/*
 * 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.beam.sdk.io;

import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.nio.channels.Channels;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import org.apache.beam.sdk.io.fs.CreateOptions.StandardCreateOptions;
import org.apache.beam.sdk.io.fs.MatchResult;
import org.apache.beam.sdk.io.fs.ResolveOptions.StandardResolveOptions;
import org.apache.beam.sdk.testing.RestoreSystemProperties;
import org.apache.beam.sdk.util.MimeTypes;
import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.FluentIterable;
import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.ImmutableList;
import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.Lists;
import org.apache.beam.vendor.guava.v20_0.com.google.common.io.Files;
import org.apache.beam.vendor.guava.v20_0.com.google.common.io.LineReader;
import org.apache.commons.lang3.SystemUtils;
import org.hamcrest.Matchers;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link LocalFileSystem}. */
@RunWith(JUnit4.class)
public class LocalFileSystemTest {
  @Rule public ExpectedException thrown = ExpectedException.none();
  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
  @Rule public RestoreSystemProperties restoreSystemProperties = new RestoreSystemProperties();
  private LocalFileSystem localFileSystem = new LocalFileSystem();

  @Test
  public void testCreateWithExistingFile() throws Exception {
    File existingFile = temporaryFolder.newFile();
    testCreate(existingFile.toPath());
  }

  @Test
  public void testCreateWithinExistingDirectory() throws Exception {
    testCreate(temporaryFolder.getRoot().toPath().resolve("file.txt"));
  }

  @Test
  public void testCreateWithNonExistentSubDirectory() throws Exception {
    testCreate(temporaryFolder.getRoot().toPath().resolve("non-existent-dir").resolve("file.txt"));
  }

  private void testCreate(Path path) throws Exception {
    String expected = "my test string";
    // First with the path string
    createFileWithContent(path, expected);
    assertThat(
        Files.readLines(path.toFile(), StandardCharsets.UTF_8), containsInAnyOrder(expected));

    // Delete the file before trying as URI
    assertTrue("Unable to delete file " + path, path.toFile().delete());

    // Second with the path URI
    createFileWithContent(Paths.get(path.toUri()), expected);
    assertThat(
        Files.readLines(path.toFile(), StandardCharsets.UTF_8), containsInAnyOrder(expected));
  }

  @Test
  public void testReadWithExistingFile() throws Exception {
    String expected = "my test string";
    File existingFile = temporaryFolder.newFile();
    Files.write(expected, existingFile, StandardCharsets.UTF_8);
    String data;
    try (Reader reader =
        Channels.newReader(
            localFileSystem.open(
                LocalResourceId.fromPath(existingFile.toPath(), false /* isDirectory */)),
            StandardCharsets.UTF_8.name())) {
      data = new LineReader(reader).readLine();
    }
    assertEquals(expected, data);
  }

  @Test
  public void testReadNonExistentFile() throws Exception {
    thrown.expect(FileNotFoundException.class);
    localFileSystem
        .open(
            LocalResourceId.fromPath(
                temporaryFolder.getRoot().toPath().resolve("non-existent-file.txt"),
                false /* isDirectory */))
        .close();
  }

  private void assertContents(List<Path> destFiles, List<String> contents) throws Exception {
    for (int i = 0; i < destFiles.size(); ++i) {
      assertThat(
          Files.readLines(destFiles.get(i).toFile(), StandardCharsets.UTF_8),
          containsInAnyOrder(contents.get(i)));
    }
  }

  @Test
  public void testCopyWithExistingSrcFile() throws Exception {
    Path srcPath1 = temporaryFolder.newFile().toPath();
    Path srcPath2 = temporaryFolder.newFile().toPath();

    Path destPath1 = temporaryFolder.getRoot().toPath().resolve("nonexistentdir").resolve("dest1");
    Path destPath2 = srcPath2.resolveSibling("dest2");

    createFileWithContent(srcPath1, "content1");
    createFileWithContent(srcPath2, "content2");

    localFileSystem.copy(
        toLocalResourceIds(ImmutableList.of(srcPath1, srcPath2), false /* isDirectory */),
        toLocalResourceIds(ImmutableList.of(destPath1, destPath2), false /* isDirectory */));

    assertContents(
        ImmutableList.of(destPath1, destPath2), ImmutableList.of("content1", "content2"));
  }

  @Test
  public void testMoveWithExistingSrcFile() throws Exception {
    Path srcPath1 = temporaryFolder.newFile().toPath();
    Path srcPath2 = temporaryFolder.newFile().toPath();

