/*
 * 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.flink.table.runtime.sort;

import org.apache.flink.runtime.io.disk.iomanager.FileIOChannel;

import java.io.Closeable;
import java.io.File;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;

import static org.apache.flink.util.Preconditions.checkArgument;

/**
 * Channel manager to manage the life cycle of spill channels.
 */
public class SpillChannelManager implements Closeable {

	private final HashSet<FileIOChannel.ID> channels;
	private final HashSet<FileIOChannel> openChannels;

	private volatile boolean closed;

	public SpillChannelManager() {
		this.channels = new HashSet<>(64);
		this.openChannels = new HashSet<>(64);
	}

	/**
	 * Add a new File channel.
	 */
	public synchronized void addChannel(FileIOChannel.ID id) {
		checkArgument(!closed);
		channels.add(id);
	}

	/**
	 * Open File channels.
	 */
	public synchronized void addOpenChannels(List<FileIOChannel> toOpen) {
		checkArgument(!closed);
		for (FileIOChannel channel : toOpen) {
			openChannels.add(channel);
			channels.remove(channel.getChannelID());
		}
	}

	public synchronized void removeChannel(FileIOChannel.ID id) {
		checkArgument(!closed);
		channels.remove(id);
	}

	@Override
	public synchronized void close() {

		if (this.closed) {
			return;
		}

		this.closed = true;

		for (Iterator<FileIOChannel> channels = this.openChannels.iterator(); channels.hasNext(); ) {
			final FileIOChannel channel = channels.next();
			channels.remove();
			try {
				channel.closeAndDelete();
			} catch (Throwable ignored) {
			}
		}

		for (Iterator<FileIOChannel.ID> channels = this.channels.iterator(); channels.hasNext(); ) {
			final FileIOChannel.ID channel = channels.next();
			channels.remove();
			try {
				final File f = new File(channel.getPath());
				if (f.exists()) {
					f.delete();
				}
			} catch (Throwable ignored) {
			}
		}
	}

}