/* $Id$ */

#ifndef  YAPF_H
#define  YAPF_H

#include "../debug.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(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
	@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 YapfChooseRoadTrack(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 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 YapfChooseRailTrack(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackdirBits trackdirs);

/** 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 when user sends RV to the nearest depot or if RV needs servicing.
		Returns the nearest depot (or NULL if depot was not found).
*/
Depot* YapfFindNearestRoadDepot(const Vehicle *v);

/** Used when user sends train to the nearest depot or if train needs servicing.
	@v            - train that needs to go to some depot
	@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)
	@reverse_penalty - penalty that should be added for the path that requires reversing the train first
	@depot_tile   - receives the depot tile if depot was found
	@reversed     - receives true if train needs to reversed first
	@return       - the true if depot was found.
*/
bool YapfFindNearestRailDepotTwoWay(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(Vehicle* v);

/** 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(void);
int NpfEndInterval(void* perf);


extern int _aystar_stats_open_size;
extern int _aystar_stats_closed_size;


/** Track followers. They should help whenever any new code will need to walk through
tracks, road or water tiles (pathfinders, signal controllers, vehicle controllers).
It is an attempt to introduce API that should simplify tasks listed above.
If you will need to use it:
	1. allocate/declare FollowTrack_t structure;
	2. call FollowTrackInit() and provide vehicle (if relevant)
	3. call one of 6 FollowTrackXxxx() APIs below
	4. check return value (if true then continue else stop)
	5. look at FollowTrack_t structure for the result
	6. optionally repeat steps 3..5
	7. in case of troubles contact KUDr
*/

/** Base struct for track followers. */
typedef struct FollowTrack_t
{
	const Vehicle*      m_veh;           ///< moving vehicle
	TileIndex           m_old_tile;      ///< the origin (vehicle moved from) before move
	Trackdir            m_old_td;        ///< the trackdir (the vehicle was on) before move
	TileIndex           m_new_tile;      ///< the new tile (the vehicle has entered)
	TrackdirBits        m_new_td_bits;   ///< the new set of available trackdirs
	DiagDirection       m_exitdir;       ///< exit direction (leaving the old tile)
	bool                m_is_tunnel;     ///< last turn passed tunnel
	bool                m_is_station;    ///< last turn passed station
	int                 m_tiles_skipped; ///< number of skipped tunnel or station tiles
} FollowTrack_t;

/** Initializes FollowTrack_t structure */
void FollowTrackInit(FollowTrack_t *This, const Vehicle* v);

/** Main track follower routines */
bool FollowTrackWater    (FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);
bool FollowTrackRoad     (FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);
bool FollowTrackRail     (FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);
bool FollowTrackWaterNo90(FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);
bool FollowTrackRoadNo90 (FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);
bool FollowTrackRailNo90 (FollowTrack_t *This, TileIndex old_tile, Trackdir old_td);

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

#endif /* YAPF_H */