/*
    * 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.vfs2.provider;
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.security.cert.Certificate;
  import java.util.Collections;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.vfs2.FileContent;
  import org.apache.commons.vfs2.FileContentInfo;
  import org.apache.commons.vfs2.FileContentInfoFactory;
  import org.apache.commons.vfs2.FileObject;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.RandomAccessContent;
  import org.apache.commons.vfs2.util.MonitorInputStream;
  import org.apache.commons.vfs2.util.MonitorOutputStream;
  import org.apache.commons.vfs2.util.MonitorRandomAccessContent;
  import org.apache.commons.vfs2.util.RandomAccessMode;
  import org.apache.commons.vfs2.util.RawMonitorInputStream;
  
  /**
   * The content of a file.
   */
  public final class DefaultFileContent implements FileContent {
  
      /*
       * static final int STATE_NONE = 0; static final int STATE_READING = 1; static final int STATE_WRITING = 2; static
       * final int STATE_RANDOM_ACCESS = 3;
       */
  
      private static final Certificate[] EMPTY_CERTIFICATE_ARRAY = new Certificate[0];
      static final int STATE_CLOSED = 0;
      static final int STATE_OPENED = 1;
  
      /**
       * The default buffer size for {@link #write(OutputStream)}
       */
      private static final int WRITE_BUFFER_SIZE = 4096;
  
      private final AbstractFileObject<?> fileObject;
      private Map<String, Object> attrs;
      private Map<String, Object> roAttrs;
      private FileContentInfo fileContentInfo;
      private final FileContentInfoFactory fileContentInfoFactory;
  
      private final ThreadLocal<FileContentThreadData> threadLocal = ThreadLocal.withInitial(FileContentThreadData::new);
      private boolean resetAttributes;
  
      /**
       * Counts open streams for this file.
       */
      private int openStreams;
  
      public DefaultFileContent(final AbstractFileObject file, final FileContentInfoFactory fileContentInfoFactory) {
          this.fileObject = file;
          this.fileContentInfoFactory = fileContentInfoFactory;
      }
  
      private FileContentThreadData getFileContentThreadData() {
          return this.threadLocal.get();
      }
  
      void streamOpened() {
          synchronized (this) {
              openStreams++;
          }
          ((AbstractFileSystem) fileObject.getFileSystem()).streamOpened();
      }
  
      void streamClosed() {
          synchronized (this) {
              if (openStreams > 0) {
                  openStreams--;
                  if (openStreams < 1) {
                      fileObject.notifyAllStreamsClosed();
                  }
              }
          }
          ((AbstractFileSystem) fileObject.getFileSystem()).streamClosed();
     }
 
     /**
      * Returns the file that this is the content of.
      *
      * @return the FileObject.
      */
     @Override
     public FileObject getFile() {
         return fileObject;
     }
 
     /**
      * Returns the size of the content (in bytes).
      *
      * @return The size of the content (in bytes).
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public long getSize() throws FileSystemException {
         // Do some checking
         if (!fileObject.getType().hasContent()) {
             throw new FileSystemException("vfs.provider/get-size-not-file.error", fileObject);
         }
         /*
          * if (getThreadData().getState() == STATE_WRITING || getThreadData().getState() == STATE_RANDOM_ACCESS) { throw
          * new FileSystemException("vfs.provider/get-size-write.error", file); }
          */
 
         try {
             // Get the size
             return fileObject.doGetContentSize();
         } catch (final Exception exc) {
             throw new FileSystemException("vfs.provider/get-size.error", exc, fileObject);
         }
     }
 
     /**
      * Returns the last-modified timestamp.
      *
      * @return The last modified timestamp.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public long getLastModifiedTime() throws FileSystemException {
         /*
          * if (getThreadData().getState() == STATE_WRITING || getThreadData().getState() == STATE_RANDOM_ACCESS) { throw
          * new FileSystemException("vfs.provider/get-last-modified-writing.error", file); }
          */
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/get-last-modified-no-exist.error", fileObject);
         }
         try {
             return fileObject.doGetLastModifiedTime();
         } catch (final Exception e) {
             throw new FileSystemException("vfs.provider/get-last-modified.error", fileObject, e);
         }
     }
 
     /**
      * Sets the last-modified timestamp.
      *
      * @param modTime The last modified timestamp.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public void setLastModifiedTime(final long modTime) throws FileSystemException {
         /*
          * if (getThreadData().getState() == STATE_WRITING || getThreadData().getState() == STATE_RANDOM_ACCESS) { throw
          * new FileSystemException("vfs.provider/set-last-modified-writing.error", file); }
          */
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/set-last-modified-no-exist.error", fileObject);
         }
         try {
             if (!fileObject.doSetLastModifiedTime(modTime)) {
                 throw new FileSystemException("vfs.provider/set-last-modified.error", fileObject);
             }
         } catch (final Exception e) {
             throw new FileSystemException("vfs.provider/set-last-modified.error", fileObject, e);
         }
     }
 
