactory(implementing = ResourceOriginFactory.class)
  public class ClasspathResourceOrigin extends AbstractResourceOrigin<ClasspathResource> {
  
      private final Function<ClasspathEntry, ClasspathResource> getResourceInstance = new Function<ClasspathEntry, ClasspathResource>() {
          @Override
          @SuppressWarnings("unchecked")
          public ClasspathResource<ClasspathEntry> apply(ClasspathEntry input) {
              return new ClasspathResource(ClasspathResourceOrigin.this, input);
          }
      };
  
      private final ClasspathService classpathService;
  
      public ClasspathResourceOrigin(String name, @Provided ClasspathService classpathService) {
          super(name);
          this.classpathService = classpathService;
  
      }
  
      @Override
      protected boolean isFile(ClasspathResource resource) {
          return resource.getClasspathEntry() instanceof ClasspathFile;
      }
  
      @Override
      protected boolean isDirectory(ClasspathResource resource) {
          return resource.getClasspathEntry() instanceof ClasspathDirectory;
      }
  
      @Override
      protected String getPath(ClasspathResource resource) {
          return resource.getClasspathEntry().getAbsolutePath();
      }
 
     @Override
     protected String getName(ClasspathResource resource) {
         return resource.getClasspathEntry().getName();
     }
 
     @Override
     protected long getLastModified(ClasspathResource resource) {
         return resource.getClasspathEntry().getLastModified();
     }
 
     @Override
     protected List<ClasspathResource> listChildren(ClasspathResource resource) {
         final ClasspathEntry classpathEntry = resource.getClasspathEntry();
         if (resource.isDirectory()) {
             final ClasspathDirectory folder = (ClasspathDirectory) classpathEntry;
             return Lists.transform(folder.getEntries(), getResourceInstance);
         } else {
             throw new IllegalArgumentException(String.format("%s is not a directory.", resource.getPath()));
         }
     }
 
     @Override
     protected ClasspathResource getParent(ClasspathResource resource) {
         if (getRoot().equals(resource)) {
             return null;
         }
 
         try {
             return getResourceInstance.apply(classpathService.getParent(resource.getClasspathEntry()));
         } catch (ClasspathEntryNotFoundException e) {
             throw new ResourceNotFoundException(this, String.format("Failed to resolve a parent of a resource at [%s]", resource.getPath()));
         }
     }
 
     @Override
     protected InputStream doOpenStream(ClasspathResource resource) throws IOException {
         final ClasspathEntry classpathEntry = resource.getClasspathEntry();
         if (!resource.isFile()) {
             throw new IllegalArgumentException(String.format("It is not allowed to attempt to obtain an input stream for folder classpath entries (%s)", resource.getPath()));
         }
         return ((ClasspathFile) classpathEntry).openStream();
     }
 
     @Override
     protected Charset getCharsetFor(ClasspathResource resource) {
         return classpathService.getConfiguration().getCharset();
     }
 
     @Override
     public ClasspathResource getRoot() {
         return getResourceInstance.apply(classpathService.getRoot());
     }
 
     @Override
     public ClasspathResource getByPath(String path) {
         try {
             return getResourceInstance.apply(classpathService.getEntryAt(path));
         } catch (ClasspathEntryNotFoundException e) {
             throw new ResourceNotFoundException(this, String.format("Failed to resolve a classpath resource at [%s]", path));
         }
     }
 
     @Override
     public boolean hasPath(String path) {
         return classpathService.hasEntry(path);
     }
 
     @Override
     public void watchForChanges(final ResourceVisitor visitor) {
         if (classpathService instanceof MonitoredClasspathService) {
             ((MonitoredClasspathService) classpathService).registerResourceChangeCallback(new VoidFunction<String>() {
                 @Override
                 public void doWith(String resourcePath) {
                     try {
                         final ClasspathResource resource = getByPath(resourcePath);
                         if (resource.isFile()) {
                             visitor.visitFile(resource);
                         } else {
                             visitor.visitDirectory(resource);
                         }
                     } catch (ResourceNotFoundException e) {
                         visitor.visitFile(ResourceStub.withPath(resourcePath));
                     }
                 }
             });
         }
     }
 }