/*
 * Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors.
 *
 * 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.
 */
package org.switchyard.as7.extension.admin;

import static org.switchyard.as7.extension.SwitchYardModelConstants.APPLICATION_NAME;
import static org.switchyard.as7.extension.SwitchYardModelConstants.SERVICE_NAME;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.xml.namespace.QName;

import org.jboss.as.controller.OperationContext;
import org.jboss.as.controller.OperationFailedException;
import org.jboss.as.controller.OperationStepHandler;
import org.jboss.dmr.ModelNode;
import org.jboss.msc.service.ServiceController;
import org.switchyard.admin.Application;
import org.switchyard.admin.Service;
import org.switchyard.admin.SwitchYard;
import org.switchyard.as7.extension.services.SwitchYardAdminService;

/**
 * SwitchYardSubsystemReadApplication
 * 
 * Operation returning details of the applications deployed on the SwitchYard
 * subsystem.
 * 
 * @author Rob Cernich
 */
public final class SwitchYardSubsystemReadService implements OperationStepHandler {

    /**
     * The global instance for this operation.
     */
    public static final SwitchYardSubsystemReadService INSTANCE = new SwitchYardSubsystemReadService();

    private SwitchYardSubsystemReadService() {
        // forbidden inheritance
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.jboss.as.controller.OperationStepHandler#execute(org.jboss.as.controller
     * .OperationContext, org.jboss.dmr.ModelNode)
     */
    @Override
    public void execute(final OperationContext context, final ModelNode operation) throws OperationFailedException {

        context.addStep(new OperationStepHandler() {
            @Override
            public void execute(final OperationContext context, final ModelNode operation)
                    throws OperationFailedException {
                final ServiceController<?> controller = context.getServiceRegistry(false).getRequiredService(
                        SwitchYardAdminService.SERVICE_NAME);

                List<Service> services = Collections.emptyList();
                SwitchYard switchYard = SwitchYard.class.cast(controller.getService().getValue());
                if (operation.hasDefined(APPLICATION_NAME)) {
                    final QName applicationName = QName.valueOf(operation.get(APPLICATION_NAME).asString());
                    final Application application = switchYard.getApplication(applicationName);
                    if (application != null) {
                        if (operation.hasDefined(SERVICE_NAME)) {
                            Service service = findService(QName.valueOf(operation.get(SERVICE_NAME).asString()),
                                    application);
                            if (service != null) {
                                services = Collections.singletonList(service);
                            }
                        } else {
                            services = application.getServices();
                        }
                    }
                } else if (operation.hasDefined(SERVICE_NAME)) {
                    final QName serviceName = QName.valueOf(operation.get(SERVICE_NAME).asString());
                    services = new ArrayList<Service>();
                    for (Application application : switchYard.getApplications()) {
                        Service service = findService(serviceName, application);
                        if (service != null) {
                            services.add(service);
                        }
                    }
                } else {
                    services = switchYard.getServices();
                }

                addServiceNodes(context.getResult(), services);

                context.stepCompleted();
            }
        }, OperationContext.Stage.RUNTIME);
        context.stepCompleted();
    }

    private void addServiceNodes(ModelNode result, List<Service> services) {
        for (Service service : services) {
            result.add(ModelNodeCreationUtil.createServiceNode(service));
        }
    }

    /**
     * TODO: should move this to Application
     */
    private Service findService(QName serviceName, Application application) {
        for (Service service : application.getServices()) {
            if (serviceName.equals(service.getName())) {
                return service;
            }
        }
        return null;
    }
}