/* $Id$ */

/** @vehicle.h */

#ifndef VEHICLE_H
#define VEHICLE_H

#include "oldpool.h"
#include "order.h"
#include "rail.h"
#include "road.h"

/** The returned bits of VehicleEnterTile. */
enum VehicleEnterTileStatus {
	VETS_ENTERED_STATION  = 1, ///< The vehicle entered a station
	VETS_ENTERED_WORMHOLE = 2, ///< The vehicle either entered a bridge, tunnel or depot tile (this includes the last tile of the bridge/tunnel)
	VETS_CANNOT_ENTER     = 3, ///< The vehicle cannot enter the tile

	/**
	 * Shift the VehicleEnterTileStatus this many bits
	 * to the right to get the station ID when
	 * VETS_ENTERED_STATION is set
	 */
	VETS_STATION_ID_OFFSET = 8,

	/** Bit sets of the above specified bits */
	VETSB_CONTINUE         = 0,                          ///< The vehicle can continue normally
	VETSB_ENTERED_STATION  = 1 << VETS_ENTERED_STATION,  ///< The vehicle entered a station
	VETSB_ENTERED_WORMHOLE = 1 << VETS_ENTERED_WORMHOLE, ///< The vehicle either entered a bridge, tunnel or depot tile (this includes the last tile of the bridge/tunnel)
	VETSB_CANNOT_ENTER     = 1 << VETS_CANNOT_ENTER,     ///< The vehicle cannot enter the tile
};

/** Road vehicle states */
enum RoadVehicleStates {
	/*
	 * Lower 4 bits are used for vehicle track direction. (Trackdirs)
	 * When in a road stop (bit 5 or bit 6 set) these bits give the
	 * track direction of the entry to the road stop.
	 * As the entry direction will always be a diagonal
	 * direction (X_NE, Y_SE, X_SW or Y_NW) only bits 0 and 3
	 * are needed to hold this direction. Bit 1 is then used to show
	 * that the vehicle is using the second road stop bay.
	 * Bit 2 is then used for drive-through stops to show the vehicle
	 * is stopping at this road stop.
	 */

	/* Numeric values */
	RVSB_IN_DEPOT                = 0xFE,                      ///< The vehicle is in a depot
	RVSB_WORMHOLE                = 0xFF,                      ///< The vehicle is in a tunnel and/or bridge

	/* Bit numbers */
	RVS_USING_SECOND_BAY         =    1,                      ///< Only used while in a road stop
	RVS_IS_STOPPING              =    2,                      ///< Only used for drive-through stops. Vehicle will stop here
	RVS_DRIVE_SIDE               =    4,                      ///< Only used when retrieving move data
	RVS_IN_ROAD_STOP             =    5,                      ///< The vehicle is in a road stop
	RVS_IN_DT_ROAD_STOP          =    6,                      ///< The vehicle is in a drive-through road stop

	/* Bit sets of the above specified bits */
	RVSB_IN_ROAD_STOP            = 1 << RVS_IN_ROAD_STOP,     ///< The vehicle is in a road stop
	RVSB_IN_ROAD_STOP_END        = RVSB_IN_ROAD_STOP + TRACKDIR_END,
	RVSB_IN_DT_ROAD_STOP         = 1 << RVS_IN_DT_ROAD_STOP,  ///< The vehicle is in a drive-through road stop
	RVSB_IN_DT_ROAD_STOP_END     = RVSB_IN_DT_ROAD_STOP + TRACKDIR_END,

