/*
 * 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.drill.exec.store;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.ByteBuffer;

import org.apache.commons.io.FileUtils;
import org.apache.drill.common.exceptions.UserException;
import org.apache.hadoop.fs.ByteBufferReadable;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PositionedReadable;
import org.apache.hadoop.fs.Seekable;
import org.apache.hadoop.fs.Syncable;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.util.Progressable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A syncable local extension of the Hadoop FileSystem
 */
public class LocalSyncableFileSystem extends FileSystem {
  private static final Logger logger = LoggerFactory.getLogger(LocalSyncableFileSystem.class);

  @Override
  public URI getUri() {
    try {
      return new URI("drill-local:///");
    } catch (URISyntaxException e) {
      throw new RuntimeException(e);
    }
  }

  @Override
  public FSDataInputStream open(Path path, int i) throws IOException {
    return new FSDataInputStream(new LocalInputStream(path));
  }

  @Override
  public FSDataOutputStream create(Path path, FsPermission fsPermission,
      boolean b, int i, short i2, long l, Progressable progressable) throws IOException {
    return new FSDataOutputStream(new LocalSyncableOutputStream(path),
        FileSystem.getStatistics(path.toUri().getScheme(), getClass()));
  }

  @Override
  public FSDataOutputStream append(Path path, int i, Progressable progressable) throws IOException {
    throw new IOException("Append is not supported in LocalSyncableFilesystem");
  }

  @Override
  public boolean rename(Path path, Path path2) throws IOException {
    throw new IOException("Rename not supported");
  }

  @Override
  public boolean delete(Path path) throws IOException {
    File file = new File(path.toString());
    return file.delete();
  }

  @Override
  public boolean delete(Path path, boolean b) throws IOException {
    File file = new File(path.toString());
    if (b) {
      if (file.isDirectory()) {
        FileUtils.deleteDirectory(file);
      } else {
        file.delete();
      }
    } else if (file.isDirectory()) {
      throw new IOException("Cannot delete directory");
    }
    file.delete();
    return true;
  }

  @Override
  public FileStatus[] listStatus(Path path) throws IOException {
    throw new IOException("listStatus not supported");
  }

  @Override
  public void setWorkingDirectory(Path path) { }

  @Override
  public Path getWorkingDirectory() {
    return null;
  }

  @Override
  public boolean mkdirs(Path path, FsPermission fsPermission) throws IOException {
    return new File(path.toString()).mkdirs();
  }

  @Override
  public FileStatus getFileStatus(Path path) throws IOException {
    File file = new File(Path.getPathWithoutSchemeAndAuthority(path).toString());
    return new FileStatus(file.length(), file.isDirectory(), 1, 0, file.lastModified(), path);
  }

  public class LocalSyncableOutputStream extends OutputStream implements Syncable {
    private final FileOutputStream fos;
    private final BufferedOutputStream output;

    public LocalSyncableOutputStream(Path path) throws FileNotFoundException {
      File dir = new File(path.getParent().toString());
      if (!dir.exists()) {
        boolean success = dir.mkdirs();
        if (!success) {
          throw new FileNotFoundException("failed to create parent directory");
        }
      }
      fos = new FileOutputStream(new File(path.toString()));
      output = new BufferedOutputStream(fos, 64*1024);
    }

    // TODO: remove it after upgrade MapR profile onto hadoop.version 3.1
    public void sync() throws IOException {
      hflush();
    }

    @Override
    public void hsync() throws IOException {
      output.flush();
      fos.getFD().sync();
    }

    @Override
    public void hflush() throws IOException {
      hsync();
    }

    @Override
    public void write(int b) throws IOException {
      output.write(b);
    }
  }

  public class LocalInputStream extends InputStream implements Seekable, PositionedReadable, ByteBufferReadable {

    private BufferedInputStream input;
    private final String path;
    private long position;

    @SuppressWarnings("resource")
    public LocalInputStream(Path path)  throws IOException {
      this.path = path.toString();
      this.input = new BufferedInputStream(new FileInputStream(
          new RandomAccessFile(this.path, "r").getFD()), 1024*1024);
    }

    @Override
    public int read(long l, byte[] bytes, int i, int i2) throws IOException {
      throw new IOException("unsupported operation");
    }

    @Override
    public void readFully(long l, byte[] bytes, int i, int i2) throws IOException {
      throw new IOException("unsupported operation");
    }

    @Override
    public void readFully(long l, byte[] bytes) throws IOException {
      throw new IOException("unsupported operation");
    }

    @Override
    public void seek(long l) throws IOException {
      input.close();
      @SuppressWarnings("resource")
      RandomAccessFile raf = new RandomAccessFile(path, "r");
      raf.seek(l);
      input = new BufferedInputStream(new FileInputStream(raf.getFD()), 1024*1024);
      position = l;
    }

    @Override
    public long getPos() throws IOException {
      return position;
    }

    @Override
    public boolean seekToNewSource(long l) throws IOException {
      throw new IOException("seekToNewSource not supported");
    }

    @Override
    public int read(ByteBuffer buf) throws IOException {
      buf.reset();

      if(buf.hasArray()){
        int read = read(buf.array(), buf.arrayOffset(), buf.capacity());
        buf.limit(read);
        return read;
      }else{
        byte[] b = new byte[buf.capacity()];
        int read = read(b);
        buf.put(b);
        return read;
      }
    }

    @Override
    public int read(byte[] b) throws IOException {
      return input.read(b);
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
      return input.read(b, off, len);
    }

    @Override
    public int read() throws IOException {
      byte[] b = new byte[1];
      input.read(b);
      position++;
      return b[0] & 0xFF;
    }

    @Override
    public void close() {
      try {
        input.close();
      } catch (IOException e) {
        throw UserException.dataWriteError(e)
          .addContext(
              "Failed to close local syncable file system %s, possible data loss.", path)
          .build(logger);
      }
    }
  }
}