/**
 * Copyright (C) 2011 Brian Ferris <bdferris@onebusaway.org>
 *
 * Licensed 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 org.onebusaway.transit_data_federation.impl.otp.graph;

import org.apache.commons.lang.ObjectUtils;
import org.onebusaway.gtfs.model.AgencyAndId;
import org.onebusaway.transit_data_federation.impl.otp.GraphContext;
import org.onebusaway.transit_data_federation.services.realtime.ArrivalAndDepartureInstance;
import org.onebusaway.transit_data_federation.services.realtime.BlockLocation;
import org.onebusaway.transit_data_federation.services.transit_graph.BlockStopTimeEntry;
import org.onebusaway.transit_data_federation.services.transit_graph.StopEntry;
import org.opentripplanner.routing.core.Vertex;

public abstract class AbstractBlockVertex extends AbstractVertexWithEdges implements
    HasStopTransitVertex {

  protected final ArrivalAndDepartureInstance _instance;

  public AbstractBlockVertex(GraphContext context,
      ArrivalAndDepartureInstance instance) {
    super(context);
    _instance = instance;
  }

  public ArrivalAndDepartureInstance getInstance() {
    return _instance;
  }

  @Override
  public StopEntry getStop() {
    return _instance.getStop();
  }

  @Override
  public AgencyAndId getStopId() {
    StopEntry stop = _instance.getStop();
    return stop.getId();
  }

  @Override
  public double distance(Vertex v) {

    // We can do a quick calc if the vertices are along the same block
    if (v instanceof AbstractBlockVertex) {
      AbstractBlockVertex bsv = (AbstractBlockVertex) v;
      BlockStopTimeEntry bst1 = _instance.getBlockStopTime();
      BlockStopTimeEntry bst2 = bsv._instance.getBlockStopTime();
      if (bst1.getTrip().getBlockConfiguration() == bst2.getTrip().getBlockConfiguration())
        return Math.abs(bst1.getDistanceAlongBlock()
            - bst2.getDistanceAlongBlock());
    }

    return super.distance(v);
  }

  @Override
  public double getX() {
    return _instance.getStop().getStopLon();
  }

  @Override
  public double getY() {
    return _instance.getStop().getStopLat();
  }

  /****
   * {@link Object} Interface
   ****/

  @Override
  public int hashCode() {
    return hashCode(_instance);
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    AbstractBlockVertex bav = (AbstractBlockVertex) obj;
    return equals(_instance, bav._instance);
  }

  /****
   * Private Methods
   ****/

  private static final int hashCode(ArrivalAndDepartureInstance instance) {
    final int prime = 31;
    int result = 1;

    result = prime * result + instance.getBlockInstance().hashCode();
    result = prime * result + instance.getBlockStopTime().hashCode();

    BlockLocation blockLocation = instance.getBlockLocation();

    /**
     * There can be potentially multiple vehicles serving a block instance, so
     * we key off the vehicle id when applicable
     */
    if (blockLocation != null) {
      if (blockLocation.getVehicleId() != null)
        result = prime * result + blockLocation.getVehicleId().hashCode();
    }

    return result;
  }

  private static final boolean equals(ArrivalAndDepartureInstance a,
      ArrivalAndDepartureInstance b) {
    if (!a.getBlockInstance().equals(b.getBlockInstance()))
      return false;
    if (!a.getBlockStopTime().equals(b.getBlockStopTime()))
      return false;

    /**
     * There can be potentially multiple vehicles serving a block instance, so
     * we key off the vehicle id when applicable
     */
    AgencyAndId vehicleIdA = getVehicleIdForInstance(a);
    AgencyAndId vehicleIdB = getVehicleIdForInstance(b);

    if (!ObjectUtils.equals(vehicleIdA, vehicleIdB))
      return false;

    return true;
  }

  private static final AgencyAndId getVehicleIdForInstance(
      ArrivalAndDepartureInstance instance) {
    BlockLocation location = instance.getBlockLocation();
    if (location == null)
      return null;
    return location.getVehicleId();
  }
}