EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.io.dwca.in;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.log4j.Logger;

import eu.etaxonomy.cdm.io.dwca.TermUri;

import eu.etaxonomy.cdm.io.stream.StreamImportBase;

import eu.etaxonomy.cdm.io.stream.StreamImportConfiguratorBase;

import eu.etaxonomy.cdm.io.stream.StreamImportStateBase;

import eu.etaxonomy.cdm.model.common.CdmBase;

import eu.etaxonomy.cdm.model.common.IdentifiableEntity;

import eu.etaxonomy.cdm.model.reference.Reference;

/**

 * @author a.mueller

 *

 */

public class StreamPartitioner<ITEM extends IConverterInput>

            implements INamespaceReader<IReader<MappedCdmBase<? extends CdmBase>>>{

	private static final Logger logger = Logger.getLogger(StreamPartitioner.class);

	private final int partitionSize;

	private final LookAheadStream<ITEM> inStream;

	private final IPartitionableConverter converter;

	private final StreamImportStateBase<StreamImportConfiguratorBase, StreamImportBase> state;

	private ConcatenatingReader<MappedCdmBase<? extends CdmBase>> outStream;

	public StreamPartitioner(INamespaceReader<ITEM> input, IPartitionableConverter converter,

	        StreamImportStateBase<StreamImportConfiguratorBase, StreamImportBase> state, Integer size){

		 this.inStream = new LookAheadStream<>(input);

		 this.converter = converter;

		 this.partitionSize = size;

		 this.state = state;

		 initNewOutStream();

	}

	private void initNewOutStream(){

		outStream = new ConcatenatingReader<>();

	}

	@Override

    public boolean hasNext() {

		if (this.outStream.hasNext()){

			return true;

		}else{

			return inStream.hasNext();  //TODO what, if converter returns no ouput for inStream.hasNext() ??

			//but be aware that requesting the next object from the next partition crosses the transactional borders

		}

	}

	@Override

	public IReader<MappedCdmBase<? extends CdmBase>> read() {

		logger.debug("Start partitioner read");

		handleNextPartition();

		IReader<MappedCdmBase<? extends CdmBase>> result = this.outStream;

		initNewOutStream();

		logger.debug("End partitioner read");

		return result;

	}

	private void handleNextPartition(){

	    List<ITEM> lookaheadArray = new ArrayList<>();

		while (this.inStream.hasNextLookAhead(partitionSize)){

			lookaheadArray.add(this.inStream.readLookAhead());

		}

		IReader<ITEM> lookaheadStream = new ListReader<>(lookaheadArray);

		Map<String, Set<String>> foreignKeys = converter.getPartitionForeignKeys(lookaheadStream);

		IImportMapping mapping = state.getMapping();

		InMemoryMapping partialMapping = mapping.getPartialMapping(foreignKeys);

		Reference sourceRef = state.getCurrentIO().getReferenceService().find(state.getConfig().getSourceRefUuid());

		partialMapping.putMapping(TermUri.CDM_SOURCE_REFERENCE.toString(), state.getConfig().getSourceRefUuid().toString(), sourceRef);

		state.loadRelatedObjects(partialMapping);

		while (inStream.isLookingAhead() && inStream.hasNext()){

			IReader<MappedCdmBase<? extends CdmBase>> resultReader = converter.map(inStream.read());

			List<MappedCdmBase<? extends CdmBase>> resultList = new ArrayList<>();  //maybe better let converter return list from the beginning

			while (resultReader.hasNext()){

				MappedCdmBase<? extends CdmBase> item = resultReader.read();

				resultList.add(item);

				if (item.getCdmBase().isInstanceOf(IdentifiableEntity.class)) {

				    addItemToRelatedObjects((MappedCdmBase<IdentifiableEntity>)item);

				}else{

				    logger.error("Non identifiable objects can not be added to related objects yet");

				}

			}

			outStream.add(new ListReader<>(resultList));

		}

		return;

	}

	/**

	 * Add new items to the local mapping

	 * @param item

	 */

	private void addItemToRelatedObjects(MappedCdmBase<? extends IdentifiableEntity> item) {

		CdmBase cdmBase = item.getCdmBase();

		if (cdmBase.getId() == 0){

			if (cdmBase.isInstanceOf(IdentifiableEntity.class)){

			    Set<String> requiredSourceNamespaces = converter.requiredSourceNamespaces();

				if (requiredSourceNamespaces.contains(item.getNamespace())){

					state.addRelatedObject(item.getNamespace(), item.getSourceId(), item.getCdmBase());

				}

			}

		}

	}

	@Override

	public TermUri getTerm() {

		return inStream.getTerm();

	}

}