(svn r9073) -Codechange: moved autoreplace to a file of it's own (now autoreplace has a cmd and a gui file)

3 files changed, 416 insertions, 396 deletions

diff --git a/src/autoreplace_cmd.cpp b/src/autoreplace_cmd.cpp
new file mode 100644
index 000000000..bdfded603
--- /dev/null
+++ b/src/autoreplace_cmd.cpp
@@ -0,0 +1,414 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "roadveh.h"
+#include "ship.h"
+#include "table/strings.h"
+#include "functions.h"
+#include "news.h"
+#include "command.h"
+#include "player.h"
+#include "engine.h"
+#include "debug.h"
+#include "vehicle_gui.h"
+#include "depot.h"
+#include "train.h"
+#include "aircraft.h"
+#include "cargotype.h"
+
+
+/*
+ * move the cargo from one engine to another if possible
+ */
+static void MoveVehicleCargo(Vehicle *dest, Vehicle *source)
+{
+	Vehicle *v = dest;
+	int units_moved;
+
+	do {
+		do {
+			if (source->cargo_type != dest->cargo_type)
+				continue; // cargo not compatible
+
+			if (dest->cargo_count == dest->cargo_cap)
+				continue; // the destination vehicle is already full
+
+			units_moved = min(source->cargo_count, dest->cargo_cap - dest->cargo_count);
+			source->cargo_count -= units_moved;
+			dest->cargo_count   += units_moved;
+			dest->cargo_source   = source->cargo_source;
+
+			// copy the age of the cargo
+			dest->cargo_days   = source->cargo_days;
+			dest->day_counter  = source->day_counter;
+			dest->tick_counter = source->tick_counter;
+
+		} while (source->cargo_count > 0 && (dest = dest->next) != NULL);
+		dest = v;
+	} while ((source = source->next) != NULL);
+
+	/*
+	 * The of the train will be incorrect at this moment. This is due
+	 * to the fact that removing the old wagon updates the weight of
+	 * the complete train, which is without the weight of cargo we just
+	 * moved back into some (of the) new wagon(s).
+	 */
+	if (dest->type == VEH_TRAIN) TrainConsistChanged(dest->first);
+}
+
+static bool VerifyAutoreplaceRefitForOrders(const Vehicle *v, const EngineID engine_type)
+{
+	const Order *o;
+	const Vehicle *u;
+
+	if (v->type == VEH_TRAIN) {
+		u = GetFirstVehicleInChain(v);
+	} else {
+		u = v;
+	}
+
+	FOR_VEHICLE_ORDERS(u, o) {
+		if (!(o->refit_cargo < NUM_CARGO)) continue;
+		if (!CanRefitTo(v->engine_type, o->refit_cargo)) continue;
+		if (!CanRefitTo(engine_type, o->refit_cargo)) return false;
+	}
+
+	return true;
+}
+
+/**
+ * Function to find what type of cargo to refit to when autoreplacing
+ * @param *v Original vehicle, that is being replaced
+ * @param engine_type The EngineID of the vehicle that is being replaced to
+ * @return The cargo type to replace to
+ *    CT_NO_REFIT is returned if no refit is needed
+ *    CT_INVALID is returned when both old and new vehicle got cargo capacity and refitting the new one to the old one's cargo type isn't possible
+ */
+static CargoID GetNewCargoTypeForReplace(Vehicle *v, EngineID engine_type)
+{
+	bool new_cargo_capacity = true;
+	CargoID new_cargo_type = CT_INVALID;
+
+	switch (v->type) {
+		case VEH_TRAIN:
+			new_cargo_capacity = (RailVehInfo(engine_type)->capacity > 0);
+			new_cargo_type     = RailVehInfo(engine_type)->cargo_type;
+			break;
+
+		case VEH_ROAD:
+			new_cargo_capacity = (RoadVehInfo(engine_type)->capacity > 0);
+			new_cargo_type     = RoadVehInfo(engine_type)->cargo_type;
+			break;
+		case VEH_SHIP:
+			new_cargo_capacity = (ShipVehInfo(engine_type)->capacity > 0);
+			new_cargo_type     = ShipVehInfo(engine_type)->cargo_type;
+			break;
+
+		case VEH_AIRCRAFT:
+			/* all aircraft starts as passenger planes with cargo capacity
+			 * new_cargo_capacity is always true for aircraft, which is the init value. No need to set it here */
+			new_cargo_type     = CT_PASSENGERS;
+			break;
+
+		default: NOT_REACHED(); break;
+	}
+
+	if (!new_cargo_capacity) return CT_NO_REFIT; // Don't try to refit an engine with no cargo capacity
+
+	if (v->cargo_type == new_cargo_type || CanRefitTo(engine_type, v->cargo_type)) {
+		if (VerifyAutoreplaceRefitForOrders(v, engine_type)) {
+			return v->cargo_type == new_cargo_type ? (CargoID)CT_NO_REFIT : v->cargo_type;
+		} else {
+			return CT_INVALID;
+		}
+	}
+	if (v->type != VEH_TRAIN) return CT_INVALID; // We can't refit the vehicle to carry the cargo we want
+
+	/* Below this line it's safe to assume that the vehicle in question is a train */
