/*
 * 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.geode.cache.lucene.internal.directory;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.UUID;

import org.apache.lucene.store.BaseDirectory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.OutputStreamIndexOutput;
import org.apache.lucene.store.SingleInstanceLockFactory;

import org.apache.geode.cache.lucene.internal.filesystem.File;
import org.apache.geode.cache.lucene.internal.filesystem.FileSystem;
import org.apache.geode.cache.lucene.internal.filesystem.FileSystemStats;

/**
 * An implementation of Directory that stores data in geode regions.
 *
 * Directory is an interface to file/RAM storage for lucene. This class uses the {@link FileSystem}
 * class to store the data in the provided geode regions.
 */
public class RegionDirectory extends BaseDirectory {

  private final FileSystem fs;

  /**
   * Create a region directory with a given file and chunk region. These regions may be bucket
   * regions or they may be replicated regions.
   */
  public RegionDirectory(Map fileAndChunkRegion, FileSystemStats stats) {
    super(new SingleInstanceLockFactory());
    fs = new FileSystem(fileAndChunkRegion, stats);
  }

  @Override
  public String[] listAll() throws IOException {
    ensureOpen();
    String[] array = fs.listFileNames().toArray(new String[] {});
    Arrays.sort(array);
    return array;
  }

  @Override
  public void deleteFile(String name) throws IOException {
    ensureOpen();
    fs.deleteFile(name);
  }

  @Override
  public long fileLength(String name) throws IOException {
    ensureOpen();
    return fs.getFile(name).getLength();
  }

  @Override
  public IndexOutput createOutput(final String name, final IOContext context) throws IOException {
    ensureOpen();
    final File file = fs.createFile(name);
    final OutputStream out = file.getOutputStream();

    return new OutputStreamIndexOutput(name, name, out, 1000);
  }

  @Override
  public IndexOutput createTempOutput(String prefix, String suffix, IOContext context)
      throws IOException {
    String name = prefix + "_temp_" + UUID.randomUUID() + suffix;
    final File file = fs.createTemporaryFile(name);
    final OutputStream out = file.getOutputStream();

    return new OutputStreamIndexOutput(name, name, out, 1000);
  }

  @Override
  public void sync(Collection<String> names) throws IOException {
    ensureOpen();
    // Region does not need to sync to disk
  }

  @Override
  public void syncMetaData() throws IOException {
    ensureOpen();
    // Region does not need to sync to disk
  }

  @Override
  public void rename(String source, String dest) throws IOException {
    ensureOpen();
    fs.renameFile(source, dest);
  }

  @Override
  public IndexInput openInput(String name, IOContext context) throws IOException {
    ensureOpen();
    final File file = fs.getFile(name);
    return new FileIndexInput(name, file);
  }

  @Override
  public void close() throws IOException {
    isOpen = false;
  }

  /**
   * Lucene 9.x: New required method to track pending file deletions.
   * Since Geode regions handle deletion immediately, we return an empty set.
   */
  @Override
  public Set<String> getPendingDeletions() throws IOException {
    return Collections.emptySet();
  }

  /**
   * For testing, the file system
   */
  public FileSystem getFileSystem() {
    return fs;
  }



}