    Path destPath1 = temporaryFolder.getRoot().toPath().resolve("nonexistentdir").resolve("dest1");
    Path destPath2 = srcPath2.resolveSibling("dest2");

    createFileWithContent(srcPath1, "content1");
    createFileWithContent(srcPath2, "content2");

    localFileSystem.rename(
        toLocalResourceIds(ImmutableList.of(srcPath1, srcPath2), false /* isDirectory */),
        toLocalResourceIds(ImmutableList.of(destPath1, destPath2), false /* isDirectory */));

    assertContents(
        ImmutableList.of(destPath1, destPath2), ImmutableList.of("content1", "content2"));

    assertFalse(srcPath1 + "exists", srcPath1.toFile().exists());
    assertFalse(srcPath2 + "exists", srcPath2.toFile().exists());
  }

  @Test
  public void testDelete() throws Exception {
    File f1 = temporaryFolder.newFile("file1");
    File f2 = temporaryFolder.newFile("file2");
    File f3 = temporaryFolder.newFile("other-file");
    localFileSystem.delete(
        toLocalResourceIds(Lists.newArrayList(f1.toPath(), f2.toPath()), false /* isDirectory */));
    assertFalse(f1.exists());
    assertFalse(f2.exists());
    assertTrue(f3.exists());
  }

  @Test
  public void testMatchExact() throws Exception {
    List<String> expected = ImmutableList.of(temporaryFolder.newFile("a").toString());
    temporaryFolder.newFile("aa");
    temporaryFolder.newFile("ab");

    List<MatchResult> matchResults =
        localFileSystem.match(
            ImmutableList.of(temporaryFolder.getRoot().toPath().resolve("a").toString()));
    assertThat(
        toFilenames(matchResults),
        containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchPatternNone() throws Exception {
    temporaryFolder.newFile("a");
    temporaryFolder.newFile("aa");
    temporaryFolder.newFile("ab");

    List<MatchResult> matchResults =
        matchGlobWithPathPrefix(temporaryFolder.getRoot().toPath().resolve("b"), "*");
    assertEquals(1, matchResults.size());
    assertEquals(MatchResult.Status.NOT_FOUND, matchResults.get(0).status());
  }

  @Test
  public void testMatchForNonExistentFile() throws Exception {
    temporaryFolder.newFile("aa");

    List<MatchResult> matchResults =
        localFileSystem.match(
            ImmutableList.of(temporaryFolder.getRoot().toPath().resolve("a").toString()));
    assertEquals(1, matchResults.size());
    assertEquals(MatchResult.Status.NOT_FOUND, matchResults.get(0).status());
  }

  @Test
  public void testMatchMultipleWithFileExtension() throws Exception {
    List<String> expected =
        ImmutableList.of(
            temporaryFolder.newFile("a.txt").toString(),
            temporaryFolder.newFile("aa.txt").toString(),
            temporaryFolder.newFile("ab.txt").toString());
    temporaryFolder.newFile("a.avro");
    temporaryFolder.newFile("ab.avro");

    List<MatchResult> matchResults =
        matchGlobWithPathPrefix(temporaryFolder.getRoot().toPath().resolve("a"), "*.txt");
    assertThat(
        toFilenames(matchResults),
        containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchInDirectory() throws Exception {
    List<String> expected = ImmutableList.of(temporaryFolder.newFile("a").toString());
    temporaryFolder.newFile("aa");
    temporaryFolder.newFile("ab");

    String expectedFile = expected.get(0);
    int slashIndex = expectedFile.lastIndexOf('/');
    if (SystemUtils.IS_OS_WINDOWS) {
      slashIndex = expectedFile.lastIndexOf('\\');
    }
    String directory = expectedFile.substring(0, slashIndex);
    String relative = expectedFile.substring(slashIndex + 1);
    System.setProperty("user.dir", directory);
    List<MatchResult> results = localFileSystem.match(ImmutableList.of(relative));
    assertThat(
        toFilenames(results), containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchWithFileSlashPrefix() throws Exception {
    List<String> expected = ImmutableList.of(temporaryFolder.newFile("a").toString());
    temporaryFolder.newFile("aa");
    temporaryFolder.newFile("ab");

    String file = "file:/" + temporaryFolder.getRoot().toPath().resolve("a").toString();
    List<MatchResult> results = localFileSystem.match(ImmutableList.of(file));
    assertThat(
        toFilenames(results), containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchWithFileThreeSlashesPrefix() throws Exception {
    List<String> expected = ImmutableList.of(temporaryFolder.newFile("a").toString());
    temporaryFolder.newFile("aa");
    temporaryFolder.newFile("ab");

    String file = "file:///" + temporaryFolder.getRoot().toPath().resolve("a").toString();
    List<MatchResult> results = localFileSystem.match(ImmutableList.of(file));
    assertThat(
        toFilenames(results), containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchMultipleWithoutSubdirectoryExpansion() throws Exception {
    File unmatchedSubDir = temporaryFolder.newFolder("aaa");
    File unmatchedSubDirFile = File.createTempFile("sub-dir-file", "", unmatchedSubDir);
    unmatchedSubDirFile.deleteOnExit();
    List<String> expected =
        ImmutableList.of(
            temporaryFolder.newFile("a").toString(),
            temporaryFolder.newFile("aa").toString(),
            temporaryFolder.newFile("ab").toString());
    temporaryFolder.newFile("ba");
    temporaryFolder.newFile("bb");