+
+	if (v->cargo_cap != 0) return CT_INVALID; // trying to replace a vehicle with cargo capacity into another one with incompatible cargo type
+
+	/* the old engine didn't have cargo capacity, but the new one does
+	 * now we will figure out what cargo the train is carrying and refit to fit this */
+	v = GetFirstVehicleInChain(v);
+	do {
+		if (v->cargo_cap == 0) continue;
+		/* Now we found a cargo type being carried on the train and we will see if it is possible to carry to this one */
+		if (v->cargo_type == new_cargo_type) return CT_NO_REFIT;
+		if (CanRefitTo(engine_type, v->cargo_type)) return v->cargo_type;
+	} while ((v=v->next) != NULL);
+	return CT_NO_REFIT; // We failed to find a cargo type on the old vehicle and we will not refit the new one
+}
+
+/* Replaces a vehicle (used to be called autorenew)
+ * This function is only called from MaybeReplaceVehicle()
+ * Must be called with _current_player set to the owner of the vehicle
+ * @param w Vehicle to replace
+ * @param flags is the flags to use when calling DoCommand(). Mainly DC_EXEC counts
+ * @return value is cost of the replacement or CMD_ERROR
+ */
+static int32 ReplaceVehicle(Vehicle **w, byte flags, int32 total_cost)
+{
+	int32 cost;
+	int32 sell_value;
+	Vehicle *old_v = *w;
+	const Player *p = GetPlayer(old_v->owner);
+	EngineID new_engine_type;
+	const UnitID cached_unitnumber = old_v->unitnumber;
+	bool new_front = false;
+	Vehicle *new_v = NULL;
+	char vehicle_name[32];
+	CargoID replacement_cargo_type;
+
+	new_engine_type = EngineReplacementForPlayer(p, old_v->engine_type);
+	if (new_engine_type == INVALID_ENGINE) new_engine_type = old_v->engine_type;
+
+	replacement_cargo_type = GetNewCargoTypeForReplace(old_v, new_engine_type);
+
+	/* check if we can't refit to the needed type, so no replace takes place to prevent the vehicle from altering cargo type */
+	if (replacement_cargo_type == CT_INVALID) return 0;
+
+	sell_value = DoCommand(0, old_v->index, 0, DC_QUERY_COST, GetCmdSellVeh(old_v));
+
+	/* We give the player a loan of the same amount as the sell value.
+	 * This is needed in case he needs the income from the sale to build the new vehicle.
+	 * We take it back if building fails or when we really sell the old engine */
+	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
+	SubtractMoneyFromPlayer(sell_value);
+
+	cost = DoCommand(old_v->tile, new_engine_type, 3, flags, GetCmdBuildVeh(old_v));
+	if (CmdFailed(cost)) {
+		SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
+		SubtractMoneyFromPlayer(-sell_value); // Take back the money we just gave the player
+		return cost;
+	}
+
+	if (replacement_cargo_type != CT_NO_REFIT) cost += GetRefitCost(new_engine_type); // add refit cost
+
+	if (flags & DC_EXEC) {
+		new_v = GetVehicle(_new_vehicle_id);
+		*w = new_v; //we changed the vehicle, so MaybeReplaceVehicle needs to work on the new one. Now we tell it what the new one is
+
+		/* refit if needed */
+		if (replacement_cargo_type != CT_NO_REFIT) {
+			if (CmdFailed(DoCommand(0, new_v->index, replacement_cargo_type, DC_EXEC, GetCmdRefitVeh(new_v)))) {
+				/* Being here shows a failure, which most likely is in GetNewCargoTypeForReplace() or incorrect estimation costs */
+				error("Autoreplace failed to refit. Replace engine %d to %d and refit to cargo %d", old_v->engine_type, new_v->engine_type, replacement_cargo_type);
+			}
+		}
+
+		if (new_v->type == VEH_TRAIN && HASBIT(old_v->u.rail.flags, VRF_REVERSE_DIRECTION) && !IsMultiheaded(new_v) && !(new_v->next != NULL && IsArticulatedPart(new_v->next))) {
+			// we are autorenewing to a single engine, so we will turn it as the old one was turned as well
+			SETBIT(new_v->u.rail.flags, VRF_REVERSE_DIRECTION);
+		}
+
+		if (old_v->type == VEH_TRAIN && !IsFrontEngine(old_v)) {
+			/* this is a railcar. We need to move the car into the train
+			 * We add the new engine after the old one instead of replacing it. It will give the same result anyway when we
+			 * sell the old engine in a moment
+			 */
+			DoCommand(0, (GetPrevVehicleInChain(old_v)->index << 16) | new_v->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
+			/* Now we move the old one out of the train */
+			DoCommand(0, (INVALID_VEHICLE << 16) | old_v->index, 0, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
