/* $Id$ */

#include "stdafx.h"
#include "openttd.h"
#include "train.h"
#include "ship.h"
#include "aircraft.h"
#include "debug.h"
#include "functions.h"
#include "table/sprites.h"
#include "table/strings.h"
#include "window.h"
#include "gui.h"
#include "vehicle.h"
#include "gfx.h"
#include "station.h"
#include "command.h"
#include "engine.h"
#include "player.h"
#include "depot.h"
#include "airport.h"
#include "vehicle_gui.h"
#include "newgrf_engine.h"
#include "date.h"
#include "strings.h"


enum BuildVehicleWidgets {
	BUILD_VEHICLE_WIDGET_CLOSEBOX = 0,
	BUILD_VEHICLE_WIDGET_CAPTION,
	BUILD_VEHICLE_WIDGET_SORT_ASSENDING_DESCENDING,
	BUILD_VEHICLE_WIDGET_SORT_TEXT,
	BUILD_VEHICLE_WIDGET_SORT_DROPDOWN,
	BUILD_VEHICLE_WIDGET_LIST,
	BUILD_VEHICLE_WIDGET_SCROLLBAR,
	BUILD_VEHICLE_WIDGET_PANEL,
	BUILD_VEHICLE_WIDGET_BUILD,
	BUILD_VEHICLE_WIDGET_RENAME,
	BUILD_VEHICLE_WIDGET_RESIZE,
};

static const Widget _build_vehicle_widgets[] = {
	{   WWT_CLOSEBOX,   RESIZE_NONE,    14,     0,    10,     0,    13, STR_00C5,                STR_018B_CLOSE_WINDOW },
	{    WWT_CAPTION,  RESIZE_RIGHT,    14,    11,   227,     0,    13, 0x0,                     STR_018C_WINDOW_TITLE_DRAG_THIS },
	{ WWT_PUSHTXTBTN,   RESIZE_NONE,    14,     0,    80,    14,    25, STR_SORT_BY,             STR_SORT_ORDER_TIP},
	{      WWT_PANEL,  RESIZE_RIGHT,    14,    81,   215,    14,    25, 0x0,                     STR_SORT_CRITERIA_TIP},
	{    WWT_TEXTBTN,     RESIZE_LR,    14,   216,   227,    14,    25, STR_0225,                STR_SORT_CRITERIA_TIP},
	{     WWT_MATRIX,     RESIZE_RB,    14,     0,   215,    26,   121, 0x0,                     STR_NULL },
	{  WWT_SCROLLBAR,    RESIZE_LRB,    14,   216,   227,    26,   121, 0x0,                     STR_0190_SCROLL_BAR_SCROLLS_LIST },
	{      WWT_PANEL,    RESIZE_RTB,    14,     0,   227,   122,   213, 0x0,                     STR_NULL },

	{ WWT_PUSHTXTBTN,     RESIZE_TB,    14,     0,   114,   214,   225, 0x0,                     STR_NULL },
	{ WWT_PUSHTXTBTN,    RESIZE_RTB,    14,   115,   215,   214,   225, 0x0,                     STR_NULL },
	{  WWT_RESIZEBOX,   RESIZE_LRTB,    14,   216,   227,   214,   225, 0x0,                     STR_RESIZE_BUTTON },
	{   WIDGETS_END},
};

static void ResizeButtons(Window *w)
{
	/* Make the buttons in the bottom equal in size */
	w->widget[BUILD_VEHICLE_WIDGET_RENAME].right = w->widget[BUILD_VEHICLE_WIDGET_RESIZE].left - 1;
	w->widget[BUILD_VEHICLE_WIDGET_RENAME].left  = w->widget[BUILD_VEHICLE_WIDGET_RENAME].right / 2;
	w->widget[BUILD_VEHICLE_WIDGET_BUILD].right  = w->widget[BUILD_VEHICLE_WIDGET_RENAME].left - 1;
}

