/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file smallmap_gui.cpp GUI that shows a small map of the world with metadata like owner or height. */

#include "stdafx.h"
#include "core/backup_type.hpp"
#include "clear_map.h"
#include "industry.h"
#include "station_map.h"
#include "landscape.h"
#include "tree_map.h"
#include "viewport_func.h"
#include "town.h"
#include "tunnelbridge_map.h"
#include "core/endian_func.hpp"
#include "vehicle_base.h"
#include "sound_func.h"
#include "window_func.h"
#include "company_base.h"
#include "zoom_func.h"
#include "strings_func.h"
#include "blitter/factory.hpp"
#include "linkgraph/linkgraph_gui.h"
#include "timer/timer.h"
#include "timer/timer_window.h"
#include "smallmap_gui.h"

#include "widgets/smallmap_widget.h"

#include "table/strings.h"

#include <bitset>

#include "safeguards.h"

static int _smallmap_industry_count; ///< Number of used industries
static int _smallmap_company_count;  ///< Number of entries in the owner legend.
static int _smallmap_cargo_count;    ///< Number of cargos in the link stats legend.

/** Structure for holding relevant data for legends in small map */
struct LegendAndColour {
	uint8_t colour;            ///< Colour of the item on the map.
	StringID legend;           ///< String corresponding to the coloured item.
	IndustryType type;         ///< Type of industry. Only valid for industry entries.
	uint8_t height;            ///< Height in tiles. Only valid for height legend entries.
	CompanyID company;         ///< Company to display. Only valid for company entries of the owner legend.
	bool show_on_map;          ///< For filtering industries, if \c true, industry is shown on the map in colour.
	bool end;                  ///< This is the end of the list.
	bool col_break;            ///< Perform a column break and go further at the next column.
};

/** Link stat colours shown in legenda. */
static uint8_t _linkstat_colours_in_legenda[] = {0, 1, 3, 5, 7, 9, 11};

static const int NUM_NO_COMPANY_ENTRIES = 4; ///< Number of entries in the owner legend that are not companies.

/** Macro for ordinary entry of LegendAndColour */
#define MK(a, b) {a, b, INVALID_INDUSTRYTYPE, 0, INVALID_COMPANY, true, false, false}

/** Macro for a height legend entry with configurable colour. */
#define MC(col_break)  {0, STR_TINY_BLACK_HEIGHT, INVALID_INDUSTRYTYPE, 0, INVALID_COMPANY, true, false, col_break}

/** Macro for non-company owned property entry of LegendAndColour */
#define MO(a, b) {a, b, INVALID_INDUSTRYTYPE, 0, INVALID_COMPANY, true, false, false}

/** Macro used for forcing a rebuild of the owner legend the first time it is used. */
#define MOEND() {0, 0, INVALID_INDUSTRYTYPE, 0, OWNER_NONE, true, true, false}

/** Macro for end of list marker in arrays of LegendAndColour */
#define MKEND() {0, STR_NULL, INVALID_INDUSTRYTYPE, 0, INVALID_COMPANY, true, true, false}

/**
 * Macro for break marker in arrays of LegendAndColour.
 * It will have valid data, though
 */
#define MS(a, b) {a, b, INVALID_INDUSTRYTYPE, 0, INVALID_COMPANY, true, false, true}

/** Legend text giving the colours to look for on the minimap */
static LegendAndColour _legend_land_contours[] = {
	MK(PC_BLACK,           STR_SMALLMAP_LEGENDA_ROADS),
	MK(PC_GREY,            STR_SMALLMAP_LEGENDA_RAILROADS),
	MK(PC_LIGHT_BLUE,      STR_SMALLMAP_LEGENDA_STATIONS_AIRPORTS_DOCKS),
	MK(PC_DARK_RED,        STR_SMALLMAP_LEGENDA_BUILDINGS_INDUSTRIES),
	MK(PC_WHITE,           STR_SMALLMAP_LEGENDA_VEHICLES),

	/* Placeholders for the colours and heights of the legend.
	 * The following values are set at BuildLandLegend() based
	 * on each colour scheme and the maximum map height. */
	MC(true),
	MC(false),
	MC(false),
	MC(false),
	MC(false),
	MC(false),
	MC(true),
	MC(false),
	MC(false),
	MC(false),
	MC(false),
	MC(false),
	MKEND()
};

static const LegendAndColour _legend_vehicles[] = {
	MK(PC_RED,             STR_SMALLMAP_LEGENDA_TRAINS),
	MK(PC_YELLOW,          STR_SMALLMAP_LEGENDA_ROAD_VEHICLES),
	MK(PC_LIGHT_BLUE,      STR_SMALLMAP_LEGENDA_SHIPS),
	MK(PC_WHITE,           STR_SMALLMAP_LEGENDA_AIRCRAFT),

	MS(PC_BLACK,           STR_SMALLMAP_LEGENDA_TRANSPORT_ROUTES),
	MK(PC_DARK_RED,        STR_SMALLMAP_LEGENDA_BUILDINGS_INDUSTRIES),
	MKEND()
};

static const LegendAndColour _legend_routes[] = {
	MK(PC_BLACK,           STR_SMALLMAP_LEGENDA_ROADS),
	MK(PC_GREY,            STR_SMALLMAP_LEGENDA_RAILROADS),
	MK(PC_DARK_RED,        STR_SMALLMAP_LEGENDA_BUILDINGS_INDUSTRIES),

	MS(PC_VERY_DARK_BROWN, STR_SMALLMAP_LEGENDA_RAILROAD_STATION),
	MK(PC_ORANGE,          STR_SMALLMAP_LEGENDA_TRUCK_LOADING_BAY),
	MK(PC_YELLOW,          STR_SMALLMAP_LEGENDA_BUS_STATION),
	MK(PC_RED,             STR_SMALLMAP_LEGENDA_AIRPORT_HELIPORT),
	MK(PC_LIGHT_BLUE,      STR_SMALLMAP_LEGENDA_DOCK),
	MKEND()
};

static const LegendAndColour _legend_vegetation[] = {
	MK(PC_ROUGH_LAND,      STR_SMALLMAP_LEGENDA_ROUGH_LAND),
	MK(PC_GRASS_LAND,      STR_SMALLMAP_LEGENDA_GRASS_LAND),
	MK(PC_BARE_LAND,       STR_SMALLMAP_LEGENDA_BARE_LAND),
	MK(PC_RAINFOREST,      STR_SMALLMAP_LEGENDA_RAINFOREST),
	MK(PC_FIELDS,          STR_SMALLMAP_LEGENDA_FIELDS),
	MK(PC_TREES,           STR_SMALLMAP_LEGENDA_TREES),

	MS(PC_GREEN,           STR_SMALLMAP_LEGENDA_FOREST),
	MK(PC_GREY,            STR_SMALLMAP_LEGENDA_ROCKS),
	MK(PC_ORANGE,          STR_SMALLMAP_LEGENDA_DESERT),
	MK(PC_LIGHT_BLUE,      STR_SMALLMAP_LEGENDA_SNOW),
	MK(PC_BLACK,           STR_SMALLMAP_LEGENDA_TRANSPORT_ROUTES),
	MK(PC_DARK_RED,        STR_SMALLMAP_LEGENDA_BUILDINGS_INDUSTRIES),
	MKEND()
};

static LegendAndColour _legend_land_owners[NUM_NO_COMPANY_ENTRIES + MAX_COMPANIES + 1] = {
	MO(PC_WATER,           STR_SMALLMAP_LEGENDA_WATER),
	MO(0x00,               STR_SMALLMAP_LEGENDA_NO_OWNER), // This colour will vary depending on settings.
	MO(PC_DARK_RED,        STR_SMALLMAP_LEGENDA_TOWNS),
	MO(PC_DARK_GREY,       STR_SMALLMAP_LEGENDA_INDUSTRIES),
	/* The legend will be terminated the first time it is used. */
	MOEND(),
};

#undef MK
#undef MC
#undef MS
#undef MO
#undef MOEND
#undef MKEND

/** Legend entries for the link stats view. */
static LegendAndColour _legend_linkstats[NUM_CARGO + lengthof(_linkstat_colours_in_legenda) + 1];
/**
 * Allow room for all industries, plus a terminator entry
 * This is required in order to have the industry slots all filled up
 */
static LegendAndColour _legend_from_industries[NUM_INDUSTRYTYPES + 1];
/** For connecting industry type to position in industries list(small map legend) */
static uint _industry_to_list_pos[NUM_INDUSTRYTYPES];
/** Show heightmap in industry and owner mode of smallmap window. */
static bool _smallmap_show_heightmap = false;
/** Highlight a specific industry type */
static IndustryType _smallmap_industry_highlight = INVALID_INDUSTRYTYPE;
/** State of highlight blinking */
static bool _smallmap_industry_highlight_state;
/** For connecting company ID to position in owner list (small map legend) */
static uint _company_to_list_pos[MAX_COMPANIES];

/**
 * Fills an array for the industries legends.
 */
void BuildIndustriesLegend()
{
	uint j = 0;

	/* Add each name */
	for (IndustryType ind : _sorted_industry_types) {
		const IndustrySpec *indsp = GetIndustrySpec(ind);
		if (indsp->enabled) {
			_legend_from_industries[j].legend = indsp->name;
			_legend_from_industries[j].colour = indsp->map_colour;
			_legend_from_industries[j].type = ind;
			_legend_from_industries[j].show_on_map = true;
			_legend_from_industries[j].col_break = false;
			_legend_from_industries[j].end = false;

			/* Store widget number for this industry type. */
			_industry_to_list_pos[ind] = j;
			j++;
		}
	}
	/* Terminate the list */
	_legend_from_industries[j].end = true;

	/* Store number of enabled industries */
	_smallmap_industry_count = j;
}

/**
 * Populate legend table for the link stat view.
 */
void BuildLinkStatsLegend()
{
	/* Clear the legend */
	memset(_legend_linkstats, 0, sizeof(_legend_linkstats));

	uint i = 0;
	for (; i < _sorted_cargo_specs.size(); ++i) {
		const CargoSpec *cs = _sorted_cargo_specs[i];

		_legend_linkstats[i].legend = cs->name;
		_legend_linkstats[i].colour = cs->legend_colour;
		_legend_linkstats[i].type = cs->Index();
		_legend_linkstats[i].show_on_map = true;
	}

	_legend_linkstats[i].col_break = true;
	_smallmap_cargo_count = i;

	for (; i < _smallmap_cargo_count + lengthof(_linkstat_colours_in_legenda); ++i) {
		_legend_linkstats[i].legend = STR_EMPTY;
		_legend_linkstats[i].colour = LinkGraphOverlay::LINK_COLOURS[_settings_client.gui.linkgraph_colours][_linkstat_colours_in_legenda[i - _smallmap_cargo_count]];
		_legend_linkstats[i].show_on_map = true;
	}

