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[openttd-joker.git] / src / order_cmd.cpp

/* $Id$ */

/*
 * 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 order_cmd.cpp Handling of orders. */

#include "stdafx.h"
#include "debug.h"
#include "cmd_helper.h"
#include "command_func.h"
#include "company_func.h"
#include "news_func.h"
#include "strings_func.h"
#include "timetable.h"
#include "station_base.h"
#include "station_map.h"
#include "station_func.h"
#include "map_func.h"
#include "cargotype.h"
#include "vehicle_func.h"
#include "depot_base.h"
#include "core/bitmath_func.hpp"
#include "core/pool_func.hpp"
#include "core/random_func.hpp"
#include "aircraft.h"
#include "roadveh.h"
#include "station_base.h"
#include "waypoint_base.h"
#include "company_base.h"
#include "order_backup.h"
#include "cheat_type.h"
#include "viewport_func.h"
#include "tracerestrict.h"

#include "table/strings.h"

#include "safeguards.h"

/* DestinationID must be at least as large as every these below, because it can
 * be any of them
 */
assert_compile(sizeof(DestinationID) >= sizeof(DepotID));
assert_compile(sizeof(DestinationID) >= sizeof(StationID));

OrderPool _order_pool("Order");
INSTANTIATE_POOL_METHODS(Order)
OrderListPool _orderlist_pool("OrderList");
INSTANTIATE_POOL_METHODS(OrderList)

/** Clean everything up. */
Order::~Order()
{
        if (CleaningPool()) return;

        /* We can visit oil rigs and buoys that are not our own. They will be shown in
         * the list of stations. So, we need to invalidate that window if needed. */
        if (this->IsType(OT_GOTO_STATION) || this->IsType(OT_GOTO_WAYPOINT)) {
                BaseStation *bs = BaseStation::GetIfValid(this->GetDestination());
                if (bs != nullptr && bs->owner == OWNER_NONE) InvalidateWindowClassesData(WC_STATION_LIST, 0);
        }
}

/**
 * 'Free' the order
 * @note ONLY use on "current_order" vehicle orders!
 */
void Order::Free()
{
        this->type  = OT_NOTHING;
        this->flags = 0;
        this->dest  = 0;
        this->next  = nullptr;
        DeAllocExtraInfo();
}

/**
 * Makes this order a Go To Station order.
 * @param destination the station to go to.
 */
void Order::MakeGoToStation(StationID destination)
{
        this->type = OT_GOTO_STATION;
        this->flags = 0;
        this->dest = destination;
}

/**
 * Makes this order a Go To Depot order.
 * @param destination   the depot to go to.
 * @param order         is this order a 'default' order, or an overridden vehicle order?
 * @param non_stop_type how to get to the depot?
 * @param action        what to do in the depot?
 * @param cargo         the cargo type to change to.
 */
void Order::MakeGoToDepot(DepotID destination, OrderDepotTypeFlags order, OrderNonStopFlags non_stop_type, OrderDepotActionFlags action, CargoID cargo)
{
        this->type = OT_GOTO_DEPOT;
        this->SetDepotOrderType(order);
        this->SetDepotActionType(action);
        this->SetNonStopType(non_stop_type);
        this->dest = destination;
        this->SetRefit(cargo);
}

/**
 * Makes this order a Go To Waypoint order.
 * @param destination the waypoint to go to.
 */
void Order::MakeGoToWaypoint(StationID destination)
{
        this->type = OT_GOTO_WAYPOINT;
        this->flags = 0;
        this->dest = destination;
}

/**
 * Makes this order a Loading order.
 * @param ordered is this an ordered stop?
 */
void Order::MakeLoading(bool ordered)
{
        this->type = OT_LOADING;
        if (!ordered) this->flags = 0;
}

bool Order::UpdateJumpCounter(byte percent)
{
        if(this->jump_counter >= 0) {
                this->jump_counter += (percent - 100);
                return true;
        }
        this->jump_counter += percent;
        return false;
}

/**
 * Makes this order a Leave Station order.
 */
void Order::MakeLeaveStation()
{
        this->type = OT_LEAVESTATION;
        this->flags = 0;
}

/**
 * Makes this order a Dummy order.
 */
void Order::MakeDummy()
{
        this->type = OT_DUMMY;
        this->flags = 0;
}

/**
 * Makes this order an conditional order.
 * @param order the order to jump to.
 */
void Order::MakeConditional(VehicleOrderID order)
{
        this->type = OT_CONDITIONAL;
        this->flags = order;
        this->dest = 0;
}

/**
 * Makes this order an implicit order.
 * @param destination the station to go to.
 */
void Order::MakeImplicit(StationID destination)
{
        this->type = OT_IMPLICIT;
        this->dest = destination;
}
 
void Order::MakeWaiting()
{
        this->type = OT_WAITING;
}

/**
 * Make this depot/station order also a refit order.
 * @param cargo   the cargo type to change to.
 * @pre IsType(OT_GOTO_DEPOT) || IsType(OT_GOTO_STATION).
 */
void Order::SetRefit(CargoID cargo)
{
        this->refit_cargo = cargo;
}

/**
 * Does this order have the same type, flags and destination?
 * @param other the second order to compare to.
 * @return true if the type, flags and destination match.
 */
bool Order::Equals(const Order &other) const
{
        /* In case of go to nearest depot orders we need "only" compare the flags
         * with the other and not the nearest depot order bit or the actual
         * destination because those get clear/filled in during the order
         * evaluation. If we do not do this the order will continuously be seen as
         * a different order and it will try to find a "nearest depot" every tick. */
        if ((this->IsType(OT_GOTO_DEPOT) && this->type == other.type) &&
                        ((this->GetDepotActionType() & ODATFB_NEAREST_DEPOT) != 0 ||
                         (other.GetDepotActionType() & ODATFB_NEAREST_DEPOT) != 0)) {
                return this->GetDepotOrderType() == other.GetDepotOrderType() &&
                                (this->GetDepotActionType() & ~ODATFB_NEAREST_DEPOT) == (other.GetDepotActionType() & ~ODATFB_NEAREST_DEPOT);
        }

        return this->type == other.type && this->flags == other.flags && this->dest == other.dest;
}

/**
 * Pack this order into a 32 bits integer, or actually only
 * the type, flags and destination.
 * @return the packed representation.
 * @note unpacking is done in the constructor.
 */
uint32 Order::Pack() const
{
        return this->dest << 16 | this->flags << 8 | this->type;
}

/**
 * Pack this order into a 16 bits integer as close to the TTD
 * representation as possible.
 * @return the TTD-like packed representation.
 */
uint16 Order::MapOldOrder() const
{
        uint16 order = this->GetType();
        switch (this->type) {
                case OT_GOTO_STATION:
                        if (this->GetUnloadType() & OUFB_UNLOAD) SetBit(order, 5);
                        if (this->GetLoadType() & OLFB_FULL_LOAD) SetBit(order, 6);
                        if (this->GetNonStopType() & ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS) SetBit(order, 7);
                        order |= GB(this->GetDestination(), 0, 8) << 8;
                        break;
                case OT_GOTO_DEPOT:
                        if (!(this->GetDepotOrderType() & ODTFB_PART_OF_ORDERS)) SetBit(order, 6);
                        SetBit(order, 7);
                        order |= GB(this->GetDestination(), 0, 8) << 8;
                        break;
                case OT_LOADING:
                        if (this->GetLoadType() & OLFB_FULL_LOAD) SetBit(order, 6);
                        break;
        }
        return order;
}

/**
 * Create an order based on a packed representation of that order.
 * @param packed the packed representation.
 */
Order::Order(uint32 packed)
{
        this->type    = (OrderType)GB(packed,  0,  8);
        this->flags   = GB(packed,  8,  8);
        this->dest    = GB(packed, 16, 16);
        this->extra   = nullptr;
        this->next    = nullptr;
        this->refit_cargo   = CT_NO_REFIT;
        this->wait_time     = 0;
        this->travel_time = 0;
        this->jump_counter = 0;
        this->max_speed     = UINT16_MAX;
}

/**
 *
 * Updates the widgets of a vehicle which contains the order-data
 *
 */
void InvalidateVehicleOrder(const Vehicle *v, int data)
{
        SetWindowDirty(WC_VEHICLE_VIEW, v->index);

        if (data != 0) {
                /* Calls SetDirty() too */
                InvalidateWindowData(WC_VEHICLE_ORDERS,    v->index, data);
                InvalidateWindowData(WC_VEHICLE_TIMETABLE, v->index, data);
                InvalidateWindowData(WC_VEHICLE_TRIP_HISTORY, v->index, data);
                return;
        }

        SetWindowDirty(WC_VEHICLE_ORDERS,    v->index);
        SetWindowDirty(WC_VEHICLE_TIMETABLE, v->index);
        SetWindowDirty(WC_VEHICLE_TRIP_HISTORY, v->index);
}

/**
 *
 * Assign data to an order (from another order)
 *   This function makes sure that the index is maintained correctly
 * @param other the data to copy (except next pointer).
 *
 */
void Order::AssignOrder(const Order &other)
{
        this->type  = other.type;
        this->flags = other.flags;
        this->dest  = other.dest;

        this->refit_cargo   = other.refit_cargo;

        this->wait_time   = other.wait_time;
        this->jump_counter = other.jump_counter;
        this->travel_time = other.travel_time;
        this->max_speed   = other.max_speed;

        if ((this->GetUnloadType() == OUFB_CARGO_TYPE_UNLOAD || this->GetLoadType() == OLFB_CARGO_TYPE_LOAD) && other.extra != nullptr) {
                this->AllocExtraInfo();
                *(this->extra) = *(other.extra);
        } else {
                this->DeAllocExtraInfo();
        }
}
  
void Order::AllocExtraInfo()
{
        if (!this->extra) {
                this->extra.reset(new OrderExtraInfo());
        }
}

void Order::DeAllocExtraInfo()
{
        this->extra.reset();
}
  
void CargoStationIDStackSet::FillNextStoppingStation(const Vehicle *v, const OrderList *o, const Order *first, uint hops)
{
        this->more.clear();
        this->first = o->GetNextStoppingStation(v, ~0, first, hops);
        if (this->first.cargo_mask != (uint32) ~0) {
                uint32 have_cargoes = this->first.cargo_mask;
                do {
                        this->more.push_back(o->GetNextStoppingStation(v, ~have_cargoes, first, hops));
                        have_cargoes |= this->more.back().cargo_mask;
                } while (have_cargoes != (uint32) ~0);
        }
}

/**
 * Recomputes everything.
 * @param chain first order in the chain
 * @param v one of vehicle that is using this orderlist
 */
void OrderList::Initialize(Order *chain, Vehicle *v)
{
        this->first = chain;
        this->first_shared = v;

        this->num_orders = 0;
        this->num_manual_orders = 0;
        this->num_vehicles = 1;
        this->timetable_duration = 0;
        this->total_duration = 0;

        for (Order *o = this->first; o != nullptr; o = o->next) {
                ++this->num_orders;
                if (!o->IsType(OT_IMPLICIT)) ++this->num_manual_orders;
                if (!o->IsType(OT_CONDITIONAL)) {
                        this->timetable_duration += o->GetTimetabledWait() + o->GetTimetabledTravel();
                        this->total_duration += o->GetWaitTime() + o->GetTravelTime();
                }
        }

        for (Vehicle *u = this->first_shared->PreviousShared(); u != nullptr; u = u->PreviousShared()) {
                ++this->num_vehicles;
                this->first_shared = u;
        }

        for (const Vehicle *u = v->NextShared(); u != nullptr; u = u->NextShared()) ++this->num_vehicles;
}

/**
 * Free a complete order chain.
 * @param keep_orderlist If this is true only delete the orders, otherwise also delete the OrderList.
 * @note do not use on "current_order" vehicle orders!
 */
void OrderList::FreeChain(bool keep_orderlist)
{
        Order *next;
        for (Order *o = this->first; o != nullptr; o = next) {
                next = o->next;
                delete o;
        }

        if (keep_orderlist) {
                this->first = nullptr;
                this->num_orders = 0;
                this->num_manual_orders = 0;
                this->timetable_duration = 0;
        } else {
                delete this;
        }
}

/**
 * Get a certain order of the order chain.
 * @param index zero-based index of the order within the chain.
 * @return the order at position index.
 */
Order *OrderList::GetOrderAt(int index) const
{
        if (index < 0) return nullptr;

        Order *order = this->first;

        while (order != nullptr && index-- > 0) {
                order = order->next;
        }
        return order;
}

/**
 * Get the index of an order of the order chain, or INVALID_VEH_ORDER_ID.
 * @param order order to get the index of.
 * @return the position index of the given order, or INVALID_VEH_ORDER_ID.
 */
VehicleOrderID OrderList::GetIndexOfOrder(const Order *order) const
{
        VehicleOrderID index = 0;
        const Order *o = this->first;
        while (o != nullptr) {
                if (o == order) return index;
                index++;
                o = o->next;
        }

        return INVALID_VEH_ORDER_ID;
}

/**
 * Get the next order which will make the given vehicle stop at a station
 * or refit at a depot or evaluate a non-trivial condition.
 * @param next The order to start looking at.
 * @param hops The number of orders we have already looked at.
 * @param cargo_mask The bit set of cargoes that the we are looking at, this may be reduced to indicate the set of cargoes that the result is valid for.
 * @return Either of
 *         \li a station order
 *         \li a refitting depot order
 *         \li a non-trivial conditional order
 *         \li nullptr  if the vehicle won't stop anymore.
 */
const Order *OrderList::GetNextDecisionNode(const Order *next, uint hops, uint32 &cargo_mask) const
{
        assert(cargo_mask != 0);

        if (hops > this->GetNumOrders() || next == nullptr) return nullptr;

        if (next->IsType(OT_CONDITIONAL)) {
                if (next->GetConditionVariable() != OCV_UNCONDITIONALLY) return next;

