/*
 *  Licensed to GraphHopper GmbH under one or more contributor
 *  license agreements. See the NOTICE file distributed with this work for 
 *  additional information regarding copyright ownership.
 * 
 *  GraphHopper GmbH licenses this file to you under the Apache License, 
 *  Version 2.0 (the "License"); you may not use this file except in 
 *  compliance with the License. You may obtain a copy of the License at
 * 
 *       http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.graphhopper.routing;

import com.graphhopper.routing.weighting.Weighting;
import com.graphhopper.storage.Graph;
import com.graphhopper.storage.SPTEntry;
import com.graphhopper.util.EdgeIterator;

/**
 * This class creates a DijkstraPath from two Edge's resulting from a BidirectionalDijkstra
 * <p>
 *
 * @author Peter Karich
 */
public class PathBidirRef extends Path {
    protected SPTEntry edgeTo;
    private boolean switchFromAndToSPTEntry = false;

    public PathBidirRef(Graph g, Weighting weighting) {
        super(g, weighting);
    }

    PathBidirRef(PathBidirRef p) {
        super(p);
        edgeTo = p.edgeTo;
        switchFromAndToSPTEntry = p.switchFromAndToSPTEntry;
    }

    public PathBidirRef setSwitchToFrom(boolean b) {
        switchFromAndToSPTEntry = b;
        return this;
    }

    public PathBidirRef setSPTEntryTo(SPTEntry edgeTo) {
        this.edgeTo = edgeTo;
        return this;
    }

    /**
     * Extracts path from two shortest-path-tree
     */
    @Override
    public Path extract() {
        if (sptEntry == null || edgeTo == null)
            return this;

        if (sptEntry.adjNode != edgeTo.adjNode)
            throw new IllegalStateException("Locations of the 'to'- and 'from'-Edge has to be the same." + toString() + ", fromEntry:" + sptEntry + ", toEntry:" + edgeTo);

        extractSW.start();
        if (switchFromAndToSPTEntry) {
            SPTEntry ee = sptEntry;
            sptEntry = edgeTo;
            edgeTo = ee;
        }
        SPTEntry currEdge = sptEntry;
        boolean nextEdgeValid = EdgeIterator.Edge.isValid(currEdge.edge);
        int nextEdge;
        while (nextEdgeValid) {
            // the reverse search needs the next edge
            nextEdgeValid = EdgeIterator.Edge.isValid(currEdge.parent.edge);
            nextEdge = nextEdgeValid ? currEdge.parent.edge : EdgeIterator.NO_EDGE;
            processEdge(currEdge.edge, currEdge.adjNode, nextEdge);
            currEdge = currEdge.parent;
        }

        setFromNode(currEdge.adjNode);
        reverseOrder();
        currEdge = edgeTo;
        int prevEdge = nextEdgeValid ? sptEntry.edge : EdgeIterator.NO_EDGE;
        int tmpEdge = currEdge.edge;
        while (EdgeIterator.Edge.isValid(tmpEdge)) {
            currEdge = currEdge.parent;
            processEdge(tmpEdge, currEdge.adjNode, prevEdge);
            prevEdge = tmpEdge;
            tmpEdge = currEdge.edge;
        }
        setEndNode(currEdge.adjNode);
        extractSW.stop();
        return setFound(true);
    }
}