/* Setup widget strings to fit the different types of vehicles */
static void SetupWindowStrings(const Window *w, byte type)
{
	switch (type) {
		case VEH_Train:
			w->widget[BUILD_VEHICLE_WIDGET_CAPTION].data    = STR_JUST_STRING;
			w->widget[BUILD_VEHICLE_WIDGET_LIST].tooltips   = STR_8843_TRAIN_VEHICLE_SELECTION;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].data      = STR_881F_BUILD_VEHICLE;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].tooltips  = STR_8844_BUILD_THE_HIGHLIGHTED_TRAIN;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].data     = STR_8820_RENAME;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].tooltips = STR_8845_RENAME_TRAIN_VEHICLE_TYPE;
			break;
		case VEH_Ship:
			w->widget[BUILD_VEHICLE_WIDGET_CAPTION].data    = STR_9808_NEW_SHIPS;
			w->widget[BUILD_VEHICLE_WIDGET_LIST].tooltips   = STR_9825_SHIP_SELECTION_LIST_CLICK;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].data      = STR_9809_BUILD_SHIP;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].tooltips  = STR_9826_BUILD_THE_HIGHLIGHTED_SHIP;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].data     = STR_9836_RENAME;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].tooltips = STR_9837_RENAME_SHIP_TYPE;
			break;
		case VEH_Aircraft:
			w->widget[BUILD_VEHICLE_WIDGET_CAPTION].data    = STR_A005_NEW_AIRCRAFT;
			w->widget[BUILD_VEHICLE_WIDGET_LIST].tooltips   = STR_A025_AIRCRAFT_SELECTION_LIST;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].data      = STR_A006_BUILD_AIRCRAFT;
			w->widget[BUILD_VEHICLE_WIDGET_BUILD].tooltips  = STR_A026_BUILD_THE_HIGHLIGHTED_AIRCRAFT;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].data     = STR_A037_RENAME;
			w->widget[BUILD_VEHICLE_WIDGET_RENAME].tooltips = STR_A038_RENAME_AIRCRAFT_TYPE;
			break;
	}
}

static bool _internal_sort_order; // descending/ascending

static byte _last_sort_criteria[]    = {0, 0, 0, 0};
static bool _last_sort_order[]       = {false, false, false, false};

static int CDECL EngineNumberSorter(const void *a, const void *b)
{
	const EngineID va = *(const EngineID*)a;
	const EngineID vb = *(const EngineID*)b;
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL EngineIntroDateSorter(const void *a, const void *b)
{
	const int va = GetEngine(*(const EngineID*)a)->intro_date;
	const int vb = GetEngine(*(const EngineID*)b)->intro_date;
	const int r = va - vb;

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

static int CDECL EngineNameSorter(const void *a, const void *b)
{
	static EngineID last_engine[2] = { INVALID_ENGINE, INVALID_ENGINE };
	static char     last_name[2][64] = { "\0", "\0" };

	const EngineID va = *(const EngineID*)a;
	const EngineID vb = *(const EngineID*)b;
	int r;

	if (va != last_engine[0]) {
		last_engine[0] = va;
		GetString(last_name[0], GetCustomEngineName(va), lastof(last_name[0]));
	}

	if (vb != last_engine[1]) {
		last_engine[1] = vb;
		GetString(last_name[1], GetCustomEngineName(vb), lastof(last_name[1]));
	}

	r = strcmp(last_name[0], last_name[1]); // sort by name

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

static int CDECL EngineReliabilitySorter(const void *a, const void *b)
{
	const int va = GetEngine(*(const EngineID*)a)->reliability;
	const int vb = GetEngine(*(const EngineID*)b)->reliability;
	const int r = va - vb;

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

/* Train sorting functions */
static int CDECL TrainEngineCostSorter(const void *a, const void *b)
{
	int va = RailVehInfo(*(const EngineID*)a)->base_cost;
	int vb = RailVehInfo(*(const EngineID*)b)->base_cost;
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL TrainEngineSpeedSorter(const void *a, const void *b)
{
	int va = RailVehInfo(*(const EngineID*)a)->max_speed;
	int vb = RailVehInfo(*(const EngineID*)b)->max_speed;
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL TrainEnginePowerSorter(const void *a, const void *b)
{
	const RailVehicleInfo *rvi_a = RailVehInfo(*(const EngineID*)a);
	const RailVehicleInfo *rvi_b = RailVehInfo(*(const EngineID*)b);

	int va = rvi_a->power << (rvi_a->flags & RVI_MULTIHEAD ? 1 : 0);
	int vb = rvi_b->power << (rvi_b->flags & RVI_MULTIHEAD ? 1 : 0);
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL TrainEngineRunningCostSorter(const void *a, const void *b)
{
	const RailVehicleInfo *rvi_a = RailVehInfo(*(const EngineID*)a);
	const RailVehicleInfo *rvi_b = RailVehInfo(*(const EngineID*)b);

	int va = rvi_a->running_cost_base * _price.running_rail[rvi_a->running_cost_class] * (rvi_a->flags & RVI_MULTIHEAD ? 2 : 1);
	int vb = rvi_b->running_cost_base * _price.running_rail[rvi_b->running_cost_class] * (rvi_b->flags & RVI_MULTIHEAD ? 2 : 1);
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL TrainEnginePowerVsRunningCostSorter(const void *a, const void *b)
{
	const RailVehicleInfo *rvi_a = RailVehInfo(*(const EngineID*)a);
	const RailVehicleInfo *rvi_b = RailVehInfo(*(const EngineID*)b);

