/*
 * Copyright (C) 2013 Red Hat, Inc. and/or its affiliates.
 *
 * 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.jboss.errai.common.metadata;

import com.google.common.collect.AbstractIterator;
import org.jboss.errai.reflections.vfs.Vfs;
import org.jboss.vfs.VirtualFile;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Implementation of {@link Vfs.Dir} to support JBoss VFS for proper classpath scanning on JBoss AS.
 *
 * @author Mike Brock <cbrock@redhat.com>
 * @author Jonathan Fuerth <jfuerth@redhat.com>
 */
public class JBossVfsDir implements Vfs.Dir {
  private VirtualFile virtualFile;

  public JBossVfsDir(URL url) {
    try {
      Object content = url.getContent();
      if (content instanceof VirtualFile) {
        virtualFile = (VirtualFile) content;
      }
      else {
        throw new IllegalArgumentException(
            "URL content is not a JBoss VFS VirtualFile. Type is: " +
                (content == null ? "null" : content.getClass().getName()));
      }
    }
    catch (IOException e) {
      throw new RuntimeException("could not instantiate VFS directory", e);
    }
  }

  @Override
  public String getPath() {
    return virtualFile.getPathName();
  }

  @Override
  public Iterable<Vfs.File> getFiles() {
    return new Iterable<Vfs.File>() {
      @Override
      public Iterator<Vfs.File> iterator() {
        final List<VirtualFile> toVisit = new ArrayList<VirtualFile>(virtualFile.getChildren());

        return new AbstractIterator<Vfs.File>() {

          @Override
          protected Vfs.File computeNext() {
            while (!toVisit.isEmpty()) {
              final VirtualFile nextFile = toVisit.remove(toVisit.size() - 1);
              if (nextFile.isDirectory()) {
                toVisit.addAll(nextFile.getChildren());
                continue;
              }
              return new Vfs.File() {
                @Override
                public String getName() {
                  return nextFile.getName();
                }

                @Override
                public String getRelativePath() {
                  return nextFile.getPathName();
                }

                @Override
                public String getFullPath() {
                  return nextFile.getPathName();
                }

                @Override
                public InputStream openInputStream() throws IOException {
                  return nextFile.openStream();
                }
              };
            }
            return endOfData();
          }
        };
      }
    };
  }

  @Override
  public void close() {
  }
}