/*
    * 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.giraph.block_app.framework.output;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.giraph.bsp.BspOutputFormat;
  import org.apache.giraph.conf.GiraphConfiguration;
  import org.apache.giraph.conf.GiraphConstants;
  import org.apache.giraph.conf.StrConfOption;
  import org.apache.giraph.utils.ConfigurationObjectUtils;
  import org.apache.giraph.utils.DefaultOutputCommitter;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.mapreduce.JobContext;
  import org.apache.hadoop.mapreduce.OutputCommitter;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  
  /**
   * Hadoop output format to use with block output.
   * It keeps track of all registered outputs, and knows how to create them.
   */
  public class BlockOutputFormat extends BspOutputFormat {
    private static final StrConfOption OUTPUT_CONF_OPTIONS = new StrConfOption(
        "giraph.outputConfOptions", "",
        "List of conf options for outputs used");
  
    public static <OD> void addOutputDesc(OD outputDesc, String confOption,
        GiraphConfiguration conf) {
      GiraphConstants.HADOOP_OUTPUT_FORMAT_CLASS.set(conf,
          BlockOutputFormat.class);
      String currentOutputs = OUTPUT_CONF_OPTIONS.get(conf);
      if (!currentOutputs.isEmpty()) {
        currentOutputs = currentOutputs + ",";
      }
      OUTPUT_CONF_OPTIONS.set(conf, currentOutputs + confOption);
      ConfigurationObjectUtils.setObjectKryo(outputDesc, confOption, conf);
    }
  
    /**
     * Returns an array of output configuration options set in the input
     * configuration.
     *
     * @param conf Configuration
     * @return Array of options
     */
    public static String[] getOutputConfOptions(Configuration conf) {
      String outputConfOptions = OUTPUT_CONF_OPTIONS.get(conf);
      return outputConfOptions.isEmpty() ?
          new String[0] : outputConfOptions.split(",");
    }
  
    public static <OW extends BlockOutputWriter, OD extends BlockOutputDesc<OW>>
    OD createInitAndCheckOutputDesc(String confOption, Configuration conf,
        String jobIdentifier) {
      OD outputDesc = ConfigurationObjectUtils.getObjectKryo(confOption, conf);
      outputDesc.initializeAndCheck(jobIdentifier, conf);
      return outputDesc;
    }
  
    public static Map<String, BlockOutputDesc>
    createInitAndCheckOutputDescsMap(Configuration conf, String jobIdentifier) {
      String[] outputConfOptions = getOutputConfOptions(conf);
      Map<String, BlockOutputDesc> ret = new HashMap<>(outputConfOptions.length);
      for (String outputConfOption : outputConfOptions) {
        ret.put(outputConfOption,
            createInitAndCheckOutputDesc(outputConfOption, conf, jobIdentifier));
      }
      return ret;
    }
  
    public static Map<String, BlockOutputDesc> createInitAndCheckOutputDescsMap(
        JobContext jobContext) {
      return createInitAndCheckOutputDescsMap(jobContext.getConfiguration(),
          jobContext.getJobID().toString());
    }
  
    @Override
    public void checkOutputSpecs(JobContext jobContext)
        throws IOException, InterruptedException {
      createInitAndCheckOutputDescsMap(jobContext);
    }
  
   @Override
   public OutputCommitter getOutputCommitter(
       TaskAttemptContext context) throws IOException, InterruptedException {
     return new DefaultOutputCommitter() {
       @Override
       public void commit(JobContext jobContext) throws IOException {
         Map<String, BlockOutputDesc> map =
             createInitAndCheckOutputDescsMap(jobContext);
         for (BlockOutputDesc outputDesc : map.values()) {
           outputDesc.commit();
         }
       }
     };
   }
 }