D-Net

package eu.dnetlib.enabling.locators;

import java.io.StringReader;

import java.io.StringWriter;

import java.util.*;

import java.util.stream.Collectors;

import javax.annotation.Resource;

import eu.dnetlib.rmi.common.BaseService;

import eu.dnetlib.rmi.enabling.ISLookUpException;

import eu.dnetlib.rmi.enabling.ISLookUpService;

import eu.dnetlib.soap.cxf.StandaloneCxfEndpointReferenceBuilder;

import org.apache.commons.lang3.StringUtils;

import org.apache.commons.lang3.math.NumberUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import org.springframework.beans.BeansException;

import org.springframework.beans.factory.annotation.Required;

import org.springframework.context.ApplicationContext;

import org.springframework.context.ApplicationContextAware;

public class DefaultUniqueServiceLocator implements UniqueServiceLocator, ApplicationContextAware {

	/**

	 * logger.

	 */

	private static final Log log = LogFactory.getLog(DefaultUniqueServiceLocator.class);

	/**

	 * XML Parser

	 */

	private final SAXReader reader = new SAXReader();

	// PreferLocalRunningInstanceComparator();

	private ApplicationContext appContext;

	private Comparator<ServiceRunningInstance> defaultComparator; // = new

	/**

	 * An instance of isLookupService (local or stub)

	 */

	@Resource

	private ISLookUpService isLookupService;

	/**

	 * build epr.

	 */

	@Resource

	private StandaloneCxfEndpointReferenceBuilder eprBuilder;

	@Override

	public <T extends BaseService> T getService(final Class<T> clazz) {

		return getService(clazz, true);

	}

	@Override

	public <T extends BaseService> T getService(final Class<T> clazz, final Comparator<ServiceRunningInstance> comparator) {

		final String serviceName = BaseService.getServiceName(clazz);

		return findRunningInstances(serviceName, comparator).get(0).obtainClient(clazz, this.eprBuilder);

	}

	@Override

	public <T extends BaseService> T getService(final Class<T> clazz, final String profileId) {

		final String profile = obtainServiceProfile(profileId);

		try {

			return obtainRunningInstance(profile, obtainLocalServices()).obtainClient(clazz, this.eprBuilder);

		} catch (final Exception e) {

			log.error("cannot instantiate service from id: " + profileId, e);

			throw new IllegalStateException("cannot instantiate service from id: " + profileId, e);

		}

	}

	@Override

	public <T extends BaseService> T getService(final Class<T> clazz, final boolean local) {

		if (clazz.isInstance(this.isLookupService)) { return clazz.cast(this.isLookupService); }

		if (local) {

			try {

				final Map<String, T> beans = this.appContext.getBeansOfType(clazz);

				if ((beans != null) && !beans.isEmpty()) { return beans.values().iterator().next(); }

			} catch (final Throwable e) {

				log.warn("No beans found in context, class " + clazz);

			}

		}

		return getService(clazz, this.defaultComparator);

	}

	@Override

	public <T extends BaseService> String getServiceId(final Class<T> clazz) {

		return getServiceId(clazz, this.defaultComparator);

	}

	@Override

	public <T extends BaseService> String getServiceId(final Class<T> clazz, final Comparator<ServiceRunningInstance> comparator) {

		return findRunningInstances(BaseService.getServiceName(clazz), comparator).get(0).getServiceId();

	}

	@Override

	public <T extends BaseService> String getServiceId(final Class<T> clazz, final String profileId) {

		final String profile = obtainServiceProfile(profileId);

		final ServiceRunningInstance instance = obtainRunningInstance(profile, obtainLocalServices());

		return instance.getServiceId();

	}

	@Override

	public <T extends BaseService> Set<T> getAllServices(final Class<T> clazz) {

		final Set<T> res = new HashSet<>();

		for (final ServiceRunningInstance instance : findRunningInstances(BaseService.getServiceName(clazz), null)) {

			res.add(instance.obtainClient(clazz, this.eprBuilder));

		}

		return res;

	}

	@Override

	public <T extends BaseService> Set<String> getAllServiceIds(final Class<T> clazz) {

		return

				findRunningInstances(BaseService.getServiceName(clazz), null)

						.stream()

						.map(ServiceRunningInstance::getServiceId)

						.collect(Collectors.toSet());

