/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file yapf.h Entry point for OpenTTD to YAPF. */

#ifndef  YAPF_H
#define  YAPF_H

#include "../debug.h"
#include "../depot_type.h"
#include "../direction_type.h"
#include "../station_type.h"
#include "../pbs.h"

/** Finds the best path for given ship.
 * @param v        the ship that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the ship is about to enter)
 * @param enterdir diagonal direction which the ship will enter this new tile from
 * @param tracks   available tracks on the new tile (to choose from)
 * @return         the best trackdir for next turn or INVALID_TRACKDIR if the path could not be found
 */
Trackdir YapfChooseShipTrack(const Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks);

/** Finds the best path for given road vehicle.
 * @param v        the RV that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the RV is about to enter)
 * @param enterdir diagonal direction which the RV will enter this new tile from
 * @return         the best trackdir for next turn or INVALID_TRACKDIR if the path could not be found
 */
Trackdir YapfChooseRoadTrack(const Vehicle *v, TileIndex tile, DiagDirection enterdir);

/** Finds the best path for given train.
 * @param v        the train that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the train is about to enter)
 * @param enterdir diagonal direction which the RV will enter this new tile from
 * @param tracks   available trackdirs on the new tile (to choose from)
 * @param path_not_found [out] true is returned if no path can be found (returned Trackdir is only a 'guess')
 * @param reserve_track indicates whether YAPF should try to reserve the found path
 * @param target   [out] the target tile of the reservation, free is set to true if path was reserved
 * @return         the best trackdir for next turn or INVALID_TRACKDIR if the path could not be found
 */
Trackdir YapfChooseRailTrack(const Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool *path_not_found, bool reserve_track, PBSTileInfo *target);

/** Used by RV multistop feature to find the nearest road stop that has a free slot.
 * @param v      RV (its current tile will be the origin)
 * @param tile   destination tile
 * @return       distance from origin tile to the destination (number of road tiles) or UINT_MAX if path not found
 */
uint YapfRoadVehDistanceToTile(const Vehicle *v, TileIndex tile);

/** Used to determinine the closest reachable compatible road stop for a given vehicle.
 * @param v            vehicle that needs to go to the road stop
 * @param station      the station the road stop must belong to
 * @param stop_tile    receives the stop tile if a stop was found
 * @return             true if stop was found.
 */
bool YapfFindNearestRoadVehicleCompatibleStop(const RoadVehicle *v, StationID station, TileIndex *stop_tile);

/** Used when user sends road vehicle to the nearest depot or if road vehicle needs servicing.
 * @param v            vehicle that needs to go to some depot
 * @param max_distance max distance (number of track tiles) from the current vehicle position
 *                     (used also as optimization - the pathfinder can stop path finding if max_distance
 *                     was reached and no depot was seen)
 * @param depot_tile   receives the depot tile if depot was found
 * @return             true if depot was found.
 */
bool YapfFindNearestRoadDepot(const Vehicle *v, int max_distance, TileIndex *depot_tile);

/** Used when user sends train to the nearest depot or if train needs servicing.
 * @param v            train that needs to go to some depot
 * @param max_distance max distance (number of track tiles) from the current train position
 *                     (used also as optimization - the pathfinder can stop path finding if max_distance
 *                     was reached and no depot was seen)
 * @param reverse_penalty penalty that should be added for the path that requires reversing the train first
 * @param depot_tile   receives the depot tile if depot was found
 * @param reversed     receives true if train needs to reversed first
 * @return             true if depot was found.
 */
bool YapfFindNearestRailDepotTwoWay(const Vehicle *v, int max_distance, int reverse_penalty, TileIndex *depot_tile, bool *reversed);

/** Returns true if it is better to reverse the train before leaving station */
bool YapfCheckReverseTrain(const Vehicle *v);

/**
 * Try to extend the reserved path of a train to the nearest safe tile.
 *
 * @param v    The train that needs to find a safe tile.
 * @param tile Last tile of the current reserved path.
 * @param td   Last trackdir of the current reserved path.
 * @param override_railtype Should all physically compabtible railtypes be searched, even if the vehicle can't on them on it own?
 * @return True if the path could be extended to a safe tile.
 */
bool YapfRailFindNearestSafeTile(const Vehicle *v, TileIndex tile, Trackdir td, bool override_railtype);

/** Use this function to notify YAPF that track layout (or signal configuration) has change */
void YapfNotifyTrackLayoutChange(TileIndex tile, Track track);

/** performance measurement helpers */
void *NpfBeginInterval();
int NpfEndInterval(void *perf);


extern int _aystar_stats_open_size;
extern int _aystar_stats_closed_size;


/** Base tile length units */
enum {
	YAPF_TILE_LENGTH = 100,
	YAPF_TILE_CORNER_LENGTH = 71
};

#endif /* YAPF_H */