/*
 * 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.hdfstests;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.io.FileOutputFormat;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.ExecutionEnvironmentFactory;
import org.apache.flink.api.java.LocalEnvironment;
import org.apache.flink.api.java.io.TextOutputFormat;
import org.apache.flink.configuration.BlobServerOptions;
import org.apache.flink.configuration.ConfigConstants;
import org.apache.flink.configuration.HighAvailabilityOptions;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.core.fs.Path;
import org.apache.flink.examples.java.wordcount.WordCount;
import org.apache.flink.runtime.blob.BlobCacheCorruptionTest;
import org.apache.flink.runtime.blob.BlobCacheRecoveryTest;
import org.apache.flink.runtime.blob.BlobServerCorruptionTest;
import org.apache.flink.runtime.blob.BlobServerRecoveryTest;
import org.apache.flink.runtime.blob.BlobStoreService;
import org.apache.flink.runtime.blob.BlobUtils;
import org.apache.flink.runtime.fs.hdfs.HadoopFileSystem;
import org.apache.flink.runtime.jobmanager.HighAvailabilityMode;
import org.apache.flink.util.FileUtils;
import org.apache.flink.util.OperatingSystem;

import org.apache.commons.io.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.junit.After;
import org.junit.Assert;
import org.junit.Assume;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.junit.rules.TemporaryFolder;

import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.util.Arrays;
import java.util.UUID;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

/**
 * This test should logically be located in the 'flink-runtime' tests. However, this project
 * has already all dependencies required (flink-java-examples). Also, the ParallelismOneExecEnv is here.
 */
public class HDFSTest {

	protected String hdfsURI;
	private MiniDFSCluster hdfsCluster;
	private org.apache.hadoop.fs.Path hdPath;
	protected org.apache.hadoop.fs.FileSystem hdfs;

	@Rule
	public TemporaryFolder temporaryFolder = new TemporaryFolder();

	@Rule
	public final ExpectedException exception = ExpectedException.none();

	@BeforeClass
	public static void verifyOS() {
		Assume.assumeTrue("HDFS cluster cannot be started on Windows without extensions.", !OperatingSystem.isWindows());
	}

	@Before
	public void createHDFS() {
		try {
			Configuration hdConf = new Configuration();

			File baseDir = temporaryFolder.newFolder();
			FileUtil.fullyDelete(baseDir);
			hdConf.set(MiniDFSCluster.HDFS_MINIDFS_BASEDIR, baseDir.getAbsolutePath());
			MiniDFSCluster.Builder builder = new MiniDFSCluster.Builder(hdConf);
			hdfsCluster = builder.build();

			hdfsURI = "hdfs://" + hdfsCluster.getURI().getHost() + ":" + hdfsCluster.getNameNodePort() + "/";

			hdPath = new org.apache.hadoop.fs.Path("/test");
			hdfs = hdPath.getFileSystem(hdConf);
			FSDataOutputStream stream = hdfs.create(hdPath);
			for (int i = 0; i < 10; i++) {
				stream.write("Hello HDFS\n".getBytes(ConfigConstants.DEFAULT_CHARSET));
			}
			stream.close();

		} catch (Throwable e) {
			e.printStackTrace();
			Assert.fail("Test failed " + e.getMessage());
		}
	}

	@After
	public void destroyHDFS() {
		try {
			hdfs.delete(hdPath, false);
			hdfsCluster.shutdown();
		} catch (IOException e) {
			throw new RuntimeException(e);
		}

	}

	@Test
	public void testHDFS() {

		Path file = new Path(hdfsURI + hdPath);
		org.apache.hadoop.fs.Path result = new org.apache.hadoop.fs.Path(hdfsURI + "/result");
		try {
			FileSystem fs = file.getFileSystem();
			assertTrue("Must be HadoopFileSystem", fs instanceof HadoopFileSystem);

