/**
 * 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.camel.spring;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.camel.CamelContext;
import org.apache.camel.ContextTestSupport;
import org.apache.camel.Route;
import org.apache.camel.impl.DefaultPackageScanClassResolver;
import org.apache.camel.impl.scan.AssignableToPackageScanFilter;
import org.apache.camel.impl.scan.InvertingPackageScanFilter;
import org.apache.camel.util.CastUtils;
import org.apache.camel.util.ObjectHelper;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractXmlApplicationContext;
import org.springframework.context.support.GenericApplicationContext;

/**
 * @version $Revision$
 */
public abstract class SpringTestSupport extends ContextTestSupport {
    protected AbstractXmlApplicationContext applicationContext;
    protected abstract AbstractXmlApplicationContext createApplicationContext();

    @Override
    protected void setUp() throws Exception {
        applicationContext = createApplicationContext();
        assertNotNull("Should have created a valid spring context", applicationContext);
        super.setUp();
    }

    @Override
    protected void tearDown() throws Exception {
        super.tearDown();
        if (applicationContext != null) {
            applicationContext.destroy();
        }
    }

    private static class ExcludingPackageScanClassResolver extends DefaultPackageScanClassResolver {

        public void setExcludedClasses(Set<Class<?>> excludedClasses) {
            if (excludedClasses == null) {
                excludedClasses = CastUtils.cast(Collections.emptySet());
            }
            addFilter(new InvertingPackageScanFilter(new AssignableToPackageScanFilter(excludedClasses)));
        }
    }

    /**
     * Create a parent context that initializes a
     * {@link org.apache.camel.spi.PackageScanClassResolver} to exclude a set of given classes from
     * being resolved. Typically this is used at test time to exclude certain routes,
     * which might otherwise be just noisy, from being discovered and initialized.
     * <p/>
     * To use this filtering mechanism it is necessary to provide the
     * {@link ApplicationContext} returned from here as the parent context to
     * your test context e.g.
     *
     * <pre>
     * protected AbstractXmlApplicationContext createApplicationContext() {
     *     return new ClassPathXmlApplicationContext(new String[] {&quot;test-context.xml&quot;}, getRouteExcludingApplicationContext());
     * }
     * </pre>
     *
     * This will, in turn, call the template methods <code>excludedRoutes</code>
     * and <code>excludedRoute</code> to determine the classes to be excluded from scanning.
     *
     * @see org.apache.camel.spring.config.scan.SpringComponentScanTest for an example.
     * @return ApplicationContext a parent {@link ApplicationContext} configured
     *         to exclude certain classes from package scanning
     */
    protected ApplicationContext getRouteExcludingApplicationContext() {
        GenericApplicationContext routeExcludingContext = new GenericApplicationContext();
        routeExcludingContext.registerBeanDefinition("excludingResolver", new RootBeanDefinition(ExcludingPackageScanClassResolver.class));
        routeExcludingContext.refresh();

        ExcludingPackageScanClassResolver excludingResolver = (ExcludingPackageScanClassResolver)routeExcludingContext.getBean("excludingResolver");
        List<Class<?>> excluded = CastUtils.cast(Arrays.asList(excludeRoutes()));
        excludingResolver.setExcludedClasses(new HashSet<Class<?>>(excluded));

        return routeExcludingContext;
    }

    /**
     * Template method used to exclude {@link org.apache.camel.Route} from the test time context
     * route scanning
     *
     * @return Class[] the classes to be excluded from test time context route scanning
     */
    protected Class<?>[] excludeRoutes() {
        Class<?> excludedRoute = excludeRoute();
        return excludedRoute != null ? new Class[] {excludedRoute} : new Class[0];
    }

    /**
     * Template method used to exclude a {@link org.apache.camel.Route} from the test camel context
     */
    protected Class<?> excludeRoute() {
        return null;
    }

    /**
     * Looks up the mandatory spring bean of the given name and type, failing if
     * it is not present or the correct type
     */
    public <T> T getMandatoryBean(Class<T> type, String name) {
        Object value = applicationContext.getBean(name);
        assertNotNull("No spring bean found for name <" + name + ">", value);
        if (type.isInstance(value)) {
            return type.cast(value);
        } else {
            fail("Spring bean <" + name + "> is not an instanceof " + type.getName() + " but is of type " + ObjectHelper.className(value));
            return null;
        }
    }

    @Override
    protected void assertValidContext(CamelContext context) {
        super.assertValidContext(context);

        List<Route> routes = context.getRoutes();
        int routeCount = getExpectedRouteCount();
        if (routeCount > 0) {
            assertNotNull("Should have some routes defined", routes);
            assertTrue("Should have at least one route", routes.size() >= routeCount);
        }
        log.debug("Camel Routes: " + routes);
    }

    protected int getExpectedRouteCount() {
        return 1;
    }

    @Override
    protected CamelContext createCamelContext() throws Exception {
        return SpringCamelContext.springCamelContext(applicationContext);
    }

}