    List<MatchResult> matchResults =
        matchGlobWithPathPrefix(temporaryFolder.getRoot().toPath().resolve("a"), "*");
    assertThat(
        toFilenames(matchResults),
        containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchMultipleWithSubdirectoryExpansion() throws Exception {
    File matchedSubDir = temporaryFolder.newFolder("a");
    File matchedSubDirFile = File.createTempFile("sub-dir-file", "", matchedSubDir);
    matchedSubDirFile.deleteOnExit();
    File unmatchedSubDir = temporaryFolder.newFolder("b");
    File unmatchedSubDirFile = File.createTempFile("sub-dir-file", "", unmatchedSubDir);
    unmatchedSubDirFile.deleteOnExit();

    List<String> expected =
        ImmutableList.of(
            matchedSubDirFile.toString(),
            temporaryFolder.newFile("aa").toString(),
            temporaryFolder.newFile("ab").toString());
    temporaryFolder.newFile("ba");
    temporaryFolder.newFile("bb");

    List<MatchResult> matchResults =
        matchGlobWithPathPrefix(temporaryFolder.getRoot().toPath().resolve("a"), "**");
    assertThat(
        toFilenames(matchResults),
        Matchers.hasItems(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchWithDirectoryFiltersOutDirectory() throws Exception {
    List<String> expected = ImmutableList.of(temporaryFolder.newFile("a").toString());
    temporaryFolder.newFolder("a_dir_that_should_not_be_matched");

    List<MatchResult> matchResults =
        matchGlobWithPathPrefix(temporaryFolder.getRoot().toPath().resolve("a"), "*");
    assertThat(
        toFilenames(matchResults),
        containsInAnyOrder(expected.toArray(new String[expected.size()])));
  }

  @Test
  public void testMatchWithoutParentDirectory() throws Exception {
    Path pattern =
        LocalResourceId.fromPath(temporaryFolder.getRoot().toPath(), true /* isDirectory */)
            .resolve("non_existing_dir", StandardResolveOptions.RESOLVE_DIRECTORY)
            .resolve("*", StandardResolveOptions.RESOLVE_FILE)
            .getPath();
    assertTrue(toFilenames(localFileSystem.match(ImmutableList.of(pattern.toString()))).isEmpty());
  }

  @Test
  public void testMatchNewResource() throws Exception {
    LocalResourceId fileResource =
        localFileSystem.matchNewResource("/some/test/resource/path", false /* isDirectory */);
    LocalResourceId dirResource =
        localFileSystem.matchNewResource("/some/test/resource/path", true /* isDirectory */);
    assertNotEquals(fileResource, dirResource);
    assertThat(
        fileResource
            .getCurrentDirectory()
            .resolve("path", StandardResolveOptions.RESOLVE_DIRECTORY),
        equalTo(dirResource.getCurrentDirectory()));
    assertThat(
        fileResource
            .getCurrentDirectory()
            .resolve("path", StandardResolveOptions.RESOLVE_DIRECTORY),
        equalTo(dirResource.getCurrentDirectory()));
    assertThat(dirResource.toString(), equalTo("/some/test/resource/path/"));
  }

  private void createFileWithContent(Path path, String content) throws Exception {
    try (Writer writer =
        Channels.newWriter(
            localFileSystem.create(
                LocalResourceId.fromPath(path, false /* isDirectory */),
                StandardCreateOptions.builder().setMimeType(MimeTypes.TEXT).build()),
            StandardCharsets.UTF_8.name())) {
      writer.write(content);
    }
  }

  private List<MatchResult> matchGlobWithPathPrefix(Path pathPrefix, String glob)
      throws IOException {
    // Windows doesn't like resolving paths with * in glob, so the glob is concatenated as String.
    return localFileSystem.match(ImmutableList.of(pathPrefix + glob));
  }

  private List<LocalResourceId> toLocalResourceIds(List<Path> paths, final boolean isDirectory) {
    return FluentIterable.from(paths)
        .transform(path -> LocalResourceId.fromPath(path, isDirectory))
        .toList();
  }

  private List<String> toFilenames(List<MatchResult> matchResults) {
    return FluentIterable.from(matchResults)
        .transformAndConcat(
            matchResult -> {
              try {
                return matchResult.metadata();
              } catch (IOException e) {
                throw new RuntimeException(e);
              }
            })
        .transform(metadata -> ((LocalResourceId) metadata.resourceId()).getPath().toString())
        .toList();
  }
}