+		} else {
+			// copy/clone the orders
+			DoCommand(0, (old_v->index << 16) | new_v->index, IsOrderListShared(old_v) ? CO_SHARE : CO_COPY, DC_EXEC, CMD_CLONE_ORDER);
+			new_v->cur_order_index = old_v->cur_order_index;
+			ChangeVehicleViewWindow(old_v, new_v);
+			new_v->profit_this_year = old_v->profit_this_year;
+			new_v->profit_last_year = old_v->profit_last_year;
+			new_v->service_interval = old_v->service_interval;
+			new_front = true;
+			new_v->unitnumber = old_v->unitnumber; // use the same unit number
+
+			new_v->current_order = old_v->current_order;
+			if (old_v->type == VEH_TRAIN && GetNextVehicle(old_v) != NULL){
+				Vehicle *temp_v = GetNextVehicle(old_v);
+
+				// move the entire train to the new engine, excluding the old engine
+				if (IsMultiheaded(old_v) && temp_v == old_v->u.rail.other_multiheaded_part) {
+					// we got front and rear of a multiheaded engine right after each other. We should work with the next in line instead
+					temp_v = GetNextVehicle(temp_v);
+				}
+
+				if (temp_v != NULL) {
+					DoCommand(0, (new_v->index << 16) | temp_v->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
+				}
+			}
+		}
+		/* We are done setting up the new vehicle. Now we move the cargo from the old one to the new one */
+		MoveVehicleCargo(new_v->type == VEH_TRAIN ? GetFirstVehicleInChain(new_v) : new_v, old_v);
+
+		// Get the name of the old vehicle if it has a custom name.
+		if (!IsCustomName(old_v->string_id)) {
+			vehicle_name[0] = '\0';
+		} else {
+			GetName(vehicle_name, old_v->string_id & 0x7FF, lastof(vehicle_name));
+		}
+	} else { // flags & DC_EXEC not set
+		/* Ensure that the player will not end up having negative money while autoreplacing
+		 * This is needed because the only other check is done after the income from selling the old vehicle is substracted from the cost */
+		if (p->money64 < (cost + total_cost)) {
+			SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
+			SubtractMoneyFromPlayer(-sell_value); // Pay back the loan
+			return CMD_ERROR;
+		}
+	}
+
+	/* Take back the money we just gave the player just before building the vehicle
+	 * The player will get the same amount now that the sale actually takes place */
+	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
+	SubtractMoneyFromPlayer(-sell_value);
+
+	/* sell the engine/ find out how much you get for the old engine (income is returned as negative cost) */
+	cost += DoCommand(0, old_v->index, 0, flags, GetCmdSellVeh(old_v));
+
+	if (new_front) {
+		/* now we assign the old unitnumber to the new vehicle */
+		new_v->unitnumber = cached_unitnumber;
+	}
+
+	/* Transfer the name of the old vehicle */
+	if ((flags & DC_EXEC) && vehicle_name[0] != '\0') {
+		_cmd_text = vehicle_name;
+		DoCommand(0, new_v->index, 0, DC_EXEC, CMD_NAME_VEHICLE);
+	}
+
+	return cost;
+}
+
+/** replaces a vehicle if it's set for autoreplace or is too old
+ * (used to be called autorenew)
+ * @param v The vehicle to replace
+ * if the vehicle is a train, v needs to be the front engine
+ * @param check Checks if the replace is valid. No action is done at all
+ * @param display_costs If set, a cost animation is shown (only if check is false)
+ * @return CMD_ERROR if something went wrong. Otherwise the price of the replace
+ */
+int32 MaybeReplaceVehicle(Vehicle *v, bool check, bool display_costs)
+{
+	Vehicle *w;
+	const Player *p = GetPlayer(v->owner);
+	byte flags = 0;
+	int32 cost, temp_cost = 0;
+	bool stopped;
+
+	/* Remember the length in case we need to trim train later on
+	 * If it's not a train, the value is unused
+	 * round up to the length of the tiles used for the train instead of the train length instead
+	 * Useful when newGRF uses custom length */
+	uint16 old_total_length = (v->type == VEH_TRAIN ?
+		(v->u.rail.cached_total_length + TILE_SIZE - 1) / TILE_SIZE * TILE_SIZE :
+		-1
+	);
+
+
+	_current_player = v->owner;
+
+	assert(IsPlayerBuildableVehicleType(v));
+
+	assert(v->vehstatus & VS_STOPPED); // the vehicle should have been stopped in VehicleEnteredDepotThisTick() if needed
+
+	/* Remember the flag v->leave_depot_instantly because if we replace the vehicle, the vehicle holding this flag will be sold
+	 * If it is set, then we only stopped the vehicle to replace it (if needed) and we will need to start it again.