	RVSB_TRACKDIR_MASK           = 0x0F,                      ///< The mask used to extract track dirs
	RVSB_ROAD_STOP_TRACKDIR_MASK = 0x09                       ///< Only bits 0 and 3 are used to encode the trackdir for road stops
};

enum VehicleType {
	VEH_TRAIN,
	VEH_ROAD,
	VEH_SHIP,
	VEH_AIRCRAFT,
	VEH_SPECIAL,
	VEH_DISASTER,
	VEH_END,
	VEH_INVALID = 0xFF,
};
template <> struct EnumPropsT<VehicleType> : MakeEnumPropsT<VehicleType, byte, VEH_TRAIN, VEH_END, VEH_INVALID> {};
typedef TinyEnumT<VehicleType> VehicleTypeByte;

enum VehStatus {
	VS_HIDDEN          = 0x01,
	VS_STOPPED         = 0x02,
	VS_UNCLICKABLE     = 0x04,
	VS_DEFPAL          = 0x08,
	VS_TRAIN_SLOWING   = 0x10,
	VS_SHADOW          = 0x20,
	VS_AIRCRAFT_BROKEN = 0x40,
	VS_CRASHED         = 0x80,
};

enum VehicleFlags {
	VF_LOADING_FINISHED,
	VF_CARGO_UNLOADING,
	VF_BUILT_AS_PROTOTYPE,
};

/* Effect vehicle types */
enum EffectVehicle {
	EV_CHIMNEY_SMOKE   = 0,
	EV_STEAM_SMOKE     = 1,
	EV_DIESEL_SMOKE    = 2,
	EV_ELECTRIC_SPARK  = 3,
	EV_SMOKE           = 4,
	EV_EXPLOSION_LARGE = 5,
	EV_BREAKDOWN_SMOKE = 6,
	EV_EXPLOSION_SMALL = 7,
	EV_BULLDOZER       = 8,
	EV_BUBBLE          = 9
};

struct VehicleRail {
	uint16 last_speed; // NOSAVE: only used in UI
	uint16 crash_anim_pos;

	/* cached values, recalculated on load and each time a vehicle is added to/removed from the consist. */
	uint16 cached_max_speed;  // max speed of the consist. (minimum of the max speed of all vehicles in the consist)
	uint32 cached_power;      // total power of the consist.
	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
	uint16 cached_total_length; ///< Length of the whole train, valid only for first engine.

	/* 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
	/**
	 * 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;

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

	TrackBitsByte track;
	byte force_proceed;
	RailTypeByte railtype;
	RailTypeMask compatible_railtypes;

	byte flags;

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

	/* Cached wagon override spritegroup */
	const struct SpriteGroup *cached_override;
};

enum {
	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,
};

struct VehicleAir {
	uint16 crashed_counter;
	uint16 cached_max_speed;
	byte pos;
	byte previous_pos;
	StationID targetairport;
	byte state;
};

struct VehicleRoad {
	byte state;             ///< @see RoadVehicleStates
	byte frame;
	uint16 blocked_ctr;
	byte overtaking;
	byte overtaking_ctr;
	uint16 crashed_ctr;
	byte reverse_ctr;
	struct RoadStop *slot;
	byte slot_age;

	RoadType roadtype;
	RoadTypes compatible_roadtypes;
};

struct VehicleSpecial {
	uint16 unk0;
	byte unk2;
};

struct VehicleDisaster {
	uint16 image_override;
	uint16 unk2;
};

struct VehicleShip {
	TrackBitsByte state;
};


struct Vehicle {
	VehicleTypeByte type;    ///< Type of vehicle
	byte subtype;            // subtype (Filled with values from EffectVehicles/TrainSubTypes/AircraftSubTypes)

	VehicleID index;         // NOSAVE: Index in vehicle array

	Vehicle *next;           // next
	Vehicle *first;          // NOSAVE: pointer to the first vehicle in the chain
	Vehicle *depot_list;     //NOSAVE: linked list to tell what vehicles entered a depot during the last tick. Used by autoreplace

	StringID string_id;      // Displayed string

	UnitID unitnumber;       // unit number, for display purposes only
	PlayerByte owner;        // which player owns the vehicle?

