/*
 * Copyright 2018 the original author or authors.
 *
 * 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
 *
 *      https://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 kafka.streams.word.count;

import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.kstream.Serialized;
import org.apache.kafka.streams.kstream.TimeWindows;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.annotation.StreamListener;
import org.springframework.cloud.stream.binder.kafka.streams.annotations.KafkaStreamsProcessor;
import org.springframework.messaging.handler.annotation.SendTo;

import java.util.Arrays;
import java.util.Date;

@SpringBootApplication
public class KafkaStreamsWordCountApplication {

	public static void main(String[] args) {
		SpringApplication.run(KafkaStreamsWordCountApplication.class, args);
	}

	@EnableBinding(KafkaStreamsProcessor.class)
	public static class WordCountProcessorApplication {

		@StreamListener("input")
		@SendTo("output")
		public KStream<?, WordCount> process(KStream<Object, String> input) {

			return input
					.flatMapValues(value -> Arrays.asList(value.toLowerCase().split("\\W+")))
					.map((key, value) -> new KeyValue<>(value, value))
					.groupByKey(Serialized.with(Serdes.String(), Serdes.String()))
					.windowedBy(TimeWindows.of(30000))
					.count(Materialized.as("WordCounts-1"))
					.toStream()
					.map((key, value) -> new KeyValue<>(null, new WordCount(key.key(), value, new Date(key.window().start()), new Date(key.window().end()))));
		}
	}

	static class WordCount {

		private String word;

		private long count;

		private Date start;

		private Date end;

		WordCount(String word, long count, Date start, Date end) {
			this.word = word;
			this.count = count;
			this.start = start;
			this.end = end;
		}

		public String getWord() {
			return word;
		}

		public void setWord(String word) {
			this.word = word;
		}

		public long getCount() {
			return count;
		}

		public void setCount(long count) {
			this.count = count;
		}

		public Date getStart() {
			return start;
		}

		public void setStart(Date start) {
			this.start = start;
		}

		public Date getEnd() {
			return end;
		}

		public void setEnd(Date end) {
			this.end = end;
		}
	}
}
