package org.simantics.db.tests.regression.bugs;

import java.util.Collection;

import org.junit.Test;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.CommentMetadata;
import org.simantics.db.common.UndoMetadata;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.service.ManagementSupport;
import org.simantics.db.testing.base.ExistingDatabaseTest;

/**
 * I found a bug in the database client write requests that caused the following
 * to happen:
 *
 * <ol>
 * <li>Perform a write request (NOP) which inserts a comment into the metadata
 * but does no changes to the database</li>
 * <li>Perform another request (W) that writes both comment metadata and
 * database changes</li>
 * <li>The database revision history will contain a single new revision with the
 * both comments from the NOP and W</li>
 * </ol>
 *
 * The expected result is that the database only contains the comment metadata
 * written in request W.
 *
 * @author Tuukka Lehtonen
 */
public class CommentMetadataWriteTest extends ExistingDatabaseTest {
    // Behavior of commit has been changed. Commits with only CommentMetadata are dropped.
    private void addMetadata(WriteGraph wg, String s) throws DatabaseException {
        CommentMetadata cm = wg.getMetadata(CommentMetadata.class);
        wg.addMetadata(cm.add(s));
        wg.addMetadata(new UndoMetadata(null, false, 0, 0));
    }
    @Test
    public void test() throws Exception {
        // Perform empty request, write comment
        WriteRequest nop = new WriteRequest() {
            @Override
            public void perform(WriteGraph graph) throws DatabaseException {
                addMetadata(graph, "NOP");
            }
        };
        getSession().sync(nop);

        // Perform non-empty request, write comment
        WriteRequest w = new WriteRequest() {
            @Override
            public void perform(WriteGraph graph) throws DatabaseException {
                Resource r = graph.newResource();
                graph.claim(r, L0.InstanceOf, L0.String);
                graph.claimValue(r, "FOO");
                CommentMetadata cm = graph.getMetadata(CommentMetadata.class);
                graph.addMetadata(cm.add("W"));
            }
        };
        getSession().sync(w);
        assertTrue("Metadata from empty requests should not accumulate to following requests", getSession().sync(new UniqueRead<Boolean>() {
            @Override
            public Boolean perform(ReadGraph graph) throws DatabaseException {
                ManagementSupport ms = graph.getService(ManagementSupport.class);
                long cid = ms.getHeadRevisionId();
                Collection<CommentMetadata> comments = ms.getMetadata(cid, cid, CommentMetadata.class);
                if (comments.size() != 1)
                    return false;
                CommentMetadata cm = comments.iterator().next();
                String s = cm.toString();
                // The line feed is added by the add operation.
                if (!s.matches("W\n"))
                    return false;
                else
                    return true;
            }
        }));
    }

}