/*
 * Copyright 2014 NAVER Corp.
 *
 * Licensed 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 com.navercorp.pinpoint.thrift.io;


import java.io.UnsupportedEncodingException;

import org.apache.thrift.TBase;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.protocol.TProtocolFactory;
import org.apache.thrift.transport.TIOStreamTransport;

/**
 * Generic utility for easily serializing objects into a byte array or Java
 * String.
 * copy->HeaderTBaseSerializer
 */
public class HeaderTBaseSerializer {

    private static final String UTF8 = "UTF8";

    private final ResettableByteArrayOutputStream baos;
    private final TProtocol protocol;
    private final TBaseLocator locator;

    /**
     * Create a new HeaderTBaseSerializer. 
     */
    HeaderTBaseSerializer(ResettableByteArrayOutputStream bos, TProtocolFactory protocolFactory, TBaseLocator locator) {
        this.baos = bos;
        TIOStreamTransport transport = new TIOStreamTransport(bos);
        this.protocol = protocolFactory.getProtocol(transport);
        this.locator = locator;
    }

    /**
     * Serialize the Thrift object into a byte array. The process is simple,
     * just clear the byte array output, write the object into it, and grab the
     * raw bytes.
     *
     * @param base The object to serialize
     * @return Serialized object in byte[] format
     */
    public byte[] serialize(TBase<?, ?> base) throws TException {
        final Header header = locator.headerLookup(base);
        baos.reset();
        writeHeader(header);
        base.write(protocol);
        return baos.toByteArray();
    }
    
    public byte[] continueSerialize(TBase<?, ?> base) throws TException {
        final Header header = locator.headerLookup(base);
        writeHeader(header);
        base.write(protocol);
        return baos.toByteArray();
    }
    
    public void reset() {
        baos.reset();
    }
    
    public void reset(int resetIndex) {
        baos.reset(resetIndex);
    }

    public int getInterBufferSize() {
        return baos.size();
    }

    private void writeHeader(Header header) throws TException {
        protocol.writeByte(header.getSignature());
        protocol.writeByte(header.getVersion());
        // fixed size regardless protocol
        short type = header.getType();
        protocol.writeByte(BytesUtils.writeShort1(type));
        protocol.writeByte(BytesUtils.writeShort2(type));
    }

    /**
     * Serialize the Thrift object into a Java string, using the UTF8
     * charset encoding.
     *
     * @param base The object to serialize
     * @return Serialized object as a String
     */
    public String toString(TBase<?, ?> base) throws TException {
        return toString(base, UTF8);
    }
 
    /**
     * Serialize the Thrift object into a Java string, using a specified
     * character set for encoding.
     *
     * @param base    The object to serialize
     * @param charset Valid JVM charset
     * @return Serialized object as a String
     */
    public String toString(TBase<?, ?> base, String charset) throws TException {
        try {
            return new String(serialize(base), charset);
        } catch (UnsupportedEncodingException uex) {
            throw new TException("JVM DOES NOT SUPPORT ENCODING: " + charset);
        }
    }

   
}