package org.simantics.db.layer0.util;

import java.util.Collection;
import java.util.Set;

import org.simantics.db.AsyncReadGraph;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.utils.Logger;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.procedure.AsyncContextMultiProcedure;
import org.simantics.db.service.CollectionSupport;
import org.simantics.db.service.DirectQuerySupport;
import org.simantics.layer0.Layer0;

class ConsistsOfProcess {

	final Set<Resource> result;
	final AsyncContextMultiProcedure<Resource, Resource> structure;

    public static Set<Resource> walk(ReadGraph graph, Collection<Resource> resources, Set<Resource> exclusions, boolean ignoreVirtual) throws DatabaseException {
    	ConsistsOfProcess process = new ConsistsOfProcess(graph, resources, exclusions, ignoreVirtual);
    	return process.result;
    }
	
    private ConsistsOfProcess(ReadGraph graph, final Collection<Resource> resources, final Set<Resource> exclusions, final boolean ignoreVirtual) throws DatabaseException {

		final Layer0 L0 = Layer0.getInstance(graph);
		final DirectQuerySupport dqs = graph.getService(DirectQuerySupport.class);
		
		CollectionSupport cs = graph.getService(CollectionSupport.class);
		result = cs.createSet();
		
		structure = dqs.compileForEachObject(graph, L0.ConsistsOf, new AsyncContextMultiProcedure<Resource, Resource>() {

			@Override
			public void execute(AsyncReadGraph graph, Resource parent, Resource child) {
				
				if(exclusions.contains(child)) return;
				
				if(!ignoreVirtual || child.isPersistent())
					if(result.add(child)) {
						dqs.forEachObjectCompiled(graph, child, child, structure);
					}
				
			}

			@Override
			public void finished(AsyncReadGraph graph) {
			}

			@Override
			public void exception(AsyncReadGraph graph, Throwable throwable) {
				Logger.defaultLogError(throwable);
			}

		});
		
		graph.syncRequest(new ReadRequest() {

			@Override
			public void run(ReadGraph graph) throws DatabaseException {
				for(Resource r  : resources)
					dqs.forEachObjectCompiled(graph, r, r, structure);
			}
			
		});
		
	}
	
    
}