/*
 * Copyright 2013-present Facebook, Inc.
 *
 * Licensed 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 com.facebook.buck.util;

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

import com.facebook.buck.testutil.integration.DebuggableTemporaryFolder;

import org.junit.Rule;
import org.junit.Test;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class MorePathsTest {

  @Rule
  public DebuggableTemporaryFolder tmp = new DebuggableTemporaryFolder();

  @Test
  public void testGetRelativePath() {
    // Path on base directory.
    assertEquals(
        Paths.get("file"),
        MorePaths.getRelativePath(Paths.get("file"), Paths.get("")));

    // Path on base directory (using null).
    assertEquals(
        Paths.get("file"),
        MorePaths.getRelativePath(Paths.get("file"), null));

    // Path internal to base directory.
    assertEquals(
        Paths.get("dir/file"),
        MorePaths.getRelativePath(Paths.get("base/dir/file"), Paths.get("base")));

    // Path external to base directory.
    assertEquals(
        Paths.get("../dir1/file"),
        MorePaths.getRelativePath(Paths.get("dir1/file"), Paths.get("base")));
  }

  @Test
  public void testCreateRelativeSymlinkToFilesInRoot() throws IOException {
    ProjectFilesystem projectFilesystem = new ProjectFilesystem(tmp.getRoot());
    tmp.newFile("biz.txt");

    Path pathToDesiredLinkUnderProjectRoot = Paths.get("gamma.txt");
    Path pathToExistingFileUnderProjectRoot = Paths.get("biz.txt");
    Path relativePath = MorePaths.createRelativeSymlink(
        pathToDesiredLinkUnderProjectRoot,
        pathToExistingFileUnderProjectRoot,
        projectFilesystem);
    assertEquals("biz.txt", relativePath.toString());

    Path absolutePathToDesiredLinkUnderProjectRoot = projectFilesystem.resolve(
        pathToDesiredLinkUnderProjectRoot);
    assertTrue(Files.isSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot));
    Path targetOfSymbolicLink = Files.readSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot);
    assertEquals(relativePath, targetOfSymbolicLink);

    Path absolutePathToExistingFileUnderProjectRoot = projectFilesystem.resolve(
        pathToExistingFileUnderProjectRoot);
    Files.write(absolutePathToExistingFileUnderProjectRoot, "Hello, World!".getBytes());
    String dataReadFromSymlink = new String(Files.readAllBytes(
        absolutePathToDesiredLinkUnderProjectRoot));
    assertEquals("Hello, World!", dataReadFromSymlink);
  }

  @Test
  public void testCreateRelativeSymlinkToFileInRoot() throws IOException {
    ProjectFilesystem projectFilesystem = new ProjectFilesystem(tmp.getRoot());
    tmp.newFile("biz.txt");

    tmp.newFolder("alpha", "beta");
    Path pathToDesiredLinkUnderProjectRoot = Paths.get("alpha/beta/gamma.txt");
    Path pathToExistingFileUnderProjectRoot = Paths.get("biz.txt");
    Path relativePath = MorePaths.createRelativeSymlink(
        pathToDesiredLinkUnderProjectRoot,
        pathToExistingFileUnderProjectRoot,
        projectFilesystem);
    assertEquals("../../biz.txt", relativePath.toString());

    Path absolutePathToDesiredLinkUnderProjectRoot = projectFilesystem.resolve(
        pathToDesiredLinkUnderProjectRoot);
    assertTrue(Files.isSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot));
    Path targetOfSymbolicLink = Files.readSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot);
    assertEquals(relativePath, targetOfSymbolicLink);

    Path absolutePathToExistingFileUnderProjectRoot = projectFilesystem.resolve(
        pathToExistingFileUnderProjectRoot);
    Files.write(absolutePathToExistingFileUnderProjectRoot, "Hello, World!".getBytes());
    String dataReadFromSymlink = new String(Files.readAllBytes(
        absolutePathToDesiredLinkUnderProjectRoot));
    assertEquals("Hello, World!", dataReadFromSymlink);
  }

  @Test
  public void testCreateRelativeSymlinkToFilesOfVaryingDepth() throws IOException {
    ProjectFilesystem projectFilesystem = new ProjectFilesystem(tmp.getRoot());
    tmp.newFolder("foo", "bar", "baz");
    tmp.newFile("foo/bar/baz/biz.txt");

    tmp.newFolder("alpha", "beta");
    Path pathToDesiredLinkUnderProjectRoot = Paths.get("alpha/beta/gamma.txt");
    Path pathToExistingFileUnderProjectRoot = Paths.get("foo/bar/baz/biz.txt");
    Path relativePath = MorePaths.createRelativeSymlink(
        pathToDesiredLinkUnderProjectRoot,
        pathToExistingFileUnderProjectRoot,
        projectFilesystem);
    assertEquals("../../foo/bar/baz/biz.txt", relativePath.toString());

    Path absolutePathToDesiredLinkUnderProjectRoot = projectFilesystem.resolve(
        pathToDesiredLinkUnderProjectRoot);
    assertTrue(Files.isSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot));
    Path targetOfSymbolicLink = Files.readSymbolicLink(absolutePathToDesiredLinkUnderProjectRoot);
    assertEquals(relativePath, targetOfSymbolicLink);

    Path absolutePathToExistingFileUnderProjectRoot = projectFilesystem.resolve(
        pathToExistingFileUnderProjectRoot);
    Files.write(absolutePathToExistingFileUnderProjectRoot, "Hello, World!".getBytes());
    String dataReadFromSymlink = new String(Files.readAllBytes(
        absolutePathToDesiredLinkUnderProjectRoot));
    assertEquals("Hello, World!", dataReadFromSymlink);
  }
}