/*
 * 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.demo.app;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.URI;
import java.net.URISyntaxException;

import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.tuscany.core.component.SimpleWorkContext;
import org.apache.tuscany.core.implementation.PojoWorkContextTunnel;
import org.apache.tuscany.core.implementation.java.JavaComponent;
import org.apache.tuscany.spi.component.ComponentManager;
import org.apache.tuscany.spi.component.InstanceWrapper;
import org.apache.tuscany.spi.component.ScopeContainer;
import org.apache.tuscany.spi.component.TargetResolutionException;
import org.apache.tuscany.spi.host.ServletHost;
import org.osoa.sca.annotations.EagerInit;
import org.osoa.sca.annotations.Reference;
import org.osoa.sca.annotations.Service;

import calculator.CalculatorService;

/**
 * @version $Revision$ $Date$
 */
@SuppressWarnings("serial")
@EagerInit
@Service(Servlet.class) 
public class CalculatorHandler extends HttpServlet {
    
    // Calculator service
    private ComponentManager componentManager;
    
    /**
     * Injects the servlet host.
     * 
     * @param servletHost Servlet host to use.
     */
    @Reference
    public void setServletHost(ServletHost servletHost) {
        servletHost.registerMapping("/calculate", this);        
    }
    
    /**
     * Injects the calculator.
     * 
     * @param componentManager Component manager.
     */
    @Reference
    public void setComponentManager(ComponentManager componentManager) {
        this.componentManager = componentManager;
    }
    
    /**
     * Processes the request.
     * 
     * @param req Servlet request.
     * @param res Servlet response.
     * @throws ServletException Servlet exception.
     * @throws IOException IO Exception.
     */
    protected void process(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        
        
        try {
            
            PojoWorkContextTunnel.setThreadWorkContext(new SimpleWorkContext());
            
            URI calculatorServiceUri = new URI("tuscany://./domain/CalculatorServiceComponent");
            
            JavaComponent javaComponent = (JavaComponent) componentManager.getComponent(calculatorServiceUri);
            
            ScopeContainer scopeContainer = javaComponent.getScopeContainer();
            InstanceWrapper wrapper = scopeContainer.getWrapper(javaComponent, new URI("tuscany://./domain"));
            CalculatorService calculatorService = (CalculatorService) wrapper.getInstance();
            double op1 = Double.parseDouble(req.getParameter("op1"));
            double op2 = Double.parseDouble(req.getParameter("op2"));
            double result = calculatorService.add(op1, op2);
            
            PrintWriter writer = res.getWriter();
            writer.println("Result: " + result);
            writer.flush();
            writer.close();
        } catch (URISyntaxException ex) {
            throw new ServletException(ex);
        } catch (TargetResolutionException ex) {
            throw new ServletException(ex);
        }
    }
    
    /**
     * Handles get requests.
     */
    @Override
    protected final void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        process(req, res);
    }

    /**
     * Handles post request.
     */
    @Override
    protected final void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        process(req, res);
    }

}