	TileIndex tile;          // Current tile index
	TileIndex dest_tile;     // Heading for this tile

	int32 x_pos;             // coordinates
	int32 y_pos;
	byte z_pos;
	DirectionByte direction; // facing

	byte spritenum;          // currently displayed sprite index
	                         // 0xfd == custom sprite, 0xfe == custom second head sprite
	                         // 0xff == reserved for another custom sprite
	uint16 cur_image;        // sprite number for this vehicle
	byte sprite_width;       // width of vehicle sprite
	byte sprite_height;      // height of vehicle sprite
	byte z_height;           // z-height of vehicle sprite
	int8 x_offs;             // x offset for vehicle sprite
	int8 y_offs;             // y offset for vehicle sprite
	EngineID engine_type;

	/* for randomized variational spritegroups
	 * bitmask used to resolve them; parts of it get reseeded when triggers
	 * of corresponding spritegroups get matched */
	byte random_bits;
	byte waiting_triggers;   // triggers to be yet matched

	uint16 max_speed;        // maximum speed
	uint16 cur_speed;        // current speed
	byte subspeed;           // fractional speed
	byte acceleration;       // used by train & aircraft
	byte progress;
	uint32 motion_counter;

	byte vehstatus;          // Status
	StationID last_station_visited;

	CargoID cargo_type;      // type of cargo this vehicle is carrying
	byte cargo_days;         // how many days have the pieces been in transit
	StationID cargo_source;  // source of cargo
	TileIndex cargo_source_xy; //< stores the Tile where the source station is located, in case it is removed
	uint16 cargo_cap;        // total capacity
	uint16 cargo_count;      // how many pieces are used
	byte cargo_subtype;      ///< Used for livery refits (NewGRF variations)

	byte day_counter;        // increased by one for each day
	byte tick_counter;       // increased by one for each tick

	/* Begin Order-stuff */
	Order current_order;     ///< The current order (+ status, like: loading)
	VehicleOrderID cur_order_index; ///< The index to the current order

	Order *orders;           ///< Pointer to the first order for this vehicle
	VehicleOrderID num_orders;      ///< How many orders there are in the list

	Vehicle *next_shared;    ///< If not NULL, this points to the next vehicle that shared the order
	Vehicle *prev_shared;    ///< If not NULL, this points to the prev vehicle that shared the order
	/* End Order-stuff */

	/* Boundaries for the current position in the world and a next hash link.
	 * NOSAVE: All of those can be updated with VehiclePositionChanged() */
	int32 left_coord;
	int32 top_coord;
	int32 right_coord;
	int32 bottom_coord;
	Vehicle *next_hash;

	/* Related to age and service time */
	Date age;     // Age in days
	Date max_age; // Maximum age
	Date date_of_last_service;
	Date service_interval;
	uint16 reliability;
	uint16 reliability_spd_dec;
	byte breakdown_ctr;
	byte breakdown_delay;
	byte breakdowns_since_last_service;
	byte breakdown_chance;
	Year build_year;

	bool leave_depot_instantly; // NOSAVE: stores if the vehicle needs to leave the depot it just entered. Used by autoreplace

	uint16 load_unload_time_rem;
	uint16 cargo_paid_for;      // How much of the cargo currently on board has been paid for.
	byte vehicle_flags;         // Used for gradual loading and other miscellaneous things (@see VehicleFlags enum)

	int32 profit_this_year;
	int32 profit_last_year;
	int32 cargo_feeder_share;      ///< value of feeder pickup to be paid for on delivery of cargo
	TileIndex cargo_loaded_at_xy;  ///< tile index where feeder cargo was loaded
	uint32 value;

	GroupID group_id;              ///< Index of group Pool array

	union {
		VehicleRail rail;
		VehicleAir air;
		VehicleRoad road;
		VehicleSpecial special;
		VehicleDisaster disaster;
		VehicleShip ship;
	} u;

	void BeginLoading();
	void LeaveStation();

	/**
	 * Handle the loading of the vehicle; when not it skips through dummy
	 * orders and does nothing in all other cases.
	 * @param mode is the non-first call for this vehicle in this tick?
	 */
	void HandleLoading(bool mode = false);