	_legend_linkstats[_smallmap_cargo_count].legend = STR_LINKGRAPH_LEGEND_UNUSED;
	_legend_linkstats[i - 1].legend = STR_LINKGRAPH_LEGEND_OVERLOADED;
	_legend_linkstats[(_smallmap_cargo_count + i - 1) / 2].legend = STR_LINKGRAPH_LEGEND_SATURATED;
	_legend_linkstats[i].end = true;
}

static const LegendAndColour * const _legend_table[] = {
	_legend_land_contours,
	_legend_vehicles,
	_legend_from_industries,
	_legend_linkstats,
	_legend_routes,
	_legend_vegetation,
	_legend_land_owners,
};

#define MKCOLOUR(x)         TO_LE32X(x)

#define MKCOLOUR_XXXX(x)    (MKCOLOUR(0x01010101) * (uint)(x))
#define MKCOLOUR_X0X0(x)    (MKCOLOUR(0x01000100) * (uint)(x))
#define MKCOLOUR_0X0X(x)    (MKCOLOUR(0x00010001) * (uint)(x))
#define MKCOLOUR_0XX0(x)    (MKCOLOUR(0x00010100) * (uint)(x))
#define MKCOLOUR_X00X(x)    (MKCOLOUR(0x01000001) * (uint)(x))

#define MKCOLOUR_XYXY(x, y) (MKCOLOUR_X0X0(x) | MKCOLOUR_0X0X(y))
#define MKCOLOUR_XYYX(x, y) (MKCOLOUR_X00X(x) | MKCOLOUR_0XX0(y))

#define MKCOLOUR_0000       MKCOLOUR_XXXX(0x00)
#define MKCOLOUR_0FF0       MKCOLOUR_0XX0(0xFF)
#define MKCOLOUR_F00F       MKCOLOUR_X00X(0xFF)
#define MKCOLOUR_FFFF       MKCOLOUR_XXXX(0xFF)

#include "table/heightmap_colours.h"

/** Colour scheme of the smallmap. */
struct SmallMapColourScheme {
	std::vector<uint32_t> height_colours; ///< Cached colours for each level in a map.
	std::span<const uint32_t> height_colours_base; ///< Base table for determining the colours
	uint32_t default_colour;             ///< Default colour of the land.
};

/** Available colour schemes for height maps. */
static SmallMapColourScheme _heightmap_schemes[] = {
	{{}, _green_map_heights,      MKCOLOUR_XXXX(0x54)}, ///< Green colour scheme.
	{{}, _dark_green_map_heights, MKCOLOUR_XXXX(0x62)}, ///< Dark green colour scheme.
	{{}, _violet_map_heights,     MKCOLOUR_XXXX(0x81)}, ///< Violet colour scheme.
};

/**
 * (Re)build the colour tables for the legends.
 */
void BuildLandLegend()
{
	/* The smallmap window has never been initialized, so no need to change the legend. */
	if (_heightmap_schemes[0].height_colours.empty()) return;

	/*
	 * The general idea of this function is to fill the legend with an appropriate evenly spaced
	 * selection of height levels. All entries with STR_TINY_BLACK_HEIGHT are reserved for this.
	 * At the moment there are twelve of these.
	 *
	 * The table below defines up to which height level a particular delta in the legend should be
	 * used. One could opt for just dividing the maximum height and use that as delta, but that
	 * creates many "ugly" legend labels, e.g. once every 950 meter. As a result, this table will
	 * reduce the number of deltas to 7: every 100m, 200m, 300m, 500m, 750m, 1000m and 1250m. The
	 * deltas are closer together at the lower numbers because going from 12 entries to just 4, as
	 * would happen when replacing 200m and 300m by 250m, would mean the legend would be short and
	 * that might not be considered appropriate.
	 *
	 * The current method yields at least 7 legend entries and at most 12. It can be increased to
	 * 8 by adding a 150m and 400m option, but especially 150m creates ugly heights.
	 *
	 * It tries to evenly space the legend items over the two columns that are there for the legend.
	 */

	/* Table for delta; if max_height is less than the first column, use the second column as value. */
	uint deltas[][2] = { { 24, 2 }, { 48, 4 }, { 72, 6 }, { 120, 10 }, { 180, 15 }, { 240, 20 }, { MAX_TILE_HEIGHT + 1, 25 }};
	uint i = 0;
	for (; _settings_game.construction.map_height_limit >= deltas[i][0]; i++) {
		/* Nothing to do here. */
	}
	uint delta = deltas[i][1];

	int total_entries = (_settings_game.construction.map_height_limit / delta) + 1;
	int rows = CeilDiv(total_entries, 2);
	int j = 0;

	for (i = 0; i < lengthof(_legend_land_contours) - 1 && j < total_entries; i++) {
		if (_legend_land_contours[i].legend != STR_TINY_BLACK_HEIGHT) continue;

		_legend_land_contours[i].col_break = j % rows == 0;
		_legend_land_contours[i].end = false;
		_legend_land_contours[i].height = j * delta;
		_legend_land_contours[i].colour = _heightmap_schemes[_settings_client.gui.smallmap_land_colour].height_colours[j * delta];
		j++;
	}
	_legend_land_contours[i].end = true;
}

/**
 * Completes the array for the owned property legend.
 */
void BuildOwnerLegend()
{
	_legend_land_owners[1].colour = _heightmap_schemes[_settings_client.gui.smallmap_land_colour].default_colour;

	int i = NUM_NO_COMPANY_ENTRIES;
	for (const Company *c : Company::Iterate()) {
		_legend_land_owners[i].colour = GetColourGradient(c->colour, SHADE_LIGHT);
		_legend_land_owners[i].company = c->index;
		_legend_land_owners[i].show_on_map = true;
		_legend_land_owners[i].col_break = false;
		_legend_land_owners[i].end = false;
		_company_to_list_pos[c->index] = i;
		i++;
	}

	/* Terminate the list */
	_legend_land_owners[i].end = true;

	/* Store maximum amount of owner legend entries. */
	_smallmap_company_count = i;
}

struct AndOr {
	uint32_t mor;
	uint32_t mand;
};

static inline uint32_t ApplyMask(uint32_t colour, const AndOr *mask)
{
	return (colour & mask->mand) | mask->mor;
}


/** Colour masks for "Contour" and "Routes" modes. */
static const AndOr _smallmap_contours_andor[] = {
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_CLEAR
	{MKCOLOUR_0XX0(PC_GREY      ), MKCOLOUR_F00F}, // MP_RAILWAY
	{MKCOLOUR_0XX0(PC_BLACK     ), MKCOLOUR_F00F}, // MP_ROAD
	{MKCOLOUR_0XX0(PC_DARK_RED  ), MKCOLOUR_F00F}, // MP_HOUSE
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_TREES
	{MKCOLOUR_XXXX(PC_LIGHT_BLUE), MKCOLOUR_0000}, // MP_STATION
	{MKCOLOUR_XXXX(PC_WATER     ), MKCOLOUR_0000}, // MP_WATER
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_VOID
	{MKCOLOUR_XXXX(PC_DARK_RED  ), MKCOLOUR_0000}, // MP_INDUSTRY
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_TUNNELBRIDGE
	{MKCOLOUR_0XX0(PC_DARK_RED  ), MKCOLOUR_F00F}, // MP_OBJECT
	{MKCOLOUR_0XX0(PC_GREY      ), MKCOLOUR_F00F},
};

/** Colour masks for "Vehicles", "Industry", and "Vegetation" modes. */
static const AndOr _smallmap_vehicles_andor[] = {
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_CLEAR
	{MKCOLOUR_0XX0(PC_BLACK     ), MKCOLOUR_F00F}, // MP_RAILWAY
	{MKCOLOUR_0XX0(PC_BLACK     ), MKCOLOUR_F00F}, // MP_ROAD
	{MKCOLOUR_0XX0(PC_DARK_RED  ), MKCOLOUR_F00F}, // MP_HOUSE
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_TREES
	{MKCOLOUR_0XX0(PC_BLACK     ), MKCOLOUR_F00F}, // MP_STATION
	{MKCOLOUR_XXXX(PC_WATER     ), MKCOLOUR_0000}, // MP_WATER
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_VOID
	{MKCOLOUR_XXXX(PC_DARK_RED  ), MKCOLOUR_0000}, // MP_INDUSTRY
	{MKCOLOUR_0000               , MKCOLOUR_FFFF}, // MP_TUNNELBRIDGE
	{MKCOLOUR_0XX0(PC_DARK_RED  ), MKCOLOUR_F00F}, // MP_OBJECT
	{MKCOLOUR_0XX0(PC_BLACK     ), MKCOLOUR_F00F},
};

/** Mapping of tile type to importance of the tile (higher number means more interesting to show). */
static const uint8_t _tiletype_importance[] = {
	2, // MP_CLEAR
	8, // MP_RAILWAY
	7, // MP_ROAD
	5, // MP_HOUSE
	2, // MP_TREES
	9, // MP_STATION
	2, // MP_WATER
	1, // MP_VOID
	6, // MP_INDUSTRY
	8, // MP_TUNNELBRIDGE
	2, // MP_OBJECT
	0,
};


/**
 * Return the colour a tile would be displayed with in the small map in mode "Contour".
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile in the small map in mode "Contour"
 */
static inline uint32_t GetSmallMapContoursPixels(TileIndex tile, TileType t)
{
	const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
	return ApplyMask(cs->height_colours[TileHeight(tile)], &_smallmap_contours_andor[t]);
}

/**
 * Return the colour a tile would be displayed with in the small map in mode "Vehicles".
 *
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile in the small map in mode "Vehicles"
 */
static inline uint32_t GetSmallMapVehiclesPixels(TileIndex, TileType t)
{
	const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
	return ApplyMask(cs->default_colour, &_smallmap_vehicles_andor[t]);
}

/**
 * Return the colour a tile would be displayed with in the small map in mode "Industries".
 *
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile in the small map in mode "Industries"
 */
static inline uint32_t GetSmallMapIndustriesPixels(TileIndex tile, TileType t)
{
	const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
	return ApplyMask(_smallmap_show_heightmap ? cs->height_colours[TileHeight(tile)] : cs->default_colour, &_smallmap_vehicles_andor[t]);
}

/**
 * Return the colour a tile would be displayed with in the small map in mode "Routes".
 *
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile  in the small map in mode "Routes"
 */
static inline uint32_t GetSmallMapRoutesPixels(TileIndex tile, TileType t)
{
	switch (t) {
		case MP_STATION:
			switch (GetStationType(tile)) {
				case STATION_RAIL:    return MKCOLOUR_XXXX(PC_VERY_DARK_BROWN);
				case STATION_AIRPORT: return MKCOLOUR_XXXX(PC_RED);
				case STATION_TRUCK:   return MKCOLOUR_XXXX(PC_ORANGE);
				case STATION_BUS:     return MKCOLOUR_XXXX(PC_YELLOW);
				case STATION_DOCK:    return MKCOLOUR_XXXX(PC_LIGHT_BLUE);
				default:              return MKCOLOUR_FFFF;
			}

		case MP_RAILWAY: {
			AndOr andor = {
				MKCOLOUR_0XX0(GetRailTypeInfo(GetRailType(tile))->map_colour),
				_smallmap_contours_andor[t].mand
			};

			const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
			return ApplyMask(cs->default_colour, &andor);
		}

		case MP_ROAD: {
			const RoadTypeInfo *rti = nullptr;
			if (GetRoadTypeRoad(tile) != INVALID_ROADTYPE) {
				rti = GetRoadTypeInfo(GetRoadTypeRoad(tile));
			} else {
				rti = GetRoadTypeInfo(GetRoadTypeTram(tile));
			}
			if (rti != nullptr) {
				AndOr andor = {
					MKCOLOUR_0XX0(rti->map_colour),
					_smallmap_contours_andor[t].mand
				};

				const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
				return ApplyMask(cs->default_colour, &andor);
			}
			[[fallthrough]];
		}

		default:
			/* Ground colour */
			const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
			return ApplyMask(cs->default_colour, &_smallmap_contours_andor[t]);
	}
}

