/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.tools;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  /**
   * The Class BackwardsLineReaderTest.
   */
  class BackwardsLineReaderTest {
  
    /**
     * Read lines backwards test.
     *
     * @throws IOException Signals that an I/O exception has occurred.
     */
    @Test
    void readLinesBackwardsTest() throws IOException {
      File file = Files.createTempFile("backwards-reader-", ".log").toFile();
      Files.writeString(file.toPath(), "line1\nline2\nline3", StandardCharsets.UTF_8);
  
      try (BackwardsFileStream stream = new BackwardsFileStream(file)) {
        BackwardsLineReader reader = new BackwardsLineReader(stream);
        Assertions.assertEquals("line3", reader.readLine());
        Assertions.assertEquals("line2", reader.readLine());
        Assertions.assertEquals("line1", reader.readLine());
        Assertions.assertNull(reader.readLine());
        reader.close();
      } finally {
        Files.deleteIfExists(file.toPath());
      }
    }
  
    /**
     * Read lines backwards with CRLF test.
     *
     * @throws IOException Signals that an I/O exception has occurred.
     */
    @Test
    void readLinesBackwardsCrLfTest() throws IOException {
      File file = Files.createTempFile("backwards-reader-crlf-", ".log").toFile();
      Files.writeString(file.toPath(), "left\r\nright", StandardCharsets.UTF_8);
  
      try (BackwardsFileStream stream = new BackwardsFileStream(file)) {
        BackwardsLineReader reader = new BackwardsLineReader(stream, StandardCharsets.UTF_8.name());
        Assertions.assertEquals("right", reader.readLine());
        Assertions.assertEquals("left", reader.readLine());
        Assertions.assertNull(reader.readLine());
        reader.close();
      } finally {
        Files.deleteIfExists(file.toPath());
      }
    }
  
    /**
     * Backwards file stream from position test.
     *
     * @throws IOException Signals that an I/O exception has occurred.
     */
    @Test
    void backwardsFileStreamFromPositionTest() throws IOException {
      File file = Files.createTempFile("backwards-stream-pos-", ".txt").toFile();
      Files.writeString(file.toPath(), "abcde", StandardCharsets.UTF_8);
  
      try (BackwardsFileStream stream = new BackwardsFileStream(file, 3)) {
        Assertions.assertEquals('c', stream.read());
        Assertions.assertEquals('b', stream.read());
        Assertions.assertEquals('a', stream.read());
        Assertions.assertEquals(-1, stream.read());
      } finally {
        Files.deleteIfExists(file.toPath());
      }
    }
  }