/*
    * 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
    *
    *      https://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.codec.binary;
  
  import static org.junit.jupiter.api.Assertions.assertArrayEquals;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.BufferedReader;
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  
  import org.apache.commons.codec.CodecPolicy;
  import org.apache.commons.io.IOUtils;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link Base64InputStream}.
   */
  class Base64InputStreamTest {
  
      /**
       * Decodes to {0, 0, 0, 255, 255, 255}
       */
      private static final String ENCODED_B64 = "AAAA////";
  
      private static final byte[] CRLF = { (byte) '\r', (byte) '\n' };
  
      private static final byte[] LF = { (byte) '\n' };
  
      private static final String STRING_FIXTURE = "Hello World";
  
      /**
       * Tests skipping past the end of a stream.
       *
       * @throws Throwable
       *             for some failure scenarios.
       */
      @Test
      void testAvailable() throws Throwable {
          final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
          try (Base64InputStream b64stream = new Base64InputStream(ins)) {
              assertEquals(1, b64stream.available());
              assertEquals(6, b64stream.skip(10));
              // End of stream reached
              assertEquals(0, b64stream.available());
              assertEquals(-1, b64stream.read());
              assertEquals(-1, b64stream.read());
              assertEquals(0, b64stream.available());
          }
      }
  
      private void testBase64EmptyInputStream(final int chuckSize) throws Exception {
          final byte[] emptyEncoded = {};
          final byte[] emptyDecoded = {};
          testByteByByte(emptyEncoded, emptyDecoded, chuckSize, CRLF);
          testByChunk(emptyEncoded, emptyDecoded, chuckSize, CRLF);
      }
  
      /**
       * Tests the Base64InputStream implementation against empty input.
       *
       * @throws Exception
       *             for some failure scenarios.
       */
      @Test
      void testBase64EmptyInputStreamMimeChuckSize() throws Exception {
          testBase64EmptyInputStream(BaseNCodec.MIME_CHUNK_SIZE);
      }
  
      /**
       * Tests the Base64InputStream implementation against empty input.
       *
       * @throws Exception
       *             for some failure scenarios.
       */
      @Test
      void testBase64EmptyInputStreamPemChuckSize() throws Exception {
         testBase64EmptyInputStream(BaseNCodec.PEM_CHUNK_SIZE);
     }
 
     /**
      * Tests the Base64InputStream implementation.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testBase64InputStreamByChunk() throws Exception {
         // Hello World test.
         byte[] encoded = StringUtils.getBytesUtf8("SGVsbG8gV29ybGQ=\r\n");
         byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         testByChunk(encoded, decoded, BaseNCodec.MIME_CHUNK_SIZE, CRLF);
 
         // Single Byte test.
         encoded = StringUtils.getBytesUtf8("AA==\r\n");
         decoded = new byte[] { (byte) 0 };
         testByChunk(encoded, decoded, BaseNCodec.MIME_CHUNK_SIZE, CRLF);
 
         // OpenSSL interop test.
         encoded = StringUtils.getBytesUtf8(Base64TestData.ENCODED_64_CHARS_PER_LINE);
         decoded = BaseNTestData.DECODED;
         testByChunk(encoded, decoded, BaseNCodec.PEM_CHUNK_SIZE, LF);
 
         // Single Line test.
         final String singleLine = Base64TestData.ENCODED_64_CHARS_PER_LINE.replace("\n", "");
         encoded = StringUtils.getBytesUtf8(singleLine);
         decoded = BaseNTestData.DECODED;
         testByChunk(encoded, decoded, 0, LF);
 
         // test random data of sizes 0 through 150
         final BaseNCodec codec = new Base64(0, null, false);
         for (int i = 0; i <= 150; i++) {
             final byte[][] randomData = BaseNTestData.randomData(codec, i);
             encoded = randomData[1];
             decoded = randomData[0];
             testByChunk(encoded, decoded, 0, LF);
         }
     }
 
     /**
      * Tests the Base64InputStream implementation.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testBase64InputStreamByteByByte() throws Exception {
         // Hello World test.
         byte[] encoded = StringUtils.getBytesUtf8("SGVsbG8gV29ybGQ=\r\n");
         byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         testByteByByte(encoded, decoded, BaseNCodec.MIME_CHUNK_SIZE, CRLF);
 