/**
 * Return the colour a tile would be displayed with in the small map in mode "link stats".
 *
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile in the small map in mode "link stats"
 */
static inline uint32_t GetSmallMapLinkStatsPixels(TileIndex tile, TileType t)
{
	return _smallmap_show_heightmap ? GetSmallMapContoursPixels(tile, t) : GetSmallMapRoutesPixels(tile, t);
}

static const uint32_t _vegetation_clear_bits[] = {
	MKCOLOUR_XXXX(PC_GRASS_LAND), ///< full grass
	MKCOLOUR_XXXX(PC_ROUGH_LAND), ///< rough land
	MKCOLOUR_XXXX(PC_GREY),       ///< rocks
	MKCOLOUR_XXXX(PC_FIELDS),     ///< fields
	MKCOLOUR_XXXX(PC_LIGHT_BLUE), ///< snow
	MKCOLOUR_XXXX(PC_ORANGE),     ///< desert
	MKCOLOUR_XXXX(PC_GRASS_LAND), ///< unused
	MKCOLOUR_XXXX(PC_GRASS_LAND), ///< unused
};

/**
 * Return the colour a tile would be displayed with in the smallmap in mode "Vegetation".
 *
 * @param tile The tile of which we would like to get the colour.
 * @param t    Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @return The colour of tile  in the smallmap in mode "Vegetation"
 */
static inline uint32_t GetSmallMapVegetationPixels(TileIndex tile, TileType t)
{
	switch (t) {
		case MP_CLEAR:
			if (IsClearGround(tile, CLEAR_GRASS)) {
				if (GetClearDensity(tile) < 3) return MKCOLOUR_XXXX(PC_BARE_LAND);
				if (GetTropicZone(tile) == TROPICZONE_RAINFOREST) return MKCOLOUR_XXXX(PC_RAINFOREST);
			}
			return _vegetation_clear_bits[GetClearGround(tile)];

		case MP_INDUSTRY:
			return IsTileForestIndustry(tile) ? MKCOLOUR_XXXX(PC_GREEN) : MKCOLOUR_XXXX(PC_DARK_RED);

		case MP_TREES:
			if (GetTreeGround(tile) == TREE_GROUND_SNOW_DESERT || GetTreeGround(tile) == TREE_GROUND_ROUGH_SNOW) {
				return (_settings_game.game_creation.landscape == LT_ARCTIC) ? MKCOLOUR_XYYX(PC_LIGHT_BLUE, PC_TREES) : MKCOLOUR_XYYX(PC_ORANGE, PC_TREES);
			}
			return (GetTropicZone(tile) == TROPICZONE_RAINFOREST) ? MKCOLOUR_XYYX(PC_RAINFOREST, PC_TREES) : MKCOLOUR_XYYX(PC_GRASS_LAND, PC_TREES);

		default:
			return ApplyMask(MKCOLOUR_XXXX(PC_GRASS_LAND), &_smallmap_vehicles_andor[t]);
	}
}

/**
 * Return the colour a tile would be displayed with in the small map in mode "Owner".
 *
 * @note If include_heightmap is IH_NEVER, the return value can safely be used as a palette colour (by masking it to a uint8_t)
 * @param tile              The tile of which we would like to get the colour.
 * @param t                 Effective tile type of the tile (see #SmallMapWindow::GetTileColours).
 * @param include_heightmap Whether to return the heightmap/contour colour of this tile (instead of the default land tile colour)
 * @return The colour of tile in the small map in mode "Owner"
 */
uint32_t GetSmallMapOwnerPixels(TileIndex tile, TileType t, IncludeHeightmap include_heightmap)
{
	Owner o;

	switch (t) {
		case MP_VOID:     return MKCOLOUR_XXXX(PC_BLACK);
		case MP_INDUSTRY: return MKCOLOUR_XXXX(PC_DARK_GREY);
		case MP_HOUSE:    return MKCOLOUR_XXXX(PC_DARK_RED);
		default:          o = GetTileOwner(tile); break;
		/* FIXME: For MP_ROAD there are multiple owners.
		 * GetTileOwner returns the rail owner (level crossing) resp. the owner of ROADTYPE_ROAD (normal road),
		 * even if there are no ROADTYPE_ROAD bits on the tile.
		 */
	}

	if ((o < MAX_COMPANIES && !_legend_land_owners[_company_to_list_pos[o]].show_on_map) || o == OWNER_NONE || o == OWNER_WATER) {
		if (t == MP_WATER) return MKCOLOUR_XXXX(PC_WATER);
		const SmallMapColourScheme *cs = &_heightmap_schemes[_settings_client.gui.smallmap_land_colour];
		return ((include_heightmap == IncludeHeightmap::IfEnabled && _smallmap_show_heightmap) || include_heightmap == IncludeHeightmap::Always)
			? cs->height_colours[TileHeight(tile)] : cs->default_colour;
	} else if (o == OWNER_TOWN) {
		return MKCOLOUR_XXXX(PC_DARK_RED);
	}

	return MKCOLOUR_XXXX(_legend_land_owners[_company_to_list_pos[o]].colour);
}

/** Vehicle colours in #SMT_VEHICLES mode. Indexed by #VehicleType. */
static const uint8_t _vehicle_type_colours[6] = {
	PC_RED, PC_YELLOW, PC_LIGHT_BLUE, PC_WHITE, PC_BLACK, PC_RED
};

/** Types of legends in the #WID_SM_LEGEND widget. */
enum SmallMapType : uint8_t {
	SMT_CONTOUR,
	SMT_VEHICLES,
	SMT_INDUSTRY,
	SMT_LINKSTATS,
	SMT_ROUTES,
	SMT_VEGETATION,
	SMT_OWNER,
};
DECLARE_ENUM_AS_ADDABLE(SmallMapType)

/** Class managing the smallmap window. */
class SmallMapWindow : public Window {
protected:
	/** Available kinds of zoomlevel changes. */
	enum ZoomLevelChange {
		ZLC_INITIALIZE, ///< Initialize zoom level.
		ZLC_ZOOM_OUT,   ///< Zoom out.
		ZLC_ZOOM_IN,    ///< Zoom in.
	};

	static SmallMapType map_type; ///< Currently displayed legends.
	static bool show_towns;       ///< Display town names in the smallmap.
	static int map_height_limit;  ///< Currently used/cached map height limit.

	static const uint INDUSTRY_MIN_NUMBER_OF_COLUMNS = 2; ///< Minimal number of columns in the #WID_SM_LEGEND widget for the #SMT_INDUSTRY legend.

	uint min_number_of_columns;    ///< Minimal number of columns in legends.
	uint min_number_of_fixed_rows; ///< Minimal number of rows in the legends for the fixed layouts only (all except #SMT_INDUSTRY).
	uint column_width;             ///< Width of a column in the #WID_SM_LEGEND widget.
	uint legend_width;             ///< Width of legend 'blob'.

	int32_t scroll_x;  ///< Horizontal world coordinate of the base tile left of the top-left corner of the smallmap display.
	int32_t scroll_y;  ///< Vertical world coordinate of the base tile left of the top-left corner of the smallmap display.
	int32_t subscroll; ///< Number of pixels (0..3) between the right end of the base tile and the pixel at the top-left corner of the smallmap display.
	int zoom;        ///< Zoom level. Bigger number means more zoom-out (further away).

	std::unique_ptr<LinkGraphOverlay> overlay;

	/** Notify the industry chain window to stop sending newly selected industries. */
	static void BreakIndustryChainLink()
	{
		InvalidateWindowClassesData(WC_INDUSTRY_CARGOES, NUM_INDUSTRYTYPES);
	}

	static inline Point SmallmapRemapCoords(int x, int y)
	{
		Point pt;
		pt.x = (y - x) * 2;
		pt.y = y + x;
		return pt;
	}

	/**
	 * Draws vertical part of map indicator
	 * @param x X coord of left/right border of main viewport
	 * @param y Y coord of top border of main viewport
	 * @param y2 Y coord of bottom border of main viewport
	 */
	static inline void DrawVertMapIndicator(int x, int y, int y2)
	{
		GfxFillRect(x, y,      x, y + 3, PC_VERY_LIGHT_YELLOW);
		GfxFillRect(x, y2 - 3, x, y2,    PC_VERY_LIGHT_YELLOW);
	}

	/**
	 * Draws horizontal part of map indicator
	 * @param x X coord of left border of main viewport
	 * @param x2 X coord of right border of main viewport
	 * @param y Y coord of top/bottom border of main viewport
	 */
	static inline void DrawHorizMapIndicator(int x, int x2, int y)
	{
		GfxFillRect(x,      y, x + 3, y, PC_VERY_LIGHT_YELLOW);
		GfxFillRect(x2 - 3, y, x2,    y, PC_VERY_LIGHT_YELLOW);
	}

	/**
	 * Compute minimal required width of the legends.
	 * @return Minimally needed width for displaying the smallmap legends in pixels.
	 */
	inline uint GetMinLegendWidth() const
	{
		return WidgetDimensions::scaled.framerect.left + this->min_number_of_columns * this->column_width;
	}

	/**
	 * Return number of columns that can be displayed in \a width pixels.
	 * @return Number of columns to display.
	 */
	inline uint GetNumberColumnsLegend(uint width) const
	{
		return width / this->column_width;
	}

	/**
	 * Compute height given a number of columns.
	 * @param num_columns Number of columns.
	 * @return Needed height for displaying the smallmap legends in pixels.
	 */
	inline uint GetLegendHeight(uint num_columns) const
	{
		return WidgetDimensions::scaled.framerect.Vertical() +
				this->GetNumberRowsLegend(num_columns) * GetCharacterHeight(FS_SMALL);
	}

	/**
	 * Get a bitmask for company links to be displayed. Usually this will be
	 * the _local_company. Spectators get to see all companies' links.
	 * @return Company mask.
	 */
	inline CompanyMask GetOverlayCompanyMask() const
	{
		return Company::IsValidID(_local_company) ? 1U << _local_company : MAX_UVALUE(CompanyMask);
	}

	/** Blink the industries (if selected) on a regular interval. */
	IntervalTimer<TimerWindow> blink_interval = {std::chrono::milliseconds(450), [this](auto) {
		Blink();
	}};

