/*
 * 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.samoa.apex.topology.impl;

import java.util.UUID;

import com.datatorrent.api.Context;
import com.datatorrent.api.DAG;
import com.datatorrent.common.partitioner.StatelessPartitioner;

import org.apache.samoa.core.ContentEvent;
import org.apache.samoa.core.Processor;
import org.apache.samoa.topology.AbstractProcessingItem;
import org.apache.samoa.topology.ProcessingItem;
import org.apache.samoa.topology.Stream;
import org.apache.samoa.utils.PartitioningScheme;

public class ApexProcessingItem extends AbstractProcessingItem implements ApexTopologyNode {

  private final ApexOperator operator;
  private DAG dag;
  private int numStreams;
  private int numPartitions = 1;

  // Constructor
  public ApexProcessingItem(Processor processor, int parallelismHint) {
    this(processor, UUID.randomUUID().toString(), parallelismHint);
  }

  public ApexProcessingItem() {
    operator = null;
  }

  // Constructor
  public ApexProcessingItem(Processor processor, String friendlyId, int parallelismHint) {
    super(processor, parallelismHint);
    this.operator = new ApexOperator(processor, parallelismHint);
    this.setName(friendlyId);
    this.numPartitions = parallelismHint;
  }

  @Override
  protected ProcessingItem addInputStream(Stream inputStream, PartitioningScheme scheme) {
    ApexStream apexStream = (ApexStream) inputStream;
    this.operator.addInputStream(apexStream);
    dag.addStream(apexStream.getStreamId(), apexStream.outputPort, apexStream.inputPort);

    // Setup stream codecs here
    switch (scheme) {
    case SHUFFLE:
      dag.setInputPortAttribute(apexStream.inputPort, Context.PortContext.STREAM_CODEC,
          new ApexStreamUtils.RandomStreamCodec<ContentEvent>());
      break;
    case BROADCAST:
      dag.setAttribute(this.operator, Context.OperatorContext.PARTITIONER,
          new ApexStreamUtils.AllPartitioner<ApexOperator>(numPartitions));
      dag.setInputPortAttribute(apexStream.inputPort, Context.PortContext.STREAM_CODEC,
          new ApexStreamUtils.JavaSerializationStreamCodec<ContentEvent>());
      break;
    case GROUP_BY_KEY:
      dag.setInputPortAttribute(apexStream.inputPort, Context.PortContext.STREAM_CODEC,
          new ApexStreamUtils.KeyBasedStreamCodec<ContentEvent>());
      break;
    default:
      // Should never occur
      throw new RuntimeException("Unknown partitioning scheme");
    }

    if (!dag.getAttributes().contains(Context.OperatorContext.PARTITIONER)) {
      dag.setAttribute(this.operator, Context.OperatorContext.PARTITIONER, new StatelessPartitioner<>(numPartitions));
    }
    return this;
  }

  @Override
  public void addToTopology(ApexTopology topology, int parallelismHint) {
    DAG dag = topology.getDAG();
    this.dag = dag;
    this.operator.instances = parallelismHint;
    String fqcn = this.getName();
    dag.addOperator(fqcn, this.operator);
  }

  @Override
  public ApexStream createStream() {
    return operator.createStream("Stream_from_" + this.getName() + "_#" + numStreams++);
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder(super.toString());
    sb.insert(0, String.format("id: %s, ", this.getName()));
    return sb.toString();
  }
}