package com.yahoo.labs.samoa.topology.impl;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * Licensed 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.
 * #L%
 */

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import org.apache.s4.base.KeyFinder;
import org.apache.s4.core.App;
import org.apache.s4.core.ProcessingElement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.yahoo.labs.samoa.core.Processor;
import com.yahoo.labs.samoa.topology.ProcessingItem;
import com.yahoo.labs.samoa.topology.Stream;

/**
 * S4 Platform platform specific processing item, inherits from S4 ProcessinElemnt.
 * 
 * @author severien
 * 
 */
public class S4ProcessingItem extends ProcessingElement implements
    ProcessingItem {

  public static final Logger logger = LoggerFactory
      .getLogger(S4ProcessingItem.class);

  private Processor processor;
  private int paralellismLevel;
  private S4DoTask app;

  private static final String NAME = "PROCESSING-ITEM-";
  private static int OBJ_COUNTER = 0;

  /**
   * Constructor of S4 ProcessingItem.
   * 
   * @param app
   *          : S4 application
   */
  public S4ProcessingItem(App app) {
    super(app);
    super.setName(NAME + OBJ_COUNTER);
    OBJ_COUNTER++;
    this.app = (S4DoTask) app;
    this.paralellismLevel = 1;
  }

  @Override
  public String getName() {
    return super.getName();
  }

  /**
   * Gets processing item paralellism level.
   * 
   * @return int
   */
  public int getParalellismLevel() {
    return paralellismLevel;
  }

  /**
   * Sets processing item paralellism level.
   * 
   * @param paralellismLevel
   */
  public void setParalellismLevel(int paralellismLevel) {
    this.paralellismLevel = paralellismLevel;
  }

  /**
   * onEvent method.
   * 
   * @param event
   */
  public void onEvent(S4Event event) {
    if (processor.process(event.getContentEvent()) == true) {
      close();
    }
  }

  /**
   * Sets S4 processing item processor.
   * 
   * @param processor
   */
  public void setProcessor(Processor processor) {
    this.processor = processor;
  }

  // Methods from ProcessingItem
  @Override
  public Processor getProcessor() {
    return processor;
  }

  /**
   * KeyFinder sets the keys for a specific event.
   * 
   * @return KeyFinder
   */
  private KeyFinder<S4Event> getKeyFinder() {
    KeyFinder<S4Event> keyFinder = new KeyFinder<S4Event>() {
      @Override
      public List<String> get(S4Event s4event) {
        List<String> results = new ArrayList<String>();
        results.add(s4event.getKey());
        return results;
      }
    };

    return keyFinder;
  }

  @Override
  public ProcessingItem connectInputAllStream(Stream inputStream) {

    S4Stream stream = (S4Stream) inputStream;
    stream.setParallelism(this.paralellismLevel);
    stream.addStream(inputStream.getStreamId(),
        getKeyFinder(), this, S4Stream.BROADCAST);
    return this;
  }

  @Override
  public ProcessingItem connectInputKeyStream(Stream inputStream) {

    S4Stream stream = (S4Stream) inputStream;
    stream.setParallelism(this.paralellismLevel);
    stream.addStream(inputStream.getStreamId(),
        getKeyFinder(), this, S4Stream.GROUP_BY_KEY);

    return this;
  }

  @Override
  public ProcessingItem connectInputShuffleStream(Stream inputStream) {
    S4Stream stream = (S4Stream) inputStream;
    stream.setParallelism(this.paralellismLevel);
    stream.addStream(inputStream.getStreamId(),
        getKeyFinder(), this, S4Stream.SHUFFLE);

    return this;
  }

  // Methods from ProcessingElement
  @Override
  protected void onCreate() {
    logger.debug("PE ID {}", getId());
    if (this.processor != null) {
      this.processor = this.processor.newProcessor(this.processor);
      this.processor.onCreate(Integer.parseInt(getId()));
    }
  }

  @Override
  protected void onRemove() {
    // do nothing
  }

  @Override
  public int getParallelism() {
    return this.paralellismLevel;
  }
}