/* $Id$ */

/** @file train.h Base for the train class. */

#ifndef TRAIN_H
#define TRAIN_H

#include "stdafx.h"
#include "core/bitmath_func.hpp"
#include "vehicle_base.h"

struct Train;

enum VehicleRailFlags {
	VRF_REVERSING         = 0,

	/* used to calculate if train is going up or down */
	VRF_GOINGUP           = 1,
	VRF_GOINGDOWN         = 2,

	/* used to store if a wagon is powered or not */
	VRF_POWEREDWAGON      = 3,

	/* used to reverse the visible direction of the vehicle */
	VRF_REVERSE_DIRECTION = 4,

	/* used to mark train as lost because PF can't find the route */
	VRF_NO_PATH_TO_DESTINATION = 5,

	/* used to mark that electric train engine is allowed to run on normal rail */
	VRF_EL_ENGINE_ALLOWED_NORMAL_RAIL = 6,

	/* used for vehicle var 0xFE bit 8 (toggled each time the train is reversed, accurate for first vehicle only) */
	VRF_TOGGLE_REVERSE = 7,

	/* used to mark a train that can't get a path reservation */
	VRF_TRAIN_STUCK    = 8,
};


/** enum to handle train subtypes
 * Do not access it directly unless you have to. Use the access functions below
 * This is an enum to tell what bit to access as it is a bitmask
 */
enum TrainSubtype {
	TS_FRONT             = 0, ///< Leading engine of a train
	TS_ARTICULATED_PART  = 1, ///< Articulated part of an engine
	TS_WAGON             = 2, ///< Wagon
	TS_ENGINE            = 3, ///< Engine, that can be front engines, but might be placed behind another engine
	TS_FREE_WAGON        = 4, ///< First in a wagon chain (in depot)
	TS_MULTIHEADED       = 5, ///< Engine is a multiheaded
};

/** Set front engine state
 * @param v vehicle to change
 */
static inline void SetFrontEngine(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_FRONT);
}

/** Remove the front engine state
 * @param v vehicle to change
 */
static inline void ClearFrontEngine(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_FRONT);
}

/** Check if a vehicle is an articulated part of an engine
 * @param v vehicle to check
 * @return Returns true if vehicle is an articulated part
 */
static inline bool IsArticulatedPart(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return HasBit(v->subtype, TS_ARTICULATED_PART);
}

/** Set a vehicle to be an articulated part
 * @param v vehicle to change
 */
static inline void SetArticulatedPart(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_ARTICULATED_PART);
}

/** Clear a vehicle from being an articulated part
 * @param v vehicle to change
 */
static inline void ClearArticulatedPart(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_ARTICULATED_PART);
}

/** Check if a vehicle is a wagon
 * @param v vehicle to check
 * @return Returns true if vehicle is a wagon
 */
static inline bool IsTrainWagon(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return HasBit(v->subtype, TS_WAGON);
}

/** Set a vehicle to be a wagon
 * @param v vehicle to change
 */
static inline void SetTrainWagon(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_WAGON);
}

/** Clear wagon property
 * @param v vehicle to change
 */
static inline void ClearTrainWagon(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_WAGON);
}

/** Check if a vehicle is an engine (can be first in a train)
 * @param v vehicle to check
 * @return Returns true if vehicle is an engine
 */
static inline bool IsTrainEngine(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return HasBit(v->subtype, TS_ENGINE);
}

/** Set engine status
 * @param v vehicle to change
 */
static inline void SetTrainEngine(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_ENGINE);
}

/** Clear engine status
 * @param v vehicle to change
 */
static inline void ClearTrainEngine(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_ENGINE);
}

/** Check if a vehicle is a free wagon (got no engine in front of it)
 * @param v vehicle to check
 * @return Returns true if vehicle is a free wagon
 */
static inline bool IsFreeWagon(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return HasBit(v->subtype, TS_FREE_WAGON);
}

/** Set if a vehicle is a free wagon
 * @param v vehicle to change
 */
static inline void SetFreeWagon(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_FREE_WAGON);
}

/** Clear a vehicle from being a free wagon
 * @param v vehicle to change
 */
static inline void ClearFreeWagon(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_FREE_WAGON);
}