     /**
      * Checks if an attribute exists.
      *
      * @param attrName The name of the attribute to check.
      * @return true if the attribute is associated with the file.
      * @throws FileSystemException if an error occurs.
      * @since 2.0
      */
     @Override
     public boolean hasAttribute(final String attrName) throws FileSystemException {
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/exists-attributes-no-exist.error", fileObject);
         }
         getAttributes();
         return attrs.containsKey(attrName);
     }
 
     /**
      * Returns a read-only map of this file's attributes.
      *
      * @return a Map of the file's attributes.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public Map<String, Object> getAttributes() throws FileSystemException {
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/get-attributes-no-exist.error", fileObject);
         }
         if (resetAttributes || roAttrs == null) {
             try {
                 synchronized (this) {
                     attrs = fileObject.doGetAttributes();
                     roAttrs = Collections.unmodifiableMap(attrs);
                     resetAttributes = false;
                 }
             } catch (final Exception e) {
                 throw new FileSystemException("vfs.provider/get-attributes.error", fileObject, e);
             }
         }
         return roAttrs;
     }
 
     /**
      * Used internally to flag situations where the file attributes should be reretrieved.
      *
      * @since 2.0
      */
     public void resetAttributes() {
         resetAttributes = true;
     }
 
     /**
      * Lists the attributes of this file.
      *
      * @return An array of attribute names.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public String[] getAttributeNames() throws FileSystemException {
         getAttributes();
         final Set<String> names = attrs.keySet();
         return names.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
     }
 
     /**
      * Gets the value of an attribute.
      *
      * @param attrName The attribute name.
      * @return The value of the attribute or null.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public Object getAttribute(final String attrName) throws FileSystemException {
         getAttributes();
         return attrs.get(attrName);
     }
 
     /**
      * Sets the value of an attribute.
      *
      * @param attrName The name of the attribute to add.
      * @param value The value of the attribute.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public void setAttribute(final String attrName, final Object value) throws FileSystemException {
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/set-attribute-no-exist.error", attrName, fileObject);
         }
         try {
             fileObject.doSetAttribute(attrName, value);
         } catch (final Exception e) {
             throw new FileSystemException("vfs.provider/set-attribute.error", e, attrName, fileObject);
         }
 
         if (attrs != null) {
             attrs.put(attrName, value);
         }
     }
 
     /**
      * Removes an attribute.
      *
      * @param attrName The name of the attribute to remove.
      * @throws FileSystemException if an error occurs.
      * @since 2.0
      */
     @Override
     public void removeAttribute(final String attrName) throws FileSystemException {
         if (!fileObject.getType().hasAttributes()) {
             throw new FileSystemException("vfs.provider/remove-attribute-no-exist.error", fileObject);
         }
 
         try {
             fileObject.doRemoveAttribute(attrName);
         } catch (final Exception e) {
             throw new FileSystemException("vfs.provider/remove-attribute.error", e, attrName, fileObject);
         }
 
         if (attrs != null) {
             attrs.remove(attrName);
         }
     }
 
     /**
      * Returns the certificates used to sign this file.
      *
      * @return An array of Certificates.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public Certificate[] getCertificates() throws FileSystemException {
         if (!fileObject.exists()) {
             throw new FileSystemException("vfs.provider/get-certificates-no-exist.error", fileObject);
         }
         /*
          * if (getThreadData().getState() == STATE_WRITING || getThreadData().getState() == STATE_RANDOM_ACCESS) { throw
          * new FileSystemException("vfs.provider/get-certificates-writing.error", file); }
          */
 
         try {
             final Certificate[] certs = fileObject.doGetCertificates();
             if (certs != null) {
                 return certs;
             }
             return EMPTY_CERTIFICATE_ARRAY;
         } catch (final Exception e) {
             throw new FileSystemException("vfs.provider/get-certificates.error", fileObject, e);
         }
     }
 
     /**
      * Returns an input stream for reading the content.
      *
      * @return The InputStream
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public InputStream getInputStream() throws FileSystemException {
         return buildInputStream(0);
     }
 
     /**
      * Returns an input stream for reading the content.
      *
      * @param bufferSize The buffer size to use.
      * @return The InputStream
      * @throws FileSystemException if an error occurs.
      * @since 2.4
      */
     @Override
     public InputStream getInputStream(final int bufferSize) throws FileSystemException {
         return buildInputStream(bufferSize);
     }
 
