/*
 * 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.servicemix.sca;

import java.io.StringWriter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.UndeclaredThrowableException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.jbi.component.ComponentContext;
import javax.jbi.messaging.DeliveryChannel;
import javax.jbi.messaging.ExchangeStatus;
import javax.jbi.messaging.MessageExchange;
import javax.jbi.messaging.NormalizedMessage;
import javax.jbi.messaging.MessageExchange.Role;
import javax.jbi.servicedesc.ServiceEndpoint;
import javax.xml.bind.JAXBContext;

import org.apache.servicemix.common.Endpoint;
import org.apache.servicemix.common.ExchangeProcessor;
import org.apache.servicemix.jbi.jaxp.StringSource;
import org.apache.tuscany.core.context.EntryPointContext;
import org.apache.tuscany.model.assembly.ConfiguredReference;
import org.apache.tuscany.model.assembly.ConfiguredService;
import org.apache.tuscany.model.assembly.EntryPoint;

/**
 * 
 * @author gnodet
 * @version $Revision$
 * @org.apache.xbean.XBean element="endpoint" description="A sca endpoint"
 * 
 */
public class ScaEndpoint extends Endpoint implements ExchangeProcessor {

    protected ServiceEndpoint activated;

    protected EntryPoint entryPoint;

    protected Map<Class, Method> methodMap;

    protected JAXBContext jaxbContext;

    protected DeliveryChannel channel;

    public ScaEndpoint(EntryPoint entryPoint) {
        this.entryPoint = entryPoint;
    }

    public Role getRole() {
        return Role.PROVIDER;
    }

    public void activate() throws Exception {
        logger = this.serviceUnit.getComponent().getLogger();
        ComponentContext ctx = this.serviceUnit.getComponent().getComponentContext();
        activated = ctx.activateEndpoint(service, endpoint);
        channel = ctx.getDeliveryChannel();
        // Get the target service
        ConfiguredReference referenceValue = entryPoint.getConfiguredReference();
        ConfiguredService targetServiceEndpoint = referenceValue.getTargetConfiguredServices().get(0);
        // Get the business interface
        Class serviceInterface = targetServiceEndpoint.getService().getServiceContract().getInterface();
        List<Class> classes = new ArrayList<Class>();
        methodMap = new HashMap<Class, Method>();
        for (Method mth : serviceInterface.getMethods()) {
            Class[] params = mth.getParameterTypes();
            if (params.length != 1) {
                throw new IllegalStateException("Supports only methods with one parameter");
            }
            methodMap.put(params[0], mth);
            classes.add(mth.getReturnType());
            classes.add(params[0]);
        }
        jaxbContext = JAXBContext.newInstance(classes.toArray(new Class[0]));
    }

    public void deactivate() throws Exception {
        ServiceEndpoint ep = activated;
        activated = null;
        ComponentContext ctx = this.serviceUnit.getComponent().getComponentContext();
        ctx.deactivateEndpoint(ep);
    }

    public ExchangeProcessor getProcessor() {
        return this;
    }

    public void process(MessageExchange exchange) throws Exception {
        if (exchange.getStatus() == ExchangeStatus.DONE) {
            return;
        } else if (exchange.getStatus() == ExchangeStatus.ERROR) {
            return;
        }
        Object input = jaxbContext.createUnmarshaller().unmarshal(exchange.getMessage("in").getContent());
        Method method = methodMap.get(input.getClass());
        if (method == null) {
            throw new IllegalStateException("Could not determine invoked web method");
        }
        boolean oneWay = method.getReturnType() == null;
        Object output;
        try {
            EntryPointContext entryPointContext = (EntryPointContext) ((ScaServiceUnit) serviceUnit)
                    .getTuscanyRuntime().getModuleContext().getContext(entryPoint.getName());
            InvocationHandler handler = (InvocationHandler) entryPointContext.getImplementationInstance();
            output = handler.invoke(null, method, new Object[] { input });
        } catch (UndeclaredThrowableException e) {
            throw e;
        } catch (RuntimeException e) {
            throw e;
        } catch (Error e) {
            throw e;
        } catch (Exception e) {
            throw e;
        } catch (Throwable e) {
            throw new RuntimeException(e);
        }
        if (oneWay) {
            exchange.setStatus(ExchangeStatus.DONE);
            channel.send(exchange);
        } else {
            NormalizedMessage msg = exchange.createMessage();
            exchange.setMessage(msg, "out");
            StringWriter writer = new StringWriter();
            jaxbContext.createMarshaller().marshal(output, writer);
            msg.setContent(new StringSource(writer.toString()));
            channel.send(exchange);
        }
    }

    public void start() throws Exception {
    }

    public void stop() throws Exception {
    }

}