	}

	private synchronized ServiceRunningInstance obtainRunningInstance(final String profile, final Map<String, BaseService> locals) {

		try {

			final Document doc = this.reader.read(new StringReader(profile));

			final String url = doc.valueOf("//PROTOCOL[@name = 'SOAP']/@address");

			final String id = doc.valueOf("//RESOURCE_IDENTIFIER/@value");

			final Map<String, String> props = new HashMap<>();

			final BaseService local = locals.containsKey(id) ? locals.get(id) : null;

			final int usedDiskspace = NumberUtils.toInt(doc.valueOf("//USED_DISKSPACE"), 0);

			final int handledDataStructures = NumberUtils.toInt(doc.valueOf("//HANDLED_DATASTRUCTURE"), 0);;

			for (final Object o : doc.selectNodes("//SERVICE_PROPERTIES/PROPERTY")) {

				final Element p = (Element) o;

				props.put(p.valueOf("@key"), p.valueOf("@value"));

			}

			return new ServiceRunningInstance(id, url, local, usedDiskspace, handledDataStructures, props);

		} catch (final DocumentException e) {

			log.error("Error parsing profile: " + profile, e);

			throw new RuntimeException("Error parsing profile: " + profile, e);

		}

	}

	private List<ServiceRunningInstance> findRunningInstances(final String serviceName, final Comparator<ServiceRunningInstance> comparator) {

		final List<ServiceRunningInstance> list = findRegisteredServices(serviceName);

		if (list.isEmpty()) {

			log.error("Service not found, name: " + serviceName);

			throw new RuntimeException("Service not found, name: " + serviceName);

		}

		if (comparator != null) {

			Collections.sort(list, comparator);

		}

		return list;

	}

	private List<ServiceRunningInstance> findRegisteredServices(final String serviceName) {

		log.debug("searching for service: " + serviceName);

		final String xquery = "for $x in collection('/db/DRIVER/ServiceResources/" + serviceName + "ResourceType') return $x";

		log.debug(xquery);

		try {

			final List<String> services = this.isLookupService.quickSearchProfile(xquery);

			final List<ServiceRunningInstance> instances = new ArrayList<>();

			final Map<String, BaseService> locals = obtainLocalServices();

			if (services != null) {

				for (final String source : services) {

					final ServiceRunningInstance instance = obtainRunningInstance(source, locals);

					instances.add(instance);

				}

			}

			return instances;

		} catch (final Exception e) {

			throw new IllegalStateException("cannot locate service " + serviceName, e);

		}

	}

	private Map<String, BaseService> obtainLocalServices() {

		final Map<String, BaseService> locals = new HashMap<>();

		this.appContext.getBeansOfType(BaseService.class).values().stream()

				.filter(s -> StringUtils.isNotBlank(s.getProfileId()))

				.forEach(s -> {

					locals.put(s.getProfileId(), s);

					log.debug(" -> Service: " + s.getServiceName() + " has id " + s.getProfileId());

				});

		return locals;

	}

	private String obtainServiceProfile(final String profileId) {

		final StringWriter sw = new StringWriter();

		sw.append("let $uri:=/RESOURCE_PROFILE/HEADER[./RESOURCE_IDENTIFIER/@value='");

		sw.append(profileId);

		sw.append("']/RESOURCE_URI/@value/string()");

		sw.append("\n\n");

		sw.append("for $x in collection('/db/DRIVER/ServiceResources')");

		sw.append("\n");

		sw.append("where $x/RESOURCE_PROFILE/HEADER/RESOURCE_URI/@value = $uri");

		sw.append("\n");

		sw.append("return $x");

		final String xq = sw.toString();

		try {

			return this.isLookupService.getResourceProfileByQuery(xq);

		} catch (final ISLookUpException e) {

			log.error("cannot locate service using query: " + xq, e);

			throw new IllegalStateException("cannot locate service using query: " + xq, e);

		}

	}

	@Override

	public void setApplicationContext(final ApplicationContext appContext) throws BeansException {

		this.appContext = appContext;

	}

	public Comparator<ServiceRunningInstance> getDefaultComparator() {

		return this.defaultComparator;

	}

	@Required

	public void setDefaultComparator(final Comparator<ServiceRunningInstance> defaultComparator) {

		this.defaultComparator = defaultComparator;

	}

	public ISLookUpService getIsLookupService() {

		return this.isLookupService;

	}

	public void setIsLookupService(final ISLookUpService isLookupService) {

		this.isLookupService = isLookupService;

	}

}