//  Copyright 2017 Twitter. All rights reserved.
//
//  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.
package com.twitter.heron.api.bolt;

import java.io.Serializable;
import java.time.Duration;
import java.util.Map;
import java.util.logging.Logger;

import com.twitter.heron.api.topology.OutputFieldsDeclarer;
import com.twitter.heron.api.topology.TopologyContext;
import com.twitter.heron.api.windowing.TimestampExtractor;
import com.twitter.heron.api.windowing.TupleFieldTimestampExtractor;
import com.twitter.heron.api.windowing.WindowingConfigs;

public abstract class BaseWindowedBolt implements IWindowedBolt {
  private static final Logger LOG = Logger.getLogger(BaseWindowedBolt.class.getName());
  private static final long serialVersionUID = 5688213068448231559L;

  protected final transient WindowingConfigs windowConfiguration;
  protected TimestampExtractor timestampExtractor;

  /**
   * Holds a count value for count based windows and sliding intervals.
   */
  public static class Count implements Serializable {
    private static final long serialVersionUID = -6420372171917099657L;
    public final int value;

    public Count(int value) {
      this.value = value;
    }

    /**
     * Returns a {@link Count} of given value.
     *
     * @param value the count value
     * @return the Count
     */
    public static Count of(int value) {
      return new Count(value);
    }

    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }

      Count count = (Count) o;

      return value == count.value;

    }

    @Override
    public int hashCode() {
      return value;
    }

    @Override
    public String toString() {
      return "Count{" + "value=" + value + '}';
    }
  }

  protected BaseWindowedBolt() {
    windowConfiguration = new WindowingConfigs();
  }

  private BaseWindowedBolt withWindowLength(Count count) {
    if (count.value <= 0) {
      throw new IllegalArgumentException("Window length must be positive [" + count + "]");
    }
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_WINDOW_LENGTH_COUNT, count.value);
    return this;
  }

  private BaseWindowedBolt withWindowLength(Duration duration) {
    if (duration.isNegative()) {
      throw new IllegalArgumentException("Window length must be positive [" + duration + "]");
    }

    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_WINDOW_LENGTH_DURATION_MS,
        duration.toMillis());
    return this;
  }

  private BaseWindowedBolt withSlidingInterval(Count count) {
    if (count.value <= 0) {
      throw new IllegalArgumentException("Sliding interval must be positive [" + count + "]");
    }
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_SLIDING_INTERVAL_COUNT, count.value);
    return this;
  }

  private BaseWindowedBolt withSlidingInterval(Duration duration) {
    if (duration.isNegative()) {
      throw new IllegalArgumentException("Sliding interval must be positive [" + duration + "]");
    }
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_SLIDING_INTERVAL_DURATION_MS,
        duration.toMillis());
    return this;
  }

  /**
   * Tuple count based sliding window configuration.
   *
   * @param windowLength the number of tuples in the window
   * @param slidingInterval the number of tuples after which the window slides
   */
  public BaseWindowedBolt withWindow(Count windowLength, Count slidingInterval) {
    return withWindowLength(windowLength).withSlidingInterval(slidingInterval);
  }

  /**
   * Tuple count and time duration based sliding window configuration.
   *
   * @param windowLength the number of tuples in the window
   * @param slidingInterval the time duration after which the window slides
   */
  public BaseWindowedBolt withWindow(Count windowLength, Duration slidingInterval) {
    return withWindowLength(windowLength).withSlidingInterval(slidingInterval);
  }

  /**
   * Time duration and count based sliding window configuration.
   *
   * @param windowLength the time duration of the window
   * @param slidingInterval the number of tuples after which the window slides
   */
  public BaseWindowedBolt withWindow(Duration windowLength, Count slidingInterval) {
    return withWindowLength(windowLength).withSlidingInterval(slidingInterval);
  }

  /**
   * Time duration based sliding window configuration.
   *
   * @param windowLength the time duration of the window
   * @param slidingInterval the time duration after which the window slides
   */
  public BaseWindowedBolt withWindow(Duration windowLength, Duration slidingInterval) {
    return withWindowLength(windowLength).withSlidingInterval(slidingInterval);
  }

