/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.io.input;
  
  import static org.apache.commons.io.StandardLineSeparator.CR;
  import static org.apache.commons.io.StandardLineSeparator.LF;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.URISyntaxException;
  import java.nio.charset.StandardCharsets;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.function.Supplier;
  import java.util.stream.IntStream;
  
  import org.apache.commons.io.TestResources;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.MethodSource;
  
  /**
   * Tests {@link ReversedLinesFileReader}.
   */
  public class ReversedLinesFileReaderParamBlockSizeTest {
  
      private static final String UTF_8 = StandardCharsets.UTF_8.name();
      private static final String ISO_8859_1 = StandardCharsets.ISO_8859_1.name();
  
      // "A Test Line. Special chars: ÄäÜüÖöß Ãáéíïçñ ©µ¥£±²®"
      private static final String TEST_LINE = "A Test Line. Special chars: "
          + "\u00C4\u00E4\u00DC\u00FC\u00D6\u00F6\u00DF \u00C3\u00E1\u00E9\u00ED\u00EF\u00E7\u00F1\u00C2 \u00A9\u00B5\u00A5\u00A3\u00B1\u00B2\u00AE";
  
      // Hiragana letters: �����
      private static final String TEST_LINE_SHIFT_JIS1 = "Hiragana letters: \u3041\u3042\u3043\u3044\u3045";
  
      // Strings are escaped in constants to avoid java source encoding issues (source file enc is UTF-8):
  
      // Kanji letters: 明輸�京
      private static final String TEST_LINE_SHIFT_JIS2 = "Kanji letters: \u660E\u8F38\u5B50\u4EAC";
      // windows-31j characters
      private static final String TEST_LINE_WINDOWS_31J_1 = "\u3041\u3042\u3043\u3044\u3045";
      private static final String TEST_LINE_WINDOWS_31J_2 = "\u660E\u8F38\u5B50\u4EAC";
      // gbk characters (Simplified Chinese)
      private static final String TEST_LINE_GBK_1 = "\u660E\u8F38\u5B50\u4EAC";
      private static final String TEST_LINE_GBK_2 = "\u7B80\u4F53\u4E2D\u6587";
      // x-windows-949 characters (Korean)
      private static final String TEST_LINE_X_WINDOWS_949_1 = "\uD55C\uAD6D\uC5B4";
      private static final String TEST_LINE_X_WINDOWS_949_2 = "\uB300\uD55C\uBBFC\uAD6D";
      // x-windows-950 characters (Traditional Chinese)
      private static final String TEST_LINE_X_WINDOWS_950_1 = "\u660E\u8F38\u5B50\u4EAC";
      private static final String TEST_LINE_X_WINDOWS_950_2 = "\u7E41\u9AD4\u4E2D\u6587";
  
      static void assertEqualsAndNoLineBreaks(final String expected, final String actual) {
          assertEqualsAndNoLineBreaks(expected, actual, null);
      }
  
      static void assertEqualsAndNoLineBreaks(final String expected, final String actual, final Supplier<String> messageSupplier) {
          if (actual != null) {
              assertFalse(actual.contains(LF.getString()), "Line contains \\n: line=" + actual);
              assertFalse(actual.contains(CR.getString()), "Line contains \\r: line=" + actual);
          }
          assertEquals(expected, actual, messageSupplier);
      }
  
      /**
       * Small and uneven block sizes are not used in reality but are good to show that the algorithm is solid.
       */
      public static IntStream blockSizes() {
          return IntStream.of(1, 3, 8, 10, 256, 4096, 8192);
      }
  
      private ReversedLinesFileReader reversedLinesFileReader;
  
      private void assertFileWithShrinkingTestLines(final ReversedLinesFileReader reversedLinesFileReader) throws IOException {
          final AtomicInteger count = new AtomicInteger();
          reversedLinesFileReader.forEach(
                  line -> assertEqualsAndNoLineBreaks(TEST_LINE.substring(0, count.incrementAndGet()), line, () -> "Line " + count + " is not matching"));
      }
  
     @AfterEach
     public void closeReader() {
         try {
             if (reversedLinesFileReader != null) {
                 reversedLinesFileReader.close();
             }
         } catch (final Exception e) {
             // ignore
         }
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testEmptyFile(final int blockSize) throws URISyntaxException, IOException {
         final File testFileEmpty = TestResources.getFile("/test-file-empty.bin");
         try (ReversedLinesFileReader reader = new ReversedLinesFileReader(testFileEmpty, blockSize, UTF_8)) {
             assertNull(reader.readLine());
         }
         try (ReversedLinesFileReader reader = ReversedLinesFileReader.builder().setFile(testFileEmpty).setBufferSize(blockSize).setCharset(UTF_8).get()) {
             assertNull(reader.readLine());
         }
     }
 
