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/* $Id$ */

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/** @file map.cpp */

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#include "stdafx.h"

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#include "openttd.h"

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#include "debug.h"

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#include "functions.h"

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#include "macros.h"

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#include "map.h"

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#include "direction.h"

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#include "helpers.hpp"

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#if defined(_MSC_VER) && _MSC_VER >= 1400 /* VStudio 2005 is stupid! */

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/* Why the hell is that not in all MSVC headers?? */

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extern "C" _CRTIMP void __cdecl _assert(void *, void *, unsigned);

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#endif

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uint _map_log_x;

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uint _map_size_x;

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uint _map_size_y;

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uint _map_tile_mask;

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uint _map_size;

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Tile* _m = NULL;

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void AllocateMap(uint size_x, uint size_y)

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{

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	/* Make sure that the map size is within the limits and that

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	 * the x axis size is a power of 2. */

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	if (size_x < 64 || size_x > 2048 ||

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			size_y < 64 || size_y > 2048 ||

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			(size_x&(size_x-1)) != 0 ||

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			(size_y&(size_y-1)) != 0)

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		error("Invalid map size");

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	DEBUG(map, 1, "Allocating map of size %dx%d", size_x, size_y);

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	_map_log_x = FindFirstBit(size_x);

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	_map_size_x = size_x;

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	_map_size_y = size_y;

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	_map_size = size_x * size_y;

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	_map_tile_mask = _map_size - 1;

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	free(_m);

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	_m = CallocT<Tile>(_map_size);

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	/* XXX TODO handle memory shortage more gracefully */

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	if (_m == NULL) error("Failed to allocate memory for the map");

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}

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#ifdef _DEBUG

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TileIndex TileAdd(TileIndex tile, TileIndexDiff add,

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	const char *exp, const char *file, int line)

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{

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	int dx;

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	int dy;

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	uint x;

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	uint y;

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	dx = add & MapMaxX();

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	if (dx >= (int)MapSizeX() / 2) dx -= MapSizeX();

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	dy = (add - dx) / (int)MapSizeX();

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	x = TileX(tile) + dx;

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	y = TileY(tile) + dy;

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	if (x >= MapSizeX() || y >= MapSizeY()) {

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		char buf[512];

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		snprintf(buf, lengthof(buf), "TILE_ADD(%s) when adding 0x%.4X and 0x%.4X failed",

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			exp, tile, add);

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#if !defined(_MSC_VER)

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		fprintf(stderr, "%s:%d %s\n", file, line, buf);

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#else

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		_assert(buf, (char*)file, line);

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#endif

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	}

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	assert(TileXY(x,y) == TILE_MASK(tile + add));

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	return TileXY(x,y);

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}

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#endif

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uint ScaleByMapSize(uint n)

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{

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	/* First shift by 12 to prevent integer overflow for large values of n.

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	 * >>12 is safe since the min mapsize is 64x64

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	 * Add (1<<4)-1 to round upwards. */

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	return (n * (MapSize() >> 12) + (1<<4) - 1) >> 4;

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}

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/* Scale relative to the circumference of the map */

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uint ScaleByMapSize1D(uint n)

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{

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	/* Normal circumference for the X+Y is 256+256 = 1<<9

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	 * Note, not actually taking the full circumference into account,

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	 * just half of it.

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	 * (1<<9) - 1 is there to scale upwards. */

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	return (n * (MapSizeX() + MapSizeY()) + (1<<9) - 1) >> 9;

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}

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/* This function checks if we add addx/addy to tile, if we

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 *  do wrap around the edges. For example, tile = (10,2) and

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 *  addx = +3 and addy = -4. This function will now return

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 *  INVALID_TILE, because the y is wrapped. This is needed in

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 *  for example, farmland. When the tile is not wrapped,

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 *  the result will be tile + TileDiffXY(addx, addy) */

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uint TileAddWrap(TileIndex tile, int addx, int addy)

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{

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	uint x = TileX(tile) + addx;

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	uint y = TileY(tile) + addy;

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	/* Are we about to wrap? */

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	if (x < MapMaxX() && y < MapMaxY())

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		return tile + TileDiffXY(addx, addy);

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	return INVALID_TILE;

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}

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extern const TileIndexDiffC _tileoffs_by_diagdir[] = {

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	{-1,  0}, ///< DIAGDIR_NE

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	{ 0,  1}, ///< DIAGDIR_SE

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	{ 1,  0}, ///< DIAGDIR_SW

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	{ 0, -1}  ///< DIAGDIR_NW

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};

