/*
    * 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) 2013 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.data.update.nvd.api;
  
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonToken;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
  import io.github.jeremylong.openvulnerability.client.nvd.DefCveItem;
  import org.apache.commons.io.IOUtils;
  
  import java.io.IOException;
  import java.io.InputStream;
  
  public class CveApiJson20CveItemSource implements CveItemSource<DefCveItem> {
  
      /**
       * The object mapper.
       */
      private final ObjectMapper mapper;
      /**
       * The input stream.
       */
      private final InputStream inputStream;
      /**
       * The JSON Parser
       */
      private final JsonParser jsonParser;
      /**
       * The current item.
       */
      private DefCveItem currentItem;
      /**
       * The next item.
       */
      private DefCveItem nextItem;
  
      /**
       * Constructs a CVE Item Source record.
       *
       * @param inputStream the input source to read from
       * @throws IOException thrown if there is an issue reading from the input
       * stream
       */
      public CveApiJson20CveItemSource(InputStream inputStream) throws IOException {
          mapper = new ObjectMapper();
          mapper.registerModule(new JavaTimeModule());
          this.inputStream = inputStream;
          jsonParser = mapper.getFactory().createParser(inputStream);
  
          JsonToken token = null;
          do {
              token = jsonParser.nextToken();
              if (token == JsonToken.FIELD_NAME) {
                  final String fieldName = jsonParser.currentName();
                  if ("vulnerabilities".equals(fieldName) && (jsonParser.nextToken() == JsonToken.START_ARRAY)) {
                      nextItem = readItem(jsonParser);
                  }
              }
          } while (token != null && nextItem == null);
      }
  
      @Override
      public void close() throws Exception {
          IOUtils.closeQuietly(jsonParser, inputStream);
      }
  
      @Override
      public boolean hasNext() {
          return nextItem != null;
      }
  
      @Override
      public DefCveItem next() throws IOException {
          currentItem = nextItem;
          nextItem = readItem(jsonParser);
          return currentItem;
      }
  
      private DefCveItem readItem(JsonParser jsonParser) throws IOException {
          if (jsonParser.nextToken() == JsonToken.START_OBJECT) {
              return mapper.readValue(jsonParser, DefCveItem.class);
          }
          return null;
     }
 }