/*
 * 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.cloudstack.framework.serializer;


import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class JsonMessageSerializer implements MessageSerializer {

	// this will be injected from external to allow installation of
	// type adapters needed by upper layer applications
	private Gson _gson;
	
	private OnwireClassRegistry _clzRegistry; 
	
	public JsonMessageSerializer() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.setVersion(1.5);
        _gson = gsonBuilder.create();
	}
	
	public Gson getGson() {
		return _gson;
	}
	
	public void setGson(Gson gson) {
		_gson = gson;
	}
	
	public OnwireClassRegistry getOnwireClassRegistry() {
		return _clzRegistry;
	}
	
	public void setOnwireClassRegistry(OnwireClassRegistry clzRegistry) {
		_clzRegistry = clzRegistry;
	}
	
	@Override
	public <T> String serializeTo(Class<?> clz, T object) {
		assert(clz != null);
		assert(object != null);
		
		StringBuffer sbuf = new StringBuffer();
		
		OnwireName onwire = clz.getAnnotation(OnwireName.class);
		if(onwire == null)
			throw new RuntimeException("Class " + clz.getCanonicalName() + " is not declared to be onwire");
		
		sbuf.append(onwire.name()).append("|");
		sbuf.append(_gson.toJson(object));
		
		return sbuf.toString();
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T> T serializeFrom(String message) {
		assert(message != null);
		int contentStartPos = message.indexOf('|');
		if(contentStartPos < 0)
			throw new RuntimeException("Invalid on-wire message format");
		
		String onwireName = message.substring(0, contentStartPos);
		Class<?> clz = _clzRegistry.getOnwireClass(onwireName);
		if(clz == null)
			throw new RuntimeException("Onwire class is not registered. name: " + onwireName);
		
		return (T)_gson.fromJson(message.substring(contentStartPos + 1), clz);
	}
}