	/* Here we are using a few tricks to get the right sort.
		* We want power/running cost, but since we usually got higher running cost than power and we store the result in an int,
		* we will actually calculate cunning cost/power (to make it more than 1).
		* Because of this, the return value have to be reversed as well and we return b - a instead of a - b.
		* Another thing is that both power and running costs should be doubled for multiheaded engines.
		* Since it would be multipling with 2 in both numerator and denumerator, it will even themselves out and we skip checking for multiheaded. */
	int va = (rvi_a->running_cost_base * _price.running_rail[rvi_a->running_cost_class]) / max((uint16)1, rvi_a->power);
	int vb = (rvi_b->running_cost_base * _price.running_rail[rvi_b->running_cost_class]) / max((uint16)1, rvi_b->power);
	int r = vb - va;

	return _internal_sort_order ? -r : r;
}

static int CDECL TrainEnginesThenWagonsSorter(const void *a, const void *b)
{
	EngineID va = *(const EngineID*)a;
	EngineID vb = *(const EngineID*)b;
	int val_a = ((RailVehInfo(va)->flags & RVI_WAGON) != 0) ? 1 : 0;
	int val_b = ((RailVehInfo(vb)->flags & RVI_WAGON) != 0) ? 1 : 0;
	int r = val_a - val_b;

	/* Use EngineID to sort instead since we want consistent sorting */
	if (r == 0) return EngineNumberSorter(a, b);

	return _internal_sort_order ? -r : r;
}

/* Aircraft sorting functions */

static int CDECL AircraftEngineCostSorter(const void *a, const void *b)
{
	const int va = AircraftVehInfo(*(const EngineID*)a)->base_cost;
	const int vb = AircraftVehInfo(*(const EngineID*)b)->base_cost;
	int r = va - vb;

	return _internal_sort_order ? -r : r;
}

static int CDECL AircraftEngineSpeedSorter(const void *a, const void *b)
{
	const int va = AircraftVehInfo(*(const EngineID*)a)->max_speed;
	const int vb = AircraftVehInfo(*(const EngineID*)b)->max_speed;
	const int r = va - vb;

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

static int CDECL AircraftEngineRunningCostSorter(const void *a, const void *b)
{
	const int va = AircraftVehInfo(*(const EngineID*)a)->running_cost;
	const int vb = AircraftVehInfo(*(const EngineID*)b)->running_cost;
	const int r = va - vb;

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

static int CDECL AircraftEngineCargoSorter(const void *a, const void *b)
{
	const int va = AircraftVehInfo(*(const EngineID*)a)->passenger_capacity;
	const int vb = AircraftVehInfo(*(const EngineID*)b)->passenger_capacity;
	const int r = va - vb;

	if (r == 0) {
		/* Use EngineID to sort instead since we want consistent sorting */
		return EngineNumberSorter(a, b);
	}
	return _internal_sort_order ? -r : r;
}

static EngList_SortTypeFunction * const _sorter[][9] = {{
	&EngineNumberSorter,
	&TrainEngineCostSorter,
	&TrainEngineSpeedSorter,
	&TrainEnginePowerSorter,
	&EngineIntroDateSorter,
	&EngineNameSorter,
	&TrainEngineRunningCostSorter,
	&TrainEnginePowerVsRunningCostSorter,
	&EngineReliabilitySorter,
},{
	&EngineNumberSorter,
	&EngineIntroDateSorter,
	&EngineNameSorter,
	&EngineReliabilitySorter,
},{
	&EngineNumberSorter,
	&EngineIntroDateSorter,
	&EngineNameSorter,
	&EngineReliabilitySorter,
},{
	&EngineNumberSorter,
	&AircraftEngineCostSorter,
	&AircraftEngineSpeedSorter,
	&EngineIntroDateSorter,
	&EngineNameSorter,
	&AircraftEngineRunningCostSorter,
	&EngineReliabilitySorter,
	&AircraftEngineCargoSorter,
}};

static const StringID _sort_listing[][10] = {{
	STR_ENGINE_SORT_ENGINE_ID,
	STR_ENGINE_SORT_COST,
	STR_SORT_BY_MAX_SPEED,
	STR_ENGINE_SORT_POWER,
	STR_ENGINE_SORT_INTRO_DATE,
	STR_SORT_BY_DROPDOWN_NAME,
	STR_ENGINE_SORT_RUNNING_COST,
	STR_ENGINE_SORT_POWER_VS_RUNNING_COST,
	STR_SORT_BY_RELIABILITY,
	INVALID_STRING_ID
},{
	STR_ENGINE_SORT_ENGINE_ID,
	STR_ENGINE_SORT_INTRO_DATE,
	STR_SORT_BY_DROPDOWN_NAME,
	STR_SORT_BY_RELIABILITY,
	INVALID_STRING_ID
},{
	STR_ENGINE_SORT_ENGINE_ID,
	STR_ENGINE_SORT_INTRO_DATE,
	STR_SORT_BY_DROPDOWN_NAME,
	STR_SORT_BY_RELIABILITY,
	INVALID_STRING_ID
},{
	STR_ENGINE_SORT_ENGINE_ID,
	STR_ENGINE_SORT_COST,
	STR_SORT_BY_MAX_SPEED,
	STR_ENGINE_SORT_INTRO_DATE,
	STR_SORT_BY_DROPDOWN_NAME,
	STR_ENGINE_SORT_RUNNING_COST,
	STR_SORT_BY_RELIABILITY,
	STR_ENGINE_SORT_CARGO_CAPACITY,
	INVALID_STRING_ID
}};