     /**
      * Returns an input/output stream to use to read and write the content of the file in an random manner.
      *
      * @param mode The RandomAccessMode.
      * @return A RandomAccessContent object to access the file.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public RandomAccessContent getRandomAccessContent(final RandomAccessMode mode) throws FileSystemException {
         /*
          * if (getThreadData().getState() != STATE_NONE) { throw new
          * FileSystemException("vfs.provider/read-in-use.error", file); }
          */
 
         // Get the content
         final RandomAccessContent rastr = fileObject.getRandomAccessContent(mode);
 
         final FileRandomAccessContent rac = new FileRandomAccessContent(fileObject, rastr);
 
         getFileContentThreadData().add(rac);
         streamOpened();
 
         return rac;
     }
 
     /**
      * Returns an output stream for writing the content.
      *
      * @return The OutputStream for the file.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public OutputStream getOutputStream() throws FileSystemException {
         return getOutputStream(false);
     }
 
     /**
      * Returns an output stream for writing the content in append mode.
      *
      * @param bAppend true if the data written should be appended.
      * @return The OutputStream for the file.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public OutputStream getOutputStream(final boolean bAppend) throws FileSystemException {
         return buildOutputStream(bAppend, 0);
     }
 
     /**
      * Returns an output stream for writing the content.
      *
      * @param bufferSize The buffer size to use.
      * @return The OutputStream for the file.
      * @throws FileSystemException if an error occurs.
      * @since 2.4
      */
     @Override
     public OutputStream getOutputStream(final int bufferSize) throws FileSystemException {
         return buildOutputStream(false, bufferSize);
     }
 
     /**
      * Returns an output stream for writing the content in append mode.
      *
      * @param bAppend true if the data written should be appended.
      * @param bufferSize The buffer size to use.
      * @return The OutputStream for the file.
      * @throws FileSystemException if an error occurs.
      * @since 2.4
      */
     @Override
     public OutputStream getOutputStream(final boolean bAppend, final int bufferSize) throws FileSystemException {
         return buildOutputStream(bAppend, bufferSize);
     }
 
     /**
      * Closes all resources used by the content, including all streams, readers and writers.
      *
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public void close() throws FileSystemException {
         FileSystemException caught = null;
         try {
             final FileContentThreadData threadData = getFileContentThreadData();
 
             // Close the input stream
             while (threadData.hasInputStream()) {
                 final InputStream inputStream = threadData.removeInputStream(0);
                 try {
                     if (inputStream instanceof FileContentInputStream) {
                         ((FileContentInputStream) inputStream).close();
                     } else if (inputStream instanceof RawFileContentInputStream) {
                         ((RawFileContentInputStream) inputStream).close();
                     } else {
                        caught = new FileSystemException("Unsupported InputStream type: " + inputStream);
                     }
                 } catch (final FileSystemException ex) {
                     caught = ex;
 
                 }
             }
 
             // Close the randomAccess stream
             while (threadData.hasRandomAccessContent()) {
                 final FileRandomAccessContent randomAccessContent = (FileRandomAccessContent) threadData
                         .removeRandomAccessContent(0);
                 try {
                     randomAccessContent.close();
                 } catch (final FileSystemException ex) {
                     caught = ex;
                 }
             }
 
             // Close the output stream
             final FileContentOutputStream outputStream = threadData.getOutputStream();
             if (outputStream != null) {
                 threadData.setOutputStream(null);
                 try {
                     outputStream.close();
                 } catch (final FileSystemException ex) {
                     caught = ex;
                 }
             }
         } finally {
             threadLocal.remove();
         }
 
         // throw last error (out >> rac >> input) after all closes have been tried
         if (caught != null) {
             throw caught;
         }
     }
 
     private InputStream buildInputStream(final int bufferSize) throws FileSystemException {
         /*
          * if (getThreadData().getState() == STATE_WRITING || getThreadData().getState() == STATE_RANDOM_ACCESS) { throw
          * new FileSystemException("vfs.provider/read-in-use.error", file); }
          */
         // Get the raw input stream
         // @formatter:off
         final InputStream inputStream = bufferSize == 0
                 ? fileObject.getInputStream()
                 : fileObject.getInputStream(bufferSize);
         // @formatter:on
         // Double buffering may take place here.
 //        final InputStream wrappedInputStream = bufferSize == 0
 //                    ? new FileContentInputStream(fileObject, inputStream)
 //                    : new FileContentInputStream(fileObject, inputStream, bufferSize);
 
