/*
    * 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.
   */
  package org.apache.commons.vfs2.provider.http4;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URI;
  
  import org.apache.commons.vfs2.FileContentInfoFactory;
  import org.apache.commons.vfs2.FileNotFoundException;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.FileSystemOptions;
  import org.apache.commons.vfs2.FileType;
  import org.apache.commons.vfs2.RandomAccessContent;
  import org.apache.commons.vfs2.provider.AbstractFileName;
  import org.apache.commons.vfs2.provider.AbstractFileObject;
  import org.apache.commons.vfs2.provider.GenericURLFileName;
  import org.apache.commons.vfs2.util.RandomAccessMode;
  import org.apache.http.Header;
  import org.apache.http.HttpResponse;
  import org.apache.http.HttpStatus;
  import org.apache.http.client.HttpClient;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpHead;
  import org.apache.http.client.methods.HttpUriRequest;
  import org.apache.http.client.protocol.HttpClientContext;
  import org.apache.http.client.utils.DateUtils;
  import org.apache.http.client.utils.URIUtils;
  import org.apache.http.protocol.HTTP;
  
  /**
   * A file object backed by Apache HttpComponents HttpClient.
   *
   * @param <FS> An {@link Http4FileSystem} subclass
   *
   * @since 2.3
   */
  public class Http4FileObject<FS extends Http4FileSystem> extends AbstractFileObject<FS> {
  
      /**
       * URL charset string.
       */
      private final String urlCharset;
  
      /**
       * Internal URI mapped to this {@code FileObject}.
       * For example, the internal URI of {@code http4://example.com/a.txt} is {@code http://example.com/a.txt}.
       */
      private final URI internalURI;
  
      /**
       * The last executed HEAD {@code HttpResponse} object.
       */
      private HttpResponse lastHeadResponse;
  
      /**
       * Construct {@code Http4FileObject}.
       *
       * @param name file name
       * @param fileSystem file system
       * @throws FileSystemException if any error occurs
       */
      protected Http4FileObject(final AbstractFileName name, final FS fileSystem)
              throws FileSystemException {
          this(name, fileSystem, Http4FileSystemConfigBuilder.getInstance());
      }
  
      /**
       * Construct {@code Http4FileObject}.
       *
       * @param name file name
       * @param fileSystem file system
       * @param builder {@code Http4FileSystemConfigBuilder} object
       * @throws FileSystemException if any error occurs
       */
      protected Http4FileObject(final AbstractFileName name, final FS fileSystem,
              final Http4FileSystemConfigBuilder builder) throws FileSystemException {
          super(name, fileSystem);
          final FileSystemOptions fileSystemOptions = fileSystem.getFileSystemOptions();
          urlCharset = builder.getUrlCharset(fileSystemOptions);
          final String pathEncoded = ((GenericURLFileName) name).getPathQueryEncoded(getUrlCharset());
          internalURI = URIUtils.resolve(fileSystem.getInternalBaseURI(), pathEncoded);
      }
  
      @Override
     protected void doDetach() throws Exception {
         lastHeadResponse = null;
     }
 
     @Override
     protected long doGetContentSize() throws Exception {
         if (lastHeadResponse == null) {
             return 0L;
         }
 
         final Header header = lastHeadResponse.getFirstHeader(HTTP.CONTENT_LEN);
 
         if (header == null) {
             // Assume 0 content-length
             return 0;
         }
 
         return Long.parseLong(header.getValue());
     }
 
     @Override
     protected InputStream doGetInputStream(final int bufferSize) throws Exception {
         final HttpGet getRequest = new HttpGet(getInternalURI());
         final HttpResponse httpResponse = executeHttpUriRequest(getRequest);
         final int status = httpResponse.getStatusLine().getStatusCode();
 
         if (status == HttpStatus.SC_NOT_FOUND) {
             throw new FileNotFoundException(getName());
         }
 
         if (status != HttpStatus.SC_OK) {
             throw new FileSystemException("vfs.provider.http/get.error", getName(), Integer.valueOf(status));
         }
 
         return new MonitoredHttpResponseContentInputStream(httpResponse, bufferSize);
     }
 
 
     @Override
     protected long doGetLastModifiedTime() throws Exception {
         FileSystemException.requireNonNull(lastHeadResponse, "vfs.provider.http/last-modified.error", getName());
 
         final Header header = lastHeadResponse.getFirstHeader("Last-Modified");
 
         FileSystemException.requireNonNull(header, "vfs.provider.http/last-modified.error", getName());
 
         return DateUtils.parseDate(header.getValue()).getTime();
     }
 
     @Override
     protected RandomAccessContent doGetRandomAccessContent(final RandomAccessMode mode) throws Exception {
         return new Http4RandomAccessContent<>(this, mode);
     }
 
     @Override
     protected FileType doGetType() throws Exception {
         lastHeadResponse = executeHttpUriRequest(new HttpHead(getInternalURI()));
         final int status = lastHeadResponse.getStatusLine().getStatusCode();
 
         if (status == HttpStatus.SC_OK
                 || status == HttpStatus.SC_METHOD_NOT_ALLOWED /* method is not allowed, but resource exist */) {
             return FileType.FILE;
         }
         if (status == HttpStatus.SC_NOT_FOUND || status == HttpStatus.SC_GONE) {
             return FileType.IMAGINARY;
         }
         throw new FileSystemException("vfs.provider.http/head.error", getName(), Integer.valueOf(status));
     }
 
     @Override
     protected boolean doIsWriteable() throws Exception {
         return false;
     }
 
     @Override
     protected String[] doListChildren() throws Exception {
         throw new UnsupportedOperationException("Not implemented.");
     }
 
     /**
      * Execute the request using the given {@code httpRequest} and return a {@code HttpResponse} from the execution.
      *
      * @param httpRequest {@code HttpUriRequest} object
      * @return {@code HttpResponse} from the execution
      * @throws IOException if IO error occurs
      *
      * @since 2.5.0
      */
     protected HttpResponse executeHttpUriRequest(final HttpUriRequest httpRequest) throws IOException {
         final HttpClient httpClient = getAbstractFileSystem().getHttpClient();
         final HttpClientContext httpClientContext = getAbstractFileSystem().getHttpClientContext();
         return httpClient.execute(httpRequest, httpClientContext);
     }
 
     @Override
     protected FileContentInfoFactory getFileContentInfoFactory() {
         return new Http4FileContentInfoFactory();
     }
 
     /**
      * Return the internal {@code URI} object mapped to this file object.
      *
      * @return the internal {@code URI} object mapped to this file object
      */
     protected URI getInternalURI() {
         return internalURI;
     }
 
     /**
      * Return the last executed HEAD {@code HttpResponse} object.
      *
      * @return the last executed HEAD {@code HttpResponse} object
      * @throws IOException if IO error occurs
      */
     HttpResponse getLastHeadResponse() throws IOException {
         if (lastHeadResponse != null) {
             return lastHeadResponse;
         }
 
         return executeHttpUriRequest(new HttpHead(getInternalURI()));
     }
 
     /**
      * Return URL charset string.
      * @return URL charset string
      */
     protected String getUrlCharset() {
         return urlCharset;
     }
 
 }