/*
 * SonarQube
 * Copyright (C) 2009-2023 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.process;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import javax.annotation.CheckForNull;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.SystemUtils;
import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.Assume.assumeTrue;

public class FileUtils2Test {
  @Rule
  public TemporaryFolder temporaryFolder = new TemporaryFolder();

  @Test
  public void cleanDirectory_throws_NPE_if_file_is_null() throws IOException {
    expectDirectoryCanNotBeNullNPE(() -> FileUtils2.cleanDirectory(null));
  }

  @Test
  public void cleanDirectory_does_nothing_if_argument_does_not_exist() throws IOException {
    FileUtils2.cleanDirectory(new File("/a/b/ToDoSSS"));
  }

  @Test
  public void cleanDirectory_throws_IAE_if_argument_is_a_file() throws IOException {
    File file = temporaryFolder.newFile();

    assertThatThrownBy(() -> FileUtils2.cleanDirectory(file))
      .isInstanceOf(IllegalArgumentException.class)
      .hasMessage("'" + file.getAbsolutePath() + "' is not a directory");
  }

  @Test
  public void cleanDirectory_removes_directories_and_files_in_target_directory_but_not_target_directory() throws IOException {
    Path target = temporaryFolder.newFolder().toPath();
    Path childFile1 = Files.createFile(target.resolve("file1.txt"));
    Path childDir1 = Files.createDirectory(target.resolve("subDir1"));
    Path childFile2 = Files.createFile(childDir1.resolve("file2.txt"));
    Path childDir2 = Files.createDirectory(childDir1.resolve("subDir2"));

    assertThat(target).isDirectory();
    assertThat(childFile1).isRegularFile();
    assertThat(childDir1).isDirectory();
    assertThat(childFile2).isRegularFile();
    assertThat(childDir2).isDirectory();

    // on supporting FileSystem, target will change if directory is recreated
    Object targetKey = getFileKey(target);

    FileUtils2.cleanDirectory(target.toFile());

    assertThat(target).isDirectory();
    assertThat(childFile1).doesNotExist();
    assertThat(childDir1).doesNotExist();
    assertThat(childFile2).doesNotExist();
    assertThat(childDir2).doesNotExist();
    assertThat(getFileKey(target)).isEqualTo(targetKey);
  }

  @Test
  public void cleanDirectory_follows_symlink_to_target_directory() throws IOException {
    assumeTrue(SystemUtils.IS_OS_UNIX);
    Path target = temporaryFolder.newFolder().toPath();
    Path symToDir = Files.createSymbolicLink(temporaryFolder.newFolder().toPath().resolve("sym_to_dir"), target);
    Path childFile1 = Files.createFile(target.resolve("file1.txt"));
    Path childDir1 = Files.createDirectory(target.resolve("subDir1"));
    Path childFile2 = Files.createFile(childDir1.resolve("file2.txt"));
    Path childDir2 = Files.createDirectory(childDir1.resolve("subDir2"));

    assertThat(target).isDirectory();
    assertThat(symToDir).isSymbolicLink();
    assertThat(childFile1).isRegularFile();
    assertThat(childDir1).isDirectory();
    assertThat(childFile2).isRegularFile();
    assertThat(childDir2).isDirectory();

    // on supporting FileSystem, target will change if directory is recreated
    Object targetKey = getFileKey(target);
    Object symLinkKey = getFileKey(symToDir);

    FileUtils2.cleanDirectory(symToDir.toFile());

    assertThat(target).isDirectory();
    assertThat(symToDir).isSymbolicLink();
    assertThat(childFile1).doesNotExist();
    assertThat(childDir1).doesNotExist();
    assertThat(childFile2).doesNotExist();
    assertThat(childDir2).doesNotExist();
    assertThat(getFileKey(target)).isEqualTo(targetKey);
    assertThat(getFileKey(symToDir)).isEqualTo(symLinkKey);
  }

  @Test
  public void deleteQuietly_does_not_fail_if_argument_is_null() {
    FileUtils2.deleteQuietly(null);
  }

  @Test
  public void deleteQuietly_does_not_fail_if_file_does_not_exist() throws IOException {
    File file = new File(temporaryFolder.newFolder(), "blablabl");
    assertThat(file).doesNotExist();

    FileUtils2.deleteQuietly(file);
  }

  @Test
  public void deleteQuietly_deletes_directory_and_content() throws IOException {
    Path target = temporaryFolder.newFolder().toPath();
    Path childFile1 = Files.createFile(target.resolve("file1.txt"));
    Path childDir1 = Files.createDirectory(target.resolve("subDir1"));
    Path childFile2 = Files.createFile(childDir1.resolve("file2.txt"));
    Path childDir2 = Files.createDirectory(childDir1.resolve("subDir2"));

    assertThat(target).isDirectory();
    assertThat(childFile1).isRegularFile();
    assertThat(childDir1).isDirectory();
    assertThat(childFile2).isRegularFile();
    assertThat(childDir2).isDirectory();

    FileUtils2.deleteQuietly(target.toFile());

    assertThat(target).doesNotExist();
    assertThat(childFile1).doesNotExist();
    assertThat(childDir1).doesNotExist();
    assertThat(childFile2).doesNotExist();
    assertThat(childDir2).doesNotExist();
  }

  @Test
  public void deleteQuietly_deletes_symbolicLink() throws IOException {
    assumeTrue(SystemUtils.IS_OS_UNIX);
    Path folder = temporaryFolder.newFolder().toPath();
    Path file1 = Files.createFile(folder.resolve("file1.txt"));
    Path symLink = Files.createSymbolicLink(folder.resolve("link1"), file1);

    assertThat(file1).isRegularFile();
    assertThat(symLink).isSymbolicLink();