			DopOneTestEnvironment.setAsContext();
			try {
				WordCount.main(new String[]{
						"--input", file.toString(),
						"--output", result.toString()});
			}
			catch (Throwable t) {
				t.printStackTrace();
				Assert.fail("Test failed with " + t.getMessage());
			}
			finally {
				DopOneTestEnvironment.unsetAsContext();
			}

			assertTrue("No result file present", hdfs.exists(result));

			// validate output:
			org.apache.hadoop.fs.FSDataInputStream inStream = hdfs.open(result);
			StringWriter writer = new StringWriter();
			IOUtils.copy(inStream, writer);
			String resultString = writer.toString();

			Assert.assertEquals("hdfs 10\n" +
					"hello 10\n", resultString);
			inStream.close();

		} catch (IOException e) {
			e.printStackTrace();
			Assert.fail("Error in test: " + e.getMessage());
		}
	}

	@Test
	public void testChangingFileNames() {
		org.apache.hadoop.fs.Path hdfsPath = new org.apache.hadoop.fs.Path(hdfsURI + "/hdfsTest");
		Path path = new Path(hdfsPath.toString());

		String type = "one";
		TextOutputFormat<String> outputFormat = new TextOutputFormat<>(path);

		outputFormat.setWriteMode(FileSystem.WriteMode.NO_OVERWRITE);
		outputFormat.setOutputDirectoryMode(FileOutputFormat.OutputDirectoryMode.ALWAYS);

		try {
			outputFormat.open(0, 2);
			outputFormat.writeRecord(type);
			outputFormat.close();

			outputFormat.open(1, 2);
			outputFormat.writeRecord(type);
			outputFormat.close();

			assertTrue("No result file present", hdfs.exists(hdfsPath));
			FileStatus[] files = hdfs.listStatus(hdfsPath);
			Assert.assertEquals(2, files.length);
			for (FileStatus file : files) {
				assertTrue("1".equals(file.getPath().getName()) || "2".equals(file.getPath().getName()));
			}

		} catch (IOException e) {
			e.printStackTrace();
			Assert.fail(e.getMessage());
		}
	}

	/**
	 * Test that {@link FileUtils#deletePathIfEmpty(FileSystem, Path)} deletes the path if it is
	 * empty. A path can only be empty if it is a directory which does not contain any
	 * files/directories.
	 */
	@Test
	public void testDeletePathIfEmpty() throws IOException {
		final Path basePath = new Path(hdfsURI);
		final Path directory = new Path(basePath, UUID.randomUUID().toString());
		final Path directoryFile = new Path(directory, UUID.randomUUID().toString());
		final Path singleFile = new Path(basePath, UUID.randomUUID().toString());

		FileSystem fs = basePath.getFileSystem();

		fs.mkdirs(directory);

		byte[] data = "HDFSTest#testDeletePathIfEmpty".getBytes(ConfigConstants.DEFAULT_CHARSET);

		for (Path file: Arrays.asList(singleFile, directoryFile)) {
			org.apache.flink.core.fs.FSDataOutputStream outputStream = fs.create(file, FileSystem.WriteMode.OVERWRITE);
			outputStream.write(data);
			outputStream.close();
		}

		// verify that the files have been created
		assertTrue(fs.exists(singleFile));
		assertTrue(fs.exists(directoryFile));

		// delete the single file
		assertFalse(FileUtils.deletePathIfEmpty(fs, singleFile));
		assertTrue(fs.exists(singleFile));

		// try to delete the non-empty directory
		assertFalse(FileUtils.deletePathIfEmpty(fs, directory));
		assertTrue(fs.exists(directory));

		// delete the file contained in the directory
		assertTrue(fs.delete(directoryFile, false));

		// now the deletion should work
		assertTrue(FileUtils.deletePathIfEmpty(fs, directory));
		assertFalse(fs.exists(directory));
	}

