/*
 * 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.core.hash;

import java.nio.charset.StandardCharsets;
import javax.annotation.Nullable;
import org.apache.commons.codec.digest.DigestUtils;
import org.junit.Test;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

public class SourceLinesHashesComputerTest {

  @Test
  public void addLine_throws_NPE_is_line_null() {
    assertThatThrownBy(() -> new SourceLineHashesComputer(1).addLine(null))
      .isInstanceOf(NullPointerException.class)
      .hasMessage("line can not be null");
  }

  @Test
  public void hash_of_empty_string_is_empty_string() {
    assertThat(hashSingleLine("")).isEmpty();
  }

  @Test
  public void tab_and_spaces_are_ignored_from_hash() {
    assertThat(hashSingleLine(" ")).isEmpty();
    assertThat(hashSingleLine("\t")).isEmpty();
    assertThat(hashSingleLine("\t \t \t\t  ")).isEmpty();

    String abHash = hashSingleLine("ab");
    assertThat(hashSingleLine("a b")).isEqualTo(abHash);
    assertThat(hashSingleLine("a\tb")).isEqualTo(abHash);
    assertThat(hashSingleLine("\t a\t \tb\t  ")).isEqualTo(abHash);
  }

  @Test
  public void hash_of_line_is_md5_of_UTF_char_array_as_an_hex_string() {
    String lineWithAccentAndSpace = "Yolo lélà";
    assertThat(hashSingleLine(lineWithAccentAndSpace)).isEqualTo(
      DigestUtils.md5Hex("Yololélà".getBytes(StandardCharsets.UTF_8)));
  }

  @Test
  public void getLineHashes_returns_line_hash_in_order_of_addLine_calls() {
    String line1 = "line 1";
    String line2 = "line 1 + 1";
    String line3 = "line 10 - 7";

    SourceLineHashesComputer underTest = new SourceLineHashesComputer();
    underTest.addLine(line1);
    underTest.addLine(line2);
    underTest.addLine(line3);

    assertThat(underTest.getLineHashes()).containsExactly(
      hashSingleLine(line1), hashSingleLine(line2), hashSingleLine(line3));
  }

  private static String hashSingleLine(@Nullable String line) {
    SourceLineHashesComputer sourceLinesHashesComputer = new SourceLineHashesComputer(1);
    sourceLinesHashesComputer.addLine(line);
    return sourceLinesHashesComputer.getLineHashes().iterator().next();
  }
}
