/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * 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 io.datakernel.aggregation;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableMap;
import io.datakernel.aggregation.fieldtype.FieldTypes;
import io.datakernel.aggregation.util.Predicates;
import io.datakernel.async.CompletionCallback;
import io.datakernel.async.ResultCallback;
import io.datakernel.codegen.DefiningClassLoader;
import io.datakernel.eventloop.Eventloop;
import io.datakernel.stream.*;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static io.datakernel.aggregation.fieldtype.FieldTypes.ofInt;
import static io.datakernel.aggregation.measure.Measures.union;
import static io.datakernel.eventloop.FatalErrorHandlers.rethrowOnAnyError;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

@SuppressWarnings({"Duplicates", "unchecked", "ArraysAsListWithZeroOrOneArgument"})
public class AggregationGroupReducerTest {

	@Rule
	public TemporaryFolder temporaryFolder = new TemporaryFolder();

	public static AggregationOperationTracker NO_OP_TRACKER = new AggregationOperationTracker() {
		@Override
		public void reportStart(AggregationChunker chunker) {
		}

		@Override
		public void reportCompletion(AggregationChunker chunker) {
		}

		@Override
		public void reportStart(AggregationGroupReducer groupReducer) {
		}

		@Override
		public void reportCompletion(AggregationGroupReducer groupReducer) {
		}
	};

	@Test
	public void test() throws IOException {
		final Eventloop eventloop = Eventloop.create().withFatalErrorHandler(rethrowOnAnyError());
		DefiningClassLoader classLoader = DefiningClassLoader.create();
		AggregationMetadataStorage aggregationMetadataStorage = new AggregationMetadataStorageStub(eventloop);
		Aggregation aggregation = Aggregation.createUninitialized()
				.withKey("word", FieldTypes.ofString())
				.withMeasure("documents", union(ofInt()));

		final List<StreamConsumer> listConsumers = new ArrayList<>();
		final List items = new ArrayList();
		AggregationChunkStorage aggregationChunkStorage = new AggregationChunkStorage() {

			@Override
			public <T> StreamProducer<T> chunkReader(Aggregation aggregation, List<String> keys, List<String> fields, Class<T> recordClass, long id, DefiningClassLoader classLoader) {
				return new StreamProducers.OfIterator<>(eventloop, items.iterator());
			}

			@Override
			public <T> void chunkWriter(Aggregation aggregation, List<String> keys, List<String> fields, Class<T> recordClass, long id, StreamProducer<T> producer, DefiningClassLoader classLoader, CompletionCallback callback) {
				StreamConsumers.ToList consumer = StreamConsumers.toList(eventloop, items);
				consumer.setCompletionCallback(callback);
				listConsumers.add(consumer);
				producer.streamTo(consumer);
			}

			@Override
			public void removeChunk(long id, CompletionCallback callback) {

			}
		};

		Class<InvertedIndexRecord> inputClass = InvertedIndexRecord.class;
		Class<?> keyClass = AggregationUtils.createKeyClass(aggregation, asList("word"), classLoader);
		Class<?> aggregationClass = AggregationUtils.createRecordClass(aggregation, asList("word"), asList("documents"), classLoader);

		Function<InvertedIndexRecord, Comparable<?>> keyFunction = AggregationUtils.createKeyFunction(inputClass, keyClass,
				asList("word"), classLoader);

		Aggregate aggregate = AggregationUtils.createPreaggregator(aggregation, inputClass, aggregationClass,
				ImmutableMap.of("word", "word"), ImmutableMap.of("documents", "documentId"), classLoader);

		int aggregationChunkSize = 2;
		final List<List<AggregationChunk.NewChunk>> listCallback = new ArrayList<>();
		ResultCallback<List<AggregationChunk.NewChunk>> chunksCallback = new ResultCallback<List<AggregationChunk.NewChunk>>() {
			@Override
			public void onResult(List<AggregationChunk.NewChunk> result) {
				listCallback.add(result);
			}

			@Override
			public void onException(Exception exception) {
				fail(exception.getMessage());
			}
		};

		AggregationGroupReducer<InvertedIndexRecord> aggregationGroupReducer = new AggregationGroupReducer<>(eventloop, aggregationChunkStorage, NO_OP_TRACKER, aggregationMetadataStorage,
				aggregation, asList("word"), asList("documents"),
				aggregationClass, Predicates.<InvertedIndexRecord, InvertedIndexRecord>alwaysTrue(), keyFunction, aggregate, aggregationChunkSize, classLoader, chunksCallback);

		StreamProducer<InvertedIndexRecord> producer = StreamProducers.ofIterable(eventloop, asList(new InvertedIndexRecord("fox", 1),
				new InvertedIndexRecord("brown", 2), new InvertedIndexRecord("fox", 3),
				new InvertedIndexRecord("brown", 3), new InvertedIndexRecord("lazy", 4),
				new InvertedIndexRecord("dog", 1), new InvertedIndexRecord("quick", 1),
				new InvertedIndexRecord("fox", 4), new InvertedIndexRecord("brown", 10)));

		producer.streamTo(aggregationGroupReducer);

		eventloop.run();

		assertEquals(producer.getProducerStatus(), StreamStatus.END_OF_STREAM);
		assertEquals(aggregationGroupReducer.getConsumerStatus(), StreamStatus.END_OF_STREAM);
		assertEquals(listCallback.size(), 1);

		assertEquals((listCallback.get(0)).size(), 5);
		for (StreamConsumer consumer : listConsumers) {
			assertEquals(consumer.getConsumerStatus(), StreamStatus.END_OF_STREAM);
		}
	}

}