	/** Update the whole map on a regular interval. */
	IntervalTimer<TimerWindow> refresh_interval = {std::chrono::milliseconds(930), [this](auto) {
		ForceRefresh();
	}};

	/**
	 * Rebuilds the colour indices used for fast access to the smallmap contour colours based on the heightlevel.
	 */
	void RebuildColourIndexIfNecessary()
	{
		/* Rebuild colour indices if necessary. */
		if (SmallMapWindow::map_height_limit == _settings_game.construction.map_height_limit) return;

		for (auto &heightmap_scheme : _heightmap_schemes) {
			/* The heights go from 0 up to and including maximum. */
			size_t heights = _settings_game.construction.map_height_limit + 1;
			heightmap_scheme.height_colours.resize(heights);

			for (size_t z = 0; z < heights; z++) {
				size_t access_index = (heightmap_scheme.height_colours_base.size() * z) / heights;

				/* Choose colour by mapping the range (0..max heightlevel) on the complete colour table. */
				heightmap_scheme.height_colours[z] = heightmap_scheme.height_colours_base[access_index];
			}
		}

		SmallMapWindow::map_height_limit = _settings_game.construction.map_height_limit;
		BuildLandLegend();
	}

	/**
	 * Get the number of rows in the legend from the number of columns. Those
	 * are at least min_number_of_fixed_rows and possibly more if there are so
	 * many cargoes, industry types or companies that they won't fit in the
	 * available space.
	 * @param columns Number of columns in the legend.
	 * @return Number of rows needed for everything to fit in.
	 */
	uint GetNumberRowsLegend(uint columns) const
	{
		/* Reserve one column for link colours */
		uint num_rows_linkstats = CeilDiv(_smallmap_cargo_count, columns - 1);
		uint num_rows_others = CeilDiv(std::max(_smallmap_industry_count, _smallmap_company_count), columns);
		return std::max({this->min_number_of_fixed_rows, num_rows_linkstats, num_rows_others});
	}

	/**
	 * Select and toggle a legend item. When CTRL is pressed, disable all other
	 * items in the group defined by begin_legend_item and end_legend_item and
	 * keep the clicked one enabled even if it was already enabled before. If
	 * the other items in the group are all disabled already and CTRL is pressed
	 * enable them instead.
	 * @param click_pos the index of the item being selected
	 * @param legend the legend from which we select
	 * @param end_legend_item index one past the last item in the group to be inverted
	 * @param begin_legend_item index of the first item in the group to be inverted
	 */
	void SelectLegendItem(int click_pos, LegendAndColour *legend, int end_legend_item, int begin_legend_item = 0)
	{
		if (_ctrl_pressed) {
			/* Disable all, except the clicked one */
			bool changes = false;
			for (int i = begin_legend_item; i != end_legend_item; i++) {
				bool new_state = (i == click_pos);
				if (legend[i].show_on_map != new_state) {
					changes = true;
					legend[i].show_on_map = new_state;
				}
			}
			if (!changes) {
				/* Nothing changed? Then show all (again). */
				for (int i = begin_legend_item; i != end_legend_item; i++) {
					legend[i].show_on_map = true;
				}
			}
		} else {
			legend[click_pos].show_on_map = !legend[click_pos].show_on_map;
		}

		if (this->map_type == SMT_INDUSTRY) this->BreakIndustryChainLink();
	}

	/**
	 * Select a new map type.
	 * @param map_type New map type.
	 */
	void SwitchMapType(SmallMapType map_type)
	{
		this->RaiseWidget(WID_SM_CONTOUR + this->map_type);
		this->map_type = map_type;
		this->LowerWidget(WID_SM_CONTOUR + this->map_type);

		this->SetupWidgetData();

		if (map_type == SMT_LINKSTATS) this->overlay->SetDirty();
		if (map_type != SMT_INDUSTRY) this->BreakIndustryChainLink();
		this->SetDirty();
	}

	/**
	 * Set new #scroll_x, #scroll_y, and #subscroll values after limiting them such that the center
	 * of the smallmap always contains a part of the map.
	 * @param sx  Proposed new #scroll_x
	 * @param sy  Proposed new #scroll_y
	 * @param sub Proposed new #subscroll
	 */
	void SetNewScroll(int sx, int sy, int sub)
	{
		const NWidgetBase *wi = this->GetWidget<NWidgetBase>(WID_SM_MAP);
		Point hv = InverseRemapCoords(wi->current_x * ZOOM_BASE * TILE_SIZE / 2, wi->current_y * ZOOM_BASE * TILE_SIZE / 2);
		hv.x *= this->zoom;
		hv.y *= this->zoom;

		if (sx < -hv.x) {
			sx = -hv.x;
			sub = 0;
		}
		if (sx > (int)(Map::MaxX() * TILE_SIZE) - hv.x) {
			sx = Map::MaxX() * TILE_SIZE - hv.x;
			sub = 0;
		}
		if (sy < -hv.y) {
			sy = -hv.y;
			sub = 0;
		}
		if (sy > (int)(Map::MaxY() * TILE_SIZE) - hv.y) {
			sy = Map::MaxY() * TILE_SIZE - hv.y;
			sub = 0;
		}

		this->scroll_x = sx;
		this->scroll_y = sy;
		this->subscroll = sub;
		if (this->map_type == SMT_LINKSTATS) this->overlay->SetDirty();
	}

	/**
	 * Adds map indicators to the smallmap.
	 */
	void DrawMapIndicators() const
	{
		/* Find main viewport. */
		const Viewport *vp = GetMainWindow()->viewport;

		Point upper_left_smallmap_coord  = InverseRemapCoords2(vp->virtual_left, vp->virtual_top);
		Point lower_right_smallmap_coord = InverseRemapCoords2(vp->virtual_left + vp->virtual_width - 1, vp->virtual_top + vp->virtual_height - 1);

		Point upper_left = this->RemapTile(upper_left_smallmap_coord.x / (int)TILE_SIZE, upper_left_smallmap_coord.y / (int)TILE_SIZE);
		upper_left.x -= this->subscroll;

		Point lower_right = this->RemapTile(lower_right_smallmap_coord.x / (int)TILE_SIZE, lower_right_smallmap_coord.y / (int)TILE_SIZE);
		lower_right.x -= this->subscroll;

		SmallMapWindow::DrawVertMapIndicator(upper_left.x, upper_left.y, lower_right.y);
		SmallMapWindow::DrawVertMapIndicator(lower_right.x, upper_left.y, lower_right.y);

		SmallMapWindow::DrawHorizMapIndicator(upper_left.x, lower_right.x, upper_left.y);
		SmallMapWindow::DrawHorizMapIndicator(upper_left.x, lower_right.x, lower_right.y);
	}

	/**
	 * Draws one column of tiles of the small map in a certain mode onto the screen buffer, skipping the shifted rows in between.
	 *
	 * @param dst Pointer to a part of the screen buffer to write to.
	 * @param xc The X coordinate of the first tile in the column.
	 * @param yc The Y coordinate of the first tile in the column
	 * @param pitch Number of pixels to advance in the screen buffer each time a pixel is written.
	 * @param reps Number of lines to draw
	 * @param start_pos Position of first pixel to draw.
	 * @param end_pos Position of last pixel to draw (exclusive).
	 * @param blitter current blitter
	 * @note If pixel position is below \c 0, skip drawing.
	 */
	void DrawSmallMapColumn(void *dst, uint xc, uint yc, int pitch, int reps, int start_pos, int end_pos, Blitter *blitter) const
	{
		void *dst_ptr_abs_end = blitter->MoveTo(_screen.dst_ptr, 0, _screen.height);
		uint min_xy = _settings_game.construction.freeform_edges ? 1 : 0;

		do {
			/* Check if the tile (xc,yc) is within the map range */
			if (xc >= Map::MaxX() || yc >= Map::MaxY()) continue;

			/* Check if the dst pointer points to a pixel inside the screen buffer */
			if (dst < _screen.dst_ptr) continue;
			if (dst >= dst_ptr_abs_end) continue;

			/* Construct tilearea covered by (xc, yc, xc + this->zoom, yc + this->zoom) such that it is within min_xy limits. */
			TileArea ta;
			if (min_xy == 1 && (xc == 0 || yc == 0)) {
				if (this->zoom == 1) continue; // The tile area is empty, don't draw anything.

				ta = TileArea(TileXY(std::max(min_xy, xc), std::max(min_xy, yc)), this->zoom - (xc == 0), this->zoom - (yc == 0));
			} else {
				ta = TileArea(TileXY(xc, yc), this->zoom, this->zoom);
			}
			ta.ClampToMap(); // Clamp to map boundaries (may contain MP_VOID tiles!).

			uint32_t val = this->GetTileColours(ta);
			uint8_t *val8 = (uint8_t *)&val;
			int idx = std::max(0, -start_pos);
			for (int pos = std::max(0, start_pos); pos < end_pos; pos++) {
				blitter->SetPixel(dst, idx, 0, val8[idx]);
				idx++;
			}
		/* Switch to next tile in the column */
		} while (xc += this->zoom, yc += this->zoom, dst = blitter->MoveTo(dst, pitch, 0), --reps != 0);
	}

	/**
	 * Adds vehicles to the smallmap.
	 * @param dpi the part of the smallmap to be drawn into
	 * @param blitter current blitter
	 */
	void DrawVehicles(const DrawPixelInfo *dpi, Blitter *blitter) const
	{
		for (const Vehicle *v : Vehicle::Iterate()) {
			if (v->type == VEH_EFFECT) continue;
			if (v->vehstatus & (VS_HIDDEN | VS_UNCLICKABLE)) continue;

			/* Remap into flat coordinates. */
			Point pt = this->RemapTile(v->x_pos / (int)TILE_SIZE, v->y_pos / (int)TILE_SIZE);

			int y = pt.y - dpi->top;
			if (!IsInsideMM(y, 0, dpi->height)) continue; // y is out of bounds.

			bool skip = false; // Default is to draw both pixels.
			int x = pt.x - this->subscroll - 3 - dpi->left; // Offset X coordinate.
			if (x < 0) {
				/* if x+1 is 0, that means we're on the very left edge,
				 * and should thus only draw a single pixel */
				if (++x != 0) continue;
				skip = true;
			} else if (x >= dpi->width - 1) {
				/* Check if we're at the very right edge, and if so draw only a single pixel */
				if (x != dpi->width - 1) continue;
				skip = true;
			}

			/* Calculate pointer to pixel and the colour */
			uint8_t colour = (this->map_type == SMT_VEHICLES) ? _vehicle_type_colours[v->type] : PC_WHITE;

			/* And draw either one or two pixels depending on clipping */
			blitter->SetPixel(dpi->dst_ptr, x, y, colour);
			if (!skip) blitter->SetPixel(dpi->dst_ptr, x + 1, y, colour);
		}
	}

	/**
	 * Adds town names to the smallmap.
	 * @param dpi the part of the smallmap to be drawn into
	 */
	void DrawTowns(const DrawPixelInfo *dpi) const
	{
		for (const Town *t : Town::Iterate()) {
			/* Remap the town coordinate */
			Point pt = this->RemapTile(TileX(t->xy), TileY(t->xy));
			int x = pt.x - this->subscroll - (t->cache.sign.width_small >> 1);
			int y = pt.y;