/* Draw rail wagon specific details */
static int DrawVehiclePurchaseInfo(int x, int y, EngineID engine_number, const RailVehicleInfo *rvi)
{
	/* Purchase cost */
	SetDParam(0, (rvi->base_cost * _price.build_railwagon) >> 8);
	DrawString(x, y, STR_PURCHASE_INFO_COST, 0);
	y += 10;

	/* Wagon weight - (including cargo) */
	SetDParam(0, rvi->weight);
	SetDParam(1, (_cargoc.weights[rvi->cargo_type] * rvi->capacity >> 4) + rvi->weight);
	DrawString(x, y, STR_PURCHASE_INFO_WEIGHT_CWEIGHT, 0);
	y += 10;

	/* Wagon speed limit, displayed if above zero */
	if (rvi->max_speed > 0 && _patches.wagon_speed_limits) {
		SetDParam(0, rvi->max_speed);
		DrawString(x,y, STR_PURCHASE_INFO_SPEED, 0);
		y += 10;
	}
	return y;
}

/* Draw locomotive specific details */
static int DrawVehiclePurchaseInfo(int x, int y, EngineID engine_number, const RailVehicleInfo *rvi, const Engine *e)
{
	int multihead = (rvi->flags&RVI_MULTIHEAD?1:0);

	/* Purchase Cost - Engine weight */
	SetDParam(0, rvi->base_cost * (_price.build_railvehicle >> 3) >> 5);
	SetDParam(1, rvi->weight << multihead);
	DrawString(x,y, STR_PURCHASE_INFO_COST_WEIGHT, 0);
	y += 10;

	/* Max speed - Engine power */
	SetDParam(0, rvi->max_speed);
	SetDParam(1, rvi->power << multihead);
	DrawString(x,y, STR_PURCHASE_INFO_SPEED_POWER, 0);
	y += 10;

	/* Max tractive effort - not applicable if old acceleration or maglev */
	if (_patches.realistic_acceleration && e->railtype != RAILTYPE_MAGLEV) {
		SetDParam(0, ((rvi->weight << multihead) * 10 * rvi->tractive_effort) / 256);
		DrawString(x, y, STR_PURCHASE_INFO_MAX_TE, 0);
		y += 10;
	}

	/* Running cost */
	SetDParam(0, (rvi->running_cost_base * _price.running_rail[rvi->running_cost_class] >> 8) << multihead);
	DrawString(x,y, STR_PURCHASE_INFO_RUNNINGCOST, 0);
	y += 10;

	/* Powered wagons power - Powered wagons extra weight */
	if (rvi->pow_wag_power != 0) {
		SetDParam(0, rvi->pow_wag_power);
		SetDParam(1, rvi->pow_wag_weight);
		DrawString(x,y, STR_PURCHASE_INFO_PWAGPOWER_PWAGWEIGHT, 0);
		y += 10;
	};

	return y;
}

/* Draw ship specific details */
static int DrawVehiclePurchaseInfo(int x, int y, EngineID engine_number, const ShipVehicleInfo *svi)
{
	/* Purchase cost - Max speed */
	SetDParam(0, svi->base_cost * (_price.ship_base>>3)>>5);
	SetDParam(1, svi->max_speed / 2);
	DrawString(x,y, STR_PURCHASE_INFO_COST_SPEED, 0);
	y += 10;

	/* Cargo type + capacity */
	SetDParam(0, svi->cargo_type);
	SetDParam(1, svi->capacity);
	SetDParam(2, svi->refittable ? STR_9842_REFITTABLE : STR_EMPTY);
	DrawString(x,y, STR_PURCHASE_INFO_CAPACITY, 0);
	y += 10;

	/* Running cost */
	SetDParam(0, svi->running_cost * _price.ship_running >> 8);
	DrawString(x,y, STR_PURCHASE_INFO_RUNNINGCOST, 0);
	y += 10;

	return y;
}

/* Draw aircraft specific details */
static int DrawVehiclePurchaseInfo(int x, int y, EngineID engine_number, const AircraftVehicleInfo *avi)
{
	CargoID cargo;