                /* We can evaluate trivial conditions right away. They're conceptually
                 * the same as regular order progression. */
                return this->GetNextDecisionNode(
                                this->GetOrderAt(next->GetConditionSkipToOrder()),
                                hops + 1, cargo_mask);
        }

        if (next->IsType(OT_GOTO_DEPOT)) {
                if (next->GetDepotActionType() & ODATFB_HALT) return nullptr;
                if (next->IsRefit()) return next;
        }

        
        bool can_load_or_unload = false;
        if ((next->IsType(OT_GOTO_STATION) || next->IsType(OT_IMPLICIT)) &&
                        (next->GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) == 0) {
                if (next->GetUnloadType() == OUFB_CARGO_TYPE_UNLOAD || next->GetLoadType() == OLFB_CARGO_TYPE_LOAD) {
                        /* This is a cargo-specific load/unload order.
                         * If the first cargo is both a no-load and no-unload order, skip it.
                         * Drop cargoes which don't match the first one. */
                        can_load_or_unload = CargoMaskValueFilter<bool>(cargo_mask, [&](CargoID cargo) {
                                return ((next->GetCargoLoadType(cargo) & OLFB_NO_LOAD) == 0 || (next->GetCargoUnloadType(cargo) & OUFB_NO_UNLOAD) == 0);
                        });
                } else if ((next->GetLoadType() & OLFB_NO_LOAD) == 0 || (next->GetUnloadType() & OUFB_NO_UNLOAD) == 0) {
                        can_load_or_unload = true;
                }
        }

        if (!can_load_or_unload) {
                return this->GetNextDecisionNode(this->GetNext(next), hops + 1, cargo_mask);
        }

        return next;
}

/**
 * Recursively determine the next deterministic station to stop at.
 * @param v The vehicle we're looking at.
 * @param uint32 cargo_mask Bit-set of the cargo IDs of interest.
 * @param first Order to start searching at or nullptr to start at cur_implicit_order_index + 1.
 * @param hops Number of orders we have already looked at.
 * @return A CargoMaskedStationIDStack of the cargo mask the result is valid for, and the next stoppping station or INVALID_STATION.
 * @pre The vehicle is currently loading and v->last_station_visited is meaningful.
 * @note This function may draw a random number. Don't use it from the GUI.
 */
CargoMaskedStationIDStack OrderList::GetNextStoppingStation(const Vehicle *v, uint32 cargo_mask, const Order *first, uint hops) const
{
        assert(cargo_mask != 0);

        const Order *next = first;
        if (first == nullptr) {
                next = this->GetOrderAt(v->cur_implicit_order_index);
                if (next == nullptr) {
                        next = this->GetFirstOrder();
                        if (next == nullptr) return CargoMaskedStationIDStack(cargo_mask, INVALID_STATION);
                } else {
                        /* GetNext never returns nullptr if there is a valid station in the list.
                         * As the given "next" is already valid and a station in the list, we
                         * don't have to check for nullptr here. */
                        next = this->GetNext(next);
                        assert(next != nullptr);
                }
        }

        do {
                next = this->GetNextDecisionNode(next, ++hops, cargo_mask);

                /* Resolve possibly nested conditionals by estimation. */
                while (next != nullptr && next->IsType(OT_CONDITIONAL)) {
                        /* We return both options of conditional orders. */
                        const Order *skip_to = this->GetNextDecisionNode(
                                this->GetOrderAt(next->GetConditionSkipToOrder()), hops, cargo_mask);
                        const Order *advance = this->GetNextDecisionNode(
                                this->GetNext(next), hops, cargo_mask);
                        if (advance == nullptr || advance == first || skip_to == advance) {
                                next = (skip_to == first) ? nullptr : skip_to;
                        } else if (skip_to == nullptr || skip_to == first) {
                                next = (advance == first) ? nullptr : advance;
                        } else {
                                CargoMaskedStationIDStack st1 = this->GetNextStoppingStation(v, cargo_mask, skip_to, hops);
                                cargo_mask &= st1.cargo_mask;
                                CargoMaskedStationIDStack st2 = this->GetNextStoppingStation(v, cargo_mask, advance, hops);
                                st1.cargo_mask &= st2.cargo_mask;
                                while (!st2.station.IsEmpty()) st1.station.Push(st2.station.Pop());
                                return st1;
                        }
                        ++hops;
                }
  
                if (next == nullptr) return CargoMaskedStationIDStack(cargo_mask, INVALID_STATION);

                /* Don't return a next stop if the vehicle has to unload everything. */
                if ((next->IsType(OT_GOTO_STATION) || next->IsType(OT_IMPLICIT)) &&
                                next->GetDestination() == v->last_station_visited) {
                        /* This is a cargo-specific load/unload order.
                         * Don't return a next stop if first cargo has transfer or unload set.
                         * Drop cargoes which don't match the first one. */
                        bool invalid = CargoMaskValueFilter<bool>(cargo_mask, [&](CargoID cargo) {
                                return ((next->GetCargoUnloadType(cargo) & (OUFB_TRANSFER | OUFB_UNLOAD)) != 0);
                        });
                        if (invalid) return CargoMaskedStationIDStack(cargo_mask, INVALID_STATION);
                }
        } while (next->IsType(OT_GOTO_DEPOT) || next->GetDestination() == v->last_station_visited);

        return CargoMaskedStationIDStack(cargo_mask, next->GetDestination());
}

/**
 * Insert a new order into the order chain.
 * @param new_order is the order to insert into the chain.
 * @param index is the position where the order is supposed to be inserted.
 */
void OrderList::InsertOrderAt(Order *new_order, int index)
{
        if (this->first == nullptr) {
                this->first = new_order;
        } else {
                if (index == 0) {
                        /* Insert as first or only order */
                        new_order->next = this->first;
                        this->first = new_order;
                } else if (index >= this->num_orders) {
                        /* index is after the last order, add it to the end */
                        this->GetLastOrder()->next = new_order;
                } else {
                        /* Put the new order in between */
                        Order *order = this->GetOrderAt(index - 1);
                        new_order->next = order->next;
                        order->next = new_order;
                }
        }
        ++this->num_orders;
        if (!new_order->IsType(OT_IMPLICIT)) ++this->num_manual_orders;
        if (!new_order->IsType(OT_CONDITIONAL)) {
                this->timetable_duration += new_order->GetTimetabledWait() + new_order->GetTimetabledTravel();
                this->total_duration += new_order->GetWaitTime() + new_order->GetTravelTime();
        }

        /* We can visit oil rigs and buoys that are not our own. They will be shown in
         * the list of stations. So, we need to invalidate that window if needed. */
        if (new_order->IsType(OT_GOTO_STATION) || new_order->IsType(OT_GOTO_WAYPOINT)) {
                BaseStation *bs = BaseStation::Get(new_order->GetDestination());
                if (bs->owner == OWNER_NONE) InvalidateWindowClassesData(WC_STATION_LIST, 0);
        }

}


/**
 * Remove an order from the order list and delete it.
 * @param index is the position of the order which is to be deleted.
 */
void OrderList::DeleteOrderAt(int index)
{
        if (index >= this->num_orders) return;

        Order *to_remove;

        if (index == 0) {
                to_remove = this->first;
                this->first = to_remove->next;
        } else {
                Order *prev = GetOrderAt(index - 1);
                to_remove = prev->next;
                prev->next = to_remove->next;
        }
        --this->num_orders;
        if (!to_remove->IsType(OT_IMPLICIT)) --this->num_manual_orders;
        if (!to_remove->IsType(OT_CONDITIONAL)) {
                this->timetable_duration -= (to_remove->GetTimetabledWait() + to_remove->GetTimetabledTravel());
                this->total_duration -= (to_remove->GetWaitTime() + to_remove->GetTravelTime());
        }
        delete to_remove;
}

/**
 * Move an order to another position within the order list.
 * @param from is the zero-based position of the order to move.
 * @param to is the zero-based position where the order is moved to.
 */
void OrderList::MoveOrder(int from, int to)
{
        if (from >= this->num_orders || to >= this->num_orders || from == to) return;

        Order *moving_one;

        /* Take the moving order out of the pointer-chain */
        if (from == 0) {
                moving_one = this->first;
                this->first = moving_one->next;
        } else {
                Order *one_before = GetOrderAt(from - 1);
                moving_one = one_before->next;
                one_before->next = moving_one->next;
        }

        /* Insert the moving_order again in the pointer-chain */
        if (to == 0) {
                moving_one->next = this->first;
                this->first = moving_one;
        } else {
                Order *one_before = GetOrderAt(to - 1);
                moving_one->next = one_before->next;
                one_before->next = moving_one;
        }
}

/**
 * Removes the vehicle from the shared order list.
 * @note This is supposed to be called when the vehicle is still in the chain
 * @param v vehicle to remove from the list
 */
void OrderList::RemoveVehicle(Vehicle *v)
{
        --this->num_vehicles;
        if (v == this->first_shared) this->first_shared = v->NextShared();
}

/**
 * Checks whether a vehicle is part of the shared vehicle chain.
 * @param v is the vehicle to search in the shared vehicle chain.
 */
bool OrderList::IsVehicleInSharedOrdersList(const Vehicle *v) const
{
        for (const Vehicle *v_shared = this->first_shared; v_shared != nullptr; v_shared = v_shared->NextShared()) {
                if (v_shared == v) return true;
        }

        return false;
}

/**
 * Gets the position of the given vehicle within the shared order vehicle list.
 * @param v is the vehicle of which to get the position
 * @return position of v within the shared vehicle chain.
 */
int OrderList::GetPositionInSharedOrderList(const Vehicle *v) const
{
        int count = 0;
        for (const Vehicle *v_shared = v->PreviousShared(); v_shared != nullptr; v_shared = v_shared->PreviousShared()) count++;
        return count;
}

/**
 * Checks whether all orders of the list have a filled timetable.
 * @return whether all orders have a filled timetable.
 */
bool OrderList::IsCompleteTimetable() const
{
        for (Order *o = this->first; o != nullptr; o = o->next) {
                /* Implicit orders are, by definition, not timetabled. */
                if (o->IsType(OT_IMPLICIT)) continue;
                if (!o->IsCompletelyTimetabled()) return false;
        }
        return true;
}

/**
 * Checks for internal consistency of order list. Triggers assertion if something is wrong.
 */
void OrderList::DebugCheckSanity() const
{
        VehicleOrderID check_num_orders = 0;
        VehicleOrderID check_num_manual_orders = 0;
        uint check_num_vehicles = 0;
        Ticks check_timetable_duration = 0;
        Ticks check_total_duration = 0;

        DEBUG(misc, 6, "Checking OrderList %hu for sanity...", this->index);

        for (const Order *o = this->first; o != nullptr; o = o->next) {
                ++check_num_orders;
                if (!o->IsType(OT_IMPLICIT)) ++check_num_manual_orders;
                if (!o->IsType(OT_CONDITIONAL)) {
                        check_timetable_duration += o->GetTimetabledWait() + o->GetTimetabledTravel();
                        check_total_duration += o->GetWaitTime() + o->GetTravelTime();
                }
        }
        assert(this->num_orders == check_num_orders);
        assert(this->num_manual_orders == check_num_manual_orders);
        assert(this->timetable_duration == check_timetable_duration);
        assert(this->total_duration == check_total_duration);

        for (const Vehicle *v = this->first_shared; v != nullptr; v = v->NextShared()) {
                ++check_num_vehicles;
                assert(v->HasSpecificOrderList(this));
        }
        assert(this->num_vehicles == check_num_vehicles);
        DEBUG(misc, 6, "... detected %u orders (%u manual), %u vehicles, %i timetabled, %i total",
                        (uint)this->num_orders, (uint)this->num_manual_orders,
                        this->num_vehicles, this->timetable_duration, this->total_duration);
}

/** Returns the number of running (i.e. not stopped) vehicles in the shared orders list. */
int OrderList::GetNumRunningVehicles()
{
        int num_running_vehicles = 0;

        for (const Vehicle *v = this->first_shared; v != nullptr; v = v->NextShared()) {
                if (!(v->vehstatus & (VS_STOPPED | VS_CRASHED)) || v->current_order.IsType(OT_WAITING)) {
                        num_running_vehicles++;
                }
        }

        return num_running_vehicles;
}

/** (Re-)Initializes Separation if necessary and possible. */
void OrderList::InitializeSeparation()
{
        // Check whether separation can be used at all
        if (!this->IsCompleteTimetable() || this->current_sep_mode == TTS_MODE_OFF) {
                this->is_separation_valid = false;
                return;
        }