	/**
	 * An overriden version of new, so you can use the vehicle instance
	 * instead of a newly allocated piece of memory.
	 * @param size the size of the variable (unused)
	 * @param v    the vehicle to use as 'storage' backend
	 * @return the memory that is 'allocated'
	 */
	void* operator new(size_t size, Vehicle *v) { return v; }

	/**
	 * 'Free' the memory allocated by the overriden new.
	 * @param p the memory to 'free'
	 * @param v the vehicle that was given to 'new' on creation.
	 * @note This function isn't used (at the moment) and only added
	 *       to please some compiler.
	 */
	void operator delete(void *p, Vehicle *v) {}

	/**
	 * 'Free' the memory allocated by the overriden new.
	 * @param p the memory to 'free'
	 * @note This function isn't used (at the moment) and only added
	 *       as the above function was needed to please some compiler
	 *       which made it necessary to add this to please yet
	 *       another compiler...
	 */
	void operator delete(void *p) {}

	/** We want to 'destruct' the right class. */
	virtual ~Vehicle() {}

	/**
	 * Get a string 'representation' of the vehicle type.
	 * @return the string representation.
	 */
	virtual const char* GetTypeString() const = 0;

	/**
	 * Marks the vehicles to be redrawn and updates cached variables
	 */
	virtual void MarkDirty() {}

	/**
	 * Updates the x and y offsets and the size of the sprite used
	 * for this vehicle.
	 * @param direction the direction the vehicle is facing
	 */
	virtual void UpdateDeltaXY(Direction direction) {}

	/**
	 * Sets the expense type associated to this vehicle type
	 * @param income whether this is income or (running) expenses of the vehicle
	 */
	virtual ExpensesType GetExpenseType(bool income) const { return EXPENSES_OTHER; }

	/**
	 * Invalidates the vehicle list window of this type of vehicle
	 */
	virtual WindowClass GetVehicleListWindowClass() const { return WC_NONE; }

	/**
	 * Play the sound associated with leaving the station
	 */
	virtual void PlayLeaveStationSound() const {}
};

/**
 * This class 'wraps' Vehicle; you do not actually instantiate this class.
 * You create a Vehicle using AllocateVehicle, so it is added to the pool
 * and you reinitialize that to a Train using:
 *   v = new (v) Train();
 *
 * As side-effect the vehicle type is set correctly.
 *
 * A special vehicle is one of the following:
 *  - smoke
 *  - electric sparks for trains
 *  - explosions
 *  - bulldozer (road works)
 *  - bubbles (industry)
 */
struct SpecialVehicle : public Vehicle {
	/** Initializes the Vehicle to a special vehicle */
	SpecialVehicle() { this->type = VEH_SPECIAL; }

	/** We want to 'destruct' the right class. */
	virtual ~SpecialVehicle() {}

	const char *GetTypeString() const { return "special vehicle"; }
	void UpdateDeltaXY(Direction direction);
};

/**
 * This class 'wraps' Vehicle; you do not actually instantiate this class.
 * You create a Vehicle using AllocateVehicle, so it is added to the pool
 * and you reinitialize that to a Train using:
 *   v = new (v) Train();
 *
 * As side-effect the vehicle type is set correctly.
 */
struct DisasterVehicle : public Vehicle {
	/** Initializes the Vehicle to a disaster vehicle */
	DisasterVehicle() { this->type = VEH_DISASTER; }

	/** We want to 'destruct' the right class. */
	virtual ~DisasterVehicle() {}

	const char *GetTypeString() const { return "disaster vehicle"; }
	void UpdateDeltaXY(Direction direction);
};