	/* Purchase cost - Max speed */
	SetDParam(0, avi->base_cost * (_price.aircraft_base>>3)>>5);
	SetDParam(1, avi->max_speed * 128 / 10);
	DrawString(x, y, STR_PURCHASE_INFO_COST_SPEED, 0);
	y += 10;

	/* Cargo capacity */
	cargo = FindFirstRefittableCargo(engine_number);
	if (cargo == CT_INVALID || cargo == CT_PASSENGERS) {
		SetDParam(0, avi->passenger_capacity);
		SetDParam(1, avi->mail_capacity);
		DrawString(x, y, STR_PURCHASE_INFO_AIRCRAFT_CAPACITY, 0);
	} else {
		/* Note, if the default capacity is selected by the refit capacity
		* callback, then the capacity shown is likely to be incorrect. */
		SetDParam(0, cargo);
		SetDParam(1, AircraftDefaultCargoCapacity(cargo, engine_number));
		SetDParam(2, STR_9842_REFITTABLE);
		DrawString(x, y, STR_PURCHASE_INFO_CAPACITY, 0);
	}
	y += 10;

	/* Running cost */
	SetDParam(0, avi->running_cost * _price.aircraft_running >> 8);
	DrawString(x, y, STR_PURCHASE_INFO_RUNNINGCOST, 0);
	y += 10;

	return y;
}

/**
 * Draw the purchase info details of a vehicle at a given location.
 * @param x,y location where to draw the info
 * @param w how wide are the text allowed to be (size of widget/window to Draw in)
 * @param engine_number the engine of which to draw the info of
 */
void DrawVehiclePurchaseInfo(int x, int y, uint w, EngineID engine_number)
{
	const Engine *e = GetEngine(engine_number);
	YearMonthDay ymd;
	ConvertDateToYMD(e->intro_date, &ymd);

	switch (e->type) {
		case VEH_Train: {
			const RailVehicleInfo *rvi = RailVehInfo(engine_number);

			if (rvi->flags & RVI_WAGON) {
				y = DrawVehiclePurchaseInfo(x, y, engine_number, rvi);
			} else {
				y = DrawVehiclePurchaseInfo(x, y, engine_number, rvi, e);
			}

			/* Cargo type + capacity, or N/A */
			if (rvi->capacity == 0) {
				SetDParam(0, CT_INVALID);
				SetDParam(2, STR_EMPTY);
			} else {
				int multihead = (rvi->flags & RVI_MULTIHEAD ? 1 : 0);
				SetDParam(0, rvi->cargo_type);
				SetDParam(1, (rvi->capacity * (CountArticulatedParts(engine_number) + 1)) << multihead);
				SetDParam(2, STR_9842_REFITTABLE);
			}
			DrawString(x,y, STR_PURCHASE_INFO_CAPACITY, 0);
			y += 10;
		}
			break;
		case VEH_Ship:
			y = DrawVehiclePurchaseInfo(x, y, engine_number, ShipVehInfo(engine_number));
			break;
		case VEH_Aircraft:
			y = DrawVehiclePurchaseInfo(x, y, engine_number, AircraftVehInfo(engine_number));
			break;
		default: NOT_REACHED();
	}

	/* Draw details, that applies to all types except rail wagons */
	if (e->type != VEH_Train || (RailVehInfo(engine_number)->flags & RVI_WAGON == 0)) {
		/* Design date - Life length */
		SetDParam(0, ymd.year);
		SetDParam(1, e->lifelength);
		DrawString(x, y, STR_PURCHASE_INFO_DESIGNED_LIFE, 0);
		y += 10;

		/* Reliability */
		SetDParam(0, e->reliability * 100 >> 16);
		DrawString(x, y, STR_PURCHASE_INFO_RELIABILITY, 0);
		y += 10;
	}

	/* Additional text from NewGRF */
	y += ShowAdditionalText(x, y, w, engine_number);
	switch (e->type) {
		case VEH_Train: {
			const RailVehicleInfo *rvi = RailVehInfo(engine_number);
			if (rvi->capacity > 0) y += ShowRefitOptionsList(x, y, w, engine_number);
		} break;
		case VEH_Ship: {
			const ShipVehicleInfo *svi = ShipVehInfo(engine_number);
			if (svi->refittable) y += ShowRefitOptionsList(x, y, w, engine_number);
		} break;
		case VEH_Aircraft:
			y += ShowRefitOptionsList(x, y, w, engine_number);
			break;
	}
}

/* Figure out what train EngineIDs to put in the list */
static void GenerateBuildTrainList(Window *w)
{
	EngineID eid, sel_id;
	int num_engines = 0;
	int num_wagons  = 0;
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	bv->filter.railtype = (w->window_number == 0) ? RAILTYPE_END : GetRailType(w->window_number);

	EngList_RemoveAll(&bv->eng_list);