+	 * We also need to reset the flag since it should remain false except from when the vehicle enters a depot until autoreplace is handled in the same tick */
+	stopped = v->leave_depot_instantly;
+	v->leave_depot_instantly = false;
+
+	for (;;) {
+		cost = 0;
+		w = v;
+		do {
+			if (w->type == VEH_TRAIN && IsMultiheaded(w) && !IsTrainEngine(w)) {
+				/* we build the rear ends of multiheaded trains with the front ones */
+				continue;
+			}
+
+			// check if the vehicle should be replaced
+			if (!p->engine_renew ||
+					w->age - w->max_age < (p->engine_renew_months * 30) || // replace if engine is too old
+					w->max_age == 0) { // rail cars got a max age of 0
+				if (!EngineHasReplacementForPlayer(p, w->engine_type)) // updates to a new model
+					continue;
+			}
+
+			/* Now replace the vehicle */
+			temp_cost = ReplaceVehicle(&w, flags, cost);
+
+			if (flags & DC_EXEC &&
+					(w->type != VEH_TRAIN || w->u.rail.first_engine == INVALID_ENGINE)) {
+				/* now we bought a new engine and sold the old one. We need to fix the
+				 * pointers in order to avoid pointing to the old one for trains: these
+				 * pointers should point to the front engine and not the cars
+				 */
+				v = w;
+			}
+
+			if (!CmdFailed(temp_cost)) {
+				cost += temp_cost;
+			}
+		} while (w->type == VEH_TRAIN && (w = GetNextVehicle(w)) != NULL);
+
+		if (!(flags & DC_EXEC) && (p->money64 < (int32)(cost + p->engine_renew_money) || cost == 0)) {
+			if (!check && p->money64 < (int32)(cost + p->engine_renew_money) && ( _local_player == v->owner ) && cost != 0) {
+				StringID message;
+				SetDParam(0, v->unitnumber);
+				switch (v->type) {
+					case VEH_TRAIN:    message = STR_TRAIN_AUTORENEW_FAILED;       break;
+					case VEH_ROAD:     message = STR_ROADVEHICLE_AUTORENEW_FAILED; break;
+					case VEH_SHIP:     message = STR_SHIP_AUTORENEW_FAILED;        break;
+					case VEH_AIRCRAFT: message = STR_AIRCRAFT_AUTORENEW_FAILED;    break;
+						// This should never happen
+					default: NOT_REACHED(); message = 0; break;
+				}
+
+				AddNewsItem(message, NEWS_FLAGS(NM_SMALL, NF_VIEWPORT|NF_VEHICLE, NT_ADVICE, 0), v->index, 0);
+			}
+			if (stopped) v->vehstatus &= ~VS_STOPPED;
+			if (display_costs) _current_player = OWNER_NONE;
+			return CMD_ERROR;
+		}
+
+		if (flags & DC_EXEC) {
+			break; // we are done replacing since the loop ran once with DC_EXEC
+		} else if (check) {
+			/* It's a test only and we know that we can do this
+			 * NOTE: payment for wagon removal is NOT included in this price */
+			return cost;
+		}
+		// now we redo the loop, but this time we actually do stuff since we know that we can do it
+		flags |= DC_EXEC;
+	}
+
+	/* If setting is on to try not to exceed the old length of the train with the replacement */
+	if (v->type == VEH_TRAIN && p->renew_keep_length) {
+		Vehicle *temp;
+		w = v;
+
+		while (v->u.rail.cached_total_length > old_total_length) {
+			// the train is too long. We will remove cars one by one from the start of the train until it's short enough
+			while (w != NULL && RailVehInfo(w->engine_type)->railveh_type != RAILVEH_WAGON) {
+				w = GetNextVehicle(w);
+			}
+			if (w == NULL) {
+				// we failed to make the train short enough
+				SetDParam(0, v->unitnumber);
+				AddNewsItem(STR_TRAIN_TOO_LONG_AFTER_REPLACEMENT, NEWS_FLAGS(NM_SMALL, NF_VIEWPORT|NF_VEHICLE, NT_ADVICE, 0), v->index, 0);
+				break;
+			}
+			temp = w;
+			w = GetNextVehicle(w);
+			DoCommand(0, (INVALID_VEHICLE << 16) | temp->index, 0, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
+			MoveVehicleCargo(v, temp);
+			cost += DoCommand(0, temp->index, 0, DC_EXEC, CMD_SELL_RAIL_WAGON);
+		}
+	}
+
+	if (stopped) v->vehstatus &= ~VS_STOPPED;
+	if (display_costs) {
+		if (IsLocalPlayer()) ShowCostOrIncomeAnimation(v->x_pos, v->y_pos, v->z_pos, cost);
+		_current_player = OWNER_NONE;
+	}
+	return cost;
+}
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index d5852b0a9..79f12dfea 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -37,7 +37,6 @@
 #include "newgrf_engine.h"
 #include "newgrf_sound.h"
 #include "helpers.hpp"
-#include "cargotype.h"
 
 #define INVALID_COORD (-0x8000)
 #define GEN_HASH(x, y) ((GB((y), 6, 6) << 6) + GB((x), 7, 6))
@@ -606,7 +605,6 @@ void Ship_Tick(Vehicle *v);
 void Train_Tick(Vehicle *v);
 static void EffectVehicle_Tick(Vehicle *v);
 void DisasterVehicle_Tick(Vehicle *v);
-static int32 MaybeReplaceVehicle(Vehicle *v, bool check, bool display_costs);
 
 // head of the linked list to tell what vehicles that visited a depot in a tick
 static Vehicle* _first_veh_in_depot_list;
@@ -1888,400 +1886,6 @@ int32 CmdCloneVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	return total_cost;
