Add feature to append the reverse of an order list

src/lang/english.txt

@@ -4877,6 +4877,7 @@ STR_ORDERS_SKIP_TOOLTIP                                         :{BLACK}Skip the
 STR_ORDERS_MANAGE_LIST                                          :{BLACK}Manage List
 STR_ORDERS_MANAGE_LIST_TOOLTIP                                  :{BLACK}Manage this order list
 STR_ORDER_REVERSE_ORDER_LIST                                    :Reverse order list
+STR_ORDER_APPEND_REVERSED_ORDER_LIST                            :Append reversed order list
 
 STR_ORDERS_DELETE_BUTTON                                        :{BLACK}Delete
 STR_ORDERS_DELETE_TOOLTIP                                       :{BLACK}Delete the highlighted order

src/order_cmd.cpp

@@ -1578,7 +1578,9 @@ CommandCost CmdMoveOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
  * @param tile unused
  * @param flags operation to perform
  * @param p1 the ID of the vehicle
- * @param p2 unused
+ * @param p2 subcommand
+ *        0: reverse whole order list
+ *        1: append reversed order list
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -1590,13 +1592,54 @@ CommandCost CmdReverseOrderList(TileIndex tile, DoCommandFlag flags, uint32 p1,
 	if (v == nullptr || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
 	uint order_count = v->GetNumOrders();
+
+	switch (p2) {
+		case 0: {
 			if (order_count < 2) return CMD_ERROR;
 			uint max_order = order_count - 1;
-
 			for (uint i = 0; i < max_order; i++) {
 				CommandCost cost = DoCommand(tile, p1, max_order | (i << 16), flags, CMD_MOVE_ORDER);
 				if (cost.Failed()) return cost;
 			}
+			break;
+		}
+
+		case 1: {
+			if (order_count < 3) return CMD_ERROR;
+			uint max_order = order_count - 1;
+			if (((order_count * 2) - 2) > MAX_VEH_ORDER_ID) return_cmd_error(STR_ERROR_TOO_MANY_ORDERS);
+			if (!Order::CanAllocateItem(order_count - 2)) return_cmd_error(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);
+			for (uint i = 0; i < order_count; i++) {
+				if (v->GetOrder(i)->IsType(OT_CONDITIONAL)) return CMD_ERROR;
+			}
+			for (uint i = 1; i < max_order; i++) {
+				Order new_order;
+				new_order.AssignOrder(*v->GetOrder(i));
+				const bool wait_fixed = new_order.IsWaitFixed();
+				const bool wait_timetabled = wait_fixed && new_order.IsWaitTimetabled();
+				new_order.SetWaitTimetabled(false);
+				new_order.SetTravelTimetabled(false);
+				new_order.SetTravelTime(0);
+				new_order.SetTravelFixed(false);
+				CommandCost cost = CmdInsertOrderIntl(flags, v, order_count, new_order, true);
+				if (cost.Failed()) return cost;
+				if (flags & DC_EXEC) {
+					Order *order = v->orders.list->GetOrderAt(order_count);
+					order->SetRefit(new_order.GetRefitCargo());
+					order->SetMaxSpeed(new_order.GetMaxSpeed());
+					if (wait_fixed) {
+						extern void SetOrderFixedWaitTime(Vehicle *v, VehicleOrderID order_number, uint32 wait_time, bool wait_timetabled);
+						SetOrderFixedWaitTime(v, order_count, new_order.GetWaitTime(), wait_timetabled);
+					}
+				}
+				new_order.Free();
+			}
+			break;
+		};
+
+		default:
+			return CMD_ERROR;
+	}
 
 	return CommandCost();
 }

src/order_gui.cpp

@@ -633,6 +633,7 @@ static const StringID _order_goto_dropdown_aircraft[] = {
 
 static const StringID _order_manage_list_dropdown[] = {
 	STR_ORDER_REVERSE_ORDER_LIST,
+	STR_ORDER_APPEND_REVERSED_ORDER_LIST,
 	INVALID_STRING_ID
 };
 
@@ -1527,9 +1528,9 @@ private:
 	/**
 	 * Handle the click on the reverse order list button.
 	 */
-	void OrderClick_ReverseOrderList()
+	void OrderClick_ReverseOrderList(uint subcommand)
 	{
-		DoCommandP(this->vehicle->tile, this->vehicle->index, 0, CMD_REVERSE_ORDER_LIST | CMD_MSG(STR_ERROR_CAN_T_MOVE_THIS_ORDER));
+		DoCommandP(this->vehicle->tile, this->vehicle->index, subcommand, CMD_REVERSE_ORDER_LIST | CMD_MSG(STR_ERROR_CAN_T_MOVE_THIS_ORDER));
 	}
 
 	/** Cache auto-refittability of the vehicle chain. */
@@ -2195,7 +2196,14 @@ public:
 				break;
 
 			case WID_O_MANAGE_LIST: {
-				uint disabled_mask = (this->vehicle->GetNumOrders() < 2 ? 1 : 0);
+				uint disabled_mask = (this->vehicle->GetNumOrders() < 2 ? 1 : 0) | (this->vehicle->GetNumOrders() < 3 ? 2 : 0);
+				uint order_count = this->vehicle->GetNumOrders();
+				for (uint i = 0; i < order_count; i++) {
+					if (this->vehicle->GetOrder(i)->IsType(OT_CONDITIONAL)) {
+						disabled_mask |= 2;
+						break;
+					}
+				}
 				ShowDropDownMenu(this, _order_manage_list_dropdown, -1, WID_O_MANAGE_LIST, disabled_mask, 0, 0, DDSF_LOST_FOCUS);
 				break;
 			}
@@ -2512,7 +2520,8 @@ public:
 
 			case WID_O_MANAGE_LIST:
 				switch (index) {
-					case 0: this->OrderClick_ReverseOrderList(); break;
+					case 0: this->OrderClick_ReverseOrderList(0); break;
+					case 1: this->OrderClick_ReverseOrderList(1); break;
 					default: NOT_REACHED();
 				}
 				break;