/*
 * 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.fs.s3.common.utils;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.RefCountedFile;
import org.apache.flink.util.IOUtils;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;

/**
 * A reference counted file which is deleted as soon as no caller
 * holds a reference to the wrapped {@link File}.
 */
@Internal
public class RefCountedFileWithStream extends RefCountedFile {

	private final OffsetAwareOutputStream stream;

	private RefCountedFileWithStream(
			final File file,
			final OutputStream currentOut,
			final long bytesInCurrentPart) {
		super(file);
		this.stream = new OffsetAwareOutputStream(currentOut, bytesInCurrentPart);
	}

	public OffsetAwareOutputStream getStream() {
		return stream;
	}

	public long getLength() {
		return stream.getLength();
	}

	public void write(byte[] b, int off, int len) throws IOException {
		requireOpened();
		if (len > 0) {
			stream.write(b, off, len);
		}
	}

	void flush() throws IOException {
		requireOpened();
		stream.flush();
	}

	void closeStream() {
		if (!closed) {
			IOUtils.closeQuietly(stream);
			closed = true;
		}
	}

	private void requireOpened() throws IOException {
		if (closed) {
			throw new IOException("Stream closed.");
		}
	}

	// ------------------------------ Factory methods for initializing a temporary file ------------------------------

	public static RefCountedFileWithStream newFile(
			final File file,
			final OutputStream currentOut) throws IOException {
		return new RefCountedFileWithStream(file, currentOut, 0L);
	}

	public static RefCountedFileWithStream restoredFile(
			final File file,
			final OutputStream currentOut,
			final long bytesInCurrentPart) {
		return new RefCountedFileWithStream(file, currentOut, bytesInCurrentPart);
	}
}
