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package de.taimos.dvalin.jaxrs.websocket;

/*
 * #%L
 * Daemon with Spring and CXF
 * %%
 * Copyright (C) 2013 - 2015 Taimos GmbH
 * %%
 * 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.
 * #L%
 */

import java.io.IOException;

import org.eclipse.jetty.websocket.api.Session;
import org.eclipse.jetty.websocket.api.WebSocketAdapter;
import org.eclipse.jetty.websocket.api.WriteCallback;
import org.eclipse.jetty.websocket.client.ClientUpgradeRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import de.taimos.dvalin.jaxrs.MapperFactory;

/**
 * Socket adapter for clients
 *
 * @author thoeger
 */
public class ClientSocketAdapter extends WebSocketAdapter {

    private static final Logger LOGGER = LoggerFactory.getLogger(ClientSocketAdapter.class);

    private ObjectMapper mapper = MapperFactory.createDefault();


    /**
     * this method is called when the request to the server is created. You can use it to modify the request like settings headers for
     * example.
     *
     * @param req the created request that can be modified
     */
    @SuppressWarnings("unused")
    public void modifyRequest(ClientUpgradeRequest req) {
        //
    }

    /**
     * send the given object to the server using JSON serialization
     *
     * @param o the object to send to the server
     */
    public final void sendObjectToSocket(Object o) {
        Session sess = this.getSession();
        if (sess != null) {
            String json;
            try {
                json = this.mapper.writeValueAsString(o);
            } catch (JsonProcessingException e) {
                ClientSocketAdapter.LOGGER.error("Failed to serialize object", e);
                return;
            }
            sess.getRemote().sendString(json, new WriteCallback() {

                @Override
                public void writeSuccess() {
                    ClientSocketAdapter.LOGGER.info("Send data to socket");
                }

                @Override
                public void writeFailed(Throwable x) {
                    ClientSocketAdapter.LOGGER.error("Error sending message to socket", x);
                }
            });
        }
    }

    /**
     * reads the received string into the given class by parsing JSON
     *
     * @param      the expected type
     * @param message the JSON string
     * @param clazz   the target class of type T
     * @return the parsed object or null if parsing was not possible or message is null
     */
    protected final  T readMessage(String message, Class clazz) {
        if ((message == null) || message.isEmpty()) {
            ClientSocketAdapter.LOGGER.info("Got empty session data");
            return null;
        }
        try {
            return this.mapper.readValue(message, clazz);
        } catch (IOException e1) {
            ClientSocketAdapter.LOGGER.info("Got invalid session data", e1);
            return null;
        }
    }
}