/*
    * 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.junit.jupiter.api.Assertions.assertDoesNotThrow;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  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.CharArrayReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.nio.charset.CharacterCodingException;
  import java.nio.charset.Charset;
  import java.nio.charset.CharsetEncoder;
  import java.nio.charset.CodingErrorAction;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  import java.util.Random;
  import java.util.concurrent.TimeUnit;
  import java.util.stream.Stream;
  
  import javax.xml.parsers.DocumentBuilderFactory;
  
  import org.apache.commons.io.IOUtils;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.Timeout;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.Arguments;
  import org.junit.jupiter.params.provider.MethodSource;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  public class ReaderInputStreamTest {
  
      private static final String UTF_16 = StandardCharsets.UTF_16.name();
      private static final String UTF_8 = StandardCharsets.UTF_8.name();
      private static final String TEST_STRING = "\u00e0 peine arriv\u00e9s nous entr\u00e2mes dans sa chambre";
      private static final String LARGE_TEST_STRING;
  
      static {
          final StringBuilder buffer = new StringBuilder();
          for (int i = 0; i < 100; i++) {
              buffer.append(TEST_STRING);
          }
          LARGE_TEST_STRING = buffer.toString();
      }
  
      static Stream<Arguments> charsetData() {
          // @formatter:off
          return Stream.of(
                  Arguments.of("Cp930", "\u0391"),
                  Arguments.of("ISO_8859_1", "A"),
                  Arguments.of(UTF_8, "\u0391"));
          // @formatter:on
      }
  
      private final Random random = new Random();
  
      @Test
      @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
      public void testBufferSmallest() throws IOException {
          final Charset charset = StandardCharsets.UTF_8;
          // @formatter:off
          try (InputStream in = new ReaderInputStream(
                  new StringReader("\uD800"),
                  charset, (int)
                  ReaderInputStream.minBufferSize(charset.newEncoder()))) {
              in.read();
          }
          try (InputStream in = ReaderInputStream.builder()
                  .setReader(new StringReader("\uD800"))
                  .setCharset(charset)
                  .setBufferSize((int) ReaderInputStream.minBufferSize(charset.newEncoder()))
                  .get()) {
              in.read();
          }
          // @formatter:on
      }
  
      @Test
      public void testBufferTooSmall() {
          assertThrows(IllegalArgumentException.class, () -> new ReaderInputStream(new StringReader("\uD800"), StandardCharsets.UTF_8, -1));
         assertThrows(IllegalArgumentException.class, () -> new ReaderInputStream(new StringReader("\uD800"), StandardCharsets.UTF_8, 0));
         assertThrows(IllegalArgumentException.class, () -> new ReaderInputStream(new StringReader("\uD800"), StandardCharsets.UTF_8, 1));
     }
 
     @ParameterizedTest
     @MethodSource("charsetData")
     public void testCharsetEncoderFlush(final String charsetName, final String data) throws IOException {
         final Charset charset = Charset.forName(charsetName);
         final byte[] expected = data.getBytes(charset);
         try (InputStream in = new ReaderInputStream(new StringReader(data), charset)) {
             assertEquals(Arrays.toString(expected), Arrays.toString(IOUtils.toByteArray(in)));
         }
         try (InputStream in = ReaderInputStream.builder().setReader(new StringReader(data)).setCharset(charset).get()) {
             assertEquals(Arrays.toString(expected), Arrays.toString(IOUtils.toByteArray(in)));
         }
     }
 
     /*
      * Tests https://issues.apache.org/jira/browse/IO-277
      */
     @Test
     public void testCharsetMismatchInfiniteLoop() throws IOException {
         // Input is UTF-8 bytes: 0xE0 0xB2 0xA0
         final char[] inputChars = { (char) 0xE0, (char) 0xB2, (char) 0xA0 };
         // Charset charset = Charset.forName("UTF-8"); // works
         final Charset charset = StandardCharsets.US_ASCII; // infinite loop
         try (ReaderInputStream stream = new ReaderInputStream(new CharArrayReader(inputChars), charset)) {
             IOUtils.toCharArray(stream, charset);
         }
     }
 