			/* Check if the town sign is within bounds */
			if (x + t->cache.sign.width_small > dpi->left &&
					x < dpi->left + dpi->width &&
					y + GetCharacterHeight(FS_SMALL) > dpi->top &&
					y < dpi->top + dpi->height) {
				/* And draw it. */
				SetDParam(0, t->index);
				DrawString(x, x + t->cache.sign.width_small, y, STR_SMALLMAP_TOWN);
			}
		}
	}

	/**
	 * Draws the small map.
	 *
	 * Basically, the small map is draw column of pixels by column of pixels. The pixels
	 * are drawn directly into the screen buffer. The final map is drawn in multiple passes.
	 * The passes are:
	 * <ol><li>The colours of tiles in the different modes.</li>
	 * <li>Town names (optional)</li></ol>
	 *
	 * @param dpi pointer to pixel to write onto
	 */
	void DrawSmallMap(DrawPixelInfo *dpi) const
	{
		Blitter *blitter = BlitterFactory::GetCurrentBlitter();
		AutoRestoreBackup dpi_backup(_cur_dpi, dpi);

		/* Clear it */
		GfxFillRect(dpi->left, dpi->top, dpi->left + dpi->width - 1, dpi->top + dpi->height - 1, PC_BLACK);

		/* Which tile is displayed at (dpi->left, dpi->top)? */
		int dx;
		Point tile = this->PixelToTile(dpi->left, dpi->top, &dx);
		int tile_x = this->scroll_x / (int)TILE_SIZE + tile.x;
		int tile_y = this->scroll_y / (int)TILE_SIZE + tile.y;

		void *ptr = blitter->MoveTo(dpi->dst_ptr, -dx - 4, 0);
		int x = - dx - 4;
		int y = 0;

		for (;;) {
			/* Distance from left edge */
			if (x >= -3) {
				if (x >= dpi->width) break; // Exit the loop.

				int end_pos = std::min(dpi->width, x + 4);
				int reps = (dpi->height - y + 1) / 2; // Number of lines.
				if (reps > 0) {
					this->DrawSmallMapColumn(ptr, tile_x, tile_y, dpi->pitch * 2, reps, x, end_pos, blitter);
				}
			}

			if (y == 0) {
				tile_y += this->zoom;
				y++;
				ptr = blitter->MoveTo(ptr, 0, 1);
			} else {
				tile_x -= this->zoom;
				y--;
				ptr = blitter->MoveTo(ptr, 0, -1);
			}
			ptr = blitter->MoveTo(ptr, 2, 0);
			x += 2;
		}

		/* Draw vehicles */
		if (this->map_type == SMT_CONTOUR || this->map_type == SMT_VEHICLES) this->DrawVehicles(dpi, blitter);

		/* Draw link stat overlay */
		if (this->map_type == SMT_LINKSTATS) this->overlay->Draw(dpi);

		/* Draw town names */
		if (this->show_towns) this->DrawTowns(dpi);

		/* Draw map indicators */
		this->DrawMapIndicators();
	}

	/**
	 * Remap tile to location on this smallmap.
	 * @param tile_x X coordinate of the tile.
	 * @param tile_y Y coordinate of the tile.
	 * @return Position to draw on.
	 */
	Point RemapTile(int tile_x, int tile_y) const
	{
		int x_offset = tile_x - this->scroll_x / (int)TILE_SIZE;
		int y_offset = tile_y - this->scroll_y / (int)TILE_SIZE;

		if (this->zoom == 1) return SmallmapRemapCoords(x_offset, y_offset);

		/* For negative offsets, round towards -inf. */
		if (x_offset < 0) x_offset -= this->zoom - 1;
		if (y_offset < 0) y_offset -= this->zoom - 1;

		return SmallmapRemapCoords(x_offset / this->zoom, y_offset / this->zoom);
	}

	/**
	 * Determine the tile relative to the base tile of the smallmap, and the pixel position at
	 * that tile for a point in the smallmap.
	 * @param px       Horizontal coordinate of the pixel.
	 * @param py       Vertical coordinate of the pixel.
	 * @param[out] sub Pixel position at the tile (0..3).
	 * @param add_sub  Add current #subscroll to the position.
	 * @return Tile being displayed at the given position relative to #scroll_x and #scroll_y.
	 * @note The #subscroll offset is already accounted for.
	 */
	Point PixelToTile(int px, int py, int *sub, bool add_sub = true) const
	{
		if (add_sub) px += this->subscroll;  // Total horizontal offset.

		/* For each two rows down, add a x and a y tile, and
		 * For each four pixels to the right, move a tile to the right. */
		Point pt = {((py >> 1) - (px >> 2)) * this->zoom, ((py >> 1) + (px >> 2)) * this->zoom};
		px &= 3;

		if (py & 1) { // Odd number of rows, handle the 2 pixel shift.
			if (px < 2) {
				pt.x += this->zoom;
				px += 2;
			} else {
				pt.y += this->zoom;
				px -= 2;
			}
		}

		*sub = px;
		return pt;
	}

	/**
	 * Compute base parameters of the smallmap such that tile (\a tx, \a ty) starts at pixel (\a x, \a y).
	 * @param tx       Tile x coordinate.
	 * @param ty       Tile y coordinate.
	 * @param x        Non-negative horizontal position in the display where the tile starts.
	 * @param y        Non-negative vertical position in the display where the tile starts.
	 * @param[out] sub Value of #subscroll needed.
	 * @return #scroll_x, #scroll_y values.
	 */
	Point ComputeScroll(int tx, int ty, int x, int y, int *sub) const
	{
		assert(x >= 0 && y >= 0);

		int new_sub;
		Point tile_xy = PixelToTile(x, y, &new_sub, false);
		tx -= tile_xy.x;
		ty -= tile_xy.y;

		Point scroll;
		if (new_sub == 0) {
			*sub = 0;
			scroll.x = (tx + this->zoom) * TILE_SIZE;
			scroll.y = (ty - this->zoom) * TILE_SIZE;
		} else {
			*sub = 4 - new_sub;
			scroll.x = (tx + 2 * this->zoom) * TILE_SIZE;
			scroll.y = (ty - 2 * this->zoom) * TILE_SIZE;
		}
		return scroll;
	}

	/**
	 * Initialize or change the zoom level.
	 * @param change  Way to change the zoom level.
	 * @param zoom_pt Position to keep fixed while zooming.
	 * @pre \c *zoom_pt should contain a point in the smallmap display when zooming in or out.
	 */
	void SetZoomLevel(ZoomLevelChange change, const Point *zoom_pt)
	{
		static const int zoomlevels[] = {1, 2, 4, 6, 8}; // Available zoom levels. Bigger number means more zoom-out (further away).
		static const int MIN_ZOOM_INDEX = 0;
		static const int MAX_ZOOM_INDEX = lengthof(zoomlevels) - 1;

		int new_index, cur_index, sub;
		Point tile;
		switch (change) {
			case ZLC_INITIALIZE:
				cur_index = - 1; // Definitely different from new_index.
				new_index = MIN_ZOOM_INDEX;
				tile.x = tile.y = 0;
				break;

			case ZLC_ZOOM_IN:
			case ZLC_ZOOM_OUT:
				for (cur_index = MIN_ZOOM_INDEX; cur_index <= MAX_ZOOM_INDEX; cur_index++) {
					if (this->zoom == zoomlevels[cur_index]) break;
				}
				assert(cur_index <= MAX_ZOOM_INDEX);

				tile = this->PixelToTile(zoom_pt->x, zoom_pt->y, &sub);
				new_index = Clamp(cur_index + ((change == ZLC_ZOOM_IN) ? -1 : 1), MIN_ZOOM_INDEX, MAX_ZOOM_INDEX);
				break;

			default: NOT_REACHED();
		}

		if (new_index != cur_index) {
			this->zoom = zoomlevels[new_index];
			if (cur_index >= 0) {
				Point new_tile = this->PixelToTile(zoom_pt->x, zoom_pt->y, &sub);
				this->SetNewScroll(this->scroll_x + (tile.x - new_tile.x) * TILE_SIZE,
						this->scroll_y + (tile.y - new_tile.y) * TILE_SIZE, sub);
			} else if (this->map_type == SMT_LINKSTATS) {
				this->overlay->SetDirty();
			}
			this->SetWidgetDisabledState(WID_SM_ZOOM_IN,  this->zoom == zoomlevels[MIN_ZOOM_INDEX]);
			this->SetWidgetDisabledState(WID_SM_ZOOM_OUT, this->zoom == zoomlevels[MAX_ZOOM_INDEX]);
			this->SetDirty();
		}
	}

	/**
	 * Set the link graph overlay cargo mask from the legend.
	 */
	void SetOverlayCargoMask()
	{
		CargoTypes cargo_mask = 0;
		for (int i = 0; i != _smallmap_cargo_count; ++i) {
			if (_legend_linkstats[i].show_on_map) SetBit(cargo_mask, _legend_linkstats[i].type);
		}
		this->overlay->SetCargoMask(cargo_mask);
	}

	/**
	 * Function to set up widgets depending on the information being shown on the smallmap.
	 */
	void SetupWidgetData()
	{
		StringID legend_tooltip;
		StringID enable_all_tooltip;
		StringID disable_all_tooltip;
		int plane;
		switch (this->map_type) {
			case SMT_INDUSTRY:
				legend_tooltip = STR_SMALLMAP_TOOLTIP_INDUSTRY_SELECTION;
				enable_all_tooltip = STR_SMALLMAP_TOOLTIP_ENABLE_ALL_INDUSTRIES;
				disable_all_tooltip = STR_SMALLMAP_TOOLTIP_DISABLE_ALL_INDUSTRIES;
				plane = 0;
				break;

			case SMT_OWNER:
				legend_tooltip = STR_SMALLMAP_TOOLTIP_COMPANY_SELECTION;
				enable_all_tooltip = STR_SMALLMAP_TOOLTIP_ENABLE_ALL_COMPANIES;
				disable_all_tooltip = STR_SMALLMAP_TOOLTIP_DISABLE_ALL_COMPANIES;
				plane = 0;
				break;

			case SMT_LINKSTATS:
				legend_tooltip = STR_SMALLMAP_TOOLTIP_CARGO_SELECTION;
				enable_all_tooltip = STR_SMALLMAP_TOOLTIP_ENABLE_ALL_CARGOS;
				disable_all_tooltip = STR_SMALLMAP_TOOLTIP_DISABLE_ALL_CARGOS;
				plane = 0;
				break;

			default:
				legend_tooltip = STR_NULL;
				enable_all_tooltip = STR_NULL;
				disable_all_tooltip = STR_NULL;
				plane = 1;
				break;
		}

		this->GetWidget<NWidgetCore>(WID_SM_LEGEND)->SetDataTip(STR_NULL, legend_tooltip);
		this->GetWidget<NWidgetCore>(WID_SM_ENABLE_ALL)->SetDataTip(STR_SMALLMAP_ENABLE_ALL, enable_all_tooltip);
		this->GetWidget<NWidgetCore>(WID_SM_DISABLE_ALL)->SetDataTip(STR_SMALLMAP_DISABLE_ALL, disable_all_tooltip);
		this->GetWidget<NWidgetStacked>(WID_SM_SELECT_BUTTONS)->SetDisplayedPlane(plane);
	}