         // Single Byte test.
         encoded = StringUtils.getBytesUtf8("AA==\r\n");
         decoded = new byte[] { (byte) 0 };
         testByteByByte(encoded, decoded, BaseNCodec.MIME_CHUNK_SIZE, CRLF);
 
         // OpenSSL interop test.
         encoded = StringUtils.getBytesUtf8(Base64TestData.ENCODED_64_CHARS_PER_LINE);
         decoded = BaseNTestData.DECODED;
         testByteByByte(encoded, decoded, BaseNCodec.PEM_CHUNK_SIZE, LF);
 
         // Single Line test.
         final String singleLine = Base64TestData.ENCODED_64_CHARS_PER_LINE.replace("\n", "");
         encoded = StringUtils.getBytesUtf8(singleLine);
         decoded = BaseNTestData.DECODED;
         testByteByByte(encoded, decoded, 0, LF);
 
         // test random data of sizes 0 through 150
         final BaseNCodec codec = new Base64(0, null, false);
         for (int i = 0; i <= 150; i++) {
             final byte[][] randomData = BaseNTestData.randomData(codec, i);
             encoded = randomData[1];
             decoded = randomData[0];
             testByteByByte(encoded, decoded, 0, LF);
         }
     }
 
     @Test
     void testBuilder() {
         assertNotNull(Base64InputStream.builder().getBaseNCodec());
     }
 
     /**
      * Tests method does three tests on the supplied data: 1. encoded ---[DECODE]--> decoded 2. decoded ---[ENCODE]--> encoded 3. decoded
      * ---[WRAP-WRAP-WRAP-etc...] --> decoded
      * <p/>
      * By "[WRAP-WRAP-WRAP-etc...]" we mean situation where the Base64InputStream wraps itself in encode and decode mode over and over
      * again.
      *
      * @param encoded
      *            base64 encoded data
      * @param decoded
      *            the data from above, but decoded
      * @param chunkSize
      *            chunk size (line-length) of the base64 encoded data.
      * @param separator
      *            Line separator in the base64 encoded data.
      * @throws Exception
      *             Usually signifies a bug in the Base64 commons-codec implementation.
      */
     private void testByChunk(final byte[] encoded, final byte[] decoded, final int chunkSize, final byte[] separator) throws Exception {
         // Start with encode.
         try (InputStream in = new Base64InputStream(new ByteArrayInputStream(decoded), true, chunkSize, separator)) {
             final byte[] output = IOUtils.toByteArray(in);
             assertEquals(-1, in.read(), "EOF");
             assertEquals(-1, in.read(), "Still EOF");
             assertArrayEquals(encoded, output, "Streaming base64 encode");
         }
 
         // Now let's try to decode.
         InputStream in = new Base64InputStream(new ByteArrayInputStream(encoded));
         final InputStream in1 = in;
         byte[] output = IOUtils.toByteArray(in1);
 
         assertEquals(-1, in.read(), "EOF");
         assertEquals(-1, in.read(), "Still EOF");
         assertArrayEquals(decoded, output, "Streaming base64 decode");
 
         // I always wanted to do this! (wrap encoder with decoder etc.).
         in = new ByteArrayInputStream(decoded);
         for (int i = 0; i < 10; i++) {
             in = new Base64InputStream(in, true, chunkSize, separator);
             in = new Base64InputStream(in, false);
         }
         final InputStream in2 = in;
         output = IOUtils.toByteArray(in2);
 
         assertEquals(-1, in.read(), "EOF");
         assertEquals(-1, in.read(), "Still EOF");
         assertArrayEquals(decoded, output, "Streaming base64 wrap-wrap-wrap!");
         in.close();
     }
 
     /**
      * Tests method does three tests on the supplied data: 1. encoded ---[DECODE]--> decoded 2. decoded ---[ENCODE]--> encoded 3. decoded
      * ---[WRAP-WRAP-WRAP-etc...] --> decoded
      * <p/>
      * By "[WRAP-WRAP-WRAP-etc...]" we mean situation where the Base64InputStream wraps itself in encode and decode mode over and over
      * again.
      *
      * @param encoded
      *            base64 encoded data
      * @param decoded
      *            the data from above, but decoded
      * @param chunkSize
      *            chunk size (line-length) of the base64 encoded data.
      * @param separator
      *            Line separator in the base64 encoded data.
      * @throws Exception
      *             Usually signifies a bug in the Base64 commons-codec implementation.
      */
     private void testByteByByte(final byte[] encoded, final byte[] decoded, final int chunkSize, final byte[] separator) throws Exception {
         byte[] output = new byte[encoded.length];
         // Start with encode.
         try (InputStream in = new Base64InputStream(new ByteArrayInputStream(decoded), true, chunkSize, separator)) {
             for (int i = 0; i < output.length; i++) {
                 output[i] = (byte) in.read();
             }
 
             assertEquals(-1, in.read(), "EOF");
             assertEquals(-1, in.read(), "Still EOF");
             assertArrayEquals(encoded, output, "Streaming base64 encode");
 