        // Save current tick count as reference for future timetable start dates and reset the separation counter.
        this->last_timetable_init = GetCurrentTickCount();
        this->separation_counter = 0;

        this->UpdateSeparationTime();

        this->is_separation_valid = true;
}

void OrderList::UpdateSeparationTime()
{
        // Calculate separation amount depending on mode of operation.
        switch (current_sep_mode) {
        case TTS_MODE_AUTO: {
                const int num_running_vehicles = this->GetNumRunningVehicles();
                assert(num_running_vehicles > 0);

                this->current_separation = this->GetTimetableTotalDuration() / num_running_vehicles;
                break;
        }

        case TTS_MODE_MAN_N:
                assert(this->num_sep_vehicles > 0);
                this->current_separation = this->GetTimetableTotalDuration() / this->num_sep_vehicles;
                break;

        case TTS_MODE_MAN_T:
                // separation is set manually -> nothing to do
                break;

        case TTS_MODE_BUFFERED_AUTO: {
                int num_running_vehicles = this->GetNumRunningVehicles();
                assert(num_running_vehicles > 0);

                if (num_running_vehicles > 1)
                        num_running_vehicles--;
                
                this->current_separation = this->GetTimetableTotalDuration() / num_running_vehicles;
                break;
        }

        default:
                NOT_REACHED();
                break;
        }
}

/**
* Returns the delay setting required for correct separation and increases the separation counter by 1.
* @return the delay setting required for correct separation. */
Ticks OrderList::SeparateVehicle()
{
        if (!this->is_separation_valid || this->current_sep_mode == TTS_MODE_OFF)
                return INVALID_TICKS;

        UpdateSeparationTime();

        Ticks result = GetCurrentTickCount() - (this->separation_counter * this->current_separation + this->last_timetable_init);
        this->IncreaseSeparationCounter();
        if (this->separation_counter == UINT16_MAX) {
                this->MarkSeparationInvalid();
        }

        return result;
}

/**
* Returns the current separation settings.
* @return the current separation settings.
*/
TTSepSettings OrderList::GetSepSettings()
{
        TTSepSettings result;

        result.mode = this->current_sep_mode;
        result.sep_ticks = GetSepTime();

        // Depending on the operation mode return either the user setting or the true amount of vehicles running the timetable.
        result.num_veh = (result.mode == TTS_MODE_MAN_N) ? this->num_sep_vehicles : GetNumVehicles();
        return result;
}

/**
* Sets new separation settings.
* @param mode      Contains the operation mode that is to be used for separation.
* @param parameter Depending on the operation mode this contains either the number of vehicles (#TTS_MODE_MAN_N)
*                  or the time between vehicles in ticks (#TTS_MODE_MAN_T). For other modes, this is undefined.
*/
void OrderList::SetSepSettings(TTSepMode mode, uint32 parameter)
{
        this->current_sep_mode = mode;

        switch (this->current_sep_mode)
        {
        case TTS_MODE_MAN_N:
                assert(parameter > 0);
                this->current_separation = this->GetTimetableTotalDuration() / parameter;
                this->num_sep_vehicles = parameter;
                break;

        case TTS_MODE_MAN_T:
                this->current_separation = parameter;
                assert(this->current_separation > 0);
                this->num_sep_vehicles = this->GetTimetableTotalDuration() / this->current_separation;
                break;

        case TTS_MODE_AUTO:
        case TTS_MODE_BUFFERED_AUTO:
        case TTS_MODE_OFF:
                /* nothing to do */
                break;

        default:
                NOT_REACHED();
                break;
        }

        this->is_separation_valid = false;
}


/**
 * Checks whether the order goes to a station or not, i.e. whether the
 * destination is a station
 * @param v the vehicle to check for
 * @param o the order to check
 * @return true if the destination is a station
 */
static inline bool OrderGoesToStation(const Vehicle *v, const Order *o)
{
        return o->IsType(OT_GOTO_STATION) ||
                        (v->type == VEH_AIRCRAFT && o->IsType(OT_GOTO_DEPOT) && !(o->GetDepotActionType() & ODATFB_NEAREST_DEPOT));
}

/**
 * Delete all news items regarding defective orders about a vehicle
 * This could kill still valid warnings (for example about void order when just
 * another order gets added), but assume the company will notice the problems,
 * when (s)he's changing the orders.
 */
void DeleteOrderWarnings(const Vehicle *v)
{
        DeleteVehicleNews(v->index, STR_NEWS_VEHICLE_HAS_TOO_FEW_ORDERS);
        DeleteVehicleNews(v->index, STR_NEWS_VEHICLE_HAS_VOID_ORDER);
        DeleteVehicleNews(v->index, STR_NEWS_VEHICLE_HAS_DUPLICATE_ENTRY);
        DeleteVehicleNews(v->index, STR_NEWS_VEHICLE_HAS_INVALID_ENTRY);
        DeleteVehicleNews(v->index, STR_NEWS_PLANE_USES_TOO_SHORT_RUNWAY);
}

/**
 * Returns a tile somewhat representing the order destination (not suitable for pathfinding).
 * @param v The vehicle to get the location for.
 * @param airport Get the airport tile and not the station location for aircraft.
 * @return destination of order, or INVALID_TILE if none.
 */
TileIndex Order::GetLocation(const Vehicle *v, bool airport) const
{
        switch (this->GetType()) {
                case OT_GOTO_WAYPOINT:
                case OT_GOTO_STATION:
                case OT_IMPLICIT:
                        if (airport && v->type == VEH_AIRCRAFT) return Station::Get(this->GetDestination())->airport.tile;
                        return BaseStation::Get(this->GetDestination())->xy;

                case OT_GOTO_DEPOT:
                        if ((this->GetDepotActionType() & ODATFB_NEAREST_DEPOT) != 0) return INVALID_TILE;
                        return (v->type == VEH_AIRCRAFT) ? Station::Get(this->GetDestination())->xy : Depot::Get(this->GetDestination())->xy;

                default:
                        return INVALID_TILE;
        }
}

/**
 * Get the distance between two orders of a vehicle. Conditional orders are resolved
 * and the bigger distance of the two order branches is returned.
 * @param prev Origin order.
 * @param cur Destination order.
 * @param v The vehicle to get the distance for.
 * @param conditional_depth Internal param for resolving conditional orders.
 * @return Maximum distance between the two orders.
 */
uint GetOrderDistance(const Order *prev, const Order *cur, const Vehicle *v, int conditional_depth)
{
        if (cur->IsType(OT_CONDITIONAL)) {
                if (conditional_depth > v->GetNumOrders()) return 0;

                conditional_depth++;

                int dist1 = GetOrderDistance(prev, v->GetOrder(cur->GetConditionSkipToOrder()), v, conditional_depth);
                int dist2 = GetOrderDistance(prev, cur->next == nullptr ? v->GetFirstOrder() : cur->next, v, conditional_depth);
                return max(dist1, dist2);
        }

        TileIndex prev_tile = prev->GetLocation(v, true);
        TileIndex cur_tile = cur->GetLocation(v, true);
        if (prev_tile == INVALID_TILE || cur_tile == INVALID_TILE) return 0;
        return v->type == VEH_AIRCRAFT ? DistanceSquare(prev_tile, cur_tile) : DistanceManhattan(prev_tile, cur_tile);
}

/**
 * Add an order to the orderlist of a vehicle.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0 - 19) - ID of the vehicle
 * - p1 = (bit 24 - 31) - the selected order (if any). If the last order is given,
 *                        the order will be inserted before that one
 *                        the maximum vehicle order id is 254.
 * @param p2 packed order to insert
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdInsertOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh          = GB(p1,  0, 20);
        VehicleOrderID sel_ord = GB(p1, 20, 8);
        Order new_order(p2);

        Vehicle *v = Vehicle::GetIfValid(veh);
        if (v == nullptr || !v->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        /* Check if the inserted order is to the correct destination (owner, type),
         * and has the correct flags if any */
        switch (new_order.GetType()) {
                case OT_GOTO_STATION: {
                        const Station *st = Station::GetIfValid(new_order.GetDestination());
                        if (st == nullptr) return CommandError();

                        if (st->owner != OWNER_NONE) {
                                CommandCost ret = CheckOwnership(st->owner);
                                if (ret.Failed()) return ret;
                        }

                        if (!CanVehicleUseStation(v, st)) return CommandError(STR_ERROR_CAN_T_ADD_ORDER);
                        for (Vehicle *u = v->FirstShared(); u != nullptr; u = u->NextShared()) {
                                if (!CanVehicleUseStation(u, st)) return CommandError(STR_ERROR_CAN_T_ADD_ORDER_SHARED);
                        }

                        /* Non stop only allowed for ground vehicles. */
                        if (new_order.GetNonStopType() != ONSF_STOP_EVERYWHERE && !v->IsGroundVehicle()) return CommandError();

                        /* Filter invalid load/unload types. */
                        switch (new_order.GetLoadType()) {
                                case OLF_LOAD_IF_POSSIBLE: case OLFB_FULL_LOAD: case OLF_FULL_LOAD_ANY: case OLFB_NO_LOAD: break;
                                default: return CommandError();
                        }
                        switch (new_order.GetUnloadType()) {
                                case OUF_UNLOAD_IF_POSSIBLE: case OUFB_UNLOAD: case OUFB_TRANSFER: case OUFB_NO_UNLOAD: break;
                                default: return CommandError();
                        }

                        /* Filter invalid stop locations */
                        switch (new_order.GetStopLocation()) {
                                case OSL_PLATFORM_NEAR_END:
                                case OSL_PLATFORM_MIDDLE:
                                        if (v->type != VEH_TRAIN) return CommandError();
                                        FALLTHROUGH;

                                case OSL_PLATFORM_FAR_END:
                                        break;

                                default:
                                        return CommandError();
                        }

                        break;
                }

                case OT_GOTO_DEPOT: {
                        if ((new_order.GetDepotActionType() & ODATFB_NEAREST_DEPOT) == 0) {
                                if (v->type == VEH_AIRCRAFT) {
                                        const Station *st = Station::GetIfValid(new_order.GetDestination());

                                        if (st == nullptr) return CommandError();

                                        CommandCost ret = CheckOwnership(st->owner);
                                        if (ret.Failed()) return ret;

                                        if (!CanVehicleUseStation(v, st) || !st->airport.HasHangar()) {
                                                return CommandError();
                                        }
                                } else {
                                        const Depot *dp = Depot::GetIfValid(new_order.GetDestination());

                                        if (dp == nullptr) return CommandError();

                                        CommandCost ret = CheckOwnership(GetTileOwner(dp->xy));
                                        if (ret.Failed()) return ret;

                                        switch (v->type) {
                                                case VEH_TRAIN:
                                                        if (!IsRailDepotTile(dp->xy)) return CommandError();
                                                        break;

                                                case VEH_ROAD:
                                                        if (!IsRoadDepotTile(dp->xy)) return CommandError();
                                                        break;

                                                case VEH_SHIP:
                                                        if (!IsShipDepotTile(dp->xy)) return CommandError();
                                                        break;

                                                default: return CommandError();
                                        }
                                }
                        }

                        if (new_order.GetNonStopType() != ONSF_STOP_EVERYWHERE && !v->IsGroundVehicle()) return CommandError();
                        if (new_order.GetDepotOrderType() & ~(ODTFB_PART_OF_ORDERS | ((new_order.GetDepotOrderType() & ODTFB_PART_OF_ORDERS) != 0 ? ODTFB_SERVICE : 0))) return CommandError();
                        if (new_order.GetDepotActionType() & ~(ODATFB_HALT | ODATFB_NEAREST_DEPOT)) return CommandError();
                        if ((new_order.GetDepotOrderType() & ODTFB_SERVICE) && (new_order.GetDepotActionType() & ODATFB_HALT)) return CommandError();
                        break;
                }

                case OT_GOTO_WAYPOINT: {
                        const Waypoint *wp = Waypoint::GetIfValid(new_order.GetDestination());
                        if (wp == nullptr) return CommandError();

                        switch (v->type) {
                                default: return CommandError();

                                case VEH_TRAIN: {
                                        if (!(wp->facilities & FACIL_TRAIN)) return CommandError(STR_ERROR_CAN_T_ADD_ORDER);

                                        CommandCost ret = CheckOwnership(wp->owner);
                                        if (ret.Failed()) return ret;
                                        break;
                                }

                                case VEH_SHIP:
                                        if (!(wp->facilities & FACIL_DOCK)) return CommandError(STR_ERROR_CAN_T_ADD_ORDER);
                                        if (wp->owner != OWNER_NONE) {
                                                CommandCost ret = CheckOwnership(wp->owner);
                                                if (ret.Failed()) return ret;
                                        }
                                        break;
                        }

                        /* Order flags can be any of the following for waypoints:
                         * [non-stop]
                         * non-stop orders (if any) are only valid for trains */
                        if (new_order.GetNonStopType() != ONSF_STOP_EVERYWHERE && v->type != VEH_TRAIN) return CommandError();
                        break;
                }

                case OT_CONDITIONAL: {
                        VehicleOrderID skip_to = new_order.GetConditionSkipToOrder();
                        if (skip_to != 0 && skip_to >= v->GetNumOrders()) return CommandError(); // Always allow jumping to the first (even when there is no order).
                        if (new_order.GetConditionVariable() >= OCV_END) return CommandError();