	/* Make list of all available train engines and wagons.
		* Also check to see if the previously selected engine is still available,
		* and if not, reset selection to INVALID_ENGINE. This could be the case
	* when engines become obsolete and are removed */
	for (sel_id = INVALID_ENGINE, eid = 0; eid < NUM_TRAIN_ENGINES; eid++) {
		const Engine *e = GetEngine(eid);
		const RailVehicleInfo *rvi = RailVehInfo(eid);

		if (bv->filter.railtype != RAILTYPE_END && !HasPowerOnRail(e->railtype, bv->filter.railtype)) continue;
		if (!IsEngineBuildable(eid, VEH_Train, _local_player)) continue;

		EngList_Add(&bv->eng_list, eid);
		if ((rvi->flags & RVI_WAGON) == 0) {
			num_engines++;
		} else {
			num_wagons++;
		}

		if (eid == bv->sel_engine) sel_id = eid;
	}

	bv->sel_engine = sel_id;

	// make engines first, and then wagons, sorted by ListPositionOfEngine()
	_internal_sort_order = false;
	EngList_Sort(&bv->eng_list, TrainEnginesThenWagonsSorter);

	// and then sort engines
	_internal_sort_order = bv->descending_sort_order;
	EngList_SortPartial(&bv->eng_list, _sorter[0][bv->sort_criteria], 0, num_engines);

	// and finally sort wagons
	EngList_SortPartial(&bv->eng_list, _sorter[0][bv->sort_criteria], num_engines, num_wagons);
}

/* Figure out what aircraft EngineIDs to put in the list */
static void GenerateBuildShipList(Window *w)
{
	EngineID eid, sel_id;
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	EngList_RemoveAll(&bv->eng_list);

	sel_id = INVALID_ENGINE;

	for (eid = SHIP_ENGINES_INDEX; eid < SHIP_ENGINES_INDEX + NUM_SHIP_ENGINES; eid++) {
		if (!IsEngineBuildable(eid, VEH_Ship, _local_player)) continue;
		EngList_Add(&bv->eng_list, eid);

		if (eid == bv->sel_engine) sel_id = eid;
	}
	bv->sel_engine = sel_id;
}

/* Figure out what aircraft EngineIDs to put in the list */
static void GenerateBuildAircraftList(Window *w)
{
	EngineID eid, sel_id;
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	EngList_RemoveAll(&bv->eng_list);

	/* Make list of all available planes.
	 * Also check to see if the previously selected plane is still available,
	 * and if not, reset selection to INVALID_ENGINE. This could be the case
	 * when planes become obsolete and are removed */
	sel_id = INVALID_ENGINE;
	for (eid = AIRCRAFT_ENGINES_INDEX; eid < AIRCRAFT_ENGINES_INDEX + NUM_AIRCRAFT_ENGINES; eid++) {
		if (IsEngineBuildable(eid, VEH_Aircraft, _local_player)) {
			const AircraftVehicleInfo *avi = AircraftVehInfo(eid);
			switch (bv->filter.acc_planes) {
				case HELICOPTERS_ONLY:
					if (avi->subtype != 0) continue; // if not helicopter
					break;

				case AIRCRAFT_ONLY:
					if (avi->subtype == 0) continue; // if helicopter
					break;

				case ALL: break;
				default:
					NOT_REACHED();
			}
			EngList_Add(&bv->eng_list, eid);

			if (eid == bv->sel_engine) sel_id = eid;
		}
	}

	bv->sel_engine = sel_id;
}

/* Generate the list of vehicles */
static void GenerateBuildList(Window *w)
{
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	switch (bv->vehicle_type) {
		case VEH_Train:
			GenerateBuildTrainList(w);
			return; // trains should not reach the last sorting
		case VEH_Ship:
			GenerateBuildShipList(w);
			break;
		case VEH_Aircraft:
			GenerateBuildAircraftList(w);
			break;
	}
	_internal_sort_order = bv->descending_sort_order;
	EngList_Sort(&bv->eng_list, _sorter[VehTypeToIndex(bv->vehicle_type)][bv->sort_criteria]);
}

static void DrawBuildVehicleWindow(Window *w)
{
	const buildvehicle_d *bv = &WP(w, buildvehicle_d);

	SetWindowWidgetDisabledState(w, BUILD_VEHICLE_WIDGET_BUILD, w->window_number == 0);

	SetVScrollCount(w, EngList_Count(&bv->eng_list));
	SetDParam(0, bv->filter.railtype + STR_881C_NEW_RAIL_VEHICLES); // This should only affect rail vehicles
	DrawWindowWidgets(w);

