/*
    * 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.logging.log4j.core.net.server;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.charset.Charset;
  
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.LogEventListener;
  import org.apache.logging.log4j.core.impl.Log4jLogEvent;
  import org.apache.logging.log4j.util.Strings;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.ObjectReader;
  
  /**
   * Reads and logs {@link LogEvent}s from an {@link InputStream}.
   */
  public abstract class InputStreamLogEventBridge extends AbstractLogEventBridge<InputStream> {
  
      private final int bufferSize;
  
      private final Charset charset;
  
      private final String eventEndMarker;
      
      private final ObjectReader objectReader;
      
      public InputStreamLogEventBridge(final ObjectMapper mapper, final int bufferSize, final Charset charset, final String eventEndMarker) {
          this.bufferSize = bufferSize;
          this.charset = charset;
          this.eventEndMarker = eventEndMarker;
          this.objectReader = mapper.reader(Log4jLogEvent.class);
      }
  
      abstract protected int[] getEventIndices(final String text, int beginIndex);
  
      @Override
      public void logEvents(final InputStream inputStream, final LogEventListener logEventListener) throws IOException {
          String workingText = Strings.EMPTY;
          try {
              // Allocate buffer once
              final byte[] buffer = new byte[bufferSize];
              String textRemains = workingText = Strings.EMPTY;
              while (true) {
                  // Process until the stream is EOF.
                  final int streamReadLength = inputStream.read(buffer);
                  if (streamReadLength == END) {
                      // The input stream is EOF
                      break;
                  }
                  final String text = workingText = textRemains + new String(buffer, 0, streamReadLength, charset);
                  int beginIndex = 0;
                  while (true) {
                      // Extract and log all XML events in the buffer
                      final int[] pair = getEventIndices(text, beginIndex);
                      final int eventStartMarkerIndex = pair[0];
                      if (eventStartMarkerIndex < 0) {
                          // No more events or partial XML only in the buffer.
                          // Save the unprocessed string part
                          textRemains = text.substring(beginIndex);
                          break;
                      }
                      final int eventEndMarkerIndex = pair[1];
                      if (eventEndMarkerIndex > 0) {
                          final int eventEndXmlIndex = eventEndMarkerIndex + eventEndMarker.length();
                          final String textEvent = workingText = text.substring(eventStartMarkerIndex, eventEndXmlIndex);
                          final LogEvent logEvent = unmarshal(textEvent);
                          logEventListener.log(logEvent);
                          beginIndex = eventEndXmlIndex;
                      } else {
                          // No more events or partial XML only in the buffer.
                          // Save the unprocessed string part
                          textRemains = text.substring(beginIndex);
                          break;
                      }
                  }
              }
          } catch (final IOException ex) {
              logger.error(workingText, ex);
          }
      }
  
      protected Log4jLogEvent unmarshal(final String jsonEvent) throws IOException {
         return this.objectReader.readValue(jsonEvent);
     }
 
 }