                        OrderConditionComparator occ = new_order.GetConditionComparator();
                        if (occ >= OCC_END) return CommandError();
                        switch (new_order.GetConditionVariable()) {
                                case OCV_SLOT_OCCUPANCY: {
                                        TraceRestrictSlotID slot = new_order.GetXData();
                                        if (slot != INVALID_TRACE_RESTRICT_SLOT_ID && !TraceRestrictSlot::IsValidID(slot)) return CommandError();
                                        if (occ != OCC_IS_TRUE && occ != OCC_IS_FALSE) return CommandError();
                                        break;
                                }
                                case OCV_CARGO_WAITING:
                                case OCV_CARGO_ACCEPTANCE:
                                        if (!CargoSpec::Get(new_order.GetConditionValue())->IsValid()) return CommandError();
                                        /* FALL THROUGH */

                                case OCV_REQUIRES_SERVICE:
                                        if (occ != OCC_IS_TRUE && occ != OCC_IS_FALSE) return CommandError();
                                        break;

                                case OCV_UNCONDITIONALLY:
                                        if (occ != OCC_EQUALS) return CommandError();
                                        if (new_order.GetConditionValue() != 0) return CommandError();
                                        break;
 
                                case OCV_FREE_PLATFORMS:
                                        if (v->type != VEH_TRAIN) return CommandError();
                                        if (occ == OCC_IS_TRUE || occ == OCC_IS_FALSE) return CommandError();
                                        break;

                                case OCV_PERCENT:
                                        if (occ != OCC_EQUALS) return CommandError();
                                        /* FALL THROUGH */

                                case OCV_LOAD_PERCENTAGE:
                                case OCV_RELIABILITY:
                                        if (new_order.GetConditionValue() > 100) return CommandError();
                                        FALLTHROUGH;

                                default:
                                        if (occ == OCC_IS_TRUE || occ == OCC_IS_FALSE) return CommandError();
                                        break;
                        }
                        break;
                }

                default: return CommandError();
        }

        if (sel_ord > v->GetNumOrders()) return CommandError();

        if (v->GetNumOrders() >= MAX_VEH_ORDER_ID) return CommandError(STR_ERROR_TOO_MANY_ORDERS);
        if (!Order::CanAllocateItem()) return CommandError(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);
        if (!v->HasOrdersList() && !OrderList::CanAllocateItem()) return CommandError(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);

        if (v->type == VEH_SHIP && _settings_game.pf.pathfinder_for_ships != VPF_NPF) {
                /* Make sure the new destination is not too far away from the previous */
                const Order *prev = nullptr;
                uint n = 0;

                /* Find the last goto station or depot order before the insert location.
                 * If the order is to be inserted at the beginning of the order list this
                 * finds the last order in the list. */
                const Order *o;
                FOR_VEHICLE_ORDERS(v, o) {
                        switch (o->GetType()) {
                                case OT_GOTO_STATION:
                                case OT_GOTO_DEPOT:
                                case OT_GOTO_WAYPOINT:
                                        prev = o;
                                        break;

                                default: break;
                        }
                        if (++n == sel_ord && prev != nullptr) break;
                }
                if (prev != nullptr) {
                        uint dist;
                        if (new_order.IsType(OT_CONDITIONAL)) {
                                /* The order is not yet inserted, so we have to do the first iteration here. */
                                dist = GetOrderDistance(prev, v->GetOrder(new_order.GetConditionSkipToOrder()), v);
                        } else {
                                dist = GetOrderDistance(prev, &new_order, v);
                        }

                        if (dist >= 130) {
                                return CommandError(STR_ERROR_TOO_FAR_FROM_PREVIOUS_DESTINATION);
                        }
                }
        }

        if (flags & DC_EXEC) {
                Order *new_o = new Order();
                new_o->AssignOrder(new_order);
                InsertOrder(v, new_o, sel_ord);
                CheckMarkDirtyFocusedRoutePaths(v);
        }

        return CommandCost();
}

/**
 * Insert a new order but skip the validation.
 * @param v       The vehicle to insert the order to.
 * @param new_o   The new order.
 * @param sel_ord The position the order should be inserted at.
 */
void InsertOrder(Vehicle *v, Order *new_o, VehicleOrderID sel_ord)
{
        /* Create new order and link in list */
        if (!v->HasOrdersList()) {
                v->SetOrdersList(new OrderList(new_o, v));
        } else {
                v->InsertOrderAt(new_o, sel_ord);
        }

        Vehicle *u = v->FirstShared();
        DeleteOrderWarnings(u);
        for (; u != nullptr; u = u->NextShared()) {
                assert(v->IsSharingOrdersWith(u));

                /* If there is added an order before the current one, we need
                 * to update the selected order. We do not change implicit/real order indices though.
                 * If the new order is between the current implicit order and real order, the implicit order will
                 * later skip the inserted order. */
                if (sel_ord <= u->cur_real_order_index) {
                        uint cur = u->cur_real_order_index + 1;
                        /* Check if we don't go out of bound */
                        if (cur < u->GetNumOrders()) {
                                u->cur_real_order_index = cur;
                        }
                }
                if (sel_ord == u->cur_implicit_order_index && u->IsGroundVehicle()) {
                        /* We are inserting an order just before the current implicit order.
                         * We do not know whether we will reach current implicit or the newly inserted order first.
                         * So, disable creation of implicit orders until we are on track again. */
                        uint16 &gv_flags = u->GetGroundVehicleFlags();
                        SetBit(gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS);
                }
                if (sel_ord <= u->cur_implicit_order_index) {
                        uint cur = u->cur_implicit_order_index + 1;
                        /* Check if we don't go out of bound */
                        if (cur < u->GetNumOrders()) {
                                u->cur_implicit_order_index = cur;
                        }
                }
                if (u->cur_timetable_order_index != INVALID_VEH_ORDER_ID && sel_ord <= u->cur_timetable_order_index) {
                        uint cur = u->cur_timetable_order_index + 1;
                        /* Check if we don't go out of bound */
                        if (cur < u->GetNumOrders()) {
                                u->cur_timetable_order_index = cur;
                        }
                }
                /* Update any possible open window of the vehicle */
                InvalidateVehicleOrder(u, INVALID_VEH_ORDER_ID | (sel_ord << 8));
        }

        /* As we insert an order, the order to skip to will be 'wrong'. */
        VehicleOrderID cur_order_id = 0;
        Order *order;
        FOR_VEHICLE_ORDERS(v, order) {
                if (order->IsType(OT_CONDITIONAL)) {
                        VehicleOrderID order_id = order->GetConditionSkipToOrder();
                        if (order_id >= sel_ord) {
                                order->SetConditionSkipToOrder(order_id + 1);
                        }
                        if (order_id == cur_order_id) {
                                order->SetConditionSkipToOrder((order_id + 1) % v->GetNumOrders());
                        }
                }
                cur_order_id++;
        }

        /* Make sure to rebuild the whole list */
        InvalidateWindowClassesData(GetWindowClassForVehicleType(v->type), 0);
}

/**
 * Declone an order-list
 * @param *dst delete the orders of this vehicle
 * @param flags execution flags
 */
static CommandCost DecloneOrder(Vehicle *dst, DoCommandFlag flags)
{
        if (flags & DC_EXEC) {
                dst->DeleteVehicleOrders();
                InvalidateVehicleOrder(dst, VIWD_REMOVE_ALL_ORDERS);
                InvalidateWindowClassesData(GetWindowClassForVehicleType(dst->type), 0);
                CheckMarkDirtyFocusedRoutePaths(dst);
        }
        return CommandCost();
}

/**
 * Get the first cargoID that points to a valid cargo (usually 0)
 */
static CargoID GetFirstValidCargo()
{
        for (CargoID i = 0; i < NUM_CARGO; i++) {
                if (CargoSpec::Get(i)->IsValid()) return i;
        }
        /* No cargoes defined -> 'Houston, we have a problem!' */
        assert(0);
        /* Return something to avoid compiler warning */
        return 0;
}

/**
* Get the first valid TraceRestrictSlot. Or INVALID_TRACE_RESTRICT_SLOT_ID if no slots are defined.
*/
static TraceRestrictSlotID GetFirstValidTraceRestrictSlot()
{
        const TraceRestrictSlot* slot;
        FOR_ALL_TRACE_RESTRICT_SLOTS(slot)
        {
                // Stupid way to get the first valid slot but there is no "GetFirstValidSlot()".
                return slot->index;
        }
        
        return INVALID_TRACE_RESTRICT_SLOT_ID;
}

/**
 * Delete an order from the orderlist of a vehicle.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 the ID of the vehicle
 * @param p2 the order to delete (max 255)
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdDeleteOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh_id = GB(p1, 0, 20);
        VehicleOrderID sel_ord = GB(p2, 0, 8);

        Vehicle *v = Vehicle::GetIfValid(veh_id);

        if (v == nullptr || !v->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        /* If we did not select an order, we maybe want to de-clone the orders */
        if (sel_ord >= v->GetNumOrders()) return DecloneOrder(v, flags);

        if (v->GetOrder(sel_ord) == nullptr) return CommandError();

        if (flags & DC_EXEC) {
                DeleteOrder(v, sel_ord);
                CheckMarkDirtyFocusedRoutePaths(v);
        }
        return CommandCost();
}

/**
 * Cancel the current loading order of the vehicle as the order was deleted.
 * @param v the vehicle
 */
void CancelLoadingDueToDeletedOrder(Vehicle *v)
{
        assert(v->current_order.IsType(OT_LOADING));
        /* NON-stop flag is misused to see if a train is in a station that is
         * on his order list or not */
        v->current_order.SetNonStopType(ONSF_STOP_EVERYWHERE);
        /* When full loading, "cancel" that order so the vehicle doesn't
         * stay indefinitely at this station anymore. */
        if (v->current_order.GetLoadType() & OLFB_FULL_LOAD) v->current_order.SetLoadType(OLF_LOAD_IF_POSSIBLE);
}

/**
 * Delete an order but skip the parameter validation.
 * @param v       The vehicle to delete the order from.
 * @param sel_ord The id of the order to be deleted.
 */
void DeleteOrder(Vehicle *v, VehicleOrderID sel_ord)
{
        v->DeleteOrderAt(sel_ord);

        Vehicle *u = v->FirstShared();
        DeleteOrderWarnings(u);
        for (; u != nullptr; u = u->NextShared()) {
                assert(v->IsSharingOrdersWith(u));

                if (sel_ord == u->cur_real_order_index && u->current_order.IsType(OT_LOADING)) {
                        CancelLoadingDueToDeletedOrder(u);
                }

                if (sel_ord < u->cur_real_order_index) {
                        u->cur_real_order_index--;
                } else if (sel_ord == u->cur_real_order_index) {
                        u->UpdateRealOrderIndex();
                }

                if (sel_ord < u->cur_implicit_order_index) {
                        u->cur_implicit_order_index--;
                } else if (sel_ord == u->cur_implicit_order_index) {
                        /* Make sure the index is valid */
                        if (u->cur_implicit_order_index >= u->GetNumOrders()) u->cur_implicit_order_index = 0;

                        /* Skip non-implicit orders for the implicit-order-index (e.g. if the current implicit order was deleted */
                        while (u->cur_implicit_order_index != u->cur_real_order_index && !u->GetOrder(u->cur_implicit_order_index)->IsType(OT_IMPLICIT)) {
                                u->cur_implicit_order_index++;
                                if (u->cur_implicit_order_index >= u->GetNumOrders()) u->cur_implicit_order_index = 0;
                        }
                }

                if (u->cur_timetable_order_index != INVALID_VEH_ORDER_ID) {
                        if (sel_ord < u->cur_timetable_order_index) {
                                u->cur_timetable_order_index--;
                        } else if (sel_ord == u->cur_timetable_order_index) {
                                u->cur_timetable_order_index = INVALID_VEH_ORDER_ID;
                        }
                }

                /* Update any possible open window of the vehicle */
                InvalidateVehicleOrder(u, sel_ord | (INVALID_VEH_ORDER_ID << 8));
        }

        /* As we delete an order, the order to skip to will be 'wrong'. */
        VehicleOrderID cur_order_id = 0;
        Order *order = nullptr;
        FOR_VEHICLE_ORDERS(v, order) {
                if (order->IsType(OT_CONDITIONAL)) {
                        VehicleOrderID order_id = order->GetConditionSkipToOrder();
                        if (order_id >= sel_ord) {
                                order_id = max(order_id - 1, 0);
                        }
                        if (order_id == cur_order_id) {
                                order_id = (order_id + 1) % v->GetNumOrders();
                        }
                        order->SetConditionSkipToOrder(order_id);
                }
                cur_order_id++;
        }

        InvalidateWindowClassesData(GetWindowClassForVehicleType(v->type), 0);
        CheckMarkDirtyFocusedRoutePaths(v);
}

/**
 * Goto order of order-list.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 The ID of the vehicle which order is skipped
 * @param p2 the selected order to which we want to skip
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdSkipToOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh_id = GB(p1, 0, 20);
        VehicleOrderID sel_ord = GB(p2, 0, 8);

        Vehicle *v = Vehicle::GetIfValid(veh_id);

        if (v == nullptr || !v->IsPrimaryVehicle() || sel_ord == v->cur_implicit_order_index || sel_ord >= v->GetNumOrders() || v->GetNumOrders() < 2) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        if (flags & DC_EXEC) {
                if (v->current_order.IsType(OT_LOADING)) v->LeaveStation();
                if (v->current_order.IsType(OT_WAITING)) v->HandleWaiting(true);

                v->cur_implicit_order_index = v->cur_real_order_index = sel_ord;
                v->UpdateRealOrderIndex();
                v->cur_timetable_order_index = INVALID_VEH_ORDER_ID;