/** Check if a vehicle is a multiheaded engine
 * @param v vehicle to check
 * @return Returns true if vehicle is a multiheaded engine
 */
static inline bool IsMultiheaded(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return HasBit(v->subtype, TS_MULTIHEADED);
}

/** Set if a vehicle is a multiheaded engine
 * @param v vehicle to change
 */
static inline void SetMultiheaded(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	SetBit(v->subtype, TS_MULTIHEADED);
}

/** Clear multiheaded engine property
 * @param v vehicle to change
 */
static inline void ClearMultiheaded(Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	ClrBit(v->subtype, TS_MULTIHEADED);
}

/** Check if an engine has an articulated part.
 * @param v Vehicle.
 * @return True if the engine has an articulated part.
 */
static inline bool EngineHasArticPart(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return (v->Next() != NULL && IsArticulatedPart(v->Next()));
}

/** Tell if we are dealing with the rear end of a multiheaded engine.
 * @param v Vehicle.
 * @return True if the engine is the rear part of a dualheaded engine.
 */
static inline bool IsRearDualheaded(const Vehicle *v)
{
	assert(v->type == VEH_TRAIN);
	return (IsMultiheaded(v) && !IsTrainEngine(v));
}

void CcBuildLoco(bool success, TileIndex tile, uint32 p1, uint32 p2);
void CcBuildWagon(bool success, TileIndex tile, uint32 p1, uint32 p2);

byte FreightWagonMult(CargoID cargo);

int CheckTrainInDepot(const Train *v, bool needs_to_be_stopped);
int CheckTrainStoppedInDepot(const Train *v);
void UpdateTrainAcceleration(Train *v);
void CheckTrainsLengths();

void FreeTrainTrackReservation(const Train *v, TileIndex origin = INVALID_TILE, Trackdir orig_td = INVALID_TRACKDIR);
bool TryPathReserve(Train *v, bool mark_as_stuck = false, bool first_tile_okay = false);

int GetTrainStopLocation(StationID station_id, TileIndex tile, const Train *v, int *station_ahead, int *station_length);

void TrainConsistChanged(Train *v, bool same_length);
void TrainPowerChanged(Train *v);
int GetTrainCurveSpeedLimit(Train *v);
Money GetTrainRunningCost(const Train *v);

/** Variables that are cached to improve performance and such */
struct TrainCache {
	/* Cached wagon override spritegroup */
	const struct SpriteGroup *cached_override;

	uint16 last_speed; // NOSAVE: only used in UI

	/* cached values, recalculated on load and each time a vehicle is added to/removed from the consist. */
	uint32 cached_power;        ///< total power of the consist.
	uint16 cached_total_length; ///< Length of the whole train, valid only for first engine.
	uint8 cached_veh_length;    ///< length of this vehicle in units of 1/8 of normal length, cached because this can be set by a callback
	bool cached_tilt;           ///< train can tilt; feature provides a bonus in curves

	/* cached values, recalculated when the cargo on a train changes (in addition to the conditions above) */
	uint32 cached_weight;     ///< total weight of the consist.
	uint32 cached_veh_weight; ///< weight of the vehicle.
	uint32 cached_max_te;     ///< max tractive effort of consist

	/* cached max. speed / acceleration data */
	uint16 cached_max_speed;    ///< max speed of the consist. (minimum of the max speed of all vehicles in the consist)
	int cached_max_curve_speed; ///< max consist speed limited by curves

	/**
	 * Position/type of visual effect.
	 * bit 0 - 3 = position of effect relative to vehicle. (0 = front, 8 = centre, 15 = rear)
	 * bit 4 - 5 = type of effect. (0 = default for engine class, 1 = steam, 2 = diesel, 3 = electric)
	 * bit     6 = disable visual effect.
	 * bit     7 = disable powered wagons.
	 */
	byte cached_vis_effect;
	byte user_def_data;

	/* NOSAVE: for wagon override - id of the first engine in train
	 * 0xffff == not in train */
	EngineID first_engine;
};

/**
 * 'Train' is either a loco or a wagon.
 */
struct Train : public SpecializedVehicle<Train, VEH_TRAIN> {
	TrainCache tcache;

