/*
    * 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.maven.plugin.surefire.report;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.RandomAccessFile;
  import java.io.UncheckedIOException;
  import java.lang.ref.SoftReference;
  import java.nio.Buffer;
  import java.nio.ByteBuffer;
  import java.nio.file.Path;
  
  import org.apache.maven.surefire.api.util.SureFireFileManager;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  import static java.nio.file.Files.notExists;
  import static java.nio.file.Files.size;
  import static java.util.Objects.requireNonNull;
  import static org.apache.maven.surefire.api.util.internal.StringUtils.NL;
  
  /**
   * A deferred file output stream decorator that encodes the string from the VM to UTF-8.
   * <br>
   * The deferred file is temporary file, and it is created at the first {@link #write(String, boolean) write}.
   * The {@link #writeTo(OutputStream) reads} can be called anytime.
   * It is highly recommended to {@link #commit() commit} the cache which would close the file stream
   * and subsequent reads may continue.
   * The {@link #free()} method would commit and delete the deferred file.
   *
   * @author Andreas Gudian
   */
  final class Utf8RecodingDeferredFileOutputStream {
      private static final byte[] NL_BYTES = NL.getBytes(UTF_8);
      public static final int CACHE_SIZE = 64 * 1024;
  
      private final String channel;
      private Path file;
      private RandomAccessFile storage;
      private boolean closed;
      private SoftReference<byte[]> largeCache;
      private ByteBuffer cache;
      private boolean isDirty;
  
      Utf8RecodingDeferredFileOutputStream(String channel) {
          this.channel = requireNonNull(channel);
      }
  
      public synchronized void write(String output, boolean newLine) throws IOException {
          if (closed) {
              return;
          }
  
          if (storage == null) {
  
              file = SureFireFileManager.createTempFile(channel, "deferred").toPath();
              storage = new RandomAccessFile(file.toFile(), "rw");
          }
  
          if (output == null) {
              output = "null";
          }
  
          if (cache == null) {
              cache = ByteBuffer.allocate(CACHE_SIZE);
          }
  
          isDirty = true;
  
          byte[] decodedString = output.getBytes(UTF_8);
          int newLineLength = newLine ? NL_BYTES.length : 0;
          if (cache.remaining() >= decodedString.length + newLineLength) {
              cache.put(decodedString);
              if (newLine) {
                  cache.put(NL_BYTES);
              }
          } else {
              ((Buffer) cache).flip();
              int minLength = cache.remaining() + decodedString.length + NL_BYTES.length;
              byte[] buffer = getLargeCache(minLength);
              int bufferLength = 0;
              System.arraycopy(
                      cache.array(),
                     cache.arrayOffset() + ((Buffer) cache).position(),
                     buffer,
                     bufferLength,
                     cache.remaining());
             bufferLength += cache.remaining();
             ((Buffer) cache).clear();
 
             System.arraycopy(decodedString, 0, buffer, bufferLength, decodedString.length);
             bufferLength += decodedString.length;
 
             if (newLine) {
                 System.arraycopy(NL_BYTES, 0, buffer, bufferLength, NL_BYTES.length);
                 bufferLength += NL_BYTES.length;
             }
 
             storage.write(buffer, 0, bufferLength);
         }
     }
 
     public synchronized long getByteCount() {
         try {
             sync();
             if (storage != null && !closed) {
                 storage.getFD().sync();
             }
             return file == null ? 0 : size(file);
         } catch (IOException e) {
             return 0;
         }
     }
 
     @SuppressWarnings("checkstyle:innerassignment")
     public synchronized void writeTo(OutputStream out) throws IOException {
         if (file != null && notExists(file)) {
             storage = null;
         }
 
         if ((storage == null && file != null)
                 || (storage != null && !storage.getChannel().isOpen())) {
             storage = new RandomAccessFile(file.toFile(), "rw");
         }
 
         if (storage != null) {
             sync();
             final long currentFilePosition = storage.getFilePointer();
             storage.seek(0L);
             try {
                 byte[] buffer = new byte[CACHE_SIZE];
                 for (int readCount; (readCount = storage.read(buffer)) != -1; ) {
                     out.write(buffer, 0, readCount);
                 }
             } finally {
                 storage.seek(currentFilePosition);
             }
         }
     }
 
     public synchronized void commit() {
         if (storage == null) {
             return;
         }
 
         try {
             sync();
             storage.close();
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         } finally {
             storage = null;
             cache = null;
             largeCache = null;
         }
     }
 
     public synchronized void free() {
         if (!closed) {
             closed = true;
             if (file != null) {
                 try {
                     commit();
                     // todo delete( file ); uncomment L485 assertThat( file ).doesNotExist() in StatelessXmlReporterTest
                 } catch (/*todo uncomment IOException |*/ UncheckedIOException e) {
                     /*todo uncomment file.toFile()
                     .deleteOnExit();*/
                 } finally {
                     // todo should be removed after uncommented delete( file )
                     file.toFile().deleteOnExit();
                 }
 
                 storage = null;
                 cache = null;
                 largeCache = null;
             }
         }
     }
 
     private void sync() throws IOException {
         if (!isDirty) {
             return;
         }
 
         isDirty = false;
 
         if (storage != null && cache != null) {
             ((Buffer) cache).flip();
             byte[] array = cache.array();
             int offset = cache.arrayOffset() + ((Buffer) cache).position();
             int length = cache.remaining();
             ((Buffer) cache).clear();
             storage.write(array, offset, length);
             // the data that you wrote with the mode "rw" may still only be kept in memory and may be read back
             // storage.getFD().sync();
         }
     }
 
     @SuppressWarnings("checkstyle:innerassignment")
     private byte[] getLargeCache(int minLength) {
         byte[] buffer;
         if (largeCache == null || (buffer = largeCache.get()) == null || buffer.length < minLength) {
             buffer = new byte[minLength];
             largeCache = new SoftReference<>(buffer);
         }
         return buffer;
     }
 }