 }
 
-/*
- * move the cargo from one engine to another if possible
- */
-static void MoveVehicleCargo(Vehicle *dest, Vehicle *source)
-{
-	Vehicle *v = dest;
-	int units_moved;
-
-	do {
-		do {
-			if (source->cargo_type != dest->cargo_type)
-				continue; // cargo not compatible
-
-			if (dest->cargo_count == dest->cargo_cap)
-				continue; // the destination vehicle is already full
-
-			units_moved = min(source->cargo_count, dest->cargo_cap - dest->cargo_count);
-			source->cargo_count -= units_moved;
-			dest->cargo_count   += units_moved;
-			dest->cargo_source   = source->cargo_source;
-
-			// copy the age of the cargo
-			dest->cargo_days   = source->cargo_days;
-			dest->day_counter  = source->day_counter;
-			dest->tick_counter = source->tick_counter;
-
-		} while (source->cargo_count > 0 && (dest = dest->next) != NULL);
-		dest = v;
-	} while ((source = source->next) != NULL);
-
-	/*
-	 * The of the train will be incorrect at this moment. This is due
-	 * to the fact that removing the old wagon updates the weight of
-	 * the complete train, which is without the weight of cargo we just
-	 * moved back into some (of the) new wagon(s).
-	 */
-	if (dest->type == VEH_TRAIN) TrainConsistChanged(dest->first);
-}
-
-static bool VerifyAutoreplaceRefitForOrders(const Vehicle *v, const EngineID engine_type)
-{
-	const Order *o;
-	const Vehicle *u;
-
-	if (v->type == VEH_TRAIN) {
-		u = GetFirstVehicleInChain(v);
-	} else {
-		u = v;
-	}
-
-	FOR_VEHICLE_ORDERS(u, o) {
-		if (!(o->refit_cargo < NUM_CARGO)) continue;
-		if (!CanRefitTo(v->engine_type, o->refit_cargo)) continue;
-		if (!CanRefitTo(engine_type, o->refit_cargo)) return false;
-	}
-
-	return true;
-}
-
-/**
- * Function to find what type of cargo to refit to when autoreplacing
- * @param *v Original vehicle, that is being replaced
- * @param engine_type The EngineID of the vehicle that is being replaced to
- * @return The cargo type to replace to
- *    CT_NO_REFIT is returned if no refit is needed
- *    CT_INVALID is returned when both old and new vehicle got cargo capacity and refitting the new one to the old one's cargo type isn't possible
- */
-static CargoID GetNewCargoTypeForReplace(Vehicle *v, EngineID engine_type)
-{
-	bool new_cargo_capacity = true;
-	CargoID new_cargo_type = CT_INVALID;
-
-	switch (v->type) {
-		case VEH_TRAIN:
-			new_cargo_capacity = (RailVehInfo(engine_type)->capacity > 0);
-			new_cargo_type     = RailVehInfo(engine_type)->cargo_type;
-			break;
-
-		case VEH_ROAD:
-			new_cargo_capacity = (RoadVehInfo(engine_type)->capacity > 0);
-			new_cargo_type     = RoadVehInfo(engine_type)->cargo_type;
-			break;
-		case VEH_SHIP:
-			new_cargo_capacity = (ShipVehInfo(engine_type)->capacity > 0);
-			new_cargo_type     = ShipVehInfo(engine_type)->cargo_type;
-			break;
-
-		case VEH_AIRCRAFT:
-			/* all aircraft starts as passenger planes with cargo capacity
-			 * new_cargo_capacity is always true for aircraft, which is the init value. No need to set it here */
-			new_cargo_type     = CT_PASSENGERS;
-			break;
-
-		default: NOT_REACHED(); break;
-	}
-
-	if (!new_cargo_capacity) return CT_NO_REFIT; // Don't try to refit an engine with no cargo capacity
-
-	if (v->cargo_type == new_cargo_type || CanRefitTo(engine_type, v->cargo_type)) {
-		if (VerifyAutoreplaceRefitForOrders(v, engine_type)) {
-			return v->cargo_type == new_cargo_type ? (CargoID)CT_NO_REFIT : v->cargo_type;
-		} else {
-			return CT_INVALID;
-		}
-	}
-	if (v->type != VEH_TRAIN) return CT_INVALID; // We can't refit the vehicle to carry the cargo we want
-
-	/* Below this line it's safe to assume that the vehicle in question is a train */
-
-	if (v->cargo_cap != 0) return CT_INVALID; // trying to replace a vehicle with cargo capacity into another one with incompatible cargo type
-
-	/* the old engine didn't have cargo capacity, but the new one does
-	 * now we will figure out what cargo the train is carrying and refit to fit this */
-	v = GetFirstVehicleInChain(v);
-	do {
-		if (v->cargo_cap == 0) continue;
-		/* Now we found a cargo type being carried on the train and we will see if it is possible to carry to this one */
-		if (v->cargo_type == new_cargo_type) return CT_NO_REFIT;
-		if (CanRefitTo(engine_type, v->cargo_type)) return v->cargo_type;
-	} while ((v=v->next) != NULL);
-	return CT_NO_REFIT; // We failed to find a cargo type on the old vehicle and we will not refit the new one
-}
-
-/* Replaces a vehicle (used to be called autorenew)
- * This function is only called from MaybeReplaceVehicle()
- * Must be called with _current_player set to the owner of the vehicle
- * @param w Vehicle to replace