                InvalidateVehicleOrder(v, VIWD_MODIFY_ORDERS);
        }

        /* We have an aircraft/ship, they have a mini-schedule, so update them all */
        if (v->type == VEH_AIRCRAFT) SetWindowClassesDirty(WC_AIRCRAFT_LIST);
        if (v->type == VEH_SHIP) SetWindowClassesDirty(WC_SHIPS_LIST);

        return CommandCost();
}

/**
 * Move an order inside the orderlist
 * @param tile unused
 * @param flags operation to perform
 * @param p1 the ID of the vehicle
 * @param p2 order to move and target
 *           bit 0-15  : the order to move
 *           bit 16-31 : the target order
 * @param text unused
 * @return the cost of this operation or an error
 * @note The target order will move one place down in the orderlist
 *  if you move the order upwards else it'll move it one place down
 */
CommandCost CmdMoveOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh = GB(p1, 0, 20);
        VehicleOrderID moving_order = GB(p2,  0, 16);
        VehicleOrderID target_order = GB(p2, 16, 16);

        Vehicle *v = Vehicle::GetIfValid(veh);
        if (v == nullptr || !v->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        /* Don't make senseless movements */
        if (moving_order >= v->GetNumOrders() || target_order >= v->GetNumOrders() ||
                        moving_order == target_order || v->GetNumOrders() <= 1) return CommandError();

        Order *moving_one = v->GetOrder(moving_order);
        /* Don't move an empty order */
        if (moving_one == nullptr) return CommandError();

        if (flags & DC_EXEC) {
                v->MoveOrder(moving_order, target_order);

                /* Update shared list */
                Vehicle *u = v->FirstShared();

                DeleteOrderWarnings(u);

                for (; u != nullptr; u = u->NextShared()) {
                        /* Update the current order.
                         * There are multiple ways to move orders, which result in cur_implicit_order_index
                         * and cur_real_order_index to not longer make any sense. E.g. moving another
                         * real order between them.
                         *
                         * Basically one could choose to preserve either of them, but not both.
                         * While both ways are suitable in this or that case from a human point of view, neither
                         * of them makes really sense.
                         * However, from an AI point of view, preserving cur_real_order_index is the most
                         * predictable and transparent behaviour.
                         *
                         * With that decision it basically does not matter what we do to cur_implicit_order_index.
                         * If we change orders between the implicit- and real-index, the implicit orders are mostly likely
                         * completely out-dated anyway. So, keep it simple and just keep cur_implicit_order_index as well.
                         * The worst which can happen is that a lot of implicit orders are removed when reaching current_order.
                         */
                        if (u->cur_real_order_index == moving_order) {
                                u->cur_real_order_index = target_order;
                        } else if (u->cur_real_order_index > moving_order && u->cur_real_order_index <= target_order) {
                                u->cur_real_order_index--;
                        } else if (u->cur_real_order_index < moving_order && u->cur_real_order_index >= target_order) {
                                u->cur_real_order_index++;
                        }

                        if (u->cur_implicit_order_index == moving_order) {
                                u->cur_implicit_order_index = target_order;
                        } else if (u->cur_implicit_order_index > moving_order && u->cur_implicit_order_index <= target_order) {
                                u->cur_implicit_order_index--;
                        } else if (u->cur_implicit_order_index < moving_order && u->cur_implicit_order_index >= target_order) {
                                u->cur_implicit_order_index++;
                        }

                        u->cur_timetable_order_index = INVALID_VEH_ORDER_ID;

                        assert(v->IsSharingOrdersWith(u));

                        /* Update any possible open window of the vehicle */
                        InvalidateVehicleOrder(u, moving_order | (target_order << 8));
                }

                /* As we move an order, the order to skip to will be 'wrong'. */
                Order *order;
                FOR_VEHICLE_ORDERS(v, order) {
                        if (order->IsType(OT_CONDITIONAL)) {
                                VehicleOrderID order_id = order->GetConditionSkipToOrder();
                                if (order_id == moving_order) {
                                        order_id = target_order;
                                } else if (order_id > moving_order && order_id <= target_order) {
                                        order_id--;
                                } else if (order_id < moving_order && order_id >= target_order) {
                                        order_id++;
                                }
                                order->SetConditionSkipToOrder(order_id);
                        }
                }

                /* Make sure to rebuild the whole list */
                InvalidateWindowClassesData(GetWindowClassForVehicleType(v->type), 0);
        }

        return CommandCost();
}

/**
 * Modify an order in the orderlist of a vehicle.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0 - 19) - ID of the vehicle
 * - p1 = (bit 20 - 27) - the selected order (if any). If the last order is given,
 *                        the order will be inserted before that one
 *                        the maximum vehicle order id is 254.
 * @param p2 various bitstuffed elements
 *  - p2 = (bit  0 -  3) - what data to modify (@see ModifyOrderFlags)
 *  - p2 = (bit  4 - 19) - the data to modify
 *  - p2 = (bit 20 - 27) - a CargoID for cargo type orders (MOF_CARGO_TYPE_UNLOAD or MOF_CARGO_TYPE_LOAD)
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleOrderID sel_ord = GB(p1, 20,  8);
        VehicleID veh          = GB(p1,  0, 20);
        ModifyOrderFlags mof   = Extract<ModifyOrderFlags, 0, 4>(p2);
        uint16 data            = GB(p2,  4, 16);
        CargoID cargo_id = (mof == MOF_CARGO_TYPE_UNLOAD || mof == MOF_CARGO_TYPE_LOAD) ? (CargoID)GB(p2, 20, 8) : (CargoID)CT_INVALID;

        if (mof >= MOF_END) return CommandError();

        Vehicle *v = Vehicle::GetIfValid(veh);
        if (v == nullptr || !v->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        /* Is it a valid order? */
        if (sel_ord >= v->GetNumOrders()) return CommandError();

        Order *order = v->GetOrder(sel_ord);
        switch (order->GetType()) {
                case OT_GOTO_STATION:
                        if (mof != MOF_NON_STOP && mof != MOF_STOP_LOCATION && mof != MOF_UNLOAD && mof != MOF_LOAD && mof != MOF_CARGO_TYPE_UNLOAD && mof != MOF_CARGO_TYPE_LOAD) return CommandError();
                        break;

                case OT_GOTO_DEPOT:
                        if (mof != MOF_NON_STOP && mof != MOF_DEPOT_ACTION) return CommandError();
                        break;

                case OT_GOTO_WAYPOINT:
                        if (mof != MOF_NON_STOP && mof != MOF_WAYPOINT_FLAGS) return CommandError();
                        break;

                case OT_CONDITIONAL:
                        if (mof != MOF_COND_VARIABLE && mof != MOF_COND_COMPARATOR && mof != MOF_COND_VALUE && mof != MOF_COND_DESTINATION) return CommandError();
                        break;

                default:
                        return CommandError();
        }

        switch (mof) {
                default: NOT_REACHED();

                case MOF_NON_STOP:
                        if (!v->IsGroundVehicle()) return CommandError();
                        if (data >= ONSF_END) return CommandError();
                        if (data == order->GetNonStopType()) return CommandError();
                        break;

                case MOF_STOP_LOCATION:
                        if (v->type != VEH_TRAIN) return CommandError();
                        if (data >= OSL_END) return CommandError();
                        break;                  
  
                case MOF_CARGO_TYPE_UNLOAD:
                        if (cargo_id >= NUM_CARGO) return CommandError();
                        if (data == OUFB_CARGO_TYPE_UNLOAD) return CommandError();
                        /* FALL THROUGH */
                case MOF_UNLOAD:
                        if (order->GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) return CommandError();
                        if ((data & ~(OUFB_UNLOAD | OUFB_TRANSFER | OUFB_NO_UNLOAD | OUFB_CARGO_TYPE_UNLOAD)) != 0) return CommandError();
                        /* Unload and no-unload are mutual exclusive and so are transfer and no unload. */
                        if (data != 0 && (data & OUFB_CARGO_TYPE_UNLOAD) == 0 && ((data & (OUFB_UNLOAD | OUFB_TRANSFER)) != 0) == ((data & OUFB_NO_UNLOAD) != 0)) return CommandError();
                        /* Cargo-type-unload exclude all the other flags. */
                        if ((data & OUFB_CARGO_TYPE_UNLOAD) != 0 && data != OUFB_CARGO_TYPE_UNLOAD) return CommandError();
                        if (data == order->GetUnloadType()) return CommandError();
                        break;                  
  
                case MOF_CARGO_TYPE_LOAD:
                        if (cargo_id >= NUM_CARGO) return CommandError();
                        if (data == OLFB_CARGO_TYPE_LOAD || data == OLF_FULL_LOAD_ANY) return CommandError();
                        /* FALL THROUGH */
                case MOF_LOAD:
                        if (order->GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) return CommandError();
                        if ((data > OLFB_NO_LOAD && data != OLFB_CARGO_TYPE_LOAD) || data == 1) return CommandError();
                        if (data == order->GetLoadType()) return CommandError();
                        break;

                case MOF_DEPOT_ACTION:
                        if (data >= DA_END) return CommandError();
                        break;

                case MOF_COND_VARIABLE:
                        if (data == OCV_FREE_PLATFORMS && v->type != VEH_TRAIN) return CommandError();
                        if (data >= OCV_END) return CommandError();
                        break;

                case MOF_COND_COMPARATOR:
                        if (data >= OCC_END) return CommandError();
                        switch (order->GetConditionVariable()) {
                                case OCV_UNCONDITIONALLY:
                                case OCV_PERCENT:
                                        return CommandError();

                                case OCV_REQUIRES_SERVICE:
                                case OCV_CARGO_ACCEPTANCE:
                                case OCV_CARGO_WAITING:
                                case OCV_SLOT_OCCUPANCY:
                                        if (data != OCC_IS_TRUE && data != OCC_IS_FALSE) return CommandError();
                                        break;

                                default:
                                        if (data == OCC_IS_TRUE || data == OCC_IS_FALSE) return CommandError();
                                        break;
                        }
                        break;

                case MOF_COND_VALUE:
                        switch (order->GetConditionVariable()) {
                                case OCV_UNCONDITIONALLY:
                                case OCV_REQUIRES_SERVICE:
                                        return CommandError();

                                case OCV_LOAD_PERCENTAGE:
                                case OCV_RELIABILITY:
                                case OCV_PERCENT:
                                        if (data > 100) return CommandError();
                                        break;

                                case OCV_SLOT_OCCUPANCY:
                                        if (data != INVALID_TRACE_RESTRICT_SLOT_ID && !TraceRestrictSlot::IsValidID(data)) return CommandError();
                                        break;
 
                                case OCV_CARGO_ACCEPTANCE:
                                case OCV_CARGO_WAITING:
                                        if (!(data < NUM_CARGO && CargoSpec::Get(data)->IsValid())) return CommandError();
                                        break;

                                default:
                                        if (data > 2047) return CommandError();
                                        break;
                        }
                        break;

                case MOF_COND_DESTINATION:
                        if (data >= v->GetNumOrders()) return CommandError();
                        break;

                case MOF_WAYPOINT_FLAGS:
                        if (data != (data & OWF_REVERSE)) return CommandError();
                        break;
        }

        if (flags & DC_EXEC) {
                switch (mof) {
                        case MOF_NON_STOP:
                                order->SetNonStopType((OrderNonStopFlags)data);
                                if (data & ONSF_NO_STOP_AT_DESTINATION_STATION) {
                                        order->SetRefit(CT_NO_REFIT);
                                        order->SetLoadType(OLF_LOAD_IF_POSSIBLE);
                                        order->SetUnloadType(OUF_UNLOAD_IF_POSSIBLE);
                                }
                                break;

                        case MOF_STOP_LOCATION:
                                order->SetStopLocation((OrderStopLocation)data);
                                break;

                        case MOF_UNLOAD:
                                order->SetUnloadType((OrderUnloadFlags)data);
                                break;
  
                        case MOF_CARGO_TYPE_UNLOAD:
                                order->SetUnloadType((OrderUnloadFlags)data, cargo_id);
                                break;

                        case MOF_LOAD:
                                order->SetLoadType((OrderLoadFlags)data);
                                if (data & OLFB_NO_LOAD) order->SetRefit(CT_NO_REFIT);
                                break;
  
                        case MOF_CARGO_TYPE_LOAD:
                                order->SetLoadType((OrderLoadFlags)data, cargo_id);
                                break;

                        case MOF_DEPOT_ACTION: {
                                switch (data) {
                                        case DA_ALWAYS_GO:
                                                order->SetDepotOrderType((OrderDepotTypeFlags)(order->GetDepotOrderType() & ~ODTFB_SERVICE));
                                                order->SetDepotActionType((OrderDepotActionFlags)(order->GetDepotActionType() & ~ODATFB_HALT));
                                                break;

                                        case DA_SERVICE:
                                                order->SetDepotOrderType((OrderDepotTypeFlags)(order->GetDepotOrderType() | ODTFB_SERVICE));
                                                order->SetDepotActionType((OrderDepotActionFlags)(order->GetDepotActionType() & ~ODATFB_HALT));
                                                order->SetRefit(CT_NO_REFIT);
                                                break;

