/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.flink.formats.sequencefile;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.typeinfo.TypeHint;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.Path;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.sink.filesystem.StreamingFileSink;
import org.apache.flink.streaming.util.FiniteTestSource;
import org.apache.flink.test.util.AbstractTestBase;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;
import org.junit.Test;

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

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;

/**
 * Integration test case for writing bulk encoded files with the
 * {@link StreamingFileSink} with SequenceFile.
 */
public class SequenceStreamingFileSinkITCase extends AbstractTestBase {

	private final Configuration configuration = new Configuration();

	private final List<Tuple2<Long, String>> testData = Arrays.asList(
			new Tuple2<>(1L, "a"),
			new Tuple2<>(2L, "b"),
			new Tuple2<>(3L, "c")
	);

	@Test
	public void testWriteSequenceFile() throws Exception {
		final File folder = TEMPORARY_FOLDER.newFolder();
		final Path testPath = Path.fromLocalFile(folder);

		final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		env.setParallelism(1);
		env.enableCheckpointing(100);

		DataStream<Tuple2<Long, String>> stream = env.addSource(
				new FiniteTestSource<>(testData),
				TypeInformation.of(new TypeHint<Tuple2<Long, String>>() {

				})
		);

		stream.map(new MapFunction<Tuple2<Long, String>, Tuple2<LongWritable, Text>>() {
			@Override
			public Tuple2<LongWritable, Text> map(Tuple2<Long, String> value) throws Exception {
				return new Tuple2<>(new LongWritable(value.f0), new Text(value.f1));
			}
		}).addSink(
			StreamingFileSink.forBulkFormat(
				testPath,
				new SequenceFileWriterFactory<>(configuration, LongWritable.class, Text.class, "BZip2")
			).build());

		env.execute();

		validateResults(folder, testData);
	}

	private List<Tuple2<Long, String>> readSequenceFile(File file) throws IOException {
		SequenceFile.Reader reader = new SequenceFile.Reader(
			configuration, SequenceFile.Reader.file(new org.apache.hadoop.fs.Path(file.toURI())));
		LongWritable key = new LongWritable();
		Text val = new Text();
		ArrayList<Tuple2<Long, String>> results = new ArrayList<>();
		while (reader.next(key, val)) {
			results.add(new Tuple2<>(key.get(), val.toString()));
		}
		reader.close();
		return results;
	}

	private void validateResults(File folder, List<Tuple2<Long, String>> expected) throws Exception {
		File[] buckets = folder.listFiles();
		assertNotNull(buckets);
		assertEquals(1, buckets.length);

		final File[] partFiles = buckets[0].listFiles();
		assertNotNull(partFiles);
		assertEquals(2, partFiles.length);

		for (File partFile : partFiles) {
			assertTrue(partFile.length() > 0);

			final List<Tuple2<Long, String>> fileContent = readSequenceFile(partFile);
			assertEquals(expected, fileContent);
		}
	}
}