/*
    * 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.io.gora;
  
  import java.io.IOException;
  
  import org.apache.giraph.edge.Edge;
  import org.apache.giraph.edge.EdgeFactory;
  import org.apache.giraph.io.gora.generated.GEdge;
  import org.apache.hadoop.io.FloatWritable;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.mapreduce.InputSplit;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  
  /**
   * Implementation of a specific reader for a generated data bean.
   */
  public class GoraTestEdgeInputFormat
    extends GoraEdgeInputFormat<LongWritable, FloatWritable> {
  
    /**
     * Default constructor
     */
    public GoraTestEdgeInputFormat() {
    }
  
    /**
     * Creates specific vertex reader to be used inside Hadoop.
     * @param split split to be read.
     * @param context JobContext to be used.
     * @return GoraEdgeReader Edge reader to be used by Hadoop.
     */
    @Override
    public GoraEdgeReader createEdgeReader(
        InputSplit split, TaskAttemptContext context) throws IOException {
      putArtificialData();
      return new GoraGEdgeEdgeReader();
    }
  
    /**
     * Writes data into the data store in order to test it out.
     */
    @SuppressWarnings("unchecked")
    private static void putArtificialData() {
      getDataStore().put("11-22",
          createEdge("11-22", "11", "22", "11-22", (float)(11+22)));
      getDataStore().put("22-11",
          createEdge("22-11", "22", "11", "22-11", (float)(22+11)));
      getDataStore().put("11-33",
          createEdge("11-33", "11", "33", "11-33", (float)(11+33)));
      getDataStore().put("33-11",
          createEdge("33-11", "33", "11", "33-11", (float)(33+11)));
      getDataStore().flush();
    }
  
    /**
     * Creates an edge using an id and a set of edges.
     * @param id Vertex id.
     * @param vertexInId Vertex source Id.
     * @param vertexOutId Vertex destination Id.
     * @param edgeLabel Edge label.
     * @param edgeWeight Edge wight.
     * @return GEdge created.
     */
    private static GEdge createEdge(String id, String vertexInId,
        String vertexOutId, String edgeLabel, float edgeWeight) {
      GEdge newEdge = new GEdge();
      newEdge.setEdgeId(id);
      newEdge.setVertexInId(vertexInId);
      newEdge.setVertexOutId(vertexOutId);
      newEdge.setLabel(edgeLabel);
      newEdge.setEdgeWeight(edgeWeight);
      return newEdge;
    }
  
    /**
     * Gora edge reader
     */
    protected class GoraGEdgeEdgeReader extends GoraEdgeReader {
  
      /** source vertex of the edge */
      private LongWritable sourceId;
  
      /**
      * Transforms a GoraObject into an Edge object.
      * @param goraObject Object from Gora to be translated.
      * @return Edge Result from transforming the gora object.
      */
     @Override
     protected Edge<LongWritable, FloatWritable> transformEdge
     (Object goraObject) {
       Edge<LongWritable, FloatWritable> edge = null;
       GEdge goraEdge = (GEdge) goraObject;
       Long dest;
       Float value;
       dest = Long.valueOf(goraEdge.getVertexOutId().toString());
       this.sourceId = new LongWritable();
       this.sourceId.set(Long.valueOf(goraEdge.getVertexInId().toString()));
       value = (float) goraEdge.getEdgeWeight();
       edge = EdgeFactory.create(new LongWritable(dest),
           new FloatWritable(value));
       return edge;
     }
 
     /**
      * Gets the currentSourceId for the edge.
      * @return LongWritable currentSourceId for the edge.
      */
     @Override
     public LongWritable getCurrentSourceId() throws IOException,
         InterruptedException {
       return this.sourceId;
     }
   }
 }