/*
    * This file is part of dependency-check-core.
    *
    * 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.
   *
   * Copyright (c) 2019 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.xml.assembly;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.Reader;
  import java.nio.charset.StandardCharsets;
  import javax.annotation.concurrent.ThreadSafe;
  import javax.xml.parsers.ParserConfigurationException;
  
  import org.owasp.dependencycheck.utils.AutoCloseableInputSource;
  import org.owasp.dependencycheck.utils.XmlUtils;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.XMLReader;
  
  import static org.owasp.dependencycheck.utils.AutoCloseableInputSource.fromResource;
  
  /**
   * A simple validating parser for XML Grok Assembly XML files.
   *
   * @author Jeremy Long
   */
  @ThreadSafe
  public class GrokParser {
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(GrokParser.class);
      /**
       * The grok assembly schema file location.
       */
      public static final String GROK_SCHEMA = "schema/grok-assembly.1.0.xsd";
  
      /**
       * Parses the given XML file and returns the assembly data.
       *
       * @param file an XML file containing assembly data
       * @return the assembly data
       * @throws GrokParseException thrown if the XML file cannot be parsed
       */
      @SuppressFBWarnings(justification = "try with resources will clean up the input stream", value = {"OBL_UNSATISFIED_OBLIGATION"})
      public AssemblyData parse(File file) throws GrokParseException {
          try (FileInputStream fis = new FileInputStream(file)) {
              return parse(fis);
          } catch (IOException ex) {
              LOGGER.debug("", ex);
              throw new GrokParseException(ex);
          }
      }
  
      /**
       * Parses the given XML stream and returns the contained assembly data.
       *
       * @param inputStream an InputStream containing assembly data
       * @return the assembly data
       * @throws GrokParseException thrown if the XML cannot be parsed
       */
      public AssemblyData parse(InputStream inputStream) throws GrokParseException {
          try (AutoCloseableInputSource schema = fromResource(GROK_SCHEMA)) {
              final GrokHandler handler = new GrokHandler();
              final XMLReader xmlReader = XmlUtils.buildSecureValidatingXmlReader(schema);
              xmlReader.setErrorHandler(new GrokErrorHandler());
              xmlReader.setContentHandler(handler);
              try (Reader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8)) {
                  final InputSource in = new InputSource(reader);
                  xmlReader.parse(in);
                  return handler.getAssemblyData();
              }
          } catch (ParserConfigurationException | IOException ex) {
              LOGGER.debug("", ex);
              throw new GrokParseException(ex);
          } catch (SAXException ex) {
              if (ex.getMessage().contains("Cannot find the declaration of element 'assembly'.")) {
                  throw new GrokParseException("Malformed grok xml?", ex);
             } else {
                 LOGGER.debug("", ex);
                 throw new GrokParseException(ex);
             }
         }
     }
 }