         }
         // Now let's try to decode.
         try (InputStream in = new Base64InputStream(new ByteArrayInputStream(encoded))) {
             output = new byte[decoded.length];
             for (int i = 0; i < output.length; i++) {
                 output[i] = (byte) in.read();
             }
 
             assertEquals(-1, in.read(), "EOF");
             assertEquals(-1, in.read(), "Still EOF");
             assertArrayEquals(decoded, output, "Streaming base64 decode");
         }
 
         // I always wanted to do this! (wrap encoder with decoder etc.).
         InputStream in = new ByteArrayInputStream(decoded);
         for (int i = 0; i < 10; i++) {
             in = new Base64InputStream(in, true, chunkSize, separator);
             in = new Base64InputStream(in, false);
         }
         output = new byte[decoded.length];
         for (int i = 0; i < output.length; i++) {
             output[i] = (byte) in.read();
         }
 
         assertEquals(-1, in.read(), "EOF");
         assertEquals(-1, in.read(), "Still EOF");
         assertArrayEquals(decoded, output, "Streaming base64 wrap-wrap-wrap!");
     }
 
     /**
      * Test for the CODEC-101 bug: InputStream.read(byte[]) should never return 0 because Java's builtin InputStreamReader hates that.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testCodec101() throws Exception {
         final byte[] codec101 = StringUtils.getBytesUtf8(Base64TestData.CODEC_101_INPUT_LENGTH_IS_MULTIPLE_OF_3);
         final ByteArrayInputStream bais = new ByteArrayInputStream(codec101);
         try (Base64InputStream in = new Base64InputStream(bais)) {
             final byte[] result = new byte[8192];
             int c = in.read(result);
             assertTrue(c > 0, "Codec101: First read successful [c=" + c + "]");
 
             c = in.read(result);
             assertTrue(c < 0, "Codec101: Second read should report end-of-stream [c=" + c + "]");
         }
     }
 
     /**
      * Tests the bug reported in CODEC-105. Bad interactions with InputStream when reading one byte at a time.
      */
     @Test
     void testCodec105() throws IOException {
         try (Base64InputStream in = new Base64InputStream(new Codec105ErrorInputStream(), true, 0, null)) {
             for (int i = 0; i < 5; i++) {
                 in.read();
             }
         }
     }
 
     /**
      * Tests the problem reported in CODEC-130. Missing / wrong implementation of skip.
      */
     @Test
     void testCodec130() throws IOException {
         final ByteArrayOutputStream bos = new ByteArrayOutputStream();
         try (Base64OutputStream base64os = new Base64OutputStream(bos)) {
             base64os.write(StringUtils.getBytesUtf8(STRING_FIXTURE));
         }
 
         final ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
         final Base64InputStream ins = new Base64InputStream(bis);
 
         // we skip the first character read from the reader
         ins.skip(1);
         final byte[] decodedBytes = IOUtils.toByteArray(ins);
         final String str = StringUtils.newStringUtf8(decodedBytes);
 
         assertEquals(STRING_FIXTURE.substring(1), str);
     }
 
     /**
      * Test the Base64InputStream implementation against the special NPE inducing input identified in the CODEC-98 bug.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testCodec98NPE() throws Exception {
         final byte[] codec98 = StringUtils.getBytesUtf8(Base64TestData.CODEC_98_NPE);
         final ByteArrayInputStream data = new ByteArrayInputStream(codec98);
         final Base64InputStream stream = new Base64InputStream(data);
 
         // This line causes an NPE in commons-codec-1.4.jar:
         final byte[] decodedBytes = IOUtils.toByteArray(stream);
 
         final String decoded = StringUtils.newStringUtf8(decodedBytes);
         assertEquals(Base64TestData.CODEC_98_NPE_DECODED, decoded, "codec-98 NPE Base64InputStream");
     }
 