	/**
	 * Tests that with {@link HighAvailabilityMode#ZOOKEEPER} distributed JARs are recoverable from any
	 * participating BlobServer when talking to the {@link org.apache.flink.runtime.blob.BlobServer} directly.
	 */
	@Test
	public void testBlobServerRecovery() throws Exception {
		org.apache.flink.configuration.Configuration
			config = new org.apache.flink.configuration.Configuration();
		config.setString(HighAvailabilityOptions.HA_MODE, "ZOOKEEPER");
		config.setString(BlobServerOptions.STORAGE_DIRECTORY,
			temporaryFolder.newFolder().getAbsolutePath());
		config.setString(HighAvailabilityOptions.HA_STORAGE_PATH, hdfsURI);

		BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(config);

		try {
			BlobServerRecoveryTest.testBlobServerRecovery(config, blobStoreService);
		} finally {
			blobStoreService.closeAndCleanupAllData();
		}
	}

	/**
	 * Tests that with {@link HighAvailabilityMode#ZOOKEEPER} distributed corrupted JARs are
	 * recognised during the download via a {@link org.apache.flink.runtime.blob.BlobServer}.
	 */
	@Test
	public void testBlobServerCorruptedFile() throws Exception {
		org.apache.flink.configuration.Configuration
			config = new org.apache.flink.configuration.Configuration();
		config.setString(HighAvailabilityOptions.HA_MODE, "ZOOKEEPER");
		config.setString(BlobServerOptions.STORAGE_DIRECTORY,
			temporaryFolder.newFolder().getAbsolutePath());
		config.setString(HighAvailabilityOptions.HA_STORAGE_PATH, hdfsURI);

		BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(config);

		try {
			BlobServerCorruptionTest.testGetFailsFromCorruptFile(config, blobStoreService, exception);
		} finally {
			blobStoreService.closeAndCleanupAllData();
		}
	}

	/**
	 * Tests that with {@link HighAvailabilityMode#ZOOKEEPER} distributed JARs are recoverable from any
	 * participating BlobServer when uploaded via a BLOB cache.
	 */
	@Test
	public void testBlobCacheRecovery() throws Exception {
		org.apache.flink.configuration.Configuration
			config = new org.apache.flink.configuration.Configuration();
		config.setString(HighAvailabilityOptions.HA_MODE, "ZOOKEEPER");
		config.setString(BlobServerOptions.STORAGE_DIRECTORY,
			temporaryFolder.newFolder().getAbsolutePath());
		config.setString(HighAvailabilityOptions.HA_STORAGE_PATH, hdfsURI);

		BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(config);

		try {
			BlobCacheRecoveryTest.testBlobCacheRecovery(config, blobStoreService);
		} finally {
			blobStoreService.closeAndCleanupAllData();
		}
	}

	/**
	 * Tests that with {@link HighAvailabilityMode#ZOOKEEPER} distributed corrupted JARs are
	 * recognised during the download via a BLOB cache.
	 */
	@Test
	public void testBlobCacheCorruptedFile() throws Exception {
		org.apache.flink.configuration.Configuration
			config = new org.apache.flink.configuration.Configuration();
		config.setString(HighAvailabilityOptions.HA_MODE, "ZOOKEEPER");
		config.setString(BlobServerOptions.STORAGE_DIRECTORY,
			temporaryFolder.newFolder().getAbsolutePath());
		config.setString(HighAvailabilityOptions.HA_STORAGE_PATH, hdfsURI);

		BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(config);

		try {
			BlobCacheCorruptionTest
				.testGetFailsFromCorruptFile(new JobID(), config, blobStoreService, exception);
		} finally {
			blobStoreService.closeAndCleanupAllData();
		}
	}

	abstract static class DopOneTestEnvironment extends ExecutionEnvironment {

		public static void setAsContext() {
			final LocalEnvironment le = new LocalEnvironment();
			le.setParallelism(1);

			initializeContextEnvironment(new ExecutionEnvironmentFactory() {

				@Override
				public ExecutionEnvironment createExecutionEnvironment() {
					return le;
				}
			});
		}

		public static void unsetAsContext() {
			resetContextEnvironment();
		}
	}
}