/**
 * This class 'wraps' Vehicle; you do not actually instantiate this class.
 * You create a Vehicle using AllocateVehicle, so it is added to the pool
 * and you reinitialize that to a Train using:
 *   v = new (v) Train();
 *
 * As side-effect the vehicle type is set correctly.
 */
struct InvalidVehicle : public Vehicle {
	/** Initializes the Vehicle to a invalid vehicle */
	InvalidVehicle() { this->type = VEH_INVALID; }

	/** We want to 'destruct' the right class. */
	virtual ~InvalidVehicle() {}

	const char *GetTypeString() const { return "invalid vehicle"; }
};

#define is_custom_sprite(x) (x >= 0xFD)
#define IS_CUSTOM_FIRSTHEAD_SPRITE(x) (x == 0xFD)
#define IS_CUSTOM_SECONDHEAD_SPRITE(x) (x == 0xFE)

typedef void *VehicleFromPosProc(Vehicle *v, void *data);

void VehicleServiceInDepot(Vehicle *v);
Vehicle *AllocateVehicle();
bool AllocateVehicles(Vehicle **vl, int num);
Vehicle *ForceAllocateVehicle();
Vehicle *ForceAllocateSpecialVehicle();
void VehiclePositionChanged(Vehicle *v);
void AfterLoadVehicles();
Vehicle *GetLastVehicleInChain(Vehicle *v);
Vehicle *GetPrevVehicleInChain(const Vehicle *v);
Vehicle *GetFirstVehicleInChain(const Vehicle *v);
uint CountVehiclesInChain(const Vehicle* v);
bool IsEngineCountable(const Vehicle *v);
void DeleteVehicleChain(Vehicle *v);
void *VehicleFromPos(TileIndex tile, void *data, VehicleFromPosProc *proc);
void CallVehicleTicks();
Vehicle *FindVehicleOnTileZ(TileIndex tile, byte z);

void InitializeTrains();
byte VehicleRandomBits();
void ResetVehiclePosHash();

bool CanRefitTo(EngineID engine_type, CargoID cid_to);
CargoID FindFirstRefittableCargo(EngineID engine_type);
int32 GetRefitCost(EngineID engine_type);

void ViewportAddVehicles(DrawPixelInfo *dpi);

/* train_cmd.h */
int GetTrainImage(const Vehicle* v, Direction direction);
int GetAircraftImage(const Vehicle* v, Direction direction);
int GetRoadVehImage(const Vehicle* v, Direction direction);
int GetShipImage(const Vehicle* v, Direction direction);
SpriteID GetRotorImage(const Vehicle *v);

Vehicle *CreateEffectVehicle(int x, int y, int z, EffectVehicle type);
Vehicle *CreateEffectVehicleAbove(int x, int y, int z, EffectVehicle type);
Vehicle *CreateEffectVehicleRel(const Vehicle *v, int x, int y, int z, EffectVehicle type);

uint32 VehicleEnterTile(Vehicle *v, TileIndex tile, int x, int y);

StringID VehicleInTheWayErrMsg(const Vehicle* v);
Vehicle *FindVehicleBetween(TileIndex from, TileIndex to, byte z, bool without_crashed = false);

bool UpdateSignalsOnSegment(TileIndex tile, DiagDirection direction);
void SetSignalsOnBothDir(TileIndex tile, byte track);

Vehicle *CheckClickOnVehicle(const ViewPort *vp, int x, int y);

void DecreaseVehicleValue(Vehicle *v);
void CheckVehicleBreakdown(Vehicle *v);
void AgeVehicle(Vehicle *v);
void VehicleEnteredDepotThisTick(Vehicle *v);

void BeginVehicleMove(Vehicle *v);
void EndVehicleMove(Vehicle *v);

void ShowAircraftViewWindow(const Vehicle* v);

