/*
 * 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.graphalgo.impl.path;

import static org.neo4j.graphdb.traversal.Evaluators.toDepth;

import org.neo4j.graphalgo.EvaluationContext;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.PathExpander;
import org.neo4j.graphdb.traversal.TraversalDescription;
import org.neo4j.graphdb.traversal.Traverser;
import org.neo4j.graphdb.traversal.Uniqueness;

public class AllPaths extends TraversalPathFinder {
    private final PathExpander expander;
    private final EvaluationContext context;
    private final int maxDepth;

    public AllPaths(EvaluationContext context, int maxDepth, PathExpander expander) {
        this.context = context;
        this.maxDepth = maxDepth;
        this.expander = expander;
    }

    protected Uniqueness uniqueness() {
        return Uniqueness.RELATIONSHIP_PATH;
    }

    @Override
    protected Traverser instantiateTraverser(Node start, Node end) {
        // Bidirectional traversal
        var transaction = context.transaction();
        TraversalDescription base =
                transaction.traversalDescription().depthFirst().uniqueness(uniqueness());
        return transaction
                .bidirectionalTraversalDescription()
                .startSide(base.expand(expander).evaluator(toDepth(maxDepth / 2)))
                .endSide(base.expand(expander.reverse()).evaluator(toDepth(maxDepth - maxDepth / 2)))
                .traverse(start, end);
    }
}