     /**
      * Another test for the CODEC-101 bug: In commons-codec-1.4 this test shows InputStreamReader explicitly hating an
      * InputStream.read(byte[]) return of 0:
      *
      * java.io.IOException: Underlying input stream returned zero bytes at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:268) at
      * sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306) at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158) at
      * java.io.InputStreamReader.read(InputStreamReader.java:167) at java.io.BufferedReader.fill(BufferedReader.java:136) at
      * java.io.BufferedReader.readLine(BufferedReader.java:299) at java.io.BufferedReader.readLine(BufferedReader.java:362) at
      * org.apache.commons.codec.binary.Base64InputStreamTest.testInputStreamReader(Base64InputStreamTest.java:75)
      *
      * But in commons-codec-1.5 it's fixed. :-)
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testInputStreamReader() throws Exception {
         final byte[] codec101 = StringUtils.getBytesUtf8(Base64TestData.CODEC_101_INPUT_LENGTH_IS_MULTIPLE_OF_3);
         final ByteArrayInputStream bais = new ByteArrayInputStream(codec101);
         final Base64InputStream in = new Base64InputStream(bais);
         final InputStreamReader isr = new InputStreamReader(in);
         try (BufferedReader br = new BufferedReader(isr)) {
             final String line = br.readLine();
             assertNotNull(line, "Codec101:  InputStreamReader works!");
         }
     }
 
     /**
      * Tests markSupported.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testMarkSupported() throws Exception {
         final byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         final ByteArrayInputStream bin = new ByteArrayInputStream(decoded);
         try (Base64InputStream in = new Base64InputStream(bin, true, 4, new byte[] { 0, 0, 0 })) {
             // Always returns false for now.
             assertFalse(in.markSupported(), "Base64InputStream.markSupported() is false");
         }
     }
 
     /**
      * Tests read returning 0
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testRead0() throws Exception {
         final byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         final byte[] buf = new byte[1024];
         int bytesRead = 0;
         final ByteArrayInputStream bin = new ByteArrayInputStream(decoded);
         try (Base64InputStream in = new Base64InputStream(bin, true, 4, new byte[] { 0, 0, 0 })) {
             bytesRead = in.read(buf, 0, 0);
             assertEquals(0, bytesRead, "Base64InputStream.read(buf, 0, 0) returns 0");
         }
     }
 
     /**
      * Tests read using different buffer sizes
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testReadMultipleBufferSizes() throws Exception {
         final byte[][] randomData = BaseNTestData.randomData(new Base64(0, null, false), 1024 * 64);
         final byte[] encoded = randomData[1];
         final byte[] decoded = randomData[0];
         final ByteArrayInputStream bin = new ByteArrayInputStream(encoded);
         final ByteArrayOutputStream out = new ByteArrayOutputStream();
         try (Base64InputStream in = new Base64InputStream(bin)) {
             for (final int i : new int[] { 4 * 1024, 4 * 1024, 8 * 1024, 8 * 1024, 16 * 1024, 16 * 1024, 8 * 1024 }) {
                 final byte[] buf = new byte[i];
                 final int bytesRead = in.read(buf);
                 assertEquals(i, bytesRead);
                 out.write(buf, 0, bytesRead);
             }
         }
         assertArrayEquals(decoded, out.toByteArray());
     }
 
     /**
      * Tests read with null.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testReadNull() throws Exception {
         final byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         final ByteArrayInputStream bin = new ByteArrayInputStream(decoded);
         try (Base64InputStream in = new Base64InputStream(bin, true, 4, new byte[] { 0, 0, 0 })) {
             assertThrows(NullPointerException.class, () -> in.read(null, 0, 0));
         }
     }
 
     /**
      * Tests read throwing IndexOutOfBoundsException
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testReadOutOfBounds() throws Exception {
         final byte[] decoded = StringUtils.getBytesUtf8(STRING_FIXTURE);
         final byte[] buf = new byte[1024];
         final ByteArrayInputStream bin = new ByteArrayInputStream(decoded);
         try (Base64InputStream in = new Base64InputStream(bin, true, 4, new byte[] {0, 0, 0})) {
             assertThrows(IndexOutOfBoundsException.class, () -> in.read(buf, -1, 0), "Base64InputStream.read(buf, -1, 0)");
             assertThrows(IndexOutOfBoundsException.class, () -> in.read(buf, 0, -1), "Base64InputStream.read(buf, 0, -1)");
             assertThrows(IndexOutOfBoundsException.class, () -> in.read(buf, buf.length + 1, 0), "Base64InputStream.read(buf, buf.length + 1, 0)");
             assertThrows(IndexOutOfBoundsException.class, () -> in.read(buf, buf.length - 1, 2), "Base64InputStream.read(buf, buf.length - 1, 2)");
         }
     }
 
