/* $Id$ */

/** @file tile.h */

#ifndef TILE_H
#define TILE_H

#include "macros.h"
#include "openttd.h"
#include "map.h"
#include "slope.h"

/** Maximum allowed tile height */
#define MAX_TILE_HEIGHT 15

/** Maximum allowed snowline height */
#define MAX_SNOWLINE_HEIGHT (MAX_TILE_HEIGHT - 2)

enum TileType {
	MP_CLEAR,
	MP_RAILWAY,
	MP_STREET,
	MP_HOUSE,
	MP_TREES,
	MP_STATION,
	MP_WATER,
	MP_VOID, // invisible tiles at the SW and SE border
	MP_INDUSTRY,
	MP_TUNNELBRIDGE,
	MP_UNMOVABLE,
};

enum TropicZone {
	TROPICZONE_INVALID    = 0,
	TROPICZONE_DESERT     = 1,
	TROPICZONE_RAINFOREST = 2,
};

Slope GetTileSlope(TileIndex tile, uint *h);
uint GetTileZ(TileIndex tile);
uint GetTileMaxZ(TileIndex tile);

static inline uint TileHeight(TileIndex tile)
{
	assert(tile < MapSize());
	return GB(_m[tile].type_height, 0, 4);
}

static inline void SetTileHeight(TileIndex tile, uint height)
{
	assert(tile < MapSize());
	assert(height < 16);
	SB(_m[tile].type_height, 0, 4, height);
}

static inline uint TilePixelHeight(TileIndex tile)
{
	return TileHeight(tile) * TILE_HEIGHT;
}

static inline TileType GetTileType(TileIndex tile)
{
	assert(tile < MapSize());
	return (TileType)GB(_m[tile].type_height, 4, 4);
}

static inline void SetTileType(TileIndex tile, TileType type)
{
	assert(tile < MapSize());
	/* VOID tiles (and no others) are exactly allowed at the lower left and right
	 * edges of the map */
	assert((TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) == (type == MP_VOID));
	SB(_m[tile].type_height, 4, 4, type);
}

static inline bool IsTileType(TileIndex tile, TileType type)
{
	return GetTileType(tile) == type;
}


static inline Owner GetTileOwner(TileIndex tile)
{
	assert(tile < MapSize());
	assert(!IsTileType(tile, MP_HOUSE));
	assert(!IsTileType(tile, MP_VOID));
	assert(!IsTileType(tile, MP_INDUSTRY));

	return (Owner)_m[tile].m1;
}

static inline void SetTileOwner(TileIndex tile, Owner owner)
{
	assert(tile < MapSize());
	assert(!IsTileType(tile, MP_HOUSE));
	assert(!IsTileType(tile, MP_VOID));
	assert(!IsTileType(tile, MP_INDUSTRY));

	_m[tile].m1 = owner;
}

static inline bool IsTileOwner(TileIndex tile, Owner owner)
{
	return GetTileOwner(tile) == owner;
}

/**
 * Set the tropic zone
 * @param tile the tile to set the zone of
 * @param type the new type
 * @pre assert(tile < MapSize());
 */
static inline void SetTropicZone(TileIndex tile, TropicZone type)
{
	assert(tile < MapSize());
	SB(_m[tile].m6, 0, 2, type);
}

/**
 * Get the tropic zone
 * @param tile the tile to get the zone of
 * @pre assert(tile < MapSize());
 * @return the zone type
 */
static inline TropicZone GetTropicZone(TileIndex tile)
{
	assert(tile < MapSize());
	return (TropicZone)GB(_m[tile].m6, 0, 2);
}
#endif /* TILE_H */