     @Test
     @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
     public void testCodingError() throws IOException {
         // Encoder which throws on malformed or unmappable input
         CharsetEncoder encoder = StandardCharsets.UTF_8.newEncoder();
         try (final ReaderInputStream in = new ReaderInputStream(new StringReader("\uD800"), encoder)) {
             // Does not throws an exception because the input is an underflow and not an error
             assertDoesNotThrow(() -> in.read());
             // assertThrows(IllegalStateException.class, () -> in.read());
         }
         encoder = StandardCharsets.UTF_8.newEncoder();
         try (final ReaderInputStream in = ReaderInputStream.builder().setReader(new StringReader("\uD800")).setCharsetEncoder(encoder).get()) {
             // TODO WIP
             assertDoesNotThrow(() -> in.read());
             // assertThrows(IllegalStateException.class, () -> in.read());
         }
     }
 
     /**
      * Tests IO-717 to avoid infinite loops.
      *
      * ReaderInputStream does not throw exception with {@link CodingErrorAction#REPORT}.
      */
     @Test
     @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
     public void testCodingErrorAction() throws IOException {
         final Charset charset = StandardCharsets.UTF_8;
         final CharsetEncoder encoder = charset.newEncoder().onMalformedInput(CodingErrorAction.REPORT);
         try (InputStream in = new ReaderInputStream(new StringReader("\uD800aa"), encoder, (int) ReaderInputStream.minBufferSize(encoder))) {
             assertThrows(CharacterCodingException.class, in::read);
         }
         try (InputStream in = ReaderInputStream.builder().setReader(new StringReader("\uD800aa")).setCharsetEncoder(encoder)
                 .setBufferSize((int) ReaderInputStream.minBufferSize(charset.newEncoder())).get()) {
             assertThrows(CharacterCodingException.class, in::read);
         }
     }
 
     @Test
     @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
     public void testConstructNullCharset() throws IOException {
         final Charset charset = Charset.defaultCharset();
         final Charset encoder = null;
         try (ReaderInputStream in = new ReaderInputStream(new StringReader("ABC"), encoder, (int) ReaderInputStream.minBufferSize(charset.newEncoder()))) {
             IOUtils.toByteArray(in);
             assertEquals(Charset.defaultCharset(), in.getCharsetEncoder().charset());
         }
     }
 
     @Test
     @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
     public void testConstructNullCharsetEncoder() throws IOException {
         final Charset charset = Charset.defaultCharset();
         final CharsetEncoder encoder = null;
         try (ReaderInputStream in = new ReaderInputStream(new StringReader("ABC"), encoder, (int) ReaderInputStream.minBufferSize(charset.newEncoder()))) {
             IOUtils.toByteArray(in);
             assertEquals(Charset.defaultCharset(), in.getCharsetEncoder().charset());
         }
     }
 
     @Test
     @Timeout(value = 500, unit = TimeUnit.MILLISECONDS)
     public void testConstructNullCharsetNameEncoder() throws IOException {
         final Charset charset = Charset.defaultCharset();
         final String charsetName = null;
         try (ReaderInputStream in = new ReaderInputStream(new StringReader("ABC"), charsetName, (int) ReaderInputStream.minBufferSize(charset.newEncoder()))) {
             IOUtils.toByteArray(in);
             assertEquals(Charset.defaultCharset(), in.getCharsetEncoder().charset());
         }
         try (ReaderInputStream in = ReaderInputStream.builder().setReader(new StringReader("ABC")).setCharset(charsetName)
                 .setBufferSize((int) ReaderInputStream.minBufferSize(charset.newEncoder())).get()) {
             IOUtils.toByteArray(in);
             assertEquals(Charset.defaultCharset(), in.getCharsetEncoder().charset());
         }
     }
 
     @Test
     public void testIo803SAXException() throws IOException {
         final StringReader reader = new StringReader("");
         try (final ReaderInputStream inputStream = ReaderInputStream.builder().setCharset(StandardCharsets.UTF_8).setReader(reader).get()) {
             final InputSource inputSource = new InputSource(inputStream);
             assertThrows(SAXException.class, () -> DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(inputSource));
         }
     }
 
     @Test
     public void testIo803StringReaderSanityCheck() {
         final StringReader reader = new StringReader("");
         final InputSource inputSource = new InputSource(reader);
         assertThrows(SAXException.class, () -> DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(inputSource));
     }
 
     @Test
     public void testLargeUTF8WithBufferedRead() throws IOException {
         testWithBufferedRead(LARGE_TEST_STRING, UTF_8);
     }
 
     @Test
     public void testLargeUTF8WithSingleByteRead() throws IOException {
         testWithSingleByteRead(LARGE_TEST_STRING, UTF_8);
     }
 