         final InputStream wrappedInputStream;
         if (inputStream instanceof BufferedInputStream) {
             // Don't double buffer.
             wrappedInputStream = new RawFileContentInputStream(fileObject, inputStream);
         } else
         {
             // @formatter:off
             wrappedInputStream = bufferSize == 0
                     ? new FileContentInputStream(fileObject, inputStream)
                     : new FileContentInputStream(fileObject, inputStream, bufferSize);
             // @formatter:on
         }
         getFileContentThreadData().add(wrappedInputStream);
         streamOpened();
 
         return wrappedInputStream;
     }
 
     private OutputStream buildOutputStream(final boolean bAppend, final int bufferSize) throws FileSystemException {
         /*
          * if (getThreadData().getState() != STATE_NONE)
          */
         final FileContentThreadData threadData = getFileContentThreadData();
 
         if (threadData.getOutputStream() != null) {
             throw new FileSystemException("vfs.provider/write-in-use.error", fileObject);
         }
 
         // Get the raw output stream
         final OutputStream outstr = fileObject.getOutputStream(bAppend);
 
         // Create and set wrapper
         final FileContentOutputStream wrapped = bufferSize == 0 ?
             new FileContentOutputStream(fileObject, outstr) :
             new FileContentOutputStream(fileObject, outstr, bufferSize);
         threadData.setOutputStream(wrapped);
         streamOpened();
 
         return wrapped;
     }
 
     /**
      * Handles the end of input stream.
      */
     private void endInput(final InputStream instr) {
         final FileContentThreadData fileContentThreadData = threadLocal.get();
         if (fileContentThreadData != null) {
             fileContentThreadData.remove(instr);
         }
         if (fileContentThreadData == null || !fileContentThreadData.hasStreams()) {
             // remove even when no value is set to remove key
             threadLocal.remove();
         }
         streamClosed();
     }
 
     /**
      * Handles the end of random access.
      */
     private void endRandomAccess(final RandomAccessContent rac) {
         final FileContentThreadData fileContentThreadData = threadLocal.get();
         if (fileContentThreadData != null) {
             fileContentThreadData.remove(rac);
         }
         if (fileContentThreadData == null || !fileContentThreadData.hasStreams()) {
             // remove even when no value is set to remove key
             threadLocal.remove();
         }
         streamClosed();
     }
 
     /**
      * Handles the end of output stream.
      */
     private void endOutput() throws Exception {
         final FileContentThreadData fileContentThreadData = threadLocal.get();
         if (fileContentThreadData != null) {
             fileContentThreadData.setOutputStream(null);
         }
         if (fileContentThreadData == null || !fileContentThreadData.hasStreams()) {
             // remove even when no value is set to remove key
             threadLocal.remove();
         }
         streamClosed();
         fileObject.endOutput();
     }
 
     /**
      * Checks if a input and/or output stream is open.
      * <p>
      * This checks only the scope of the current thread.
      * </p>
      *
      * @return true if this is the case
      */
     @Override
     public boolean isOpen() {
         final FileContentThreadData fileContentThreadData = threadLocal.get();
         if (fileContentThreadData != null && fileContentThreadData.hasStreams()) {
             return true;
         }
         // threadData.get() created empty entry
         threadLocal.remove();
         return false;
     }
 
     /**
      * Checks if an input or output stream is open. This checks all threads.
      *
      * @return true if this is the case
      */
     public boolean isOpenGlobal() {
         synchronized (this) {
             return openStreams > 0;
         }
     }
 
     /**
      * An input stream for reading content. Provides buffering, and end-of-stream monitoring.
      */
     private final class FileContentInputStream extends MonitorInputStream {
         // avoid gc
         private final FileObject file;
 
         FileContentInputStream(final FileObject file, final InputStream instr) {
             super(instr);
             this.file = file;
         }
 
         FileContentInputStream(final FileObject file, final InputStream instr, final int bufferSize) {
             super(instr, bufferSize);
             this.file = file;
         }
 
         /**
          * Closes this input stream.
          */
         @Override
         public void close() throws FileSystemException {
             try {
                 super.close();
             } catch (final IOException e) {
                 throw new FileSystemException("vfs.provider/close-instr.error", file, e);
             }
         }
 
         /**
          * Called after the stream has been closed.
          */
         @Override
         protected void onClose() throws IOException {
             try {
                 super.onClose();
             } finally {
                 endInput(this);
             }
         }
     }
 
     /**
      * An input stream for reading content. Provides buffering, and end-of-stream monitoring.
      * <p>
      * This is the same as {@link FileContentInputStream} but without the buffering.
      * </p>
      */
     private final class RawFileContentInputStream extends RawMonitorInputStream {
         // avoid gc
         private final FileObject file;
 
