/*
 * 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.fs.s3hadoop;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.CoreOptions;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.core.fs.Path;
import org.apache.flink.core.fs.RecoverableFsDataOutputStream;
import org.apache.flink.core.fs.RecoverableWriter;
import org.apache.flink.fs.s3.common.FlinkS3FileSystem;
import org.apache.flink.testutils.s3.S3TestCredentials;
import org.apache.flink.util.StringUtils;
import org.apache.flink.util.TestLogger;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Random;
import java.util.UUID;

import static org.apache.flink.fs.s3.common.AbstractS3FileSystemFactory.MAX_CONCURRENT_UPLOADS;
import static org.apache.flink.fs.s3.common.AbstractS3FileSystemFactory.PART_UPLOAD_MIN_SIZE;

/**
 * Tests for exception throwing in the
 * {@link org.apache.flink.fs.s3.common.writer.S3RecoverableWriter S3RecoverableWriter}.
 */
public class HadoopS3RecoverableWriterExceptionITCase extends TestLogger {

	// ----------------------- S3 general configuration -----------------------

	private static final long PART_UPLOAD_MIN_SIZE_VALUE = 7L << 20;
	private static final int MAX_CONCURRENT_UPLOADS_VALUE = 2;

	// ----------------------- Test Specific configuration -----------------------

	private static final Random RND = new Random();

	private static Path basePath;

	private static FlinkS3FileSystem fileSystem;

	// this is set for every test @Before
	private Path basePathForTest;

	// ----------------------- Test Data to be used -----------------------

	private static final String testData1 = "THIS IS A TEST 1.";
	private static final String testData2 = "THIS IS A TEST 2.";
	private static final String testData3 = "THIS IS A TEST 3.";

	private static boolean skipped = true;

	@ClassRule
	public static final TemporaryFolder TEMP_FOLDER = new TemporaryFolder();

	@BeforeClass
	public static void checkCredentialsAndSetup() throws IOException {
		// check whether credentials exist
		S3TestCredentials.assumeCredentialsAvailable();

		basePath = new Path(S3TestCredentials.getTestBucketUri() + "tests-" + UUID.randomUUID());

		// initialize configuration with valid credentials
		final Configuration conf = new Configuration();
		conf.setString("s3.access.key", S3TestCredentials.getS3AccessKey());
		conf.setString("s3.secret.key", S3TestCredentials.getS3SecretKey());

		conf.setLong(PART_UPLOAD_MIN_SIZE, PART_UPLOAD_MIN_SIZE_VALUE);
		conf.setInteger(MAX_CONCURRENT_UPLOADS, MAX_CONCURRENT_UPLOADS_VALUE);

		final String defaultTmpDir = TEMP_FOLDER.getRoot().getAbsolutePath() + "s3_tmp_dir";
		conf.setString(CoreOptions.TMP_DIRS, defaultTmpDir);

		FileSystem.initialize(conf);

		skipped = false;
	}

	@AfterClass
	public static void cleanUp() throws Exception {
		if (!skipped) {
			getFileSystem().delete(basePath, true);
		}
		FileSystem.initialize(new Configuration());
	}

	@Before
	public void prepare() throws Exception {
		basePathForTest = new Path(
				basePath,
				StringUtils.getRandomString(RND, 16, 16, 'a', 'z'));

		final String defaultTmpDir = getFileSystem().getLocalTmpDir();
		final java.nio.file.Path path = Paths.get(defaultTmpDir);

		if (!Files.exists(path)) {
			Files.createDirectory(path);
		}
	}

	@After
	public void cleanup() throws Exception {
		getFileSystem().delete(basePathForTest, true);
	}

	private static FlinkS3FileSystem getFileSystem() throws Exception {
		if (fileSystem == null) {
			fileSystem = (FlinkS3FileSystem) FileSystem.get(basePath.toUri());
		}
		return fileSystem;
	}

	@Test(expected = IOException.class)
	public void testExceptionWritingAfterCloseForCommit() throws Exception {
		final Path path = new Path(basePathForTest, "part-0");

		final RecoverableFsDataOutputStream stream = getFileSystem().createRecoverableWriter().open(path);
		stream.write(testData1.getBytes(StandardCharsets.UTF_8));

		stream.closeForCommit().getRecoverable();
		stream.write(testData2.getBytes(StandardCharsets.UTF_8));
	}

	// IMPORTANT FOR THE FOLLOWING TWO TESTS:

	// These tests illustrate a difference in the user-perceived behavior of the different writers.
	// In HDFS this will fail when trying to recover the stream while here is will fail at "commit", i.e.
	// when we try to "publish" the multipart upload and we realize that the MPU is no longer active.

	@Test(expected = IOException.class)
	public void testResumeAfterCommit() throws Exception {
		final RecoverableWriter writer = getFileSystem().createRecoverableWriter();
		final Path path = new Path(basePathForTest, "part-0");

		final RecoverableFsDataOutputStream stream = writer.open(path);
		stream.write(testData1.getBytes(StandardCharsets.UTF_8));

		final RecoverableWriter.ResumeRecoverable recoverable = stream.persist();
		stream.write(testData2.getBytes(StandardCharsets.UTF_8));

		stream.closeForCommit().commit();

		final RecoverableFsDataOutputStream recoveredStream = writer.recover(recoverable);
		recoveredStream.closeForCommit().commit();
	}

	@Test(expected = IOException.class)
	public void testResumeWithWrongOffset() throws Exception {
		// this is a rather unrealistic scenario, but it is to trigger
		// truncation of the file and try to resume with missing data.

		final RecoverableWriter writer = getFileSystem().createRecoverableWriter();
		final Path path = new Path(basePathForTest, "part-0");

		final RecoverableFsDataOutputStream stream = writer.open(path);
		stream.write(testData1.getBytes(StandardCharsets.UTF_8));

		final RecoverableWriter.ResumeRecoverable recoverable1 = stream.persist();
		stream.write(testData2.getBytes(StandardCharsets.UTF_8));

		final RecoverableWriter.ResumeRecoverable recoverable2 = stream.persist();
		stream.write(testData3.getBytes(StandardCharsets.UTF_8));

		final RecoverableFsDataOutputStream recoveredStream = writer.recover(recoverable1);
		recoveredStream.closeForCommit().commit();

		// this should throw an exception
		final RecoverableFsDataOutputStream newRecoveredStream = writer.recover(recoverable2);
		newRecoveredStream.closeForCommit().commit();
	}
}