                                        case DA_STOP:
                                                order->SetDepotOrderType((OrderDepotTypeFlags)(order->GetDepotOrderType() & ~ODTFB_SERVICE));
                                                order->SetDepotActionType((OrderDepotActionFlags)(order->GetDepotActionType() | ODATFB_HALT));
                                                order->SetRefit(CT_NO_REFIT);
                                                break;

                                        default:
                                                NOT_REACHED();
                                }
                                break;
                        }

                        case MOF_COND_VARIABLE: {
                                /* Check whether old conditional variable had a cargo as value */
                                bool old_var_was_cargo = (order->GetConditionVariable() == OCV_CARGO_ACCEPTANCE || order->GetConditionVariable() == OCV_CARGO_WAITING);
                                bool old_var_was_slot = (order->GetConditionVariable() == OCV_SLOT_OCCUPANCY);
                                order->SetConditionVariable((OrderConditionVariable)data);

                                OrderConditionComparator occ = order->GetConditionComparator();
                                switch (order->GetConditionVariable()) {
                                        case OCV_UNCONDITIONALLY:
                                                order->SetConditionComparator(OCC_EQUALS);
                                                order->SetConditionValue(0);
                                                break;

                                        case OCV_SLOT_OCCUPANCY:
                                                if (!old_var_was_slot) order->GetXDataRef() = INVALID_TRACE_RESTRICT_SLOT_ID;
                                                if (occ != OCC_IS_TRUE && occ != OCC_IS_FALSE) order->SetConditionComparator(OCC_IS_TRUE);
                                                break;
 
                                        case OCV_CARGO_ACCEPTANCE:
                                        case OCV_CARGO_WAITING:
                                                if (!old_var_was_cargo) order->SetConditionValue((uint16) GetFirstValidCargo());
                                                if (occ != OCC_IS_TRUE && occ != OCC_IS_FALSE) order->SetConditionComparator(OCC_IS_TRUE);
                                                break;

                                        case OCV_REQUIRES_SERVICE:
                                                if (old_var_was_cargo || old_var_was_slot) order->SetConditionValue(0);
                                                if (occ != OCC_IS_TRUE && occ != OCC_IS_FALSE) order->SetConditionComparator(OCC_IS_TRUE);
                                                order->SetConditionValue(0);
                                                break;
 
                                        case OCV_PERCENT:
                                                order->SetConditionComparator(OCC_EQUALS);
                                                /* FALL THROUGH */

                                        case OCV_LOAD_PERCENTAGE:
                                        case OCV_RELIABILITY:
                                                if (order->GetConditionValue() > 100) order->SetConditionValue(100);
                                                FALLTHROUGH;

                                        default:
                                                if (old_var_was_cargo || old_var_was_slot) order->SetConditionValue(0);
                                                if (occ == OCC_IS_TRUE || occ == OCC_IS_FALSE) order->SetConditionComparator(OCC_EQUALS);
                                                break;
                                }
                                break;
                        }

                        case MOF_COND_COMPARATOR:
                                order->SetConditionComparator((OrderConditionComparator)data);
                                break;

                        case MOF_COND_VALUE:
                                switch (order->GetConditionVariable()) {
                                        case OCV_SLOT_OCCUPANCY:
                                                order->GetXDataRef() = data;
                                                break;

                                        default:
                                                order->SetConditionValue(data);
                                                break;
                                }
                                break;

                        case MOF_COND_DESTINATION:
                                order->SetConditionSkipToOrder(data);
                                break;
 
                        case MOF_WAYPOINT_FLAGS:
                                order->SetWaypointFlags((OrderWaypointFlags)data);
                                break;

                        default: NOT_REACHED();
                }

                /* Update the windows and full load flags, also for vehicles that share the same order list */
                Vehicle *u = v->FirstShared();
                DeleteOrderWarnings(u);
                for (; u != nullptr; u = u->NextShared()) {
                        /* Toggle u->current_order "Full load" flag if it changed.
                         * However, as the same flag is used for depot orders, check
                         * whether we are not going to a depot as there are three
                         * cases where the full load flag can be active and only
                         * one case where the flag is used for depot orders. In the
                         * other cases for the OrderTypeByte the flags are not used,
                         * so do not care and those orders should not be active
                         * when this function is called.
                         */
                        if (sel_ord == u->cur_real_order_index &&
                                        (u->current_order.IsType(OT_GOTO_STATION) || u->current_order.IsType(OT_LOADING)) &&
                                        u->current_order.GetLoadType() != order->GetLoadType()) {
                                u->current_order.SetLoadType(order->GetLoadType());
                        }
                        InvalidateVehicleOrder(u, VIWD_MODIFY_ORDERS);
                }
                CheckMarkDirtyFocusedRoutePaths(v);
        }

        return CommandCost();
}

/**
 * Check if an aircraft has enough range for an order list.
 * @param v_new Aircraft to check.
 * @param v_order Vehicle currently holding the order list.
 * @param first First order in the source order list.
 * @return True if the aircraft has enough range for the orders, false otherwise.
 */
static bool CheckAircraftOrderDistance(const Aircraft *v_new, const Vehicle *v_order, const Order *first)
{
        if (first == nullptr || v_new->acache.cached_max_range == 0) return true;

        /* Iterate over all orders to check the distance between all
         * 'goto' orders and their respective next order (of any type). */
        for (const Order *o = first; o != nullptr; o = o->next) {
                switch (o->GetType()) {
                        case OT_GOTO_STATION:
                        case OT_GOTO_DEPOT:
                        case OT_GOTO_WAYPOINT:
                                /* If we don't have a next order, we've reached the end and must check the first order instead. */
                                if (GetOrderDistance(o, o->next != nullptr ? o->next : first, v_order) > v_new->acache.cached_max_range_sqr) return false;
                                break;

                        default: break;
                }
        }

        return true;
}

/**
 * Clone/share/copy an order-list of another vehicle.
 * @param tile unused
 * @param flags operation to perform
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0-19) - destination vehicle to clone orders to
 * - p1 = (bit 30-31) - action to perform
 * @param p2 source vehicle to clone orders from, if any (none for CO_UNSHARE)
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdCloneOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh_src = GB(p2, 0, 20);
        VehicleID veh_dst = GB(p1, 0, 20);

        Vehicle *dst = Vehicle::GetIfValid(veh_dst);
        if (dst == nullptr || !dst->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(dst->owner);
        if (ret.Failed()) return ret;

        switch (GB(p1, 30, 2)) {
                case CO_SHARE: {
                        Vehicle *src = Vehicle::GetIfValid(veh_src);

                        /* Sanity checks */
                        if (src == nullptr || !src->IsPrimaryVehicle() || dst->type != src->type || dst == src) return CommandError();

                        CommandCost ret = CheckOwnership(src->owner);
                        if (ret.Failed()) return ret;

                        /* Trucks can't share orders with busses (and visa versa) */
                        if (src->type == VEH_ROAD && RoadVehicle::From(src)->IsBus() != RoadVehicle::From(dst)->IsBus()) {
                                return CommandError();
                        }

                        /* Is the vehicle already in the shared list? */
                        if (src->FirstShared() == dst->FirstShared()) return CommandError();

                        const Order *order;

                        FOR_VEHICLE_ORDERS(src, order) {
                                if (!OrderGoesToStation(dst, order)) continue;

                                /* Allow copying unreachable destinations if they were already unreachable for the source.
                                 * This is basically to allow cloning / autorenewing / autoreplacing vehicles, while the stations
                                 * are temporarily invalid due to reconstruction. */
                                const Station *st = Station::Get(order->GetDestination());
                                if (CanVehicleUseStation(src, st) && !CanVehicleUseStation(dst, st)) {
                                        return CommandError(STR_ERROR_CAN_T_COPY_SHARE_ORDER);
                                }
                        }

                        /* Check for aircraft range limits. */
                        if (dst->type == VEH_AIRCRAFT && !CheckAircraftOrderDistance(Aircraft::From(dst), src, src->GetFirstOrder())) {
                                return CommandError(STR_ERROR_AIRCRAFT_NOT_ENOUGH_RANGE);
                        }

                        if (!src->HasOrdersList() && !OrderList::CanAllocateItem()) {
                                return CommandError(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);
                        }

                        if (flags & DC_EXEC) {
                                /* If the destination vehicle had a OrderList, destroy it.
                                 * We only reset the order indices, if the new orders are obviously different.
                                 * (We mainly do this to keep the order indices valid and in range.) */
                                dst->DeleteVehicleOrders(false, dst->GetNumOrders() != src->GetNumOrders());

                                dst->ShareOrdersWith(src);

                                /* Link this vehicle in the shared-list */
                                dst->AddToShared(src);

                                /* Set automation bit if target has it. */
                                if (HasBit(src->vehicle_flags, VF_AUTOMATE_TIMETABLE)) {
                                        SetBit(dst->vehicle_flags, VF_AUTOMATE_TIMETABLE);
                                }
                                else {
                                        ClrBit(dst->vehicle_flags, VF_AUTOMATE_TIMETABLE);
                                }

                                if (HasBit(src->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME)) {
                                        SetBit(dst->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME);
                                }
                                else {
                                        ClrBit(dst->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME);
                                }

                                InvalidateVehicleOrder(dst, VIWD_REMOVE_ALL_ORDERS);
                                InvalidateVehicleOrder(src, VIWD_MODIFY_ORDERS);

                                InvalidateWindowClassesData(GetWindowClassForVehicleType(dst->type), 0);
                                CheckMarkDirtyFocusedRoutePaths(dst);
                        }
                        break;
                }

                case CO_COPY: {
                        Vehicle *src = Vehicle::GetIfValid(veh_src);

                        /* Sanity checks */
                        if (src == nullptr || !src->IsPrimaryVehicle() || dst->type != src->type || dst == src) return CommandError();

                        CommandCost ret = CheckOwnership(src->owner);
                        if (ret.Failed()) return ret;

                        /* Trucks can't copy all the orders from busses (and visa versa),
                         * and neither can helicopters and aircraft. */
                        const Order *order;
                        FOR_VEHICLE_ORDERS(src, order) {
                                if (OrderGoesToStation(dst, order) &&
                                                !CanVehicleUseStation(dst, Station::Get(order->GetDestination()))) {
                                        return CommandError(STR_ERROR_CAN_T_COPY_SHARE_ORDER);
                                }
                        }

                        /* Check for aircraft range limits. */
                        if (dst->type == VEH_AIRCRAFT && !CheckAircraftOrderDistance(Aircraft::From(dst), src, src->GetFirstOrder())) {
                                return CommandError(STR_ERROR_AIRCRAFT_NOT_ENOUGH_RANGE);
                        }

                        /* make sure there are orders available */
                        if (!Order::CanAllocateItem(src->GetNumOrders()) || !OrderList::CanAllocateItem()) {
                                return CommandError(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);
                        }

                        if (flags & DC_EXEC) {
                                const Order *order;
                                Order *first = nullptr;
                                Order **order_dst;

                                /* If the destination vehicle had an order list, destroy the chain but keep the OrderList.
                                 * We only reset the order indices, if the new orders are obviously different.
                                 * (We mainly do this to keep the order indices valid and in range.) */
                                dst->DeleteVehicleOrders(true, dst->GetNumOrders() != src->GetNumOrders());

                                order_dst = &first;
                                FOR_VEHICLE_ORDERS(src, order) {
                                        *order_dst = new Order();
                                        (*order_dst)->AssignOrder(*order);
                                        order_dst = &(*order_dst)->next;
                                }
                                if (!dst->HasOrdersList()) {
                                        dst->SetOrdersList(new OrderList(first, dst));
                                } else {
                                        assert(dst->GetFirstOrder() == nullptr);
                                        assert(!dst->HasSharedOrdersList());
                                        dst->DeleteAndReplaceOrdersList(new OrderList(first, dst));
                                }

                                /* Set automation bit if target has it. */
                                if (HasBit(src->vehicle_flags, VF_AUTOMATE_TIMETABLE)) {
                                        SetBit(dst->vehicle_flags, VF_AUTOMATE_TIMETABLE);
                                }
                                else {
                                        ClrBit(dst->vehicle_flags, VF_AUTOMATE_TIMETABLE);
                                }

                                if (HasBit(src->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME)) {
                                        SetBit(dst->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME);
                                }
                                else {
                                        ClrBit(dst->vehicle_flags, VF_AUTOMATE_PRES_WAIT_TIME);
                                }

                                InvalidateVehicleOrder(dst, VIWD_REMOVE_ALL_ORDERS);

                                InvalidateWindowClassesData(GetWindowClassForVehicleType(dst->type), 0);
                                CheckMarkDirtyFocusedRoutePaths(dst);
                        }
                        break;
                }

                case CO_UNSHARE: return DecloneOrder(dst, flags);
                default: return CommandError();
        }

        return CommandCost();
}

/**
 * Add/remove refit orders from an order
 * @param tile Not used
 * @param flags operation to perform
 * @param p1 VehicleIndex of the vehicle having the order
 * @param p2 bitmask
 *   - bit 0-7 CargoID
 *   - bit 16-23 number of order to modify
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdOrderRefit(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        VehicleID veh = GB(p1, 0, 20);
        VehicleOrderID order_number  = GB(p2, 16, 8);
        CargoID cargo = GB(p2, 0, 8);

        if (cargo >= NUM_CARGO && cargo != CT_NO_REFIT && cargo != CT_AUTO_REFIT) return CommandError();

        const Vehicle *v = Vehicle::GetIfValid(veh);
        if (v == nullptr || !v->IsPrimaryVehicle()) return CommandError();

