/* $Id$ */

#ifndef BRIDGE_MAP_H
#define BRIDGE_MAP_H

#include "direction.h"
#include "macros.h"
#include "map.h"
#include "rail.h"
#include "road_map.h"
#include "tile.h"


void DrawBridgeMiddle(const TileInfo* ti); // XXX

#define M(x) (1 << (x))
enum {
	// foundation, whole tile is leveled up --> 3 corners raised
	BRIDGE_FULL_LEVELED_FOUNDATION = M(SLOPE_WSE) | M(SLOPE_NWS) | M(SLOPE_ENW) | M(SLOPE_SEN),
	// foundation, tile is partly leveled up --> 1 corner raised
	BRIDGE_PARTLY_LEVELED_FOUNDATION = M(SLOPE_W) | M(SLOPE_S) | M(SLOPE_E) | M(SLOPE_N),
	// no foundations (X,Y direction)
	BRIDGE_NO_FOUNDATION = M(SLOPE_FLAT) | M(SLOPE_SW) | M(SLOPE_SE) | M(SLOPE_NW) | M(SLOPE_NE),
	BRIDGE_HORZ_RAMP = (BRIDGE_PARTLY_LEVELED_FOUNDATION | BRIDGE_NO_FOUNDATION) & ~M(SLOPE_FLAT)
};
#undef M


static inline bool IsBridgeTile(TileIndex t)
{
	return IsTileType(t, MP_STREET_BRIDGE) || IsTileType(t, MP_RAILWAY_BRIDGE);
}

static inline bool MayHaveBridgeAbove(TileIndex t)
{
	return
		IsTileType(t, MP_CLEAR) ||
		IsTileType(t, MP_RAILWAY) ||
		IsTileType(t, MP_STREET) ||
		IsTileType(t, MP_WATER) ||
		IsTileType(t, MP_TUNNEL) ||
		IsTileType(t, MP_STREET_BRIDGE) ||
		IsTileType(t, MP_RAILWAY_BRIDGE) ||
		IsTileType(t, MP_UNMOVABLE);
}


static inline bool IsBridgeAbove(TileIndex t)
{
	assert(MayHaveBridgeAbove(t));
	return GB(_m[t].extra, 6, 2) != 0;
}


/**
 * Determines the type of bridge on a tile
 * @param tile The tile to analyze
 * @return The bridge type
 */
static inline uint GetBridgeType(TileIndex t)
{
	assert(IsBridgeTile(t));
	return GB(_m[t].m2, 4, 4);
}


/**
 * Get the direction pointing onto the bridge
 */
static inline DiagDirection GetBridgeRampDirection(TileIndex t)
{
	assert(IsBridgeTile(t));
	return (DiagDirection)GB(_m[t].m4, 5, 2);
}


static inline Axis GetBridgeAxis(TileIndex t)
{
	assert(IsBridgeAbove(t));
	return (Axis)(GB(_m[t].extra, 6, 2) - 1);
}


static inline TransportType GetBridgeTransportType(TileIndex t)
{
	assert(IsBridgeTile(t));
	if (IsTileType(t, MP_STREET_BRIDGE)) return TRANSPORT_ROAD;

	return TRANSPORT_RAIL;
}


static inline bool HasBridgeSnowOrDesert(TileIndex t)
{
	assert(IsBridgeTile(t));
	return HASBIT(_m[t].m4, 7);
}


static inline void SetBridgeSnowOrDesert(TileIndex t, bool snow_or_desert)
{
	assert(IsBridgeTile(t));
	SB(_m[t].m4, 7, 1, snow_or_desert);
}

/**
 * Finds the end of a bridge in the specified direction starting at a middle tile
 */
TileIndex GetBridgeEnd(TileIndex, DiagDirection);

/**
 * Finds the northern end of a bridge starting at a middle tile
 */
TileIndex GetNorthernBridgeEnd(TileIndex t);

/**
 * Finds the southern end of a bridge starting at a middle tile
 */
TileIndex GetSouthernBridgeEnd(TileIndex t);


/**
 * Starting at one bridge end finds the other bridge end
 */
TileIndex GetOtherBridgeEnd(TileIndex);

uint GetBridgeHeight(TileIndex tile);
uint GetBridgeFoundation(Slope tileh, Axis axis);

static inline void ClearSingleBridgeMiddle(TileIndex t, Axis a)
{
	assert(MayHaveBridgeAbove(t));
	CLRBIT(_m[t].extra, 6 + a);
}


static inline void ClearBridgeMiddle(TileIndex t)
{
	ClearSingleBridgeMiddle(t, AXIS_X);
	ClearSingleBridgeMiddle(t, AXIS_Y);
}

static inline void SetBridgeMiddle(TileIndex t, Axis a)
{
	assert(MayHaveBridgeAbove(t));
	SETBIT(_m[t].extra, 6 + a);
}


static inline void MakeBridgeRamp(TileIndex t, Owner o, uint bridgetype, DiagDirection d, TransportType tt)
{
	SetTileOwner(t, o);
	_m[t].m2 = bridgetype << 4;
	_m[t].m4 = d << 5;
	_m[t].m5 = 0;
}

static inline void MakeRoadBridgeRamp(TileIndex t, Owner o, uint bridgetype, DiagDirection d)
{
	MakeBridgeRamp(t, o, bridgetype, d, TRANSPORT_ROAD);
	SetTileType(t, MP_STREET_BRIDGE);
	_m[t].m3 = 0;
}

static inline void MakeRailBridgeRamp(TileIndex t, Owner o, uint bridgetype, DiagDirection d, RailType r)
{
	MakeBridgeRamp(t, o, bridgetype, d, TRANSPORT_RAIL);
	SetTileType(t, MP_RAILWAY_BRIDGE);
	_m[t].m3 = r;
	_m[t].m5 = DiagDirToAxis(d) == AXIS_X ? TRACK_BIT_X : TRACK_BIT_Y;
}


#endif /* BRIDGE_MAP_H */