/*
 * 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.scm.svn;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.junit.Test;

import static java.util.Collections.singleton;
import static org.assertj.core.api.Assertions.assertThat;

public class ChangedLinesComputerTest {

  private final Path rootBaseDir = Paths.get("/foo");
  private final ChangedLinesComputer underTest = new ChangedLinesComputer(rootBaseDir, new HashSet<>(Arrays.asList(
    rootBaseDir.resolve("sample1"),
    rootBaseDir.resolve("sample2"),
    rootBaseDir.resolve("sample3"),
    rootBaseDir.resolve("sample4"))));

  @Test
  public void do_not_count_deleted_line() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -1 +0,0 @@\n"
      + "-deleted line\n";

    printDiff(example);
    assertThat(underTest.changedLines()).isEmpty();
  }

  @Test
  public void count_single_added_line() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -0,0 +1 @@\n"
      + "+added line\n";

    printDiff(example);
    assertThat(underTest.changedLines()).isEqualTo(Collections.singletonMap(rootBaseDir.resolve("sample1"), singleton(1)));
  }

  @Test
  public void count_multiple_added_lines() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -1 +1,3 @@\n"
      + " same line\n"
      + "+added line 1\n"
      + "+added line 2\n";

    printDiff(example);
    assertThat(underTest.changedLines()).isEqualTo(Collections.singletonMap(rootBaseDir.resolve("sample1"), new HashSet<>(Arrays.asList(2, 3))));
  }

  @Test
  public void handle_index_using_absolute_paths() throws IOException {
    String example = "Index: /foo/sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -1 +1,3 @@\n"
      + " same line\n"
      + "+added line 1\n"
      + "+added line 2\n";

    printDiff(example);
    assertThat(underTest.changedLines()).isEqualTo(Collections.singletonMap(rootBaseDir.resolve("sample1"), new HashSet<>(Arrays.asList(2, 3))));
  }

  @Test
  public void compute_from_multiple_hunks() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- lao\t2002-02-21 23:30:39.942229878 -0800\n"
      + "+++ tzu\t2002-02-21 23:30:50.442260588 -0800\n"
      + "@@ -1,7 +1,6 @@\n"
      + "-The Way that can be told of is not the eternal Way;\n"
      + "-The name that can be named is not the eternal name.\n"
      + " The Nameless is the origin of Heaven and Earth;\n"
      + "-The Named is the mother of all things.\n"
      + "+The named is the mother of all things.\n"
      + "+\n"
      + " Therefore let there always be non-being,\n"
      + "   so we may see their subtlety,\n"
      + " And let there always be being,\n"
      + "@@ -9,3 +8,6 @@\n"
      + " The two are the same,\n"
      + " But after they are produced,\n"
      + "   they have different names.\n"
      + "+They both may be called deep and profound.\n"
      + "+Deeper and more profound,\n"
      + "+The door of all subtleties!\n";
    printDiff(example);
    assertThat(underTest.changedLines()).isEqualTo(Collections.singletonMap(rootBaseDir.resolve("sample1"), new HashSet<>(Arrays.asList(2, 3, 11, 12, 13))));
  }

  @Test(expected = IllegalStateException.class)
  public void crash_on_invalid_start_line_format() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -1 +x1,3 @@\n"
      + " same line\n"
      + "+added line 1\n"
      + "+added line 2\n";

    printDiff(example);
    underTest.changedLines();
  }

  @Test
  public void parse_diff_with_multiple_files() throws IOException {
    String example = "Index: sample1\n"
      + "===================================================================\n"
      + "--- a/sample1\n"
      + "+++ b/sample1\n"
      + "@@ -1 +0,0 @@\n"
      + "-deleted line\n"
      + "Index: sample2\n"
      + "===================================================================\n"
      + "--- a/sample2\n"
      + "+++ b/sample2\n"
      + "@@ -0,0 +1 @@\n"
      + "+added line\n"
      + "Index: sample3\n"
      + "===================================================================\n"
      + "--- a/sample3\n"
      + "+++ b/sample3\n"
      + "@@ -0,0 +1,2 @@\n"
      + "+added line 1\n"
      + "+added line 2\n"
      + "Index: sample3-not-included\n"
      + "===================================================================\n"
      + "--- a/sample3-not-included\n"
      + "+++ b/sample3-not-included\n"
      + "@@ -0,0 +1,2 @@\n"
      + "+added line 1\n"
      + "+added line 2\n"
      + "Index: sample4\n"
      + "===================================================================\n"
      + "--- a/sample4\n"
      + "+++ b/sample4\n"
      + "@@ -1 +1,3 @@\n"
      + " same line\n"
      + "+added line 1\n"
      + "+added line 2\n";

    printDiff(example);
    Map<Path, Set<Integer>> expected = new HashMap<>();
    expected.put(rootBaseDir.resolve("sample2"), Collections.singleton(1));
    expected.put(rootBaseDir.resolve("sample3"), new HashSet<>(Arrays.asList(1, 2)));
    expected.put(rootBaseDir.resolve("sample4"), new HashSet<>(Arrays.asList(2, 3)));

    assertThat(underTest.changedLines()).isEqualTo(expected);
  }

  private void printDiff(String unifiedDiff) throws IOException {
    try (OutputStreamWriter writer = new OutputStreamWriter(underTest.receiver())) {
      writer.write(unifiedDiff);
    }
  }
}