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extern const TileIndexDiffC _tileoffs_by_dir[] = {

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	{-1, -1}, ///< DIR_N

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	{-1,  0}, ///< DIR_NE

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	{-1,  1}, ///< DIR_E

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	{ 0,  1}, ///< DIR_SE

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	{ 1,  1}, ///< DIR_S

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	{ 1,  0}, ///< DIR_SW

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	{ 1, -1}, ///< DIR_W

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	{ 0, -1}  ///< DIR_NW

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};

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uint DistanceManhattan(TileIndex t0, TileIndex t1)

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{

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	const uint dx = delta(TileX(t0), TileX(t1));

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	const uint dy = delta(TileY(t0), TileY(t1));

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	return dx + dy;

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}

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uint DistanceSquare(TileIndex t0, TileIndex t1)

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{

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	const int dx = TileX(t0) - TileX(t1);

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	const int dy = TileY(t0) - TileY(t1);

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	return dx * dx + dy * dy;

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}

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uint DistanceMax(TileIndex t0, TileIndex t1)

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{

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	const uint dx = delta(TileX(t0), TileX(t1));

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	const uint dy = delta(TileY(t0), TileY(t1));

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	return dx > dy ? dx : dy;

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}

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uint DistanceMaxPlusManhattan(TileIndex t0, TileIndex t1)

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{

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	const uint dx = delta(TileX(t0), TileX(t1));

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	const uint dy = delta(TileY(t0), TileY(t1));

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	return dx > dy ? 2 * dx + dy : 2 * dy + dx;

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}

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uint DistanceFromEdge(TileIndex tile)

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{

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	const uint xl = TileX(tile);

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	const uint yl = TileY(tile);

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	const uint xh = MapSizeX() - 1 - xl;

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	const uint yh = MapSizeY() - 1 - yl;

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	const uint minl = xl < yl ? xl : yl;

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	const uint minh = xh < yh ? xh : yh;

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	return minl < minh ? minl : minh;

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}

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/**

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 * Function performing a search around a center tile and going outward, thus in circle.

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 * Although it really is a square search...

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 * Every tile will be tested by means of the callback function proc,

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 * which will determine if yes or no the given tile meets criteria of search.

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 * @param tile to start the search from

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 * @param size: number of tiles per side of the desired search area

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 * @param proc: callback testing function pointer.

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 * @param data to be passed to the callback function. Depends on the implementation

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 * @return result of the search

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 * @pre proc != NULL

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 * @pre size > 0

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 */

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bool CircularTileSearch(TileIndex tile, uint size, TestTileOnSearchProc proc, uint32 data)

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{

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	uint n, x, y;

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	DiagDirection dir;

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	assert(proc != NULL);

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	assert(size > 0);

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	x = TileX(tile);

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	y = TileY(tile);

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	if (size % 2 == 1) {

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		/* If the length of the side is uneven, the center has to be checked

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		 * separately, as the pattern of uneven sides requires to go around the center */

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		n = 2;

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		if (proc(TileXY(x, y), data)) return true;

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		/* If tile test is not successfull, get one tile down and left,

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		 * ready for a test in first circle around center tile */

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		x += _tileoffs_by_dir[DIR_W].x;

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		y += _tileoffs_by_dir[DIR_W].y;

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	} else {

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		n = 1;

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		/* To use _tileoffs_by_diagdir's order, we must relocate to

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		 * another tile, as we now first go 'up', 'right', 'down', 'left'

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		 * instead of 'right', 'down', 'left', 'up', which the calling

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		 * function assume. */

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		x++;

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	}

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	for (; n < size; n += 2) {

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		for (dir = DIAGDIR_NE; dir < DIAGDIR_END; dir++) {

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			uint j;

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			for (j = n; j != 0; j--) {

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				if (x <= MapMaxX() && y <= MapMaxY() && ///< Is the tile within the map?

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						proc(TileXY(x, y), data)) {     ///< Is the callback successfulll?

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					return true;                        ///< then stop the search

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				}

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				/* Step to the next 'neighbour' in the circular line */

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				x += _tileoffs_by_diagdir[dir].x;

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				y += _tileoffs_by_diagdir[dir].y;

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			}

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		}

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		/* Jump to next circle to test */

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		x += _tileoffs_by_dir[DIR_W].x;

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		y += _tileoffs_by_dir[DIR_W].y;

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	}

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	return false;

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}