/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.common.content;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.channels.ReadableByteChannel;
  import java.nio.channels.SeekableByteChannel;
  import java.nio.file.CopyOption;
  import java.nio.file.FileSystem;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.StandardCopyOption;
  import java.nio.file.StandardOpenOption;
  import java.nio.file.attribute.BasicFileAttributes;
  import java.util.Objects;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.mycore.datamodel.niofs.MCRFileAttributes;
  
  /**
   * MCRContent implementation that uses Java 7 {@link FileSystem} features.
   * 
   * @author Thomas Scheffler (yagee)
   */
  public class MCRPathContent extends MCRContent implements MCRSeekableChannelContent {
  
      private static final Logger LOGGER = LogManager.getLogger();
  
      private Path path;
  
      private BasicFileAttributes attrs;
  
      private static int BUFFER_SIZE = 8192;
  
      public MCRPathContent(Path path) {
          this(path, null);
      }
  
      public MCRPathContent(Path path, BasicFileAttributes attrs) {
          this.path = Objects.requireNonNull(path).toAbsolutePath().normalize();
          this.attrs = attrs;
      }
  
      /* (non-Javadoc)
       * @see org.mycore.common.content.MCRSeekableChannelContent#getSeekableByteChannel()
       */
      @Override
      public SeekableByteChannel getSeekableByteChannel() throws IOException {
          return Files.newByteChannel(path, StandardOpenOption.READ);
      }
  
      @Override
      public InputStream getInputStream() throws IOException {
          return Files.newInputStream(path, StandardOpenOption.READ);
      }
  
      @Override
      public ReadableByteChannel getReadableByteChannel() throws IOException {
          return getSeekableByteChannel();
      }
  
      @Override
      public byte[] asByteArray() throws IOException {
          return Files.readAllBytes(path);
      }
  
      @Override
      public long length() throws IOException {
          return attrs != null ? attrs.size() : Files.size(path);
      }
  
      @Override
      public long lastModified() throws IOException {
          return (attrs != null ? attrs.lastModifiedTime() : Files.getLastModifiedTime(path)).toMillis();
      }
  
      @Override
      public String getETag() throws IOException {
          if (attrs instanceof MCRFileAttributes) {
             return ((MCRFileAttributes) attrs).md5sum();
         }
 
         if (Files.getFileStore(path).supportsFileAttributeView("md5")) {
             Object fileKey = Files.getAttribute(path, "md5:md5");
             if (fileKey instanceof String) {
                 return fileKey.toString();
             }
         }
 
         return super.getETag();
     }
 
     @Override
     public String getMimeType() throws IOException {
         return mimeType == null ? Files.probeContentType(path) : mimeType;
     }
 
     @Override
     public String getSystemId() {
         return path.toUri().toString();
     }
 
     @Override
     public String getName() {
         return name == null ? path.getFileName().toString() : super.getName();
     }
 
     @Override
     public void sendTo(OutputStream out) throws IOException {
         Files.copy(path, out);
     }
 
     @Override
     public void sendTo(File target) throws IOException {
         Files.copy(path, target.toPath(), StandardCopyOption.REPLACE_EXISTING);
     }
 
     @Override
     public void sendTo(Path target, CopyOption... options) throws IOException {
         Files.copy(path, target, options);
     }
 }