/* $Id$ */

#include "stdafx.h"

#include "openttd.h"

#include "debug.h"

#include "functions.h"

#include "macros.h"

#include "map.h"

#include "direction.h"

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

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

_CRTIMP void __cdecl _assert(void *, void *, unsigned);

#endif

uint _map_log_x;

uint _map_size_x;

uint _map_size_y;

uint _map_tile_mask;

uint _map_size;

Tile* _m = NULL;

void AllocateMap(uint size_x, uint size_y)

{

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

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

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

			size_y < 64 || size_y > 2048 ||

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

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

		error("Invalid map size");

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

	_map_log_x = FindFirstBit(size_x);

	_map_size_x = size_x;

	_map_size_y = size_y;

	_map_size = size_x * size_y;

	_map_tile_mask = _map_size - 1;

	free(_m);

	_m = calloc(_map_size, sizeof(*_m));

	// XXX TODO handle memory shortage more gracefully

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

}

#ifdef _DEBUG

TileIndex TileAdd(TileIndex tile, TileIndexDiff add,

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

{

	int dx;

	int dy;

	uint x;

	uint y;

	dx = add & MapMaxX();

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

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

	x = TileX(tile) + dx;

	y = TileY(tile) + dy;

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

		char buf[512];

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

			exp, tile, add);

#if !defined(_MSC_VER)

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

#else

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

#endif

	}

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

	return TileXY(x,y);

}

#endif

uint ScaleByMapSize(uint n)

{

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

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

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

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

}

// Scale relative to the circumference of the map

uint ScaleByMapSize1D(uint n)

{

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

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

	// just half of it.

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

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

}

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

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

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

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

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

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

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

{

	uint x = TileX(tile) + addx;

	uint y = TileY(tile) + addy;

	// Are we about to wrap?

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

		return tile + TileDiffXY(addx, addy);

	return INVALID_TILE;

}

const TileIndexDiffC _tileoffs_by_diagdir[] = {

	{-1,  0}, // DIAGDIR_NE

	{ 0,  1}, // DIAGDIR_SE

	{ 1,  0}, // DIAGDIR_SW

	{ 0, -1}  // DIAGDIR_NW

};

const TileIndexDiffC _tileoffs_by_dir[] = {

	{-1, -1}, // DIR_N

	{-1,  0}, // DIR_NE

	{-1,  1}, // DIR_E

	{ 0,  1}, // DIR_SE

	{ 1,  1}, // DIR_S

	{ 1,  0}, // DIR_SW

	{ 1, -1}, // DIR_W

	{ 0, -1}  // DIR_NW

};

uint DistanceManhattan(TileIndex t0, TileIndex t1)

{

	const uint dx = abs(TileX(t0) - TileX(t1));

	const uint dy = abs(TileY(t0) - TileY(t1));

	return dx + dy;

}

uint DistanceSquare(TileIndex t0, TileIndex t1)

{

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

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

	return dx * dx + dy * dy;

}

uint DistanceMax(TileIndex t0, TileIndex t1)

{

	const uint dx = abs(TileX(t0) - TileX(t1));

	const uint dy = abs(TileY(t0) - TileY(t1));

	return dx > dy ? dx : dy;

}

uint DistanceMaxPlusManhattan(TileIndex t0, TileIndex t1)

{

	const uint dx = abs(TileX(t0) - TileX(t1));

	const uint dy = abs(TileY(t0) - TileY(t1));

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

}

uint DistanceFromEdge(TileIndex tile)

{

	const uint xl = TileX(tile);

	const uint yl = TileY(tile);

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

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

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

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

	return minl < minh ? minl : minh;

}

/**

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

 * Although it really is a square search...

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

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

 * @param tile to start the search from

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

 * @param proc: callback testing function pointer.

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

 * @result of the search

 * @pre proc != NULL

 * @pre size > 0

 */

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

{

	uint n, x, y;

	DiagDirection dir;

	assert(proc != NULL);

	assert(size > 0);

	x = TileX(tile);

	y = TileY(tile);

	if (size % 2 == 1) {

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

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

		n = 2;

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

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

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

		x += _tileoffs_by_dir[DIR_W].x;

		y += _tileoffs_by_dir[DIR_W].y;

	} else {

		n = 1;

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

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

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

		 * function assume. */

		x++;

	}

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

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

			uint j;

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

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

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

					return true;                        ///< then stop the search

				}

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

				x += _tileoffs_by_diagdir[dir].x;

				y += _tileoffs_by_diagdir[dir].y;

			}

		}

		/* Jump to next circle to test */

		x += _tileoffs_by_dir[DIR_W].x;

		y += _tileoffs_by_dir[DIR_W].y;

	}

	return false;

}