     @Test
     public void testReadEofTwice() throws IOException {
         try (ReaderInputStream reader = ReaderInputStream.builder().setCharset(StandardCharsets.UTF_8).setReader(new StringReader("123")).get()) {
             assertEquals('1', reader.read());
             assertEquals('2', reader.read());
             assertEquals('3', reader.read());
             assertEquals(-1, reader.read());
             assertEquals(-1, reader.read());
         }
     }
 
     @SuppressWarnings("deprecation")
     @Test
     public void testReadZero() throws Exception {
         final String inStr = "test";
         try (ReaderInputStream inputStream = new ReaderInputStream(new StringReader(inStr))) {
             testReadZero(inStr, inputStream);
         }
         try (ReaderInputStream inputStream = ReaderInputStream.builder().setReader(new StringReader(inStr)).get()) {
             testReadZero(inStr, inputStream);
         }
     }
 
     private void testReadZero(final String inStr, final ReaderInputStream inputStream) throws IOException {
         final byte[] bytes = new byte[30];
         assertEquals(0, inputStream.read(bytes, 0, 0));
         assertEquals(inStr.length(), inputStream.read(bytes, 0, inStr.length() + 1));
         // Should always return 0 for length == 0
         assertEquals(0, inputStream.read(bytes, 0, 0));
     }
 
     @SuppressWarnings("deprecation")
     @Test
     public void testReadZeroEmptyString() throws Exception {
         try (ReaderInputStream inputStream = new ReaderInputStream(new StringReader(""))) {
             final byte[] bytes = new byte[30];
             // Should always return 0 for length == 0
             assertEquals(0, inputStream.read(bytes, 0, 0));
             assertEquals(-1, inputStream.read(bytes, 0, 1));
             assertEquals(0, inputStream.read(bytes, 0, 0));
             assertEquals(-1, inputStream.read(bytes, 0, 1));
         }
     }
 
     @Test
     public void testResetCharset() {
         assertNotNull(ReaderInputStream.builder().setReader(new StringReader("\uD800")).setCharset((Charset) null).getCharset());
     }
 
     @Test
     public void testResetCharsetEncoder() {
         assertNotNull(ReaderInputStream.builder().setReader(new StringReader("\uD800")).setCharsetEncoder(null).getCharsetEncoder());
     }
 
     @Test
     public void testResetCharsetName() {
         assertNotNull(ReaderInputStream.builder().setReader(new StringReader("\uD800")).setCharset((String) null).getCharset());
     }
 
     @Test
     public void testUTF16WithSingleByteRead() throws IOException {
         testWithSingleByteRead(TEST_STRING, UTF_16);
     }
 
     @Test
     public void testUTF8WithBufferedRead() throws IOException {
         testWithBufferedRead(TEST_STRING, UTF_8);
     }
 
     @Test
     public void testUTF8WithSingleByteRead() throws IOException {
         testWithSingleByteRead(TEST_STRING, UTF_8);
     }
 
     private void testWithBufferedRead(final byte[] expected, final ReaderInputStream in) throws IOException {
         final byte[] buffer = new byte[128];
         int offset = 0;
         while (true) {
             int bufferOffset = random.nextInt(64);
             final int bufferLength = random.nextInt(64);
             int read = in.read(buffer, bufferOffset, bufferLength);
             if (read == -1) {
                 assertEquals(offset, expected.length);
                 break;
             }
             assertTrue(read <= bufferLength);
             while (read > 0) {
                 assertTrue(offset < expected.length);
                 assertEquals(expected[offset], buffer[bufferOffset]);
                 offset++;
                 bufferOffset++;
                 read--;
             }
         }
     }
 
     private void testWithBufferedRead(final String testString, final String charsetName) throws IOException {
         final byte[] expected = testString.getBytes(charsetName);
         try (ReaderInputStream in = new ReaderInputStream(new StringReader(testString), charsetName)) {
             testWithBufferedRead(expected, in);
         }
         try (ReaderInputStream in = ReaderInputStream.builder().setReader(new StringReader(testString)).setCharset(charsetName).get()) {
             testWithBufferedRead(expected, in);
         }
     }
 
     private void testWithSingleByteRead(final String testString, final String charsetName) throws IOException {
         final byte[] bytes = testString.getBytes(charsetName);
         try (ReaderInputStream in = new ReaderInputStream(new StringReader(testString), charsetName)) {
             for (final byte b : bytes) {
                 final int read = in.read();
                 assertTrue(read >= 0);
                 assertTrue(read <= 255);
                 assertEquals(b, (byte) read);
             }
             assertEquals(-1, in.read());
         }
     }
 }