// Copyright 2016 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.examples;

import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import org.apache.storm.Config;
import org.apache.storm.StormSubmitter;
import org.apache.storm.spout.SpoutOutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.BasicOutputCollector;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.TopologyBuilder;
import org.apache.storm.topology.base.BaseBasicBolt;
import org.apache.storm.topology.base.BaseRichSpout;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;

import com.twitter.heron.common.basics.ByteAmount;

public final class SentenceWordCountTopology {
  private SentenceWordCountTopology() {

  }

  // Utils class to generate random String at given length
  public static class RandomString {
    private final char[] symbols;

    private final Random random = new Random();

    private final char[] buf;

    public RandomString(int length) {
      // Construct the symbol set
      StringBuilder tmp = new StringBuilder();
      for (char ch = '0'; ch <= '9'; ++ch) {
        tmp.append(ch);
      }

      for (char ch = 'a'; ch <= 'z'; ++ch) {
        tmp.append(ch);
      }

      symbols = tmp.toString().toCharArray();
      if (length < 1) {
        throw new IllegalArgumentException("length < 1: " + length);
      }

      buf = new char[length];
    }

    public String nextString() {
      for (int idx = 0; idx < buf.length; ++idx) {
        buf[idx] = symbols[random.nextInt(symbols.length)];
      }

      return new String(buf);
    }
  }

  /**
   * A spout that emits a random word
   */
  public static class FastRandomSentenceSpout extends BaseRichSpout {
    private static final long serialVersionUID = 8068075156393183973L;

    private static final int ARRAY_LENGTH = 128 * 1024;
    private static final int WORD_LENGTH = 20;
    private static final int SENTENCE_LENGTH = 10;

    // Every sentence would be words generated randomly, split by space
    private final String[] sentences = new String[ARRAY_LENGTH];

    private final Random rnd = new Random(31);

    private SpoutOutputCollector collector;

    @Override
    public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
      outputFieldsDeclarer.declare(new Fields("sentence"));
    }

    @Override
    @SuppressWarnings("rawtypes")
    public void open(Map map, TopologyContext topologyContext,
                     SpoutOutputCollector spoutOutputCollector) {
      RandomString randomString = new RandomString(WORD_LENGTH);
      for (int i = 0; i < ARRAY_LENGTH; i++) {
        StringBuilder sb = new StringBuilder(randomString.nextString());
        for (int j = 1; j < SENTENCE_LENGTH; j++) {
          sb.append(" ");
          sb.append(randomString.nextString());
        }
        sentences[i] = sb.toString();
      }

      collector = spoutOutputCollector;
    }

    @Override
    public void nextTuple() {
      int nextInt = rnd.nextInt(ARRAY_LENGTH);
      collector.emit(new Values(sentences[nextInt]));
    }
  }

  public static class SplitSentence extends BaseBasicBolt {
    private static final long serialVersionUID = 1249629174039601217L;

    @Override
    public void execute(Tuple tuple, BasicOutputCollector collector) {
      String sentence = tuple.getString(0);
      for (String word : sentence.split("\\s+")) {
        collector.emit(new Values(word, 1));
      }
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
      declarer.declare(new Fields("word", "count"));
    }
  }

  public static class WordCount extends BaseBasicBolt {
    private static final long serialVersionUID = -8492566595062774310L;

    private Map<String, Integer> counts = new HashMap<String, Integer>();

    @Override
    public void execute(Tuple tuple, BasicOutputCollector collector) {
      String word = tuple.getString(0);
      Integer count = counts.get(word);
      if (count == null) {
        count = 0;
      }
      count++;
      counts.put(word, count);
      collector.emit(new Values(word, count));
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
      declarer.declare(new Fields("word", "count"));
    }
  }

  public static void main(String[] args) throws Exception {
    String name = "fast-word-count-topology";
    if (args != null && args.length > 0) {
      name = args[0];
    }

    TopologyBuilder builder = new TopologyBuilder();

    builder.setSpout("spout", new FastRandomSentenceSpout(), 1);
    builder.setBolt("split", new SplitSentence(), 2).shuffleGrouping("spout");
    builder.setBolt("count", new WordCount(), 2).fieldsGrouping("split", new Fields("word"));

    Config conf = new Config();
    com.twitter.heron.api.Config.setComponentRam(conf, "split", ByteAmount.fromGigabytes(2));
    com.twitter.heron.api.Config.setComponentRam(conf, "count", ByteAmount.fromGigabytes(3));
    conf.setNumWorkers(1);
    com.twitter.heron.api.Config.setContainerDiskRequested(conf, ByteAmount.fromGigabytes(5));
    com.twitter.heron.api.Config.setContainerCpuRequested(conf, 8);

    StormSubmitter.submitTopology(name, conf, builder.createTopology());
  }
}