package org.gcube.datacatalogue.metadatadiscovery;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.datacatalogue.metadatadiscovery.bean.MetadataProfile;
import org.gcube.datacatalogue.metadatadiscovery.bean.jaxb.MetadataFormat;
import org.gcube.datacatalogue.metadatadiscovery.bean.jaxb.NamespaceCategory;
import org.gcube.datacatalogue.metadatadiscovery.reader.MetadataFormatDiscovery;
import org.gcube.datacatalogue.metadatadiscovery.reader.MetadataFormatReader;
import org.gcube.datacatalogue.metadatadiscovery.reader.NamespaceCategoryReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;



/**
 * The Class DataCalogueMetadataReader.
 *
 * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it
 * Jun 8, 2016
 */
public class DataCalogueMetadataFormatReader implements DataCatalogueMetadataDiscovery{

	private MetadataFormatDiscovery medataFormatDiscovery;
	private ScopeBean scope;
	private Map<String, MetadataFormat> hashMetadataFormats = null;
	private List<NamespaceCategory> namespaceCategories = null;

	private static Logger logger = LoggerFactory.getLogger(DataCalogueMetadataFormatReader.class);

	/**
	 * Instantiates a new data calogue metadata format reader.
	 *
	 * @throws Exception the exception
	 */
	public DataCalogueMetadataFormatReader() throws Exception {

		String scopeString = ScopeProvider.instance.get();
		logger.debug("Read scope "+scopeString +" from ScopeProvider");

		if(scopeString==null || scopeString.isEmpty())
			throw new Exception("Please set a valid scope into ScopeProvider");

		scope  = new ScopeBean(scopeString);
		readNamespaces();
		readMetadaFormats();
	}


	/**
	 * Read metada formats.
	 *
	 * @throws Exception the exception
	 */
	private void readMetadaFormats() throws Exception{

		medataFormatDiscovery = new MetadataFormatDiscovery(scope);
		logger.info("MedataFormatDiscovery has retrieved: "+medataFormatDiscovery.getMetadataProfiles().size() +" metadata type/s");
		logger.debug("filling cache for MedataFormat");
		hashMetadataFormats = new HashMap<String, MetadataFormat>(medataFormatDiscovery.getMetadataProfiles().size());
		for (MetadataProfile mT : medataFormatDiscovery.getMetadataProfiles()) {
			if(mT==null)
				continue;

			MetadataFormatReader reader = new MetadataFormatReader(scope, mT.getId());
			hashMetadataFormats.put(mT.getId(), reader.getMetadataFormat());
			logger.debug("MetadataType id: "+mT.getId() +" cached as: "+reader.getMetadataFormat());
		}
	}


	/**
	 * Read namespaces.
	 */
	private void readNamespaces() {

		try{
			if(namespaceCategories == null || namespaceCategories.isEmpty()){

				if(namespaceCategories == null)
					namespaceCategories = new ArrayList<NamespaceCategory>();

				NamespaceCategoryReader rd = new NamespaceCategoryReader(scope);
				namespaceCategories.addAll(rd.getNamespaces().getNamespaceCategories());
			}
		}catch(Exception e){
			logger.debug("An error occurred during read namespaces for categories: ", e);
		}
	}

	/* (non-Javadoc)
	 * @see org.gcube.datacatalogue.metadatadiscovery.DataCatalogueMetadataDiscovery#getMetadataFormatForMetadataType(org.gcube.datacatalogue.metadatadiscovery.bean.MetadataType)
	 */
	@Override
	public MetadataFormat getMetadataFormatForMetadataProfile(MetadataProfile profile) throws Exception {

		if(profile==null)
			throw new Exception("Input "+ MetadataProfile.class.getSimpleName() + " is null");

		MetadataFormat format = hashMetadataFormats.get(profile.getId());
		if(format!=null)
			return format;

		MetadataFormatReader reader = new MetadataFormatReader(scope, profile.getId());
		return reader.getMetadataFormat();
	}

	/* (non-Javadoc)
	 * @see org.gcube.datacatalogue.metadatadiscovery.DataCatalogueMetadataDiscovery#getListOfMetadataTypes()
	 */
	@Override
	public List<MetadataProfile> getListOfMetadataProfiles() throws Exception {

		if(medataFormatDiscovery==null)
			readMetadaFormats();

		return medataFormatDiscovery.getMetadataProfiles();
	}

	/* (non-Javadoc)
	 * @see org.gcube.datacatalogue.metadatadiscovery.DataCatalogueMetadataDiscovery#getListOfNamespaceCategories()
	 */
	@Override
	public List<NamespaceCategory> getListOfNamespaceCategories() throws Exception {

		if(namespaceCategories == null)
			readNamespaces();

		return namespaceCategories;
	}


	/* (non-Javadoc)
	 * @see org.gcube.datacatalogue.metadatadiscovery.DataCatalogueMetadataDiscovery#resetMetadataProfile()
	 */
	@Override
	public void resetMetadataProfile() {

		medataFormatDiscovery = null;
		hashMetadataFormats = null;
	}


	/* (non-Javadoc)
	 * @see org.gcube.datacatalogue.metadatadiscovery.DataCatalogueMetadataDiscovery#resetNamespaceCategories()
	 */
	@Override
	public void resetNamespaceCategories() {

		namespaceCategories = null;
	}

}