        CommandCost ret = CheckOwnership(v->owner);
        if (ret.Failed()) return ret;

        Order *order = v->GetOrder(order_number);
        if (order == nullptr) return CommandError();

        /* Automatic refit cargo is only supported for goto station orders. */
        if (cargo == CT_AUTO_REFIT && !order->IsType(OT_GOTO_STATION)) return CommandError();

        if (order->GetLoadType() & OLFB_NO_LOAD) return CommandError();

        if (flags & DC_EXEC) {
                order->SetRefit(cargo);

                /* Make the depot order an 'always go' order. */
                if (cargo != CT_NO_REFIT && order->IsType(OT_GOTO_DEPOT)) {
                        order->SetDepotOrderType((OrderDepotTypeFlags)(order->GetDepotOrderType() & ~ODTFB_SERVICE));
                        order->SetDepotActionType((OrderDepotActionFlags)(order->GetDepotActionType() & ~ODATFB_HALT));
                }

                for (Vehicle *u = v->FirstShared(); u != nullptr; u = u->NextShared()) {
                        /* Update any possible open window of the vehicle */
                        InvalidateVehicleOrder(u, VIWD_MODIFY_ORDERS);

                        /* If the vehicle already got the current depot set as current order, then update current order as well */
                        if (u->cur_real_order_index == order_number && (u->current_order.GetDepotOrderType() & ODTFB_PART_OF_ORDERS)) {
                                u->current_order.SetRefit(cargo);
                        }
                }
                CheckMarkDirtyFocusedRoutePaths(v);
        }

        return CommandCost();
}


/**
 *
 * Check the orders of a vehicle, to see if there are invalid orders and stuff
 *
 */
void CheckOrders(const Vehicle *v)
{
        /* Does the user wants us to check things? */
        if (_settings_client.gui.order_review_system == 0) return;

        /* Do nothing for crashed vehicles */
        if (v->vehstatus & VS_CRASHED) return;

        /* Do nothing for stopped vehicles if setting is '1' */
        if (_settings_client.gui.order_review_system == 1 && (v->vehstatus & VS_STOPPED)) return;

        /* do nothing we we're not the first vehicle in a share-chain */
        if (v->FirstShared() != v) return;

        /* Only check every 20 days, so that we don't flood the message log */
        /* The check is skipped entirely in case the current vehicle is virtual (a.k.a a 'template train') */
        if (v->owner == _local_company && v->day_counter % 20 == 0 && !HasBit(v->subtype, GVSF_VIRTUAL) ) {
                const Order *order;
                StringID message = INVALID_STRING_ID;

                /* Check the order list */
                int n_st = 0;

                FOR_VEHICLE_ORDERS(v, order) {
                        /* Dummy order? */
                        if (order->IsType(OT_DUMMY)) {
                                message = STR_NEWS_VEHICLE_HAS_VOID_ORDER;
                                break;
                        }
                        /* Does station have a load-bay for this vehicle? */
                        if (order->IsType(OT_GOTO_STATION)) {
                                const Station *st = Station::Get(order->GetDestination());

                                n_st++;
                                if (!CanVehicleUseStation(v, st)) {
                                        message = STR_NEWS_VEHICLE_HAS_INVALID_ENTRY;
                                } else if (v->type == VEH_AIRCRAFT &&
                                                        (AircraftVehInfo(v->engine_type)->subtype & AIR_FAST) &&
                                                        (st->airport.GetFTA()->flags & AirportFTAClass::SHORT_STRIP) &&
                                                        _settings_game.vehicle.plane_crashes != 0 &&
                                                        !_cheats.no_jetcrash.value &&
                                                        message == INVALID_STRING_ID) {
                                        message = STR_NEWS_PLANE_USES_TOO_SHORT_RUNWAY;
                                }
                        }
                }

                /* Check if the last and the first order are the same */
                if (v->GetNumOrders() > 1) {
                        const Order *last = v->GetLastOrder();

                        if (v->GetFirstOrder()->Equals(*last)) {
                                message = STR_NEWS_VEHICLE_HAS_DUPLICATE_ENTRY;
                        }
                }

                /* Do we only have 1 station in our order list? */
                if (n_st < 2 && message == INVALID_STRING_ID) message = STR_NEWS_VEHICLE_HAS_TOO_FEW_ORDERS;

#ifndef NDEBUG
                v->DebugCheckSanity();
#endif

                /* We don't have a problem */
                if (message == INVALID_STRING_ID) return;

                SetDParam(0, v->index);
                AddVehicleAdviceNewsItem(message, v->index);
        }
}

/**
 * Removes an order from all vehicles. Triggers when, say, a station is removed.
 * @param type The type of the order (OT_GOTO_[STATION|DEPOT|WAYPOINT]).
 * @param destination The destination. Can be a StationID, DepotID or WaypointID.
 */
void RemoveOrderFromAllVehicles(OrderType type, DestinationID destination)
{
        Vehicle *v;

        /* Aircraft have StationIDs for depot orders and never use DepotIDs
         * This fact is handled specially below
         */

        /* Go through all vehicles */
        FOR_ALL_VEHICLES(v) {
                Order *order;

                order = &v->current_order;
                if ((v->type == VEH_AIRCRAFT && order->IsType(OT_GOTO_DEPOT) ? OT_GOTO_STATION : order->GetType()) == type &&
                                v->current_order.GetDestination() == destination) {
                        order->MakeDummy();
                        SetWindowDirty(WC_VEHICLE_VIEW, v->index);
                }

                /* Clear the order from the order-list */
                int id = -1;
                FOR_VEHICLE_ORDERS(v, order) {
                        id++;
restart:

                        OrderType ot = order->GetType();
                        if (ot == OT_GOTO_DEPOT && (order->GetDepotActionType() & ODATFB_NEAREST_DEPOT) != 0) continue;
                        if (ot == OT_IMPLICIT || (v->type == VEH_AIRCRAFT && ot == OT_GOTO_DEPOT)) ot = OT_GOTO_STATION;
                        if (ot == type && order->GetDestination() == destination) {
                                /* We want to clear implicit orders, but we don't want to make them
                                 * dummy orders. They should just vanish. Also check the actual order
                                 * type as ot is currently OT_GOTO_STATION. */
                                if (order->IsType(OT_IMPLICIT)) {
                                        order = order->next; // DeleteOrder() invalidates current order
                                        DeleteOrder(v, id);
                                        if (order != nullptr) goto restart;
                                        break;
                                }

                                /* Clear wait time */
                                v->UpdateTotalDuration(-order->GetWaitTime());
                                if (order->IsWaitTimetabled()) {
                                        v->UpdateTimetableDuration(-order->GetTimetabledWait());
                                        order->SetWaitTimetabled(false);
                                }
                                order->SetWaitTime(0);

                                /* Clear order, preserving travel time */
                                bool travel_timetabled = order->IsTravelTimetabled();
                                order->MakeDummy();
                                order->SetTravelTimetabled(travel_timetabled);

                                for (const Vehicle *w = v->FirstShared(); w != nullptr; w = w->NextShared()) {
                                        /* In GUI, simulate by removing the order and adding it back */
                                        InvalidateVehicleOrder(w, id | (INVALID_VEH_ORDER_ID << 8));
                                        InvalidateVehicleOrder(w, (INVALID_VEH_ORDER_ID << 8) | id);
                                }
                        }
                }
        }

        OrderBackup::RemoveOrder(type, destination);
}

/**
 * Checks if a vehicle has a depot in its order list.
 * @return True iff at least one order is a depot order.
 */
bool Vehicle::HasDepotOrder() const
{
        const Order *order;

        FOR_VEHICLE_ORDERS(this, order) {
                if (order->IsType(OT_GOTO_DEPOT)) return true;
        }

        return false;
}

/**
 * Clamp the service interval to the correct min/max. The actual min/max values
 * depend on whether it's in percent or days.
 * @param interval proposed service interval
 * @param company_id the owner of the vehicle
 * @return Clamped service interval
 */
uint16 GetServiceIntervalClamped(uint interval, bool ispercent)
{
        return ispercent ? Clamp(interval, MIN_SERVINT_PERCENT, MAX_SERVINT_PERCENT) : Clamp(interval, MIN_SERVINT_DAYS, MAX_SERVINT_DAYS);
}

/**
 *
 * Check if a vehicle has any valid orders
 *
 * @return false if there are no valid orders
 * @note Conditional orders are not considered valid destination orders
 *
 */
static bool CheckForValidOrders(const Vehicle *v)
{
        const Order *order;

        FOR_VEHICLE_ORDERS(v, order) {
                switch (order->GetType()) {
                        case OT_GOTO_STATION:
                        case OT_GOTO_DEPOT:
                        case OT_GOTO_WAYPOINT:
                                return true;

                        default:
                                break;
                }
        }

        return false;
}

/**
 * Compare the variable and value based on the given comparator.
 */
static bool OrderConditionCompare(OrderConditionComparator occ, int variable, int value)
{
        switch (occ) {
                case OCC_EQUALS:      return variable == value;
                case OCC_NOT_EQUALS:  return variable != value;
                case OCC_LESS_THAN:   return variable <  value;
                case OCC_LESS_EQUALS: return variable <= value;
                case OCC_MORE_THAN:   return variable >  value;
                case OCC_MORE_EQUALS: return variable >= value;
                case OCC_IS_TRUE:     return variable != 0;
                case OCC_IS_FALSE:    return variable == 0;
                default: NOT_REACHED();
        }
}
 
/* Get the number of free (train) platforms in a station.
 * @param st_id The StationID of the station.
 * @return The number of free train platforms.
 */
static uint16 GetFreeStationPlatforms(StationID st_id)
{
        assert(Station::IsValidID(st_id));
        const Station *st = Station::Get(st_id);
        if (!(st->facilities & FACIL_TRAIN)) return 0;
        bool is_free;
        TileIndex t2;
        uint16 counter = 0;
        TILE_AREA_LOOP(t1, st->train_station) {
                if (st->TileBelongsToRailStation(t1)) {
                        /* We only proceed if this tile is a track tile and the north(-east/-west) end of the platform */
                        if (IsCompatibleTrainStationTile(t1 + TileOffsByDiagDir(GetRailStationAxis(t1) == AXIS_X ? DIAGDIR_NE : DIAGDIR_NW), t1) || IsStationTileBlocked(t1)) continue;
                        is_free = true;
                        t2 = t1;
                        do {
                                if (GetStationReservationTrackBits(t2)) {
                                        is_free = false;
                                        break;
                                }
                                t2 += TileOffsByDiagDir(GetRailStationAxis(t1) == AXIS_X ? DIAGDIR_SW : DIAGDIR_SE);
                        } while (IsCompatibleTrainStationTile(t2, t1));
                        if (is_free) counter++;
                }
        }
        return counter;
}

/** Gets the next 'real' station in the order list
 * @param v the vehicle in question
 * @param order the current (conditional) order
 * @return the StationID of the next valid station in the order list, or INVALID_STATION if there is none.
 */
static StationID GetNextRealStation(const Vehicle *v, const Order *order, int conditional_depth = 0)
{
        if (order->IsType(OT_GOTO_STATION)) {
                if (Station::IsValidID(order->GetDestination())) return order->GetDestination();
        }
        //nothing conditional about this
        if (conditional_depth > v->GetNumOrders()) return INVALID_STATION;
        return GetNextRealStation(v, (order->next != nullptr) ? order->next : v->GetFirstOrder(), ++conditional_depth);
}

/**
 * Process a conditional order and determine the next order.
 * @param order the order the vehicle currently has
 * @param v the vehicle to update
 * @return index of next order to jump to, or INVALID_VEH_ORDER_ID to use the next order
 */
VehicleOrderID ProcessConditionalOrder(const Order *order, const Vehicle *v)
{
        if (order->GetType() != OT_CONDITIONAL) return INVALID_VEH_ORDER_ID;

        bool skip_order = false;
        OrderConditionComparator occ = order->GetConditionComparator();
        uint16 value = order->GetConditionValue();
        bool has_manual_depot_order = (HasBit(v->vehicle_flags, VF_SHOULD_GOTO_DEPOT) || HasBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT));