	/**
	 * Decide which colours to show to the user for a group of tiles.
	 * @param ta Tile area to investigate.
	 * @return Colours to display.
	 */
	uint32_t GetTileColours(const TileArea &ta) const
	{
		int importance = 0;
		TileIndex tile = INVALID_TILE; // Position of the most important tile.
		TileType et = MP_VOID;         // Effective tile type at that position.

		for (TileIndex ti : ta) {
			TileType ttype = GetTileType(ti);

			switch (ttype) {
				case MP_TUNNELBRIDGE: {
					TransportType tt = GetTunnelBridgeTransportType(ti);

					switch (tt) {
						case TRANSPORT_RAIL: ttype = MP_RAILWAY; break;
						case TRANSPORT_ROAD: ttype = MP_ROAD;    break;
						default:             ttype = MP_WATER;   break;
					}
					break;
				}

				case MP_INDUSTRY:
					/* Special handling of industries while in "Industries" smallmap view. */
					if (this->map_type == SMT_INDUSTRY) {
						/* If industry is allowed to be seen, use its colour on the map.
						 * This has the highest priority above any value in _tiletype_importance. */
						IndustryType type = Industry::GetByTile(ti)->type;
						if (_legend_from_industries[_industry_to_list_pos[type]].show_on_map) {
							if (type == _smallmap_industry_highlight) {
								if (_smallmap_industry_highlight_state) return MKCOLOUR_XXXX(PC_WHITE);
							} else {
								return GetIndustrySpec(type)->map_colour * 0x01010101;
							}
						}
						/* Otherwise make it disappear */
						ttype = IsTileOnWater(ti) ? MP_WATER : MP_CLEAR;
					}
					break;

				default:
					break;
			}

			if (_tiletype_importance[ttype] > importance) {
				importance = _tiletype_importance[ttype];
				tile = ti;
				et = ttype;
			}
		}

		switch (this->map_type) {
			case SMT_CONTOUR:
				return GetSmallMapContoursPixels(tile, et);

			case SMT_VEHICLES:
				return GetSmallMapVehiclesPixels(tile, et);

			case SMT_INDUSTRY:
				return GetSmallMapIndustriesPixels(tile, et);

			case SMT_LINKSTATS:
				return GetSmallMapLinkStatsPixels(tile, et);

			case SMT_ROUTES:
				return GetSmallMapRoutesPixels(tile, et);

			case SMT_VEGETATION:
				return GetSmallMapVegetationPixels(tile, et);

			case SMT_OWNER:
				return GetSmallMapOwnerPixels(tile, et, IncludeHeightmap::IfEnabled);

			default: NOT_REACHED();
		}
	}

	/**
	 * Determines the mouse position on the legend.
	 * @param pt Mouse position.
	 * @return Legend item under the mouse.
	 */
	int GetPositionOnLegend(Point pt)
	{
		const NWidgetBase *wi = this->GetWidget<NWidgetBase>(WID_SM_LEGEND);
		uint line = (pt.y - wi->pos_y - WidgetDimensions::scaled.framerect.top) / GetCharacterHeight(FS_SMALL);
		uint columns = this->GetNumberColumnsLegend(wi->current_x);
		uint number_of_rows = this->GetNumberRowsLegend(columns);
		if (line >= number_of_rows) return -1;

		bool rtl = _current_text_dir == TD_RTL;
		int x = pt.x - wi->pos_x;
		if (rtl) x = wi->current_x - x;
		uint column = (x - WidgetDimensions::scaled.framerect.left) / this->column_width;

		return (column * number_of_rows) + line;
	}

	/** Update all the links on the map. */
	void UpdateLinks()
	{
		if (this->map_type == SMT_LINKSTATS) {
			CompanyMask company_mask = this->GetOverlayCompanyMask();
			if (this->overlay->GetCompanyMask() != company_mask) {
				this->overlay->SetCompanyMask(company_mask);
			} else {
				this->overlay->SetDirty();
			}
		}
	}

	/** Blink the industries (if hover over an industry). */
	void Blink()
	{
		if (_smallmap_industry_highlight == INVALID_INDUSTRYTYPE) return;

		_smallmap_industry_highlight_state = !_smallmap_industry_highlight_state;

		this->UpdateLinks();
		this->SetDirty();
	}

	/** Force a full refresh of the map. */
	void ForceRefresh()
	{
		if (_smallmap_industry_highlight != INVALID_INDUSTRYTYPE) return;

		this->UpdateLinks();
		this->SetDirty();
	}

public:
	friend class NWidgetSmallmapDisplay;

	SmallMapWindow(WindowDesc *desc, int window_number) : Window(desc)
	{
		_smallmap_industry_highlight = INVALID_INDUSTRYTYPE;
		this->overlay = std::make_unique<LinkGraphOverlay>(this, WID_SM_MAP, 0, this->GetOverlayCompanyMask(), 1);
		this->InitNested(window_number);
		this->LowerWidget(WID_SM_CONTOUR + this->map_type);

		this->RebuildColourIndexIfNecessary();

		this->SetWidgetLoweredState(WID_SM_SHOW_HEIGHT, _smallmap_show_heightmap);

		this->SetWidgetLoweredState(WID_SM_TOGGLETOWNNAME, this->show_towns);

		this->SetupWidgetData();

		this->SetZoomLevel(ZLC_INITIALIZE, nullptr);
		this->SmallMapCenterOnCurrentPos();
		this->SetOverlayCargoMask();
	}

	/**
	 * Center the small map on the current center of the viewport.
	 */
	void SmallMapCenterOnCurrentPos()
	{
		const Viewport *vp = GetMainWindow()->viewport;
		Point viewport_center = InverseRemapCoords2(vp->virtual_left + vp->virtual_width / 2, vp->virtual_top + vp->virtual_height / 2);

		int sub;
		const NWidgetBase *wid = this->GetWidget<NWidgetBase>(WID_SM_MAP);
		Point sxy = this->ComputeScroll(viewport_center.x / (int)TILE_SIZE, viewport_center.y / (int)TILE_SIZE,
				std::max(0, (int)wid->current_x / 2 - 2), wid->current_y / 2, &sub);
		this->SetNewScroll(sxy.x, sxy.y, sub);
		this->SetDirty();
	}

	/**
	 * Get the center of the given station as point on the screen in the smallmap window.
	 * @param st Station to find in the smallmap.
	 * @return Point with coordinates of the station.
	 */
	Point GetStationMiddle(const Station *st) const
	{
		int x = CenterBounds(st->rect.left, st->rect.right, 0);
		int y = CenterBounds(st->rect.top, st->rect.bottom, 0);
		Point ret = this->RemapTile(x, y);

		/* Same magic 3 as in DrawVehicles; that's where I got it from.
		 * No idea what it is, but without it the result looks bad.
		 */
		ret.x -= 3 + this->subscroll;
		return ret;
	}

	void Close([[maybe_unused]] int data) override
	{
		this->BreakIndustryChainLink();
		this->Window::Close();
	}

	void SetStringParameters(WidgetID widget) const override
	{
		switch (widget) {
			case WID_SM_CAPTION:
				SetDParam(0, STR_SMALLMAP_TYPE_CONTOURS + this->map_type);
				break;
		}
	}

	void OnInit() override
	{
		uint min_width = 0;
		this->min_number_of_columns = INDUSTRY_MIN_NUMBER_OF_COLUMNS;
		this->min_number_of_fixed_rows = lengthof(_linkstat_colours_in_legenda);
		for (uint i = 0; i < lengthof(_legend_table); i++) {
			uint height = 0;
			uint num_columns = 1;
			for (const LegendAndColour *tbl = _legend_table[i]; !tbl->end; ++tbl) {
				StringID str;
				if (i == SMT_INDUSTRY) {
					SetDParam(0, tbl->legend);
					SetDParam(1, IndustryPool::MAX_SIZE);
					str = STR_SMALLMAP_INDUSTRY;
				} else if (i == SMT_LINKSTATS) {
					SetDParam(0, tbl->legend);
					str = STR_SMALLMAP_LINKSTATS;
				} else if (i == SMT_OWNER) {
					if (tbl->company != INVALID_COMPANY) {
						if (!Company::IsValidID(tbl->company)) {
							/* Rebuild the owner legend. */
							BuildOwnerLegend();
							this->OnInit();
							return;
						}
						/* Non-fixed legend entries for the owner view. */
						SetDParam(0, tbl->company);
						str = STR_SMALLMAP_COMPANY;
					} else {
						str = tbl->legend;
					}
				} else {
					if (tbl->col_break) {
						this->min_number_of_fixed_rows = std::max(this->min_number_of_fixed_rows, height);
						height = 0;
						num_columns++;
					}
					height++;
					str = tbl->legend;
				}
				min_width = std::max(GetStringBoundingBox(str).width, min_width);
			}
			this->min_number_of_fixed_rows = std::max(this->min_number_of_fixed_rows, height);
			this->min_number_of_columns = std::max(this->min_number_of_columns, num_columns);
		}

		/* Width of the legend blob. */
		this->legend_width = GetCharacterHeight(FS_SMALL) * 9 / 6;

		/* The width of a column is the minimum width of all texts + the size of the blob + some spacing */
		this->column_width = min_width + WidgetDimensions::scaled.hsep_normal + this->legend_width + WidgetDimensions::scaled.framerect.Horizontal();
	}

	void OnPaint() override
	{
		if (this->map_type == SMT_OWNER) {
			for (const LegendAndColour *tbl = _legend_table[this->map_type]; !tbl->end; ++tbl) {
				if (tbl->company != INVALID_COMPANY && !Company::IsValidID(tbl->company)) {
					/* Rebuild the owner legend. */
					BuildOwnerLegend();
					this->InvalidateData(1);
					break;
				}
			}
		}

		this->DrawWidgets();
	}

	void DrawWidget(const Rect &r, WidgetID widget) const override
	{
		switch (widget) {
			case WID_SM_MAP: {
				Rect ir = r.Shrink(WidgetDimensions::scaled.bevel);
				DrawPixelInfo new_dpi;
				if (!FillDrawPixelInfo(&new_dpi, ir)) return;
				this->DrawSmallMap(&new_dpi);
				break;
			}

			case WID_SM_LEGEND: {
				uint columns = this->GetNumberColumnsLegend(r.Width());
				uint number_of_rows = this->GetNumberRowsLegend(columns);
				bool rtl = _current_text_dir == TD_RTL;
				uint i = 0; // Row counter for industry legend.
				uint row_height = GetCharacterHeight(FS_SMALL);
				int padding = ScaleGUITrad(1);

