/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.kernel.impl.core;

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.Test;
import org.neo4j.configuration.GraphDatabaseSettings;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.internal.helpers.collection.Iterables;
import org.neo4j.test.extension.ImpermanentDbmsExtension;
import org.neo4j.test.extension.Inject;

@ImpermanentDbmsExtension
class DenseNodeRelChainPositionTest {
    @Inject
    private GraphDatabaseService db;

    /*
     * Tests for a particular bug with dense nodes. It used to be that if a dense node had relationships
     * for only one direction, if a request for relationships of the other direction was made, no relationships
     * would be returned, ever.
     */
    @Test
    void givenDenseNodeWhenAskForWrongDirectionThenIncorrectNrOfRelsReturned() {
        // Given
        final int denseNodeThreshold = GraphDatabaseSettings.dense_node_threshold.defaultValue()
                + 1; // We must be over the dense node threshold for the bug to manifest

        Node node1;
        try (Transaction tx = db.beginTx()) {
            node1 = tx.createNode();
            Node node2 = tx.createNode();

            for (int i = 0; i < denseNodeThreshold; i++) {
                node1.createRelationshipTo(node2, RelationshipType.withName("FOO"));
            }
            tx.commit();
        }

        // When/Then
        try (Transaction tx = db.beginTx()) {
            Node node1b = tx.getNodeById(node1.getId());
            assertEquals(0, Iterables.count(node1b.getRelationships(Direction.INCOMING)));
            assertEquals(denseNodeThreshold, Iterables.count(node1b.getRelationships(Direction.OUTGOING)));
        }
    }
}