     /**
      * Tests skipping number of characters larger than the internal buffer.
      *
      * @throws Throwable
      *             for some failure scenarios.
      */
     @Test
     void testSkipBig() throws Throwable {
         final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
         try (Base64InputStream b64stream = new Base64InputStream(ins)) {
             assertEquals(6, b64stream.skip(Integer.MAX_VALUE));
             // End of stream reached
             assertEquals(-1, b64stream.read());
             assertEquals(-1, b64stream.read());
         }
     }
 
     /**
      * Tests skipping as a noop
      *
      * @throws Throwable
      *             for some failure scenarios.
      */
     @Test
     void testSkipNone() throws Throwable {
         final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
         try (Base64InputStream b64stream = new Base64InputStream(ins)) {
             final byte[] actualBytes = new byte[6];
             assertEquals(0, b64stream.skip(0));
             b64stream.read(actualBytes, 0, actualBytes.length);
             assertArrayEquals(actualBytes, new byte[] { 0, 0, 0, (byte) 255, (byte) 255, (byte) 255 });
             // End of stream reached
             assertEquals(-1, b64stream.read());
         }
     }
 
     /**
      * Tests skipping past the end of a stream.
      *
      * @throws Throwable
      *             for some failure scenarios.
      */
     @Test
     void testSkipPastEnd() throws Throwable {
         final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
         try (Base64InputStream b64stream = new Base64InputStream(ins)) {
             // due to CODEC-130, skip now skips correctly decoded characters rather than encoded
             assertEquals(6, b64stream.skip(10));
             // End of stream reached
             assertEquals(-1, b64stream.read());
             assertEquals(-1, b64stream.read());
         }
     }
 
     /**
      * Tests skipping to the end of a stream.
      *
      * @throws Throwable
      *             for some failure scenarios.
      */
     @Test
     void testSkipToEnd() throws Throwable {
         final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
         try (Base64InputStream b64stream = new Base64InputStream(ins)) {
             // due to CODEC-130, skip now skips correctly decoded characters rather than encoded
             assertEquals(6, b64stream.skip(6));
             // End of stream reached
             assertEquals(-1, b64stream.read());
             assertEquals(-1, b64stream.read());
         }
     }
 
     /**
      * Tests if negative arguments to skip are handled correctly.
      *
      * @throws Throwable
      *             for some failure scenarios.
      */
     @Test
     void testSkipWrongArgument() throws Throwable {
         final InputStream ins = new ByteArrayInputStream(StringUtils.getBytesIso8859_1(ENCODED_B64));
         try (Base64InputStream b64stream = new Base64InputStream(ins)) {
             assertThrows(IllegalArgumentException.class, () -> b64stream.skip(-10));
         }
     }
 
     /**
      * Test strict decoding.
      *
      * @throws Exception
      *             for some failure scenarios.
      */
     @Test
     void testStrictDecoding() throws Exception {
         for (final String s : Base64Test.BASE64_IMPOSSIBLE_CASES) {
             final byte[] encoded = StringUtils.getBytesUtf8(s);
             final Base64InputStream in = new Base64InputStream(new ByteArrayInputStream(encoded), false);
             // Default is lenient decoding; it should not throw
             assertFalse(in.isStrictDecoding());
             IOUtils.toByteArray(in);
             // Strict decoding should throw
             final Base64InputStream in2 = new Base64InputStream(new ByteArrayInputStream(encoded), false, 0, null, CodecPolicy.STRICT);
             assertTrue(in2.isStrictDecoding());
             assertThrows(IllegalArgumentException.class, () -> IOUtils.toByteArray(in2));
             // Same with a builder
             try (Base64InputStream in3 = Base64InputStream.builder()
                     .setByteArray(encoded)
                     .setEncode(false)
                     .setBaseNCodec(Base64.builder().setLineLength(0).setLineSeparator(null).setDecodingPolicy(CodecPolicy.STRICT).get())
                     .get()) {
                 assertTrue(in3.isStrictDecoding());
                 assertThrows(IllegalArgumentException.class, () -> IOUtils.toByteArray(in3));
             }
         }
     }
 }