				Rect origin = r.WithWidth(this->column_width, rtl).Shrink(WidgetDimensions::scaled.framerect).WithHeight(row_height);
				Rect text = origin.Indent(this->legend_width + WidgetDimensions::scaled.hsep_normal, rtl);
				Rect icon = origin.WithWidth(this->legend_width, rtl).Shrink(0, padding, 0, 0);

				StringID string = STR_NULL;
				switch (this->map_type) {
					case SMT_INDUSTRY:
						string = STR_SMALLMAP_INDUSTRY;
						break;
					case SMT_LINKSTATS:
						string = STR_SMALLMAP_LINKSTATS;
						break;
					case SMT_OWNER:
						string = STR_SMALLMAP_COMPANY;
						break;
					default:
						break;
				}

				for (const LegendAndColour *tbl = _legend_table[this->map_type]; !tbl->end; ++tbl) {
					if (tbl->col_break || ((this->map_type == SMT_INDUSTRY || this->map_type == SMT_OWNER || this->map_type == SMT_LINKSTATS) && i++ >= number_of_rows)) {
						/* Column break needed, continue at top, COLUMN_WIDTH pixels
						 * (one "row") to the right. */
						int x = rtl ? -(int)this->column_width : this->column_width;
						int y = origin.top - text.top;
						text = text.Translate(x, y);
						icon = icon.Translate(x, y);
						i = 1;
					}

					uint8_t legend_colour = tbl->colour;

					switch (this->map_type) {
						case SMT_INDUSTRY:
							/* Industry name must be formatted, since it's not in tiny font in the specs.
							 * So, draw with a parameter and use the STR_SMALLMAP_INDUSTRY string, which is tiny font */
							SetDParam(0, tbl->legend);
							SetDParam(1, Industry::GetIndustryTypeCount(tbl->type));
							if (tbl->show_on_map && tbl->type == _smallmap_industry_highlight) {
								legend_colour = _smallmap_industry_highlight_state ? PC_WHITE : PC_BLACK;
							}
							[[fallthrough]];

						case SMT_LINKSTATS:
							SetDParam(0, tbl->legend);
							[[fallthrough]];

						case SMT_OWNER:
							if (this->map_type != SMT_OWNER || tbl->company != INVALID_COMPANY) {
								if (this->map_type == SMT_OWNER) SetDParam(0, tbl->company);
								if (!tbl->show_on_map) {
									/* Simply draw the string, not the black border of the legend colour.
									 * This will enforce the idea of the disabled item */
									DrawString(text, string, TC_GREY);
								} else {
									DrawString(text, string, TC_BLACK);
									GfxFillRect(icon, PC_BLACK); // Outer border of the legend colour
								}
								break;
							}
							[[fallthrough]];

						default:
							if (this->map_type == SMT_CONTOUR) SetDParam(0, tbl->height * TILE_HEIGHT_STEP);
							/* Anything that is not an industry or a company is using normal process */
							GfxFillRect(icon, PC_BLACK);
							DrawString(text, tbl->legend);
							break;
					}
					GfxFillRect(icon.Shrink(WidgetDimensions::scaled.bevel), legend_colour); // Legend colour

					text = text.Translate(0, row_height);
					icon = icon.Translate(0, row_height);
				}
			}
		}
	}

	void OnClick([[maybe_unused]] Point pt, WidgetID widget, [[maybe_unused]] int click_count) override
	{
		switch (widget) {
			case WID_SM_MAP: { // Map window
				if (click_count > 0) this->mouse_capture_widget = widget;

				const NWidgetBase *wid = this->GetWidget<NWidgetBase>(WID_SM_MAP);
				Window *w = GetMainWindow();
				int sub;
				pt = this->PixelToTile(pt.x - wid->pos_x, pt.y - wid->pos_y, &sub);
				ScrollWindowTo(this->scroll_x + pt.x * TILE_SIZE, this->scroll_y + pt.y * TILE_SIZE, -1, w);

				this->SetDirty();
				break;
			}

			case WID_SM_ZOOM_IN:
			case WID_SM_ZOOM_OUT: {
				const NWidgetBase *wid = this->GetWidget<NWidgetBase>(WID_SM_MAP);
				Point zoom_pt = { (int)wid->current_x / 2, (int)wid->current_y / 2};
				this->SetZoomLevel((widget == WID_SM_ZOOM_IN) ? ZLC_ZOOM_IN : ZLC_ZOOM_OUT, &zoom_pt);
				if (_settings_client.sound.click_beep) SndPlayFx(SND_15_BEEP);
				break;
			}

			case WID_SM_CONTOUR:    // Show land contours
			case WID_SM_VEHICLES:   // Show vehicles
			case WID_SM_INDUSTRIES: // Show industries
			case WID_SM_LINKSTATS:  // Show route map
			case WID_SM_ROUTES:     // Show transport routes
			case WID_SM_VEGETATION: // Show vegetation
			case WID_SM_OWNERS:     // Show land owners
				this->SwitchMapType((SmallMapType)(widget - WID_SM_CONTOUR));
				if (_settings_client.sound.click_beep) SndPlayFx(SND_15_BEEP);
				break;

			case WID_SM_CENTERMAP: // Center the smallmap again
				this->SmallMapCenterOnCurrentPos();
				this->HandleButtonClick(WID_SM_CENTERMAP);
				if (_settings_client.sound.click_beep) SndPlayFx(SND_15_BEEP);
				break;

			case WID_SM_TOGGLETOWNNAME: // Toggle town names
				this->show_towns = !this->show_towns;
				this->SetWidgetLoweredState(WID_SM_TOGGLETOWNNAME, this->show_towns);

				this->SetDirty();
				if (_settings_client.sound.click_beep) SndPlayFx(SND_15_BEEP);
				break;

			case WID_SM_LEGEND: // Legend
				if (this->map_type == SMT_INDUSTRY || this->map_type == SMT_LINKSTATS || this->map_type == SMT_OWNER) {
					int click_pos = this->GetPositionOnLegend(pt);
					if (click_pos < 0) break;

					/* If industry type small map*/
					if (this->map_type == SMT_INDUSTRY) {
						/* If click on industries label, find right industry type and enable/disable it. */
						if (click_pos < _smallmap_industry_count) {
							this->SelectLegendItem(click_pos, _legend_from_industries, _smallmap_industry_count);
						}
					} else if (this->map_type == SMT_LINKSTATS) {
						if (click_pos < _smallmap_cargo_count) {
							this->SelectLegendItem(click_pos, _legend_linkstats, _smallmap_cargo_count);
							this->SetOverlayCargoMask();
						}
					} else if (this->map_type == SMT_OWNER) {
						if (click_pos < _smallmap_company_count) {
							this->SelectLegendItem(click_pos, _legend_land_owners, _smallmap_company_count, NUM_NO_COMPANY_ENTRIES);
						}
					}
					this->SetDirty();
				}
				break;

			case WID_SM_ENABLE_ALL:
			case WID_SM_DISABLE_ALL: {
				LegendAndColour *tbl = nullptr;
				switch (this->map_type) {
					case SMT_INDUSTRY:
						tbl = _legend_from_industries;
						this->BreakIndustryChainLink();
						break;
					case SMT_OWNER:
						tbl = &(_legend_land_owners[NUM_NO_COMPANY_ENTRIES]);
						break;
					case SMT_LINKSTATS:
						tbl = _legend_linkstats;
						break;
					default:
						NOT_REACHED();
				}
				for (;!tbl->end && tbl->legend != STR_LINKGRAPH_LEGEND_UNUSED; ++tbl) {
					tbl->show_on_map = (widget == WID_SM_ENABLE_ALL);
				}
				if (this->map_type == SMT_LINKSTATS) this->SetOverlayCargoMask();
				this->SetDirty();
				break;
			}

			case WID_SM_SHOW_HEIGHT: // Enable/disable showing of heightmap.
				_smallmap_show_heightmap = !_smallmap_show_heightmap;
				this->SetWidgetLoweredState(WID_SM_SHOW_HEIGHT, _smallmap_show_heightmap);
				this->SetDirty();
				break;
		}
	}

	/**
	 * Some data on this window has become invalid.
	 * @param data Information about the changed data.
	 * - data = 0: Displayed industries at the industry chain window have changed.
	 * - data = 1: Companies have changed.
	 * - data = 2: Cheat changing the maximum heightlevel has been used, rebuild our heightlevel-to-colour index
	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
	 */
	void OnInvalidateData(int data = 0, bool gui_scope = true) override
	{
		if (!gui_scope) return;

		switch (data) {
			case 1:
				/* The owner legend has already been rebuilt. */
				this->ReInit();
				break;

			case 0: {
				extern std::bitset<NUM_INDUSTRYTYPES> _displayed_industries;
				if (this->map_type != SMT_INDUSTRY) this->SwitchMapType(SMT_INDUSTRY);

				for (int i = 0; i != _smallmap_industry_count; i++) {
					_legend_from_industries[i].show_on_map = _displayed_industries.test(_legend_from_industries[i].type);
				}
				break;
			}

			case 2:
				this->RebuildColourIndexIfNecessary();
				break;

			default: NOT_REACHED();
		}
		this->SetDirty();
	}

	bool OnRightClick(Point, WidgetID widget) override
	{
		if (widget != WID_SM_MAP || _scrolling_viewport) return false;

		_scrolling_viewport = true;
		return true;
	}

	void OnMouseWheel(int wheel) override
	{
		if (_settings_client.gui.scrollwheel_scrolling != 2) {
			const NWidgetBase *wid = this->GetWidget<NWidgetBase>(WID_SM_MAP);
			int cursor_x = _cursor.pos.x - this->left - wid->pos_x;
			int cursor_y = _cursor.pos.y - this->top  - wid->pos_y;
			if (IsInsideMM(cursor_x, 0, wid->current_x) && IsInsideMM(cursor_y, 0, wid->current_y)) {
				Point pt = {cursor_x, cursor_y};
				this->SetZoomLevel((wheel < 0) ? ZLC_ZOOM_IN : ZLC_ZOOM_OUT, &pt);
			}
		}
	}

	void OnScroll(Point delta) override
	{
		if (_settings_client.gui.scroll_mode == VSM_VIEWPORT_RMB_FIXED || _settings_client.gui.scroll_mode == VSM_MAP_RMB_FIXED) _cursor.fix_at = true;

		/* While tile is at (delta.x, delta.y)? */
		int sub;
		Point pt = this->PixelToTile(delta.x, delta.y, &sub);
		this->SetNewScroll(this->scroll_x + pt.x * TILE_SIZE, this->scroll_y + pt.y * TILE_SIZE, sub);

		this->SetDirty();
	}

	void OnMouseOver([[maybe_unused]] Point pt, WidgetID widget) override
	{
		IndustryType new_highlight = INVALID_INDUSTRYTYPE;
		if (widget == WID_SM_LEGEND && this->map_type == SMT_INDUSTRY) {
			int industry_pos = GetPositionOnLegend(pt);
			if (industry_pos >= 0 && industry_pos < _smallmap_industry_count) {
				new_highlight = _legend_from_industries[industry_pos].type;
			}
		}
		if (new_highlight != _smallmap_industry_highlight) {
			_smallmap_industry_highlight = new_highlight;
			_smallmap_industry_highlight_state = true;
			this->SetDirty();
		}
	}