     @Test
     public void testFileSizeIsExactMultipleOfBlockSize() throws URISyntaxException, IOException {
         final int blockSize = 10;
         final File testFile20Bytes = TestResources.getFile("/test-file-20byteslength.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFile20Bytes, blockSize, ISO_8859_1);
         assertEqualsAndNoLineBreaks("987654321", reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks("123456789", reversedLinesFileReader.readLine());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testGBK(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileGBK = TestResources.getFile("/test-file-gbk.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileGBK, testParamBlockSize, "GBK");
         assertEqualsAndNoLineBreaks(TEST_LINE_GBK_2, reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks(TEST_LINE_GBK_1, reversedLinesFileReader.readLine());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testIsoFileDefaults(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileIso = TestResources.getFile("/test-file-iso8859-1.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileIso, testParamBlockSize, ISO_8859_1);
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testIsoFileManyWindowsBreaksSmallBlockSize2VerifyBlockSpanningNewLines(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileIso = TestResources.getFile("/test-file-iso8859-1-shortlines-win-linebr.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileIso, testParamBlockSize, ISO_8859_1);
 
         for (int i = 3; i > 0; i--) {
             for (int j = 1; j <= 3; j++) {
                 assertEqualsAndNoLineBreaks("", reversedLinesFileReader.readLine());
             }
             assertEqualsAndNoLineBreaks("" + i, reversedLinesFileReader.readLine());
         }
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testShiftJISFile(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileShiftJIS = TestResources.getFile("/test-file-shiftjis.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileShiftJIS, testParamBlockSize, "Shift_JIS");
         assertEqualsAndNoLineBreaks(TEST_LINE_SHIFT_JIS2, reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks(TEST_LINE_SHIFT_JIS1, reversedLinesFileReader.readLine());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUnsupportedEncodingBig5(final int testParamBlockSize) throws URISyntaxException {
         final File testFileEncodingBig5 = TestResources.getFile("/test-file-empty.bin");
         assertThrows(UnsupportedEncodingException.class,
                 () -> new ReversedLinesFileReader(testFileEncodingBig5, testParamBlockSize, "Big5").close());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUnsupportedEncodingUTF16(final int testParamBlockSize) throws URISyntaxException {
         final File testFileEmpty = TestResources.getFile("/test-file-empty.bin");
         assertThrows(UnsupportedEncodingException.class,
                 () -> new ReversedLinesFileReader(testFileEmpty, testParamBlockSize, StandardCharsets.UTF_16.name()).close());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF16BEFile(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileUTF16BE = TestResources.getFile("/test-file-utf16be.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileUTF16BE, testParamBlockSize, StandardCharsets.UTF_16BE.name());
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF16LEFile(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileUTF16LE = TestResources.getFile("/test-file-utf16le.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileUTF16LE, testParamBlockSize, StandardCharsets.UTF_16LE.name());
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF8File(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileIso = TestResources.getFile("/test-file-utf8.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileIso, testParamBlockSize, UTF_8);
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF8FileCRBreaks(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileIso = TestResources.getFile("/test-file-utf8-cr-only.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileIso, testParamBlockSize, UTF_8);
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF8FileWindowsBreaks(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileIso = TestResources.getFile("/test-file-utf8-win-linebr.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileIso, testParamBlockSize, UTF_8);
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testUTF8FileWindowsBreaksSmallBlockSize2VerifyBlockSpanningNewLines(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileUtf8 = TestResources.getFile("/test-file-utf8-win-linebr.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileUtf8, testParamBlockSize, UTF_8);
         assertFileWithShrinkingTestLines(reversedLinesFileReader);
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testWindows31jFile(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFileWindows31J = TestResources.getFile("/test-file-windows-31j.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFileWindows31J, testParamBlockSize, "windows-31j");
         assertEqualsAndNoLineBreaks(TEST_LINE_WINDOWS_31J_2, reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks(TEST_LINE_WINDOWS_31J_1, reversedLinesFileReader.readLine());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testxWindows949File(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFilexWindows949 = TestResources.getFile("/test-file-x-windows-949.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFilexWindows949, testParamBlockSize, "x-windows-949");
         assertEqualsAndNoLineBreaks(TEST_LINE_X_WINDOWS_949_2, reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks(TEST_LINE_X_WINDOWS_949_1, reversedLinesFileReader.readLine());
     }
 
     @ParameterizedTest(name = "BlockSize={0}")
     @MethodSource("blockSizes")
     public void testxWindows950File(final int testParamBlockSize) throws URISyntaxException, IOException {
         final File testFilexWindows950 = TestResources.getFile("/test-file-x-windows-950.bin");
         reversedLinesFileReader = new ReversedLinesFileReader(testFilexWindows950, testParamBlockSize, "x-windows-950");
         assertEqualsAndNoLineBreaks(TEST_LINE_X_WINDOWS_950_2, reversedLinesFileReader.readLine());
         assertEqualsAndNoLineBreaks(TEST_LINE_X_WINDOWS_950_1, reversedLinesFileReader.readLine());
     }
 }