- * @param flags is the flags to use when calling DoCommand(). Mainly DC_EXEC counts
- * @return value is cost of the replacement or CMD_ERROR
- */
-static int32 ReplaceVehicle(Vehicle **w, byte flags, int32 total_cost)
-{
-	int32 cost;
-	int32 sell_value;
-	Vehicle *old_v = *w;
-	const Player *p = GetPlayer(old_v->owner);
-	EngineID new_engine_type;
-	const UnitID cached_unitnumber = old_v->unitnumber;
-	bool new_front = false;
-	Vehicle *new_v = NULL;
-	char vehicle_name[32];
-	CargoID replacement_cargo_type;
-
-	new_engine_type = EngineReplacementForPlayer(p, old_v->engine_type);
-	if (new_engine_type == INVALID_ENGINE) new_engine_type = old_v->engine_type;
-
-	replacement_cargo_type = GetNewCargoTypeForReplace(old_v, new_engine_type);
-
-	/* check if we can't refit to the needed type, so no replace takes place to prevent the vehicle from altering cargo type */
-	if (replacement_cargo_type == CT_INVALID) return 0;
-
-	sell_value = DoCommand(0, old_v->index, 0, DC_QUERY_COST, GetCmdSellVeh(old_v));
-
-	/* We give the player a loan of the same amount as the sell value.
-	 * This is needed in case he needs the income from the sale to build the new vehicle.
-	 * We take it back if building fails or when we really sell the old engine */
-	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
-	SubtractMoneyFromPlayer(sell_value);
-
-	cost = DoCommand(old_v->tile, new_engine_type, 3, flags, GetCmdBuildVeh(old_v));
-	if (CmdFailed(cost)) {
-		SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
-		SubtractMoneyFromPlayer(-sell_value); // Take back the money we just gave the player
-		return cost;
-	}
-
-	if (replacement_cargo_type != CT_NO_REFIT) cost += GetRefitCost(new_engine_type); // add refit cost
-
-	if (flags & DC_EXEC) {
-		new_v = GetVehicle(_new_vehicle_id);
-		*w = new_v; //we changed the vehicle, so MaybeReplaceVehicle needs to work on the new one. Now we tell it what the new one is
-
-		/* refit if needed */
-		if (replacement_cargo_type != CT_NO_REFIT) {
-			if (CmdFailed(DoCommand(0, new_v->index, replacement_cargo_type, DC_EXEC, GetCmdRefitVeh(new_v)))) {
-				/* Being here shows a failure, which most likely is in GetNewCargoTypeForReplace() or incorrect estimation costs */
-				error("Autoreplace failed to refit. Replace engine %d to %d and refit to cargo %d", old_v->engine_type, new_v->engine_type, replacement_cargo_type);
-			}
-		}
-
-		if (new_v->type == VEH_TRAIN && HASBIT(old_v->u.rail.flags, VRF_REVERSE_DIRECTION) && !IsMultiheaded(new_v) && !(new_v->next != NULL && IsArticulatedPart(new_v->next))) {
-			// we are autorenewing to a single engine, so we will turn it as the old one was turned as well
-			SETBIT(new_v->u.rail.flags, VRF_REVERSE_DIRECTION);
-		}
-
-		if (old_v->type == VEH_TRAIN && !IsFrontEngine(old_v)) {
-			/* this is a railcar. We need to move the car into the train
-			 * We add the new engine after the old one instead of replacing it. It will give the same result anyway when we
-			 * sell the old engine in a moment
-			 */
-			DoCommand(0, (GetPrevVehicleInChain(old_v)->index << 16) | new_v->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
-			/* Now we move the old one out of the train */
-			DoCommand(0, (INVALID_VEHICLE << 16) | old_v->index, 0, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
-		} else {
-			// copy/clone the orders
-			DoCommand(0, (old_v->index << 16) | new_v->index, IsOrderListShared(old_v) ? CO_SHARE : CO_COPY, DC_EXEC, CMD_CLONE_ORDER);
-			new_v->cur_order_index = old_v->cur_order_index;
-			ChangeVehicleViewWindow(old_v, new_v);
-			new_v->profit_this_year = old_v->profit_this_year;
-			new_v->profit_last_year = old_v->profit_last_year;
-			new_v->service_interval = old_v->service_interval;
-			new_front = true;
-			new_v->unitnumber = old_v->unitnumber; // use the same unit number
-
-			new_v->current_order = old_v->current_order;
-			if (old_v->type == VEH_TRAIN && GetNextVehicle(old_v) != NULL){
-				Vehicle *temp_v = GetNextVehicle(old_v);
-
-				// move the entire train to the new engine, excluding the old engine
-				if (IsMultiheaded(old_v) && temp_v == old_v->u.rail.other_multiheaded_part) {
-					// we got front and rear of a multiheaded engine right after each other. We should work with the next in line instead
-					temp_v = GetNextVehicle(temp_v);
-				}
-
-				if (temp_v != NULL) {
-					DoCommand(0, (new_v->index << 16) | temp_v->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
-				}
-			}
-		}
-		/* We are done setting up the new vehicle. Now we move the cargo from the old one to the new one */
-		MoveVehicleCargo(new_v->type == VEH_TRAIN ? GetFirstVehicleInChain(new_v) : new_v, old_v);
-
-		// Get the name of the old vehicle if it has a custom name.
