package org.simantics.district.network.ui;

import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.utils.OrderedSetUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.adapter.impl.EntityRemover;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.layer0.utils.binaryPredicates.OrderedSetElementsPredicate;
import org.simantics.modeling.adapters.ElementRemover;

public class DNElementRemover extends ElementRemover {

    public DNElementRemover(Resource element) {
        super(element);
    }
    
    @Override
    public void removeConnection(WriteGraph graph) throws DatabaseException {
        throw new UnsupportedOperationException("Distrct network should not have STR.Connection resources! " + resource);
    }
    
    @Override
    public void removeElement(WriteGraph graph) throws DatabaseException {
        
        DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
        
        if (graph.isInstanceOf(resource, DN.Vertex)) {
            graph.getObjects(resource, DN.HasEndVertex_Inverse).forEach(res -> {
                try {
                    doRemove(graph, res);
                } catch (DatabaseException e) {
                    e.printStackTrace();
                }
            });
            graph.getObjects(resource, DN.HasStartVertex_Inverse).forEach(res -> {
                try {
                    doRemove(graph, res);
                } catch (DatabaseException e) {
                    e.printStackTrace();
                }
            });
        }
        doRemove(graph, resource);
    }
    
    private static void doRemove(WriteGraph graph, Resource resource) throws DatabaseException {
        // 1. Disconnect element from diagrams
        for (Resource diagram : OrderedSetElementsPredicate.INSTANCE.getSubjects(graph, resource)) {
            OrderedSetUtils.remove(graph, diagram, resource);
        }

        // 2. Delete element itself
        EntityRemover.remove(graph, resource);

        // 3. Recursively remove all related degenerate connections
        // i.e. connections that only have one connector after remove the
        // one connected to this removed element.
    }

}