/**
   * Resolves a reference to a local or remote file or element. If the link refers to an element in
   * the current document, this method returns that element. If the link refers to a remote
   * document, this method will initiate asynchronous retrieval of the document, and return a URL of
   * the downloaded document in the file cache, if it is available locally. If the link identifies a
   * COLLADA document, the document will be returned as a parsed ColladaRoot.
   *
   * @param link the address of the document or element to resolve. This may be a full URL, a URL
   *     fragment that identifies an element in the current document ("#myElement"), or a URL and a
   *     fragment identifier ("http://server.com/model.dae#myElement").
   * @return the requested element, or null if the element is not found.
   * @throws IllegalArgumentException if the address is null.
   */
  public Object resolveReference(String link) {
    if (link == null) {
      String message = Logging.getMessage("nullValue.DocumentSourceIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }

    try {
      String[] linkParts = link.split("#");
      String linkBase = linkParts[0];
      String linkRef = linkParts.length > 1 ? linkParts[1] : null;

      // See if it's a reference to an internal element.
      if (WWUtil.isEmpty(linkBase) && !WWUtil.isEmpty(linkRef)) return this.getItemByID(linkRef);

      // Interpret the path relative to the current document.
      String path = this.getSupportFilePath(linkBase);
      if (path == null) path = linkBase;

      // See if it's an already found and parsed COLLADA file.
      Object o = WorldWind.getSessionCache().get(path);
      if (o != null && o instanceof ColladaRoot)
        return linkRef != null ? ((ColladaRoot) o).getItemByID(linkRef) : o;

      URL url = WWIO.makeURL(path);
      if (url == null) {
        // See if the reference can be resolved to a local file.
        o = this.resolveLocalReference(path, linkRef);
      }

      // If we didn't find a local file, treat it as a remote reference.
      if (o == null) o = this.resolveRemoteReference(path, linkRef);

      if (o != null) return o;

      // If the reference was not resolved as a remote reference, look for a local element
      // identified by the
      // reference string. This handles the case of malformed internal references that omit the #
      // sign at the
      // beginning of the reference.
      return this.getItemByID(link);
    } catch (Exception e) {
      String message = Logging.getMessage("generic.UnableToResolveReference", link);
      Logging.logger().warning(message);
    }

    return null;
  }
  /**
   * Build the resource map from the KML Model's <i>ResourceMap</i> element.
   *
   * @param model Model from which to create the resource map.
   * @return Map that relates relative paths in the COLLADA document to paths relative to the KML
   *     document.
   */
  protected Map<String, String> createResourceMap(KMLModel model) {
    Map<String, String> map = new HashMap<String, String>();

    KMLResourceMap resourceMap = model.getResourceMap();
    if (resourceMap == null) return Collections.emptyMap();

    for (KMLAlias alias : resourceMap.getAliases()) {
      if (alias != null
          && !WWUtil.isEmpty(alias.getSourceRef())
          && !WWUtil.isEmpty(alias.getTargetHref())) {
        map.put(alias.getSourceRef(), alias.getTargetHref());
      }
    }

    return map.size() > 0 ? map : Collections.<String, String>emptyMap();
  }
  /**
   * Unzips the sole entry in the specified zip file, and saves it in a temporary directory, and
   * returns a File to the temporary location.
   *
   * @param path the path to the source file.
   * @param suffix the suffix to give the temp file.
   * @return a {@link File} for the temp file.
   * @throws IllegalArgumentException if the <code>path</code> is <code>null</code> or empty.
   */
  public static File unzipAndSaveToTempFile(String path, String suffix) {
    if (WWUtil.isEmpty(path)) {
      String message = Logging.getMessage("nullValue.PathIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }

    InputStream stream = null;

    try {
      stream = WWIO.openStream(path);

      ByteBuffer buffer = WWIO.readStreamToBuffer(stream);
      File file = WWIO.saveBufferToTempFile(buffer, WWIO.getFilename(path));

      buffer = WWIO.readZipEntryToBuffer(file, null);
      return WWIO.saveBufferToTempFile(buffer, suffix);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      WWIO.closeStream(stream, path);
    }

    return null;
  }
  /**
   * Thread's off a task to determine whether the resource is local or remote and then retrieves it
   * either from disk cache or a remote server.
   *
   * @param dc the current draw context.
   */
  protected void requestResource(DrawContext dc) {
    if (WorldWind.getTaskService().isFull()) return;

    KMLLink link = this.model.getLink();
    if (link == null) return;

    String address = link.getAddress(dc);
    if (address != null) address = address.trim();

    if (WWUtil.isEmpty(address)) return;