        // OrderConditionCompare ignores the last parameter for occ == OCC_IS_TRUE or occ == OCC_IS_FALSE.
        switch (order->GetConditionVariable()) {
                case OCV_LOAD_PERCENTAGE:    skip_order = OrderConditionCompare(occ, CalcPercentVehicleFilled(v, nullptr),             value); break;
                case OCV_RELIABILITY:        skip_order = OrderConditionCompare(occ, ToPercent16(v->reliability),                   value); break;
                case OCV_MAX_SPEED:          skip_order = OrderConditionCompare(occ, v->GetDisplayMaxSpeed() * 10 / 16,             value); break;
                case OCV_AGE:                skip_order = OrderConditionCompare(occ, v->age / DAYS_IN_LEAP_YEAR,                    value); break;
                case OCV_REQUIRES_SERVICE:   skip_order = OrderConditionCompare(occ, has_manual_depot_order || v->NeedsServicing(), value); break;
                case OCV_UNCONDITIONALLY:    skip_order = true; break;
                case OCV_CARGO_WAITING: {
                        StationID next_station = GetNextRealStation(v, order);
                        if (Station::IsValidID(next_station)) skip_order = OrderConditionCompare(occ, Station::Get(next_station)->goods[value].cargo.AvailableCount() > 0, value);
                                break;
                }
                case OCV_CARGO_ACCEPTANCE: {
                        StationID next_station = GetNextRealStation(v, order);
                        if (Station::IsValidID(next_station)) skip_order = OrderConditionCompare(occ, HasBit(Station::Get(next_station)->goods[value].status, GoodsEntry::GES_ACCEPTANCE), value);
                        break;
                }
                case OCV_SLOT_OCCUPANCY: {
                        const TraceRestrictSlot* slot = TraceRestrictSlot::GetIfValid(order->GetXData());
                        if (slot != nullptr) skip_order = OrderConditionCompare(occ, slot->occupants.size() >= slot->max_occupancy, value);
                        break;
                }
                case OCV_FREE_PLATFORMS: {
                        StationID next_station = GetNextRealStation(v, order);
                        if (Station::IsValidID(next_station)) skip_order = OrderConditionCompare(occ, GetFreeStationPlatforms(next_station), value);
                        break;
                }
                case OCV_PERCENT: {
                        /* get a non-const reference to the current order */
                        Order *ord = (Order *)order;
                        skip_order = ord->UpdateJumpCounter((byte)value);
                        break;
                }
                case OCV_REMAINING_LIFETIME: skip_order = OrderConditionCompare(occ, max(v->max_age - v->age + DAYS_IN_LEAP_YEAR - 1, 0) / DAYS_IN_LEAP_YEAR, value); break;
                default: NOT_REACHED();
        }

        return skip_order ? order->GetConditionSkipToOrder() : (VehicleOrderID)INVALID_VEH_ORDER_ID;
}

/**
 * Update the vehicle's destination tile from an order.
 * @param order the order the vehicle currently has
 * @param v the vehicle to update
 * @param conditional_depth the depth (amount of steps) to go with conditional orders. This to prevent infinite loops.
 * @param pbs_look_ahead Whether we are forecasting orders for pbs reservations in advance. If true, the order indices must not be modified.
 */
bool UpdateOrderDest(Vehicle *v, const Order *order, int conditional_depth, bool pbs_look_ahead)
{
        if (conditional_depth > v->GetNumOrders()) {
                v->current_order.Free();
                v->dest_tile = 0;
                return false;
        }

        bool has_manual_depot_order = (HasBit(v->vehicle_flags, VF_SHOULD_GOTO_DEPOT) || HasBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT));

        switch (order->GetType()) {
                case OT_GOTO_STATION:
                        v->dest_tile = v->GetOrderStationLocation(order->GetDestination());
                        return true;

                case OT_GOTO_DEPOT:
                        if ((order->GetDepotOrderType() & ODTFB_SERVICE) && !(v->NeedsServicing() || has_manual_depot_order)) {
                                assert(!pbs_look_ahead);
                                UpdateVehicleTimetable(v, true);
                                v->IncrementRealOrderIndex();
                                break;
                        }

                        if (v->current_order.GetDepotActionType() & ODATFB_NEAREST_DEPOT) {
                                /* We need to search for the nearest depot (hangar). */
                                TileIndex location;
                                DestinationID destination;
                                bool reverse;

                                if (v->FindClosestDepot(&location, &destination, &reverse)) {
                                        /* PBS reservations cannot reverse */
                                        if (pbs_look_ahead && reverse) return false;

                                        v->dest_tile = location;
                                        v->current_order.MakeGoToDepot(destination, v->current_order.GetDepotOrderType(), v->current_order.GetNonStopType(), (OrderDepotActionFlags)(v->current_order.GetDepotActionType() & ~ODATFB_NEAREST_DEPOT), v->current_order.GetRefitCargo());

                                        /* If there is no depot in front, reverse automatically (trains only) */
                                        if (v->type == VEH_TRAIN && reverse) DoCommand(v->tile, v->index, 0, DC_EXEC, CMD_REVERSE_TRAIN_DIRECTION);

                                        if (v->type == VEH_AIRCRAFT) {
                                                Aircraft *a = Aircraft::From(v);
                                                if (a->state == FLYING && a->targetairport != destination) {
                                                        /* The aircraft is now heading for a different hangar than the next in the orders */
                                                        extern void AircraftNextAirportPos_and_Order(Aircraft *a);
                                                        AircraftNextAirportPos_and_Order(a);
                                                }
                                        }
                                        return true;
                                }

                                /* If there is no depot, we cannot help PBS either. */
                                if (pbs_look_ahead) return false;

                                UpdateVehicleTimetable(v, true);
                                v->IncrementRealOrderIndex();
                        } else {
                                if (v->type != VEH_AIRCRAFT) {
                                        v->dest_tile = Depot::Get(order->GetDestination())->xy;
                                }
                                return true;
                        }
                        break;

                case OT_GOTO_WAYPOINT:
                        v->dest_tile = Waypoint::Get(order->GetDestination())->xy;
                        return true;

                case OT_CONDITIONAL: {
                        assert(!pbs_look_ahead);
                        VehicleOrderID next_order = ProcessConditionalOrder(order, v);
                        if (next_order != INVALID_VEH_ORDER_ID) {
                                /* Jump to next_order. cur_implicit_order_index becomes exactly that order,
                                 * cur_real_order_index might come after next_order. */
                                UpdateVehicleTimetable(v, false);
                                v->cur_implicit_order_index = v->cur_real_order_index = next_order;
                                v->UpdateRealOrderIndex();
                                v->cur_timetable_order_index = v->GetIndexOfOrder(order);

                                /* Disable creation of implicit orders.
                                 * When inserting them we do not know that we would have to make the conditional orders point to them. */
                                if (v->IsGroundVehicle()) {
                                        uint16 &gv_flags = v->GetGroundVehicleFlags();
                                        SetBit(gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS);
                                }
                        } else {
                                v->cur_timetable_order_index = INVALID_VEH_ORDER_ID;
                                UpdateVehicleTimetable(v, true);
                                v->IncrementRealOrderIndex();
                        }
                        break;
                }

                default:
                        v->dest_tile = 0;
                        return false;
        }

        assert(v->cur_implicit_order_index < v->GetNumOrders());
        assert(v->cur_real_order_index < v->GetNumOrders());

        /* Get the current order */
        order = v->GetOrder(v->cur_real_order_index);
        if (order != nullptr && order->IsType(OT_IMPLICIT)) {
                assert(v->GetNumManualOrders() == 0);
                order = nullptr;
        }

        if (order == nullptr) {
                v->current_order.Free();
                v->dest_tile = 0;
                return false;
        }

        v->current_order = *order;
        return UpdateOrderDest(v, order, conditional_depth + 1, pbs_look_ahead);
}

/**
 * Handle the orders of a vehicle and determine the next place
 * to go to if needed.
 * @param v the vehicle to do this for.
 * @return true *if* the vehicle is eligible for reversing
 *              (basically only when leaving a station).
 */
bool ProcessOrders(Vehicle *v)
{
        // Check if we have an illegal manual depot order. Could happen if we deleted the depot order from the orders list after sending
        // the vehicle to the depot.
        if (HasBit(v->vehicle_flags, VF_SHOULD_GOTO_DEPOT) || HasBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT)) {
                int next_depot_index = -1;

                for (int i = 0; i < v->GetNumOrders(); ++i) {
                        Order* order = v->GetOrder(i);

                        bool isRegularOrder = (order->GetDepotOrderType() & ODTFB_PART_OF_ORDERS) != 0;
                        bool isDepotOrder = order->GetType() == OT_GOTO_DEPOT;

                        if (isRegularOrder && isDepotOrder) {
                                if (i >= v->cur_implicit_order_index) {
                                        next_depot_index = i;
                                        break;
                                }
                                else if (next_depot_index < 0) {
                                        next_depot_index = i;
                                }
                        }
                }

                if (next_depot_index == -1) {
                        ClrBit(v->vehicle_flags, VF_SHOULD_GOTO_DEPOT);
                        ClrBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT);
                }
        }

        switch (v->current_order.GetType()) {
                case OT_GOTO_DEPOT:
                        // Check whether the vehicle was manually ordered to go to the depot on its order list.
                        // If so mark the current depot order as manual, now that we are processing it.
                        if (HasBit(v->vehicle_flags, VF_SHOULD_GOTO_DEPOT) || HasBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT)) {
                                v->current_order.SetDepotOrderType(ODTF_MANUAL);
                                v->current_order.SetDepotActionType(HasBit(v->vehicle_flags, VF_SHOULD_SERVICE_AT_DEPOT) ? ODATF_SERVICE_ONLY : ODATFB_HALT);
                        }

                        /* Let a depot order in the order list interrupt. */
                        if (!(v->current_order.GetDepotOrderType() & ODTFB_PART_OF_ORDERS)) return false;

                        break;

                case OT_LOADING:
                        return false;
 
                case OT_WAITING:
                        return false;

                case OT_LEAVESTATION:
                        if (v->type != VEH_AIRCRAFT) return false;
                        break;

                default: break;
        }

        /**
         * Reversing because of order change is allowed only just after leaving a
         * station (and the difficulty setting to allowed, of course)
         * this can be detected because only after OT_LEAVESTATION, current_order
         * will be reset to nothing. (That also happens if no order, but in that case
         * it won't hit the point in code where may_reverse is checked)
         */
        bool may_reverse = v->current_order.IsType(OT_NOTHING);

        /* Check if we've reached a 'via' destination. */
        if (((v->current_order.IsType(OT_GOTO_STATION) && (v->current_order.GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION)) || v->current_order.IsType(OT_GOTO_WAYPOINT)) &&
                        IsTileType(v->tile, MP_STATION) &&
                        v->current_order.GetDestination() == GetStationIndex(v->tile)) {
                v->DeleteUnreachedImplicitOrders();
                /* We set the last visited station here because we do not want
                 * the train to stop at this 'via' station if the next order
                 * is a no-non-stop order; in that case not setting the last
                 * visited station will cause the vehicle to still stop. */
                v->last_station_visited = v->current_order.GetDestination();
                UpdateVehicleTimetable(v, true);
                v->IncrementImplicitOrderIndex();
        }

        /* Get the current order */
        assert(v->cur_implicit_order_index == 0 || v->cur_implicit_order_index < v->GetNumOrders());
        v->UpdateRealOrderIndex();

        const Order *order = v->GetOrder(v->cur_real_order_index);
        if (order != nullptr && order->IsType(OT_IMPLICIT)) {
                assert(v->GetNumManualOrders() == 0);
                order = nullptr;
        }

        /* If no order, do nothing. */
        if (order == nullptr || (v->type == VEH_AIRCRAFT && !CheckForValidOrders(v))) {
                if (v->type == VEH_AIRCRAFT) {
                        /* Aircraft do something vastly different here, so handle separately */
                        extern void HandleMissingAircraftOrders(Aircraft *v);
                        HandleMissingAircraftOrders(Aircraft::From(v));
                        return false;
                }

                v->current_order.Free();
                v->dest_tile = 0;
                return false;
        }

        /* If it is unchanged, keep it. */
        if (order->Equals(v->current_order) && (v->type == VEH_AIRCRAFT || v->dest_tile != 0) &&
                        (v->type != VEH_SHIP || !order->IsType(OT_GOTO_STATION) || Station::Get(order->GetDestination())->HasFacilities(FACIL_DOCK))) {
                return false;
        }

        /* Otherwise set it, and determine the destination tile. */
        v->current_order = *order;

        InvalidateVehicleOrder(v, VIWD_MODIFY_ORDERS);
        switch (v->type) {
                default:
                        NOT_REACHED();

                case VEH_ROAD:
                case VEH_TRAIN:
                        break;

                case VEH_AIRCRAFT:
                case VEH_SHIP:
                        SetWindowClassesDirty(GetWindowClassForVehicleType(v->type));
                        break;
        }

        return UpdateOrderDest(v, order) && may_reverse;
}

/**
 * Check whether the given vehicle should stop at the given station
 * based on this order and the non-stop settings.
 * @param v       the vehicle that might be stopping.
 * @param station the station to stop at.
 * @return true if the vehicle should stop.
 */
bool Order::ShouldStopAtStation(const Vehicle *v, StationID station) const
{
        bool is_dest_station = this->IsType(OT_GOTO_STATION) && this->dest == station;

        return (!this->IsType(OT_GOTO_DEPOT) || (this->GetDepotOrderType() & ODTFB_PART_OF_ORDERS) != 0) &&
                        v->last_station_visited != station && // Do stop only when we've not just been there
                        /* Finally do stop when there is no non-stop flag set for this type of station. */
                        !(this->GetNonStopType() & (is_dest_station ? ONSF_NO_STOP_AT_DESTINATION_STATION : ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS));
}

/**
 * A vehicle can leave the current station with cargo if:
 * 1. it can load cargo here OR
 * 2a. it could leave the last station with cargo AND
 * 2b. it doesn't have to unload all cargo here.
 */
bool Order::CanLeaveWithCargo(bool has_cargo, CargoID cargo) const
{
        return (this->GetCargoLoadType(cargo) & OLFB_NO_LOAD) == 0 || (has_cargo &&
                (this->GetCargoUnloadType(cargo) & (OUFB_UNLOAD | OUFB_TRANSFER)) == 0);
}