	{
		int x = 2;
		int y = 27;
		EngineID selected_id = bv->sel_engine;
		uint16 position = w->vscroll.pos;
		uint16 max = min(w->vscroll.pos + w->vscroll.cap, EngList_Count(&bv->eng_list));

		switch (bv->vehicle_type) {
			case VEH_Train:
				for (; position < max; position++, y += 14) {
					const EngineID engine = bv->eng_list[position];

					DrawString(x + 59, y + 2, GetCustomEngineName(engine), engine == selected_id ? 0xC : 0x10);
					DrawTrainEngine(x + 29, y + 6, engine, GetEnginePalette(engine, _local_player));
				}
				break;
			case VEH_Ship:
				for (; position < max; position++, y += 24) {
					const EngineID engine = bv->eng_list[position];

					DrawString(x + 75, y + 7, GetCustomEngineName(engine), engine == selected_id ? 0xC : 0x10);
					DrawShipEngine(x + 35, y + 10, engine, GetEnginePalette(engine, _local_player));
				}
				break;
			case VEH_Aircraft:
				for (; position < max; position++, y += 24) {
					const EngineID engine = bv->eng_list[position];

					DrawString(x + 62, y + 7, GetCustomEngineName(engine), engine == selected_id ? 0xC : 0x10);
					DrawAircraftEngine(x + 29, y + 10, engine, GetEnginePalette(engine, _local_player));
				}
				break;
		}

		if (selected_id != INVALID_ENGINE) {
			const Widget *wi = &w->widget[BUILD_VEHICLE_WIDGET_PANEL];
			DrawVehiclePurchaseInfo(x, wi->top + 1, wi->right - wi->left - 2, selected_id);
		}
	}
	DrawString(85, 15, _sort_listing[VehTypeToIndex(bv->vehicle_type)][bv->sort_criteria], 0x10);
	DoDrawString(bv->descending_sort_order ? DOWNARROW : UPARROW, 69, 15, 0x10);
}

static void BuildVehicleClickEvent(Window *w, WindowEvent *e)
{
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	switch (e->we.click.widget) {
		case BUILD_VEHICLE_WIDGET_SORT_ASSENDING_DESCENDING:
			bv->descending_sort_order ^= true;
			_last_sort_order[VehTypeToIndex(bv->vehicle_type)] = bv->descending_sort_order;
			bv->regenerate_list = true;
			SetWindowDirty(w);
			break;

		case BUILD_VEHICLE_WIDGET_LIST: {
			uint i = (e->we.click.pt.y - 26) / GetVehicleListHeight(bv->vehicle_type) + w->vscroll.pos;
			uint num_items = EngList_Count(&bv->eng_list);
			bv->sel_engine = (i < num_items) ? bv->eng_list[i] : INVALID_ENGINE;
			SetWindowDirty(w);
			break;
		}

		case BUILD_VEHICLE_WIDGET_SORT_TEXT: case BUILD_VEHICLE_WIDGET_SORT_DROPDOWN: // Select sorting criteria dropdown menu
			ShowDropDownMenu(w, _sort_listing[VehTypeToIndex(bv->vehicle_type)], bv->sort_criteria, BUILD_VEHICLE_WIDGET_SORT_DROPDOWN, 0, 0);
			break;

		case BUILD_VEHICLE_WIDGET_BUILD: {
			EngineID sel_eng = bv->sel_engine;
			if (sel_eng != INVALID_ENGINE) {
				switch (bv->vehicle_type) {
					case VEH_Train:
						DoCommandP(w->window_number, sel_eng, 0, (RailVehInfo(sel_eng)->flags & RVI_WAGON) ? CcBuildWagon : CcBuildLoco,
								   CMD_BUILD_RAIL_VEHICLE | CMD_MSG(STR_882B_CAN_T_BUILD_RAILROAD_VEHICLE));
						break;
					case VEH_Ship:
						DoCommandP(w->window_number, sel_eng, 0, CcBuildShip, CMD_BUILD_SHIP | CMD_MSG(STR_980D_CAN_T_BUILD_SHIP));
						break;
					case VEH_Aircraft:
						DoCommandP(w->window_number, sel_eng, 0, CcBuildAircraft, CMD_BUILD_AIRCRAFT | CMD_MSG(STR_A008_CAN_T_BUILD_AIRCRAFT));
						break;
				}
			}
			break;
		}

		case BUILD_VEHICLE_WIDGET_RENAME: {
			EngineID sel_eng = bv->sel_engine;
			if (sel_eng != INVALID_ENGINE) {
				StringID str = STR_NULL;

				bv->rename_engine = sel_eng;
				switch (bv->vehicle_type) {
					case VEH_Train:    str = STR_886A_RENAME_TRAIN_VEHICLE_TYPE; break;
					case VEH_Ship:     str = STR_9838_RENAME_SHIP_TYPE;          break;
					case VEH_Aircraft: str = STR_A039_RENAME_AIRCRAFT_TYPE;      break;
				}
				ShowQueryString(GetCustomEngineName(sel_eng), str, 31, 160, w, CS_ALPHANUMERAL);
			}
			break;
		}
	}
}