	/* Link between the two ends of a multiheaded engine */
	Train *other_multiheaded_part;

	uint16 crash_anim_pos;

	uint16 flags;
	TrackBitsByte track;
	byte force_proceed;
	RailTypeByte railtype;
	RailTypes compatible_railtypes;

	/** We don't want GCC to zero our struct! It already is zeroed and has an index! */
	Train() : SpecializedVehicle<Train, VEH_TRAIN>() {}
	/** We want to 'destruct' the right class. */
	virtual ~Train() { this->PreDestructor(); }

	const char *GetTypeString() const { return "train"; }
	void MarkDirty();
	void UpdateDeltaXY(Direction direction);
	ExpensesType GetExpenseType(bool income) const { return income ? EXPENSES_TRAIN_INC : EXPENSES_TRAIN_RUN; }
	void PlayLeaveStationSound() const;
	bool IsPrimaryVehicle() const { return this->IsFrontEngine(); }
	SpriteID GetImage(Direction direction) const;
	int GetDisplaySpeed() const { return this->tcache.last_speed; }
	int GetDisplayMaxSpeed() const { return this->tcache.cached_max_speed; }
	Money GetRunningCost() const;
	bool IsInDepot() const { return CheckTrainInDepot(this, false) != -1; }
	bool IsStoppedInDepot() const { return CheckTrainStoppedInDepot(this) >= 0; }
	bool Tick();
	void OnNewDay();
	Trackdir GetVehicleTrackdir() const;
	TileIndex GetOrderStationLocation(StationID station);
	bool FindClosestDepot(TileIndex *location, DestinationID *destination, bool *reverse);

	/**
	 * Check if a vehicle is front engine
	 * @param v vehicle to check
	 * @return Returns true if vehicle is a front engine
	 */
	FORCEINLINE bool IsFrontEngine() const { return HasBit(this->subtype, TS_FRONT); }
};

#define FOR_ALL_TRAINS(var) FOR_ALL_VEHICLES_OF_TYPE(Train, var)

/**
 * Get the next part of a multi-part engine.
 * Will only work on a multi-part engine (EngineHasArticPart(v) == true),
 * Result is undefined for normal engine.
 */
static inline Train *GetNextArticPart(const Train *v)
{
	assert(EngineHasArticPart(v));
	return v->Next();
}

/** Get the last part of a multi-part engine.
 * @param v Vehicle.
 * @return Last part of the engine.
 */
static inline Train *GetLastEnginePart(Train *v)
{
	assert(v->type == VEH_TRAIN);
	while (EngineHasArticPart(v)) v = GetNextArticPart(v);
	return v;
}

/** Get the next real (non-articulated part) vehicle in the consist.
 * @param v Vehicle.
 * @return Next vehicle in the consist.
 */
static inline Train *GetNextVehicle(const Train *v)
{
	assert(v->type == VEH_TRAIN);
	while (EngineHasArticPart(v)) v = GetNextArticPart(v);

	/* v now contains the last artic part in the engine */
	return v->Next();
}

/** Get the previous real (non-articulated part) vehicle in the consist.
 * @param w Vehicle.
 * @return Previous vehicle in the consist.
 */
static inline Train *GetPrevVehicle(const Train *w)
{
	assert(w->type == VEH_TRAIN);

	Train *v = w->Previous();
	while (v != NULL && IsArticulatedPart(v)) v = v->Previous();

	return v;
}

/** Get the next real (non-articulated part and non rear part of dualheaded engine) vehicle in the consist.
 * @param v Vehicle.
 * @return Next vehicle in the consist.
 */
static inline Train *GetNextUnit(const Train *v)
{
	assert(v->type == VEH_TRAIN);
	Train *w = GetNextVehicle(v);
	if (w != NULL && IsRearDualheaded(w)) w = GetNextVehicle(w);

	return w;
}

/** Get the previous real (non-articulated part and non rear part of dualheaded engine) vehicle in the consist.
 * @param v Vehicle.
 * @return Previous vehicle in the consist.
 */
static inline Train *GetPrevUnit(const Train *v)
{
	assert(v->type == VEH_TRAIN);
	Train *w = GetPrevVehicle(v);
	if (w != NULL && IsRearDualheaded(w)) w = GetPrevVehicle(w);

	return w;
}

#endif /* TRAIN_H */