    WorldWind.getTaskService().addTask(new RequestTask(this, address));
  }
  /**
   * Resolves a reference to a remote element identified by address and identifier, where {@code
   * linkBase} identifies a remote document, and {@code linkRef} is the id of the desired element.
   * This method retrieves resources asynchronously using the {@link
   * gov.nasa.worldwind.cache.FileStore}.
   *
   * <p>The return value is null if the file is not yet available in the FileStore. If {@code
   * linkBase} refers to a COLLADA file and {@code linkRef} is non-null, the return value is the
   * element identified by {@code linkRef}. If {@code linkBase} refers to a COLLADA file and {@code
   * linkRef} is null, the return value is a parsed {@link ColladaRoot} for the COLLADA file
   * identified by {@code linkBase}. Otherwise the return value is a {@link URL} to the file in the
   * file cache.
   *
   * @param linkBase the address of the document containing the requested element.
   * @param linkRef the element's identifier.
   * @return URL to the requested file, parsed ColladaRoot, or COLLADA element. Returns null if the
   *     document is not yet available in the FileStore.
   * @throws IllegalArgumentException if the {@code linkBase} is null.
   */
  public Object resolveRemoteReference(String linkBase, String linkRef) {
    if (linkBase == null) {
      String message = Logging.getMessage("nullValue.DocumentSourceIsNull");
      Logging.logger().severe(message);
      throw new IllegalArgumentException(message);
    }

    try {
      // See if it's in the cache. If not, requestFile will start another thread to retrieve it and
      // return null.
      URL url = WorldWind.getDataFileStore().requestFile(linkBase);
      if (url == null) return null;

      // It's in the cache. If it's a COLLADA file try to parse it so we can search for the
      // specified reference.
      // If it's not COLLADA, just return the url for the cached file.
      String contentType = WorldWind.getDataFileStore().getContentType(linkBase);
      if (contentType == null) {
        String suffix = WWIO.getSuffix(linkBase.split(";")[0]); // strip of trailing garbage
        if (!WWUtil.isEmpty(suffix)) contentType = WWIO.makeMimeTypeForSuffix(suffix);
      }

      if (!this.canParseContentType(contentType)) return url;

      // If the file is a COLLADA document, attempt to open it. We can't open it as a File with
      // createAndParse
      // because the ColladaRoot that will be created needs to have the remote address in order to
      // resolve any
      // relative references within it.
      ColladaRoot refRoot = this.parseCachedColladaFile(url, linkBase);

      // Add the parsed file to the session cache so it doesn't have to be parsed again.
      WorldWind.getSessionCache().put(linkBase, refRoot);

      // Now check the newly opened COLLADA file for the referenced item, if a reference was
      // specified.
      if (linkRef != null) return refRoot.getItemByID(linkRef);
      else return refRoot;
    } catch (Exception e) {
      String message =
          Logging.getMessage("generic.UnableToResolveReference", linkBase + "/" + linkRef);
      Logging.logger().warning(message);
      return null;
    }
  }
  /**
   * Export the placemark attributes to KML as a {@code <Style>} element. The {@code output} object
   * will receive the data. This object must be one of: java.io.Writer<br>
   * java.io.OutputStream<br>
   * javax.xml.stream.XMLStreamWriter
   *
   * @param output Object to receive the generated KML.
   * @throws XMLStreamException If an exception occurs while writing the KML
   * @see #export(String, Object)
   */
  protected void exportAsKML(Object output) throws XMLStreamException {
    XMLStreamWriter xmlWriter = null;
    XMLOutputFactory factory = XMLOutputFactory.newInstance();
    boolean closeWriterWhenFinished = true;

    if (output instanceof XMLStreamWriter) {
      xmlWriter = (XMLStreamWriter) output;
      closeWriterWhenFinished = false;
    } else if (output instanceof Writer) {
      xmlWriter = factory.createXMLStreamWriter((Writer) output);
    } else if (output instanceof OutputStream) {
      xmlWriter = factory.createXMLStreamWriter((OutputStream) output);
    }

    if (xmlWriter == null) {
      String message = Logging.getMessage("Export.UnsupportedOutputObject");
      Logging.logger().warning(message);
      throw new IllegalArgumentException(message);
    }

    xmlWriter.writeStartElement("Style");

    // Line style
    xmlWriter.writeStartElement("LineStyle");

    final Color lineColor = this.getOutlineMaterial().getDiffuse();
    if (lineColor != null) {
      xmlWriter.writeStartElement("color");
      xmlWriter.writeCharacters(KMLExportUtil.stripHexPrefix(WWUtil.encodeColorABGR(lineColor)));
      xmlWriter.writeEndElement();

      xmlWriter.writeStartElement("colorMode");
      xmlWriter.writeCharacters("normal");
      xmlWriter.writeEndElement();
    }

    final Double lineWidth = this.getOutlineWidth();
    if (lineWidth != null) {
      xmlWriter.writeStartElement("width");
      xmlWriter.writeCharacters(Double.toString(lineWidth));
      xmlWriter.writeEndElement();
    }

    xmlWriter.writeEndElement(); // LineStyle

    // Poly style
    xmlWriter.writeStartElement("PolyStyle");

    final Color fillColor = this.getInteriorMaterial().getDiffuse();
    if (fillColor != null) {
      xmlWriter.writeStartElement("color");
      xmlWriter.writeCharacters(KMLExportUtil.stripHexPrefix(WWUtil.encodeColorABGR(fillColor)));
      xmlWriter.writeEndElement();

      xmlWriter.writeStartElement("colorMode");
      xmlWriter.writeCharacters("normal");
      xmlWriter.writeEndElement();
    }

    xmlWriter.writeStartElement("fill");
    xmlWriter.writeCharacters(kmlBoolean(isDrawInterior()));
    xmlWriter.writeEndElement();

    xmlWriter.writeStartElement("outline");
    xmlWriter.writeCharacters(kmlBoolean(isDrawOutline()));
    xmlWriter.writeEndElement();

    xmlWriter.writeEndElement(); // PolyStyle
    xmlWriter.writeEndElement(); // Style

    xmlWriter.flush();
    if (closeWriterWhenFinished) xmlWriter.close();
  }