-		if (!IsCustomName(old_v->string_id)) {
-			vehicle_name[0] = '\0';
-		} else {
-			GetName(vehicle_name, old_v->string_id & 0x7FF, lastof(vehicle_name));
-		}
-	} else { // flags & DC_EXEC not set
-		/* Ensure that the player will not end up having negative money while autoreplacing
-		 * This is needed because the only other check is done after the income from selling the old vehicle is substracted from the cost */
-		if (p->money64 < (cost + total_cost)) {
-			SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
-			SubtractMoneyFromPlayer(-sell_value); // Pay back the loan
-			return CMD_ERROR;
-		}
-	}
-
-	/* Take back the money we just gave the player just before building the vehicle
-	 * The player will get the same amount now that the sale actually takes place */
-	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
-	SubtractMoneyFromPlayer(-sell_value);
-
-	/* sell the engine/ find out how much you get for the old engine (income is returned as negative cost) */
-	cost += DoCommand(0, old_v->index, 0, flags, GetCmdSellVeh(old_v));
-
-	if (new_front) {
-		/* now we assign the old unitnumber to the new vehicle */
-		new_v->unitnumber = cached_unitnumber;
-	}
-
-	/* Transfer the name of the old vehicle */
-	if ((flags & DC_EXEC) && vehicle_name[0] != '\0') {
-		_cmd_text = vehicle_name;
-		DoCommand(0, new_v->index, 0, DC_EXEC, CMD_NAME_VEHICLE);
-	}
-
-	return cost;
-}
-
-/** replaces a vehicle if it's set for autoreplace or is too old
- * (used to be called autorenew)
- * @param v The vehicle to replace
- * if the vehicle is a train, v needs to be the front engine
- * @param check Checks if the replace is valid. No action is done at all
- * @param display_costs If set, a cost animation is shown (only if check is false)
- * @return CMD_ERROR if something went wrong. Otherwise the price of the replace
- */
-static int32 MaybeReplaceVehicle(Vehicle *v, bool check, bool display_costs)
-{
-	Vehicle *w;
-	const Player *p = GetPlayer(v->owner);
-	byte flags = 0;
-	int32 cost, temp_cost = 0;
-	bool stopped;
-
-	/* Remember the length in case we need to trim train later on
-	 * If it's not a train, the value is unused
-	 * round up to the length of the tiles used for the train instead of the train length instead
-	 * Useful when newGRF uses custom length */
-	uint16 old_total_length = (v->type == VEH_TRAIN ?
-		(v->u.rail.cached_total_length + TILE_SIZE - 1) / TILE_SIZE * TILE_SIZE :
-		-1
-	);
-
-
-	_current_player = v->owner;
-
-	assert(IsPlayerBuildableVehicleType(v));
-
-	assert(v->vehstatus & VS_STOPPED); // the vehicle should have been stopped in VehicleEnteredDepotThisTick() if needed
-
-	/* Remember the flag v->leave_depot_instantly because if we replace the vehicle, the vehicle holding this flag will be sold
-	 * If it is set, then we only stopped the vehicle to replace it (if needed) and we will need to start it again.