static void NewVehicleWndProc(Window *w, WindowEvent *e)
{
	buildvehicle_d *bv = &WP(w, buildvehicle_d);

	switch (e->event) {
		case WE_INVALIDATE_DATA:
			bv->regenerate_list = true;
			SetWindowDirty(w);
			break;

		case WE_DESTROY:
			EngList_Destroy(&bv->eng_list);
			break;

		case WE_PAINT:
			if (bv->regenerate_list) {
				bv->regenerate_list = false;
				GenerateBuildList(w);
			}
			DrawBuildVehicleWindow(w);
			break;

		case WE_CLICK:
			BuildVehicleClickEvent(w, e);
			break;

		case WE_ON_EDIT_TEXT: {
			if (e->we.edittext.str[0] != '\0') {
				StringID str = STR_NULL;
				_cmd_text = e->we.edittext.str;
				switch (bv->vehicle_type) {
					case VEH_Train:    str = STR_886B_CAN_T_RENAME_TRAIN_VEHICLE; break;
					case VEH_Ship:     str = STR_9839_CAN_T_RENAME_SHIP_TYPE;     break;
					case VEH_Aircraft: str = STR_A03A_CAN_T_RENAME_AIRCRAFT_TYPE; break;
				}
				DoCommandP(0, bv->rename_engine, 0, NULL, CMD_RENAME_ENGINE | CMD_MSG(str));
			}
			break;
		}

		case WE_DROPDOWN_SELECT: /* we have selected a dropdown item in the list */
			if (bv->sort_criteria != e->we.dropdown.index) {
				bv->sort_criteria = e->we.dropdown.index;
				_last_sort_criteria[VehTypeToIndex(bv->vehicle_type)] = bv->sort_criteria;
				bv->regenerate_list = true;
			}
			SetWindowDirty(w);
			break;

		case WE_RESIZE:
			if (e->we.sizing.diff.x != 0) ResizeButtons(w);
			if (e->we.sizing.diff.y == 0) break;

			w->vscroll.cap += e->we.sizing.diff.y / GetVehicleListHeight(bv->vehicle_type);
			w->widget[BUILD_VEHICLE_WIDGET_LIST].data = (w->vscroll.cap << 8) + 1;
			break;
	}
}

static const WindowDesc _build_vehicle_desc = {
	WDP_AUTO, WDP_AUTO, 228, 226,
	WC_BUILD_VEHICLE,0,
	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_UNCLICK_BUTTONS | WDF_RESIZABLE,
	_build_vehicle_widgets,
	NewVehicleWndProc
};

void ShowBuildVehicleWindow(TileIndex tile, byte type)
{
	buildvehicle_d *bv;
	Window *w;

	assert(IsPlayerBuildableVehicleType(type));

	DeleteWindowById(WC_BUILD_VEHICLE, tile);

	w = AllocateWindowDescFront(&_build_vehicle_desc, tile);

	if (w == NULL) return;

	w->caption_color = (tile != 0) ? GetTileOwner(tile) : _local_player;
	w->resize.step_height = GetVehicleListHeight(type);
	w->vscroll.cap = w->resize.step_height == 24 ? 4 : 8;
	w->widget[BUILD_VEHICLE_WIDGET_LIST].data = (w->vscroll.cap << 8) + 1;

	bv = &WP(w, buildvehicle_d);
	EngList_Create(&bv->eng_list);
	bv->sel_engine      = INVALID_ENGINE;

	bv->vehicle_type    = type;
	bv->regenerate_list = false;

	bv->sort_criteria         = _last_sort_criteria[VehTypeToIndex(type)];
	bv->descending_sort_order = _last_sort_order[VehTypeToIndex(type)];

	switch (type) {
		case VEH_Train:
			WP(w,buildvehicle_d).filter.railtype = (tile == 0) ? RAILTYPE_END : GetRailType(tile);
			ResizeWindow(w, 0, 16);
			break;
		case VEH_Ship:
			ResizeWindow(w, 27, 0);
			break;
		case VEH_Aircraft:
			AcceptPlanes acc_planes = (tile == 0) ? ALL : GetAirport(GetStationByTile(tile)->airport_type)->acc_planes;
			bv->filter.acc_planes = acc_planes;
			ResizeWindow(w, 12, 0);
			break;
	}
	SetupWindowStrings(w, type);
	ResizeButtons(w);

	w->resize.width  = w->width;
	w->resize.height = w->height;

	GenerateBuildList(w); // generate the list, since we need it in the next line
	/* Select the first engine in the list as default when opening the window */
	if (EngList_Count(&bv->eng_list) > 0) bv->sel_engine = bv->eng_list[0];
}