         RawFileContentInputStream(final FileObject file, final InputStream instr) {
             super(instr);
             this.file = file;
         }
 
         /**
          * Closes this input stream.
          */
         @Override
         public void close() throws FileSystemException {
             try {
                 super.close();
             } catch (final IOException e) {
                 throw new FileSystemException("vfs.provider/close-instr.error", file, e);
             }
         }
 
         /**
          * Called after the stream has been closed.
          */
         @Override
         protected void onClose() throws IOException {
             try {
                 super.onClose();
             } finally {
                 endInput(this);
             }
         }
     }
 
     /**
      * An input/output stream for reading/writing content on random positions
      */
     private final class FileRandomAccessContent extends MonitorRandomAccessContent {
         // also avoids gc
         private final FileObject file;
 
         FileRandomAccessContent(final FileObject file, final RandomAccessContent content) {
             super(content);
             this.file = file;
         }
 
         /**
          * Called after the stream has been closed.
          */
         @Override
         protected void onClose() throws IOException {
             try {
                 super.onClose();
             } finally {
                 endRandomAccess(this);
             }
         }
 
         @Override
         public void close() throws FileSystemException {
             try {
                 super.close();
             } catch (final IOException e) {
                 throw new FileSystemException("vfs.provider/close-rac.error", file, e);
             }
         }
     }
 
     /**
      * An output stream for writing content.
      */
     final class FileContentOutputStream extends MonitorOutputStream {
         // avoid gc
         private final FileObject file;
 
         FileContentOutputStream(final FileObject file, final OutputStream outstr) {
             super(outstr);
             this.file = file;
         }
 
         FileContentOutputStream(final FileObject file, final OutputStream outstr, final int bufferSize) {
             super(outstr, bufferSize);
             this.file = file;
         }
 
         /**
          * Closes this output stream.
          */
         @Override
         public void close() throws FileSystemException {
             try {
                 super.close();
             } catch (final IOException e) {
                 throw new FileSystemException("vfs.provider/close-outstr.error", file, e);
             }
         }
 
         /**
          * Called after this stream is closed.
          */
         @Override
         protected void onClose() throws IOException {
             try {
                 super.onClose();
             } finally {
                 try {
                     endOutput();
                 } catch (final Exception e) {
                     throw new FileSystemException("vfs.provider/close-outstr.error", file, e);
                 }
             }
         }
     }
 
     /**
      * Gets the FileContentInfo which describes the content-type, content-encoding
      *
      * @return The FileContentInfo.
      * @throws FileSystemException if an error occurs.
      */
     @Override
     public FileContentInfo getContentInfo() throws FileSystemException {
         if (fileContentInfo == null) {
             fileContentInfo = fileContentInfoFactory.create(this);
         }
 
         return fileContentInfo;
     }
 
     /**
      * Writes this content to another FileContent.
      *
      * @param fileContent The target FileContent.
      * @return the total number of bytes written
      * @throws IOException if an error occurs writing the content.
      * @since 2.1
      */
     @Override
     public long write(final FileContent fileContent) throws IOException {
         try (OutputStream output = fileContent.getOutputStream()) {
             return this.write(output);
         }
     }
 
     /**
      * Writes this content to another FileObject.
      *
      * @param file The target FileObject.
      * @return the total number of bytes written
      * @throws IOException if an error occurs writing the content.
      * @since 2.1
      */
     @Override
     public long write(final FileObject file) throws IOException {
         return write(file.getContent());
     }
 
     /**
      * Writes this content to an OutputStream.
      *
      * @param output The target OutputStream.
      * @return the total number of bytes written
      * @throws IOException if an error occurs writing the content.
      * @since 2.1
      */
     @Override
     public long write(final OutputStream output) throws IOException {
         return write(output, WRITE_BUFFER_SIZE);
     }
 
     /**
      * Writes this content to an OutputStream.
      *
      * @param output The target OutputStream.
      * @param bufferSize The buffer size to write data chunks.
      * @return the total number of bytes written
      * @throws IOException if an error occurs writing the file.
      * @since 2.1
      */
     @Override
     public long write(final OutputStream output, final int bufferSize) throws IOException {
         final InputStream input = this.getInputStream();
         long count = 0;
         try {
             // This read/write code from Apache Commons IO
             final byte[] buffer = new byte[bufferSize];
             int n;
             while (-1 != (n = input.read(buffer))) {
                 output.write(buffer, 0, n);
                 count += n;
             }
         } finally {
             input.close();
         }
         return count;
     }
 }