/*
    * 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.edge;
  
  import com.google.common.collect.Lists;
  import org.apache.giraph.utils.ExtendedDataOutput;
  import org.apache.giraph.utils.UnsafeByteArrayInputStream;
  import org.apache.giraph.utils.UnsafeByteArrayOutputStream;
  import org.apache.hadoop.io.ByteWritable;
  import org.apache.hadoop.io.LongWritable;
  import org.junit.Assert;
  import org.junit.Test;
  
  import java.io.DataInput;
  import java.io.IOException;
  import java.util.Iterator;
  import java.util.List;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNotNull;
  
  
  public class LongByteHashMapEdgesTest {
    private static Edge<LongWritable, ByteWritable> createEdge(long id, byte value) {
      return EdgeFactory.create(new LongWritable(id), new ByteWritable(value));
    }
  
    private static void assertEdges(LongByteHashMapEdges edges, long[] expectedIds,
                                    byte[] expectedValues) {
      Assert.assertEquals(expectedIds.length, edges.size());
      for (int i = 0; i< expectedIds.length; i++) {
         ByteWritable value = edges.getEdgeValue(new LongWritable(expectedIds[i]));
         assertNotNull(value);
        assertEquals(expectedValues[i], value.get());
      }
    }
  
    @Test
    public void testEdges() {
      LongByteHashMapEdges edges = new LongByteHashMapEdges();
  
      List<Edge<LongWritable, ByteWritable>> initialEdges = Lists.newArrayList(
        createEdge(1, (byte) 99), createEdge(2, (byte) 77), createEdge(4, (byte) 66));
  
      edges.initialize(initialEdges);
      assertEdges(edges, new long[]{1, 2, 4}, new byte[]{99, 77, 66});
  
      edges.add(EdgeFactory.createReusable(new LongWritable(3), new ByteWritable((byte) 55)));
      assertEdges(edges, new long[]{1, 2, 3, 4}, new byte[]{99, 77, 55, 66});
  
      edges.remove(new LongWritable(2));
      assertEdges(edges, new long[]{1, 3, 4}, new byte[]{99, 55, 66});
    }
  
    @Test
    public void testMutateEdges() {
      LongByteHashMapEdges edges = new LongByteHashMapEdges();
  
      edges.initialize();
  
      // Add 10 edges with id and value set to i, for i = 0..9
      for (int i = 0; i < 10; ++i) {
        edges.add(createEdge(i, (byte) i));
      }
  
      // Use the mutable iterator to remove edges with even id
      Iterator<MutableEdge<LongWritable, ByteWritable>> edgeIt =
          edges.mutableIterator();
      while (edgeIt.hasNext()) {
        if (edgeIt.next().getTargetVertexId().get() % 2 == 0) {
          edgeIt.remove();
        }
      }
  
      // We should now have 5 edges
      assertEquals(5, edges.size());
      // The edge ids should be all odd
      for (Edge<LongWritable, ByteWritable> edge : edges) {
        assertEquals(1, edge.getTargetVertexId().get() % 2);
        assertEquals(1, edge.getValue().get() % 2);
      }
    }
  
    @Test
   public void testSerialization() throws IOException {
     LongByteHashMapEdges edges = new LongByteHashMapEdges();
 
     edges.initialize();
 
     // Add 10 edges with id and value set to i, for i = 0..9
     for (int i = 0; i < 10; ++i) {
       edges.add(createEdge(i, (byte) i));
     }
 
     edges.trim();
 
     // Use the mutable iterator to remove edges with even id
     Iterator<MutableEdge<LongWritable, ByteWritable>> edgeIt =
         edges.mutableIterator();
     while (edgeIt.hasNext()) {
       if (edgeIt.next().getTargetVertexId().get() % 2 == 0) {
         edgeIt.remove();
       }
     }
 
     // We should now have 5 edges
     assertEdges(edges, new long[]{1, 3, 5, 7, 9}, new byte[]{1, 3, 5, 7, 9});
 
     ExtendedDataOutput tempBuffer = new UnsafeByteArrayOutputStream();
 
     edges.write(tempBuffer);
 
     DataInput input = new UnsafeByteArrayInputStream(
       tempBuffer.getByteArray(), 0, tempBuffer.getPos());
 
     edges = new LongByteHashMapEdges();
     edges.readFields(input);
 
     assertEquals(5, edges.size());
 
     for (Edge<LongWritable, ByteWritable> edge : edges) {
       assertEquals(1, edge.getTargetVertexId().get() % 2);
       assertEquals(1, edge.getValue().get() % 2);
     }
   }
 
   /**
    * This implementation does not allow parallel edges.
    */
   @Test
   public void testParallelEdges() {
     LongByteHashMapEdges edges = new LongByteHashMapEdges();
 
     List<Edge<LongWritable, ByteWritable>> initialEdges = Lists.newArrayList(
       createEdge(2, (byte) 1), createEdge(2, (byte) 2), createEdge(2, (byte) 3));
 
     edges.initialize(initialEdges);
     assertEquals(1, edges.size());
 
     edges.remove(new LongWritable(2));
     assertEquals(0, edges.size());
 
     edges.add(EdgeFactory.create(new LongWritable(2), new ByteWritable((byte) 4)));
     assertEquals(1, edges.size());
 
     edges.trim();
     assertEquals(1, edges.size());
   }
 }