/*
 * 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.tuscany.sca.binding.websocket.runtime;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.nio.channels.SocketChannel;

import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.runtime.RuntimeEndpoint;
import org.apache.websocket.WebSocket;

public class WebSocketRequestHandler implements Runnable {

    private WebSocket<SocketChannel> websocket;
    private WebSocketOperationDispatcher dispatcher;

    public WebSocketRequestHandler(WebSocket<SocketChannel> socket, WebSocketOperationDispatcher dispatcher) {
        this.websocket = socket;
        this.dispatcher = dispatcher;
    }

    @Override
    public void run() {
        while (true) {
            try {
                // TODO use Java NIO selectors on websockets
                String request = websocket.receiveText();
                String response = handleRequest(request);
                websocket.sendText(response);
            } catch (IOException e) {
                if (!websocket.isOpen()) {
                    System.out.println("Client disconnected. Stopping WebSocketRequestHandler.");
                    break;
                } else {
                    throw new RuntimeException(e);
                }
            }
        }
    }

    // TODO handle request asynchronously in a background thread
    private String handleRequest(String jsonRequest) {
        WebSocketBindingRequest request = JSONUtil.decodeRequest(jsonRequest);
        RuntimeEndpoint wire = dispatcher.getEndpoint(request.getUri());
        Operation operation = dispatcher.getOperation(request.getUri());
        System.out.println("handleRequest - " + request.getUri() + " - " + wire + " - " + operation);
        String jsonParams = request.getPayload();
        Object[] args = JSONUtil.decodeJsonParamsForOperation(jsonParams, operation);
        try {
            Object operationResponse = wire.invoke(operation, args);
            String payload = JSONUtil.encodeResponse(operationResponse);
            WebSocketBindingResponse response = new WebSocketBindingResponse(request.getRequestId(), payload);
            return JSONUtil.encodeResponse(response);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        }
    }

}