/* $Id: bridge_map.h 4311 2006-04-07 08:42:30Z celestar $ */

#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"


static inline bool IsBridge(TileIndex t)
{
	assert(IsTileType(t, MP_TUNNELBRIDGE));
	return HASBIT(_m[t].m5, 7);
}

static inline bool IsBridgeTile(TileIndex t)
{
	return IsTileType(t, MP_TUNNELBRIDGE) && IsBridge(t);
}


static inline bool IsBridgeRamp(TileIndex t)
{
	assert(IsBridgeTile(t));
	return !HASBIT(_m[t].m5, 6);
}

static inline bool IsBridgeMiddle(TileIndex t)
{
	assert(IsBridgeTile(t));
	return HASBIT(_m[t].m5, 6);
}


/**
 * Determines which piece of a bridge is contained in the current tile
 * @param tile The tile to analyze
 * @return the piece
 */
static inline uint GetBridgePiece(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	return GB(_m[t].m2, 0, 4);
}


/**
 * 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(IsBridgeRamp(t));
	/* Heavy wizardry to convert the X/Y (bit 0) + N/S (bit 5) encoding of
	 * bridges to a DiagDirection
	 */
	return (DiagDirection)((6 - (_m[t].m5 >> 4 & 2) - (_m[t].m5 & 1)) % 4);
}


static inline Axis GetBridgeAxis(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	return (Axis)GB(_m[t].m5, 0, 1);
}


static inline TransportType GetBridgeTransportType(TileIndex t)
{
	assert(IsBridgeTile(t));
	return (TransportType)GB(_m[t].m5, 1, 2);
}


static inline bool IsClearUnderBridge(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	return GB(_m[t].m5, 3, 3) == 0;
}

static inline bool IsWaterUnderBridge(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	return GB(_m[t].m5, 3, 3) == 1;
}


static inline bool IsTransportUnderBridge(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	return HASBIT(_m[t].m5, 5);
}

static inline TransportType GetTransportTypeUnderBridge(TileIndex t)
{
	assert(IsTransportUnderBridge(t));
	return (TransportType)GB(_m[t].m5, 3, 2);
}

static inline RoadBits GetRoadBitsUnderBridge(TileIndex t)
{
	assert(GetTransportTypeUnderBridge(t) == TRANSPORT_ROAD);
	return GetBridgeAxis(t) == AXIS_X ? ROAD_Y : ROAD_X;
}

static inline TrackBits GetRailBitsUnderBridge(TileIndex t)
{
	assert(GetTransportTypeUnderBridge(t) == TRANSPORT_RAIL);
	return GetBridgeAxis(t) == AXIS_X ? TRACK_BIT_Y : TRACK_BIT_X;
}


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

/**
 * 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 t);

static inline void SetClearUnderBridge(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	SetTileOwner(t, OWNER_NONE);
	SB(_m[t].m5, 3, 3, 0 << 2 | 0);
	SB(_m[t].m3, 0, 4, 0);
}

static inline void SetWaterUnderBridge(TileIndex t)
{
	assert(IsBridgeMiddle(t));
	SetTileOwner(t, OWNER_WATER);
	SB(_m[t].m5, 3, 3, 0 << 2 | 1);
	SB(_m[t].m3, 0, 4, 0);
}

static inline void SetRailUnderBridge(TileIndex t, Owner o, RailType r)
{
	assert(IsBridgeMiddle(t));
	SetTileOwner(t, o);
	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_RAIL);
	SB(_m[t].m3, 0, 4, r);
}

static inline void SetRoadUnderBridge(TileIndex t, Owner o)
{
	assert(IsBridgeMiddle(t));
	SetTileOwner(t, o);
	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_ROAD);
	SB(_m[t].m3, 0, 4, 0);
}


static inline void MakeBridgeRamp(TileIndex t, Owner o, uint bridgetype, DiagDirection d, TransportType tt)
{
	uint northsouth = (d == DIAGDIR_NE || d == DIAGDIR_NW);

	SetTileType(t, MP_TUNNELBRIDGE);
	SetTileOwner(t, o);
	_m[t].m2 = bridgetype << 4;
	_m[t].m4 = 0;
	_m[t].m5 = 1 << 7 | 0 << 6 | northsouth << 5 | tt << 1 | DiagDirToAxis(d);
}

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


static inline void MakeBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a, TransportType tt)
{
	SetTileType(t, MP_TUNNELBRIDGE);
	SetTileOwner(t, OWNER_NONE);
	_m[t].m2 = bridgetype << 4 | piece;
	_m[t].m3 = 0;
	_m[t].m4 = 0;
	_m[t].m5 = 1 << 7 | 1 << 6 | 0 << 5 | 0 << 3 | tt << 1 | a;
}

static inline void MakeRoadBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a)
{
	MakeBridgeMiddle(t, bridgetype, piece, a, TRANSPORT_ROAD);
}

static inline void MakeRailBridgeMiddle(TileIndex t, uint bridgetype, uint piece, Axis a, RailType r)
{
	MakeBridgeMiddle(t, bridgetype, piece, a, TRANSPORT_RAIL);
	SB(_m[t].m3, 4, 4, r);
}


#endif