-	 * We also need to reset the flag since it should remain false except from when the vehicle enters a depot until autoreplace is handled in the same tick */
-	stopped = v->leave_depot_instantly;
-	v->leave_depot_instantly = false;
-
-	for (;;) {
-		cost = 0;
-		w = v;
-		do {
-			if (w->type == VEH_TRAIN && IsMultiheaded(w) && !IsTrainEngine(w)) {
-				/* we build the rear ends of multiheaded trains with the front ones */
-				continue;
-			}
-
-			// check if the vehicle should be replaced
-			if (!p->engine_renew ||
-					w->age - w->max_age < (p->engine_renew_months * 30) || // replace if engine is too old
-					w->max_age == 0) { // rail cars got a max age of 0
-				if (!EngineHasReplacementForPlayer(p, w->engine_type)) // updates to a new model
-					continue;
-			}
-
-			/* Now replace the vehicle */
-			temp_cost = ReplaceVehicle(&w, flags, cost);
-
-			if (flags & DC_EXEC &&
-					(w->type != VEH_TRAIN || w->u.rail.first_engine == INVALID_ENGINE)) {
-				/* now we bought a new engine and sold the old one. We need to fix the
-				 * pointers in order to avoid pointing to the old one for trains: these
-				 * pointers should point to the front engine and not the cars
-				 */
-				v = w;
-			}
-
-			if (!CmdFailed(temp_cost)) {
-				cost += temp_cost;
-			}
-		} while (w->type == VEH_TRAIN && (w = GetNextVehicle(w)) != NULL);
-
-		if (!(flags & DC_EXEC) && (p->money64 < (int32)(cost + p->engine_renew_money) || cost == 0)) {
-			if (!check && p->money64 < (int32)(cost + p->engine_renew_money) && ( _local_player == v->owner ) && cost != 0) {
-				StringID message;
-				SetDParam(0, v->unitnumber);
-				switch (v->type) {
-					case VEH_TRAIN:    message = STR_TRAIN_AUTORENEW_FAILED;       break;
-					case VEH_ROAD:     message = STR_ROADVEHICLE_AUTORENEW_FAILED; break;
-					case VEH_SHIP:     message = STR_SHIP_AUTORENEW_FAILED;        break;
-					case VEH_AIRCRAFT: message = STR_AIRCRAFT_AUTORENEW_FAILED;    break;
-						// This should never happen
-					default: NOT_REACHED(); message = 0; break;
-				}
-
-				AddNewsItem(message, NEWS_FLAGS(NM_SMALL, NF_VIEWPORT|NF_VEHICLE, NT_ADVICE, 0), v->index, 0);
-			}
-			if (stopped) v->vehstatus &= ~VS_STOPPED;
-			if (display_costs) _current_player = OWNER_NONE;
-			return CMD_ERROR;
-		}
-
-		if (flags & DC_EXEC) {
-			break; // we are done replacing since the loop ran once with DC_EXEC
-		} else if (check) {
-			/* It's a test only and we know that we can do this
-			 * NOTE: payment for wagon removal is NOT included in this price */
-			return cost;
-		}
-		// now we redo the loop, but this time we actually do stuff since we know that we can do it
-		flags |= DC_EXEC;
-	}
-
-	/* If setting is on to try not to exceed the old length of the train with the replacement */
-	if (v->type == VEH_TRAIN && p->renew_keep_length) {
-		Vehicle *temp;
-		w = v;
-
-		while (v->u.rail.cached_total_length > old_total_length) {
-			// the train is too long. We will remove cars one by one from the start of the train until it's short enough
-			while (w != NULL && RailVehInfo(w->engine_type)->railveh_type != RAILVEH_WAGON) {
-				w = GetNextVehicle(w);
-			}
-			if (w == NULL) {
-				// we failed to make the train short enough
-				SetDParam(0, v->unitnumber);
-				AddNewsItem(STR_TRAIN_TOO_LONG_AFTER_REPLACEMENT, NEWS_FLAGS(NM_SMALL, NF_VIEWPORT|NF_VEHICLE, NT_ADVICE, 0), v->index, 0);
-				break;
-			}
-			temp = w;
-			w = GetNextVehicle(w);
-			DoCommand(0, (INVALID_VEHICLE << 16) | temp->index, 0, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
-			MoveVehicleCargo(v, temp);
-			cost += DoCommand(0, temp->index, 0, DC_EXEC, CMD_SELL_RAIL_WAGON);
-		}
-	}
-
-	if (stopped) v->vehstatus &= ~VS_STOPPED;
-	if (display_costs) {
-		if (IsLocalPlayer()) ShowCostOrIncomeAnimation(v->x_pos, v->y_pos, v->z_pos, cost);
-		_current_player = OWNER_NONE;
-	}
-	return cost;
-}
 
 /* Extend the list size for BuildDepotVehicleList() */
 static inline void ExtendVehicleListSize(const Vehicle ***engine_list, uint16 *engine_list_length, uint16 step_size)
diff --git a/src/vehicle.h b/src/vehicle.h
index cd3c73dff..ff12a139c 100644
--- a/src/vehicle.h
+++ b/src/vehicle.h
@@ -400,6 +400,8 @@ void VehicleEnterDepot(Vehicle *v);
 
 void InvalidateAutoreplaceWindow(EngineID e);
 
+int32 MaybeReplaceVehicle(Vehicle *v, bool check, bool display_costs);
+
 /* Flags to add to p2 for goto depot commands */
 /* Note: bits 8-10 are used for VLW flags */
 enum {