  /**
   * A tuple count based window that slides with every incoming tuple.
   *
   * @param windowLength the number of tuples in the window
   */
  public BaseWindowedBolt withWindow(Count windowLength) {
    return withWindowLength(windowLength).withSlidingInterval(new Count(1));
  }

  /**
   * A time duration based window that slides with every incoming tuple.
   *
   * @param windowLength the time duration of the window
   */
  public BaseWindowedBolt withWindow(Duration windowLength) {
    return withWindowLength(windowLength).withSlidingInterval(new Count(1));
  }

  /**
   * A count based tumbling window.
   *
   * @param count the number of tuples after which the window tumbles
   */
  public BaseWindowedBolt withTumblingWindow(Count count) {
    return withWindowLength(count).withSlidingInterval(count);
  }

  /**
   * A time duration based tumbling window.
   *
   * @param duration the time duration after which the window tumbles
   */
  public BaseWindowedBolt withTumblingWindow(Duration duration) {
    return withWindowLength(duration).withSlidingInterval(duration);
  }

  /**
   * Specify a field in the tuple that represents the timestamp as a long value. If this
   * field is not present in the incoming tuple, an {@link IllegalArgumentException} will be thrown.
   *
   * @param fieldName the name of the field that contains the timestamp
   */
  public BaseWindowedBolt withTimestampField(String fieldName) {
    return withTimestampExtractor(TupleFieldTimestampExtractor.of(fieldName));
  }

  /**
   * Specify the timestamp extractor implementation.
   *
   * @param timestampExtractor the {@link TimestampExtractor} implementation
   */
  @SuppressWarnings("HiddenField")
  public BaseWindowedBolt withTimestampExtractor(TimestampExtractor timestampExtractor) {
    if (this.timestampExtractor != null) {
      throw new IllegalArgumentException(
          "Window is already configured with a timestamp " + "extractor: " + timestampExtractor);
    }
    this.timestampExtractor = timestampExtractor;
    return this;
  }

  @Override
  public TimestampExtractor getTimestampExtractor() {
    return timestampExtractor;
  }

  /**
   * Specify a stream id on which late tuples are going to be emitted. They are going to be
   * accessible via the
   * {@link WindowedBoltExecutor#LATE_TUPLE_FIELD} field.
   * It must be defined on a per-component basis, and in conjunction with the
   * {@link BaseWindowedBolt#withTimestampField}, otherwise {@link IllegalArgumentException} will
   * be thrown.
   *
   * @param streamId the name of the stream used to emit late tuples on
   */
  public BaseWindowedBolt withLateTupleStream(String streamId) {
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_LATE_TUPLE_STREAM, streamId);
    return this;
  }


  /**
   * Specify the maximum time lag of the tuple timestamp in milliseconds. It means that the tuple
   * timestamps
   * cannot be out of order by more than this amount.
   *
   * @param duration the max lag duration
   */
  public BaseWindowedBolt withLag(Duration duration) {
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_TUPLE_TIMESTAMP_MAX_LAG_MS,
        duration.toMillis());
    return this;
  }

  /**
   * Specify the watermark event generation interval. For tuple based timestamps, watermark events
   * are used to track the progress of time
   *
   * @param interval the interval at which watermark events are generated
   */
  public BaseWindowedBolt withWatermarkInterval(Duration interval) {
    windowConfiguration.put(WindowingConfigs.TOPOLOGY_BOLTS_WATERMARK_EVENT_INTERVAL_MS,
        interval.toMillis());
    return this;
  }

  @Override
  public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector
      collector) {
    // NOOP
  }

  @Override
  public void cleanup() {
    // NOOP
  }

  @Override
  public void declareOutputFields(OutputFieldsDeclarer declarer) {
    // NOOP
  }

  @Override
  public Map<String, Object> getComponentConfiguration() {
    return windowConfiguration;
  }
}