UnitID GetFreeUnitNumber(VehicleType type);

void TrainConsistChanged(Vehicle *v);
void TrainPowerChanged(Vehicle *v);
int32 GetTrainRunningCost(const Vehicle *v);

int CheckTrainStoppedInDepot(const Vehicle *v);

bool VehicleNeedsService(const Vehicle *v);

uint GenerateVehicleSortList(const Vehicle*** sort_list, uint16 *length_of_array, VehicleType type, PlayerID owner, uint32 index, uint16 window_type);
void BuildDepotVehicleList(VehicleType type, TileIndex tile, Vehicle ***engine_list, uint16 *engine_list_length, uint16 *engine_count, Vehicle ***wagon_list, uint16 *wagon_list_length, uint16 *wagon_count);
int32 SendAllVehiclesToDepot(VehicleType type, uint32 flags, bool service, PlayerID owner, uint16 vlw_flag, uint32 id);
bool IsVehicleInDepot(const Vehicle *v);
void VehicleEnterDepot(Vehicle *v);

void InvalidateAutoreplaceWindow(EngineID e);

int32 MaybeReplaceVehicle(Vehicle *v, bool check, bool display_costs);

/* Flags to add to p2 for goto depot commands */
/* Note: bits 8-10 are used for VLW flags */
enum {
	DEPOT_SERVICE       = (1 << 0), // The vehicle will leave the depot right after arrival (serivce only)
	DEPOT_MASS_SEND     = (1 << 1), // Tells that it's a mass send to depot command (type in VLW flag)
	DEPOT_DONT_CANCEL   = (1 << 2), // Don't cancel current goto depot command if any
	DEPOT_LOCATE_HANGAR = (1 << 3), // Find another airport if the target one lacks a hangar
};

struct GetNewVehiclePosResult {
	int x,y;
	TileIndex old_tile;
	TileIndex new_tile;
};

/**
 * Returns the Trackdir on which the vehicle is currently located.
 * Works for trains and ships.
 * Currently works only sortof for road vehicles, since they have a fuzzy
 * concept of being "on" a trackdir. Dunno really what it returns for a road
 * vehicle that is halfway a tile, never really understood that part. For road
 * vehicles that are at the beginning or end of the tile, should just return
 * the diagonal trackdir on which they are driving. I _think_.
 * For other vehicles types, or vehicles with no clear trackdir (such as those
 * in depots), returns 0xFF.
 */
Trackdir GetVehicleTrackdir(const Vehicle* v);

/* returns true if staying in the same tile */
GetNewVehiclePosResult GetNewVehiclePos(const Vehicle *v);
Direction GetDirectionTowards(const Vehicle* v, int x, int y);

#define BEGIN_ENUM_WAGONS(v) do {
#define END_ENUM_WAGONS(v) } while ( (v=v->next) != NULL);

DECLARE_OLD_POOL(Vehicle, Vehicle, 9, 125)

static inline VehicleID GetMaxVehicleIndex()
{
	/* TODO - This isn't the real content of the function, but
	 *  with the new pool-system this will be replaced with one that
	 *  _really_ returns the highest index. Now it just returns
	 *  the next safe value we are sure about everything is below.
	 */
	return GetVehiclePoolSize() - 1;
}

static inline uint GetNumVehicles()
{
	return GetVehiclePoolSize();
}

/**
 * Check if a Vehicle really exists.
 */
static inline bool IsValidVehicle(const Vehicle *v)
{
	return v->type != VEH_INVALID;
}

void DestroyVehicle(Vehicle *v);

static inline void DeleteVehicle(Vehicle *v)
{
	DestroyVehicle(v);
	v = new (v) InvalidVehicle();
}

static inline bool IsPlayerBuildableVehicleType(VehicleType type)
{
	switch (type) {
		case VEH_TRAIN:
		case VEH_ROAD:
		case VEH_SHIP:
		case VEH_AIRCRAFT:
			return true;

		default: return false;
	}
}

static inline bool IsPlayerBuildableVehicleType(const Vehicle *v)
{
	return IsPlayerBuildableVehicleType(v->type);
}

