package org.simantics.db.tests.api.support.virtualGraphSupport;

import org.simantics.db.ReadGraph;
import org.simantics.db.RequestProcessor;
import org.simantics.db.Resource;
import org.simantics.db.Session;
import org.simantics.db.Statement;
import org.simantics.db.VirtualGraph;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.common.request.WriteResultRequest;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.service.VirtualGraphSupport;
import org.simantics.layer0.Layer0;

/**
 * Not really created into a proper test, more a demonstration that is available
 * in <a href="http://dev.simantics.org/index.php/Virtual_Graphs">the Simantics
 * developer wiki</a>.
 * 
 * @author Tuukka Lehtonen
 */
public class VirtualGraphExample {

    public Resource createLibrary(RequestProcessor processor, VirtualGraph vg, final String libraryName) throws DatabaseException {
        return processor.syncRequest(new WriteResultRequest<Resource>(vg) {
            @Override
            public Resource perform(WriteGraph graph) throws DatabaseException {
                Layer0 L0 = Layer0.getInstance(graph);
                Resource r = graph.newResource();
                graph.claim(r, L0.InstanceOf, null, L0.Library);
                graph.claimLiteral(r, L0.HasName, libraryName);
                return r;
            }
        });
    }

    public void testVirtualGraphs(Session session) throws DatabaseException {
        VirtualGraphSupport vgSupport = session.getService(VirtualGraphSupport.class);
        VirtualGraph memory = vgSupport.getMemoryPersistent("memory");
        VirtualGraph workspace = vgSupport.getWorkspacePersistent("workspace");
        // NOTICE: resource are created in difference virtual graphs in separate
        // transactions through Session.syncRequest.
        Resource memResource = createLibrary(session, memory, "memory");
        Resource workspaceResource = createLibrary(session, workspace, "workspace");
        printVirtualGraphs(session);
    }

    public void testMultipleVirtualGraphsInSameTransaction(Session session) throws DatabaseException {
        final VirtualGraphSupport vgSupport = session.getService(VirtualGraphSupport.class);
        session.syncRequest(new WriteRequest() {
            @Override
            public void perform(WriteGraph graph) throws DatabaseException {
                VirtualGraph memory = vgSupport.getMemoryPersistent("memory");
                VirtualGraph workspace = vgSupport.getWorkspacePersistent("workspace");
                // NOTICE: resource are created in different virtual graphs in
                // the same transaction through WriteGraph.syncRequest
                Resource memResource = createLibrary(graph, memory, "memory");
                Resource workspaceResource = createLibrary(graph, workspace, "workspace");
            }
        });
        printVirtualGraphs(session);
    }

    public void printVirtualGraphs(Session session) throws DatabaseException {
        session.syncRequest(new ReadRequest() {
            @Override
            public void run(ReadGraph graph) throws DatabaseException {
                VirtualGraphSupport vgSupport = graph.getService(VirtualGraphSupport.class);
                for (VirtualGraph vg : vgSupport.listGraphs()) {
                    for (Statement stm : vgSupport.listStatements(vg)) {
                        System.out.println("Statement: " + NameUtils.toString(graph, stm));
                    }
                    for (Resource r : vgSupport.listValues(vg)) {
                        System.out.println("Literal value: " + graph.getValue(r));
                    }
                }
            }
        });
    }

}