};

SmallMapType SmallMapWindow::map_type = SMT_CONTOUR;
bool SmallMapWindow::show_towns = true;
int SmallMapWindow::map_height_limit = -1;

/**
 * Custom container class for displaying smallmap with a vertically resizing legend panel.
 * The legend panel has a smallest height that depends on its width. Standard containers cannot handle this case.
 *
 * @note The container assumes it has two children, the first is the display, the second is the bar with legends and selection image buttons.
 *       Both children should be both horizontally and vertically resizable and horizontally fillable.
 *       The bar should have a minimal size with a zero-size legends display. Child padding is not supported.
 */
class NWidgetSmallmapDisplay : public NWidgetContainer {
	const SmallMapWindow *smallmap_window; ///< Window manager instance.
public:
	NWidgetSmallmapDisplay() : NWidgetContainer(NWID_VERTICAL)
	{
		this->smallmap_window = nullptr;
	}

	void SetupSmallestSize(Window *w) override
	{
		assert(this->children.size() == 2);
		NWidgetBase *display = this->children.front().get();
		NWidgetBase *bar = this->children.back().get();

		display->SetupSmallestSize(w);
		bar->SetupSmallestSize(w);

		this->smallmap_window = dynamic_cast<SmallMapWindow *>(w);
		assert(this->smallmap_window != nullptr);
		this->smallest_x = std::max(display->smallest_x, bar->smallest_x + smallmap_window->GetMinLegendWidth());
		this->smallest_y = display->smallest_y + std::max(bar->smallest_y, smallmap_window->GetLegendHeight(smallmap_window->min_number_of_columns));
		this->fill_x = std::max(display->fill_x, bar->fill_x);
		this->fill_y = (display->fill_y == 0 && bar->fill_y == 0) ? 0 : std::min(display->fill_y, bar->fill_y);
		this->resize_x = std::max(display->resize_x, bar->resize_x);
		this->resize_y = std::min(display->resize_y, bar->resize_y);
		this->ApplyAspectRatio();
	}

	void AssignSizePosition(SizingType sizing, int x, int y, uint given_width, uint given_height, bool rtl) override
	{
		this->pos_x = x;
		this->pos_y = y;
		this->current_x = given_width;
		this->current_y = given_height;

		assert(this->children.size() == 2);
		NWidgetBase *display = this->children.front().get();
		NWidgetBase *bar = this->children.back().get();

		if (sizing == ST_SMALLEST) {
			this->smallest_x = given_width;
			this->smallest_y = given_height;
			/* Make display and bar exactly equal to their minimal size. */
			display->AssignSizePosition(ST_SMALLEST, x, y, display->smallest_x, display->smallest_y, rtl);
			bar->AssignSizePosition(ST_SMALLEST, x, y + display->smallest_y, bar->smallest_x, bar->smallest_y, rtl);
		}

		uint bar_height = std::max(bar->smallest_y, this->smallmap_window->GetLegendHeight(this->smallmap_window->GetNumberColumnsLegend(given_width - bar->smallest_x)));
		uint display_height = given_height - bar_height;
		display->AssignSizePosition(ST_RESIZE, x, y, given_width, display_height, rtl);
		bar->AssignSizePosition(ST_RESIZE, x, y + display_height, given_width, bar_height, rtl);
	}
};

/** Widget parts of the smallmap display. */
static constexpr NWidgetPart _nested_smallmap_display[] = {
	NWidget(WWT_PANEL, COLOUR_BROWN, WID_SM_MAP_BORDER),
		NWidget(WWT_INSET, COLOUR_BROWN, WID_SM_MAP), SetMinimalSize(346, 140), SetResize(1, 1), SetPadding(2, 2, 2, 2), EndContainer(),
	EndContainer(),
};

/** Widget parts of the smallmap legend bar + image buttons. */
static constexpr NWidgetPart _nested_smallmap_bar[] = {
	NWidget(WWT_PANEL, COLOUR_BROWN),
		NWidget(NWID_HORIZONTAL),
			NWidget(WWT_EMPTY, INVALID_COLOUR, WID_SM_LEGEND), SetResize(1, 1),
			NWidget(NWID_VERTICAL),
				/* Top button row. */
				NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
					NWidget(WWT_PUSHIMGBTN, COLOUR_BROWN, WID_SM_ZOOM_IN),
							SetDataTip(SPR_IMG_ZOOMIN, STR_TOOLBAR_TOOLTIP_ZOOM_THE_VIEW_IN), SetFill(1, 1),
					NWidget(WWT_PUSHIMGBTN, COLOUR_BROWN, WID_SM_CENTERMAP),
							SetDataTip(SPR_IMG_SMALLMAP, STR_SMALLMAP_CENTER), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_BLANK),
							SetDataTip(SPR_EMPTY, STR_NULL), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_CONTOUR),
							SetDataTip(SPR_IMG_SHOW_COUNTOURS, STR_SMALLMAP_TOOLTIP_SHOW_LAND_CONTOURS_ON_MAP), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_VEHICLES),
							SetDataTip(SPR_IMG_SHOW_VEHICLES, STR_SMALLMAP_TOOLTIP_SHOW_VEHICLES_ON_MAP), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_INDUSTRIES),
							SetDataTip(SPR_IMG_INDUSTRY, STR_SMALLMAP_TOOLTIP_SHOW_INDUSTRIES_ON_MAP), SetFill(1, 1),
				EndContainer(),
				/* Bottom button row. */
				NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
					NWidget(WWT_PUSHIMGBTN, COLOUR_BROWN, WID_SM_ZOOM_OUT),
							SetDataTip(SPR_IMG_ZOOMOUT, STR_TOOLBAR_TOOLTIP_ZOOM_THE_VIEW_OUT), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_TOGGLETOWNNAME),
							SetDataTip(SPR_IMG_TOWN, STR_SMALLMAP_TOOLTIP_TOGGLE_TOWN_NAMES_ON_OFF), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_LINKSTATS),
							SetDataTip(SPR_IMG_CARGOFLOW, STR_SMALLMAP_TOOLTIP_SHOW_LINK_STATS_ON_MAP), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_ROUTES),
							SetDataTip(SPR_IMG_SHOW_ROUTES, STR_SMALLMAP_TOOLTIP_SHOW_TRANSPORT_ROUTES_ON), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_VEGETATION),
							SetDataTip(SPR_IMG_PLANTTREES, STR_SMALLMAP_TOOLTIP_SHOW_VEGETATION_ON_MAP), SetFill(1, 1),
					NWidget(WWT_IMGBTN, COLOUR_BROWN, WID_SM_OWNERS),
							SetDataTip(SPR_IMG_COMPANY_GENERAL, STR_SMALLMAP_TOOLTIP_SHOW_LAND_OWNERS_ON_MAP), SetFill(1, 1),
				EndContainer(),
				NWidget(NWID_SPACER), SetResize(0, 1),
			EndContainer(),
		EndContainer(),
	EndContainer(),
};

static std::unique_ptr<NWidgetBase> SmallMapDisplay()
{
	std::unique_ptr<NWidgetBase> map_display = std::make_unique<NWidgetSmallmapDisplay>();

	map_display = MakeNWidgets(std::begin(_nested_smallmap_display), std::end(_nested_smallmap_display), std::move(map_display));
	map_display = MakeNWidgets(std::begin(_nested_smallmap_bar), std::end(_nested_smallmap_bar), std::move(map_display));
	return map_display;
}


static constexpr NWidgetPart _nested_smallmap_widgets[] = {
	NWidget(NWID_HORIZONTAL),
		NWidget(WWT_CLOSEBOX, COLOUR_BROWN),
		NWidget(WWT_CAPTION, COLOUR_BROWN, WID_SM_CAPTION), SetDataTip(STR_SMALLMAP_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
		NWidget(WWT_SHADEBOX, COLOUR_BROWN),
		NWidget(WWT_DEFSIZEBOX, COLOUR_BROWN),
		NWidget(WWT_STICKYBOX, COLOUR_BROWN),
	EndContainer(),
	NWidgetFunction(SmallMapDisplay), // Smallmap display and legend bar + image buttons.
	/* Bottom button row and resize box. */
	NWidget(NWID_HORIZONTAL),
		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_SM_SELECT_BUTTONS),
			NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
				NWidget(WWT_PUSHTXTBTN, COLOUR_BROWN, WID_SM_ENABLE_ALL), SetDataTip(STR_SMALLMAP_ENABLE_ALL, STR_NULL),
				NWidget(WWT_PUSHTXTBTN, COLOUR_BROWN, WID_SM_DISABLE_ALL), SetDataTip(STR_SMALLMAP_DISABLE_ALL, STR_NULL),
				NWidget(WWT_TEXTBTN, COLOUR_BROWN, WID_SM_SHOW_HEIGHT), SetDataTip(STR_SMALLMAP_SHOW_HEIGHT, STR_SMALLMAP_TOOLTIP_SHOW_HEIGHT),
				NWidget(WWT_PANEL, COLOUR_BROWN), SetFill(1, 0), SetResize(1, 0),
				EndContainer(),
			EndContainer(),
			NWidget(WWT_PANEL, COLOUR_BROWN), SetFill(1, 0), SetResize(1, 0),
			EndContainer(),
		EndContainer(),
		NWidget(WWT_RESIZEBOX, COLOUR_BROWN),
	EndContainer(),
};

static WindowDesc _smallmap_desc(
	WDP_AUTO, "smallmap", 484, 314,
	WC_SMALLMAP, WC_NONE,
	0,
	std::begin(_nested_smallmap_widgets), std::end(_nested_smallmap_widgets)
);

/**
 * Show the smallmap window.
 */
void ShowSmallMap()
{
	AllocateWindowDescFront<SmallMapWindow>(&_smallmap_desc, 0);
}

/**
 * Scrolls the main window to given coordinates.
 * @param x x coordinate
 * @param y y coordinate
 * @param z z coordinate; -1 to scroll to terrain height
 * @param instant scroll instantly (meaningful only when smooth_scrolling is active)
 * @return did the viewport position change?
 */
bool ScrollMainWindowTo(int x, int y, int z, bool instant)
{
	bool res = ScrollWindowTo(x, y, z, GetMainWindow(), instant);

	/* If a user scrolls to a tile (via what way what so ever) and already is on
	 * that tile (e.g.: pressed twice), move the smallmap to that location,
	 * so you directly see where you are on the smallmap. */

	if (res) return res;

	SmallMapWindow *w = dynamic_cast<SmallMapWindow*>(FindWindowById(WC_SMALLMAP, 0));
	if (w != nullptr) w->SmallMapCenterOnCurrentPos();

	return res;
}

/**
 * Determine the middle of a station in the smallmap window.
 * @param st The station we're looking for.
 * @return Middle point of the station in the smallmap window.
 */
Point GetSmallMapStationMiddle(const Window *w, const Station *st)
{
	return static_cast<const SmallMapWindow *>(w)->GetStationMiddle(st);
}