    FileUtils2.deleteQuietly(symLink.toFile());

    assertThat(symLink).doesNotExist();
    assertThat(file1).isRegularFile();
  }

  @Test
  public void deleteDirectory_throws_NPE_if_argument_is_null() throws IOException {
    expectDirectoryCanNotBeNullNPE(() -> FileUtils2.deleteDirectory(null));
  }

  @Test
  public void deleteDirectory_does_not_fail_if_file_does_not_exist() throws IOException {
    File file = new File(temporaryFolder.newFolder(), "foo.d");

    FileUtils2.deleteDirectory(file);
  }

  @Test
  public void deleteDirectory_throws_IOE_if_argument_is_a_file() throws IOException {
    File file = temporaryFolder.newFile();

    assertThatThrownBy(() -> FileUtils2.deleteDirectory(file))
      .isInstanceOf(IOException.class)
      .hasMessage("Directory '" + file.getAbsolutePath() + "' is a file");
  }

  @Test
  public void deleteDirectory_throws_IOE_if_file_is_symbolicLink() throws IOException {
    assumeTrue(SystemUtils.IS_OS_UNIX);
    Path folder = temporaryFolder.newFolder().toPath();
    Path file1 = Files.createFile(folder.resolve("file1.txt"));
    Path symLink = Files.createSymbolicLink(folder.resolve("link1"), file1);

    assertThat(file1).isRegularFile();
    assertThat(symLink).isSymbolicLink();

    assertThatThrownBy(() -> FileUtils2.deleteDirectory(symLink.toFile()))
      .isInstanceOf(IOException.class)
      .hasMessage("Directory '" + symLink.toFile().getAbsolutePath() + "' is a symbolic link");
  }

  @Test
  public void deleteDirectory_deletes_directory_and_content() throws IOException {
    Path target = temporaryFolder.newFolder().toPath();
    Path childFile1 = Files.createFile(target.resolve("file1.txt"));
    Path childDir1 = Files.createDirectory(target.resolve("subDir1"));
    Path childFile2 = Files.createFile(childDir1.resolve("file2.txt"));
    Path childDir2 = Files.createDirectory(childDir1.resolve("subDir2"));

    assertThat(target).isDirectory();
    assertThat(childFile1).isRegularFile();
    assertThat(childDir1).isDirectory();
    assertThat(childFile2).isRegularFile();
    assertThat(childDir2).isDirectory();

    FileUtils2.deleteQuietly(target.toFile());

    assertThat(target).doesNotExist();
    assertThat(childFile1).doesNotExist();
    assertThat(childDir1).doesNotExist();
    assertThat(childFile2).doesNotExist();
    assertThat(childDir2).doesNotExist();
  }

  @Test
  public void sizeOf_sums_sizes_of_all_files_in_directory() throws IOException {
    File dir = temporaryFolder.newFolder();
    File child = new File(dir, "child.txt");
    File grandChild1 = new File(dir, "grand/child1.txt");
    File grandChild2 = new File(dir, "grand/child2.txt");
    FileUtils.write(child, "foo", UTF_8);
    FileUtils.write(grandChild1, "bar", UTF_8);
    FileUtils.write(grandChild2, "baz", UTF_8);

    long childSize = FileUtils2.sizeOf(child.toPath());
    assertThat(childSize).isPositive();
    long grandChild1Size = FileUtils2.sizeOf(grandChild1.toPath());
    assertThat(grandChild1Size).isPositive();
    long grandChild2Size = FileUtils2.sizeOf(grandChild2.toPath());
    assertThat(grandChild2Size).isPositive();

    assertThat(FileUtils2.sizeOf(dir.toPath()))
      .isEqualTo(childSize + grandChild1Size + grandChild2Size);

    // sanity check by comparing commons-io
    assertThat(FileUtils2.sizeOf(dir.toPath()))
      .isEqualTo(FileUtils.sizeOfDirectory(dir));
  }

  @Test
  public void sizeOf_is_zero_on_empty_files() throws IOException {
    File file = temporaryFolder.newFile();

    assertThat(FileUtils2.sizeOf(file.toPath())).isZero();
  }

  @Test
  public void sizeOf_throws_IOE_if_path_does_not_exist() throws IOException {
    Path path = temporaryFolder.newFile().toPath();
    Files.delete(path);

    assertThatThrownBy(() -> FileUtils2.sizeOf(path))
      .isInstanceOf(IOException.class);
  }

  @Test
  public void sizeOf_ignores_size_of_non_regular_files() throws IOException {
    assumeTrue(SystemUtils.IS_OS_UNIX);
    File outside = temporaryFolder.newFile();
    FileUtils.write(outside, "outside!!!", UTF_8);
    File dir = temporaryFolder.newFolder();
    File child = new File(dir, "child1.txt");
    FileUtils.write(child, "inside!!!", UTF_8);
    File symlink = new File(dir, "child2.txt");
    Files.createSymbolicLink(symlink.toPath(), outside.toPath());

    assertThat(FileUtils2.sizeOf(dir.toPath()))
      .isPositive()
      .isEqualTo(FileUtils2.sizeOf(child.toPath()));
  }

  private void expectDirectoryCanNotBeNullNPE(ThrowingCallable callback) {
    assertThatThrownBy(callback)
      .isInstanceOf(NullPointerException.class)
        .hasMessage("Directory can not be null");
  }

  @CheckForNull
  private static Object getFileKey(Path path) throws IOException {
    BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
    return attrs.fileKey();
  }
}
