/*
 * 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.thrift.transport;

import org.apache.thrift.TConfiguration;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Objects;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;

/**
 * TZlibTransport deflates on write and inflates on read.
 */
public class TZlibTransport extends TIOStreamTransport {

    private TTransport transport_ = null;

    public static class Factory extends TTransportFactory {
        public Factory() {
        }

        @Override
        public TTransport getTransport(TTransport base) throws TTransportException {
            return new TZlibTransport(base);
        }
    }

    /**
     * Constructs a new TZlibTransport instance.
     * @param  transport the underlying transport to read from and write to
     */
    public TZlibTransport(TTransport transport) throws TTransportException {
        this(transport, Deflater.BEST_COMPRESSION);
    }

    /**
     * Constructs a new TZlibTransport instance.
     * @param  transport the underlying transport to read from and write to
     * @param  compressionLevel 0 for no compression, 9 for maximum compression
     */
    public TZlibTransport(TTransport transport, int compressionLevel) throws TTransportException {
        super(Objects.isNull(transport.getConfiguration()) ? new TConfiguration() : transport.getConfiguration());
        transport_ = transport;
        inputStream_ = new InflaterInputStream(new TTransportInputStream(transport_), new Inflater());
        outputStream_ = new DeflaterOutputStream(new TTransportOutputStream(transport_), new Deflater(compressionLevel, false), true);
    }

    @Override
    public boolean isOpen() {
        return transport_.isOpen();
    }

    @Override
    public void open() throws TTransportException {
        transport_.open();
    }

    @Override
    public void close() {
        super.close();
        if (transport_.isOpen()) {
            transport_.close();
        }
    }
}

class TTransportInputStream extends InputStream {

    private TTransport transport = null;

    public TTransportInputStream(TTransport transport) {
        this.transport = transport;
    }

    @Override
    public int read() throws IOException {
        try {
            byte[] buf = new byte[1];
            transport.read(buf, 0, 1);
            return buf[0];
        } catch (TTransportException e) {
            throw new IOException(e);
        }
    }

    @Override
    public int read(byte b[], int off, int len) throws IOException {
        try {
            return transport.read(b, off, len);
        } catch (TTransportException e) {
            throw new IOException(e);
        }
    }
}

class TTransportOutputStream extends OutputStream {

    private TTransport transport = null;

    public TTransportOutputStream(TTransport transport) {
        this.transport = transport;
    }

    @Override
    public void write(final int b) throws IOException {
        try {
            transport.write(new byte[]{(byte) b});
        } catch (TTransportException e) {
            throw new IOException(e);
        }
    }

    @Override
    public void write(byte b[], int off, int len) throws IOException {
        try {
            transport.write(b, off, len);
        } catch (TTransportException e) {
            throw new IOException(e);
        }
    }

    @Override
    public void flush() throws IOException {
        try {
            transport.flush();
        } catch (TTransportException e) {
            throw new IOException(e);
        }
    }
}