/*
 * 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.server.http.cypher.format.jolt.v1;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import java.io.IOException;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.Relationship;
import org.neo4j.server.http.cypher.format.jolt.JoltRelationship;
import org.neo4j.server.http.cypher.format.jolt.Sigil;

final class JoltPathSerializer extends StdSerializer<Path> {
    JoltPathSerializer() {
        super(Path.class);
    }

    @Override
    public void serialize(Path path, JsonGenerator generator, SerializerProvider provider) throws IOException {
        generator.writeStartObject(path);
        generator.writeFieldName(Sigil.PATH.getValue());

        generator.writeStartArray();

        var it = path.iterator();
        var lastNodeId = "";

        while (it.hasNext()) {
            var entity = it.next();
            if (entity instanceof Node node) {
                lastNodeId = node.getElementId();

                generator.writeObject(node);
            } else if (entity instanceof Relationship rel) {

                if (!rel.getStartNode().getElementId().equals(lastNodeId)) {
                    // we want a reversed relationship here so the path flows correctly
                    generator.writeObject(JoltRelationship.fromRelationshipReversed(rel));
                } else {
                    generator.writeObject(rel);
                }
            }
        }

        generator.writeEndArray();

        generator.writeEndObject();
    }
}
