/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.client5.http.impl.cache;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.concurrent.atomic.AtomicReference;
  
  import org.apache.hc.client5.http.cache.Resource;
  import org.apache.hc.client5.http.cache.ResourceIOException;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.ByteArrayBuffer;
  
  /**
   * Cache resource backed by a file.
   *
   * @since 4.1
   */
  @Contract(threading = ThreadingBehavior.SAFE)
  public class FileResource extends Resource {
  
      private static final long serialVersionUID = 4132244415919043397L;
  
      private final AtomicReference<File> fileRef;
      private final long len;
  
      public FileResource(final File file) {
          super();
          Args.notNull(file, "File");
          this.fileRef = new AtomicReference<>(file);
          this.len = file.length();
      }
  
      File getFile() {
          return this.fileRef.get();
      }
  
      @Override
      public byte[] get() throws ResourceIOException {
          final File file = this.fileRef.get();
          if (file == null) {
              throw new ResourceIOException("Resource already disposed");
          }
          try (final InputStream in = new FileInputStream(file)) {
              final ByteArrayBuffer buf = new ByteArrayBuffer(1024);
              final byte[] tmp = new byte[2048];
              int len;
              while ((len = in.read(tmp)) != -1) {
                  buf.append(tmp, 0, len);
              }
              return buf.toByteArray();
          } catch (final IOException ex) {
              throw new ResourceIOException(ex.getMessage(), ex);
          }
      }
  
      @Override
      public InputStream getInputStream() throws ResourceIOException {
          final File file = this.fileRef.get();
          if (file != null) {
              try {
                  return new FileInputStream(file);
              } catch (final FileNotFoundException ex) {
                  throw new ResourceIOException(ex.getMessage(), ex);
              }
          }
          throw new ResourceIOException("Resource already disposed");
      }
  
      @Override
     public long length() {
         return len;
     }
 
     @Override
     public void dispose() {
         final File file = this.fileRef.getAndSet(null);
         if (file != null) {
             file.delete();
         }
     }
 
 }