#define FOR_ALL_VEHICLES_FROM(v, start) for (v = GetVehicle(start); v != NULL; v = (v->index + 1U < GetVehiclePoolSize()) ? GetVehicle(v->index + 1) : NULL) if (IsValidVehicle(v))
#define FOR_ALL_VEHICLES(v) FOR_ALL_VEHICLES_FROM(v, 0)

/**
 * Check if an index is a vehicle-index (so between 0 and max-vehicles)
 * @param index of the vehicle to query
 * @return Returns true if the vehicle-id is in range
 */
static inline bool IsValidVehicleID(uint index)
{
	return index < GetVehiclePoolSize() && IsValidVehicle(GetVehicle(index));
}

/* Returns order 'index' of a vehicle or NULL when it doesn't exists */
static inline Order *GetVehicleOrder(const Vehicle *v, int index)
{
	Order *order = v->orders;

	if (index < 0) return NULL;

	while (order != NULL && index-- > 0)
		order = order->next;

	return order;
}

/**
 * Returns the last order of a vehicle, or NULL if it doesn't exists
 * @param v Vehicle to query
 * @return last order of a vehicle, if available
 */
static inline Order *GetLastVehicleOrder(const Vehicle *v)
{
	Order *order = v->orders;

	if (order == NULL) return NULL;

	while (order->next != NULL)
		order = order->next;

	return order;
}

/** Get the first vehicle of a shared-list, so we only have to walk forwards
 * @param v Vehicle to query
 * @return first vehicle of a shared-list
 */
static inline Vehicle *GetFirstVehicleFromSharedList(const Vehicle *v)
{
	Vehicle *u = (Vehicle *)v;
	while (u->prev_shared != NULL) u = u->prev_shared;

	return u;
}

/* NOSAVE: Return values from various commands. */
VARDEF VehicleID _new_vehicle_id;
VARDEF uint16 _returned_refit_capacity;

static const VehicleID INVALID_VEHICLE = 0xFFFF;

const struct Livery *GetEngineLivery(EngineID engine_type, PlayerID player, EngineID parent_engine_type, const Vehicle *v);

/**
 * Get the colour map for an engine. This used for unbuilt engines in the user interface.
 * @param engine_type ID of engine
 * @param player ID of player
 * @return A ready-to-use palette modifier
 */
SpriteID GetEnginePalette(EngineID engine_type, PlayerID player);

/**
 * Get the colour map for a vehicle.
 * @param v Vehicle to get colour map for
 * @return A ready-to-use palette modifier
 */
SpriteID GetVehiclePalette(const Vehicle *v);

/* A lot of code calls for the invalidation of the status bar, which is widget 5.
 * Best is to have a virtual value for it when it needs to change again */
#define STATUS_BAR 5

extern const uint32 _veh_build_proc_table[];
extern const uint32 _veh_sell_proc_table[];
extern const uint32 _veh_refit_proc_table[];
extern const uint32 _send_to_depot_proc_table[];

/* Functions to find the right command for certain vehicle type */
static inline uint32 GetCmdBuildVeh(VehicleType type)
{
	return _veh_build_proc_table[type];
}

static inline uint32 GetCmdBuildVeh(const Vehicle *v)
{
	return GetCmdBuildVeh(v->type);
}

static inline uint32 GetCmdSellVeh(VehicleType type)
{
	return _veh_sell_proc_table[type];
}

static inline uint32 GetCmdSellVeh(const Vehicle *v)
{
	return GetCmdSellVeh(v->type);
}

static inline uint32 GetCmdRefitVeh(VehicleType type)
{
	return _veh_refit_proc_table[type];
}

static inline uint32 GetCmdRefitVeh(const Vehicle *v)
{
	return GetCmdRefitVeh(v->type);
}

static inline uint32 GetCmdSendToDepot(VehicleType type)
{
	return _send_to_depot_proc_table[type];
}

static inline uint32 GetCmdSendToDepot(const Vehicle *v)
{
	return GetCmdSendToDepot(v->type);
}

#endif /* VEHICLE_H */