vehicle_cmd.cpp

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/*
 * 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/>.
 */
 
#include "stdafx.h"
#include "roadveh.h"
#include "news_func.h"
#include "airport.h"
#include "command_func.h"
#include "company_func.h"
#include "train.h"
#include "aircraft.h"
#include "newgrf_text.h"
#include "vehicle_func.h"
#include "string_func.h"
#include "depot_map.h"
#include "vehiclelist.h"
#include "engine_func.h"
#include "articulated_vehicles.h"
#include "autoreplace_gui.h"
#include "group.h"
#include "order_backup.h"
#include "ship.h"
#include "newgrf.h"
#include "company_base.h"
#include "core/random_func.hpp"
#include "vehicle_cmd.h"
#include "aircraft_cmd.h"
#include "autoreplace_cmd.h"
#include "group_cmd.h"
#include "order_cmd.h"
#include "roadveh_cmd.h"
#include "train_cmd.h"
#include "ship_cmd.h"
#include <sstream>
#include <iomanip>
 
#include "table/strings.h"
 
#include "safeguards.h"
 
/* Tables used in vehicle_func.h to find the right error message for a certain vehicle type */
const StringID _veh_build_msg_table[] = {
  STR_ERROR_CAN_T_BUY_TRAIN,
  STR_ERROR_CAN_T_BUY_ROAD_VEHICLE,
  STR_ERROR_CAN_T_BUY_SHIP,
  STR_ERROR_CAN_T_BUY_AIRCRAFT,
};
 
const StringID _veh_sell_msg_table[] = {
  STR_ERROR_CAN_T_SELL_TRAIN,
  STR_ERROR_CAN_T_SELL_ROAD_VEHICLE,
  STR_ERROR_CAN_T_SELL_SHIP,
  STR_ERROR_CAN_T_SELL_AIRCRAFT,
};
 
const StringID _veh_refit_msg_table[] = {
  STR_ERROR_CAN_T_REFIT_TRAIN,
  STR_ERROR_CAN_T_REFIT_ROAD_VEHICLE,
  STR_ERROR_CAN_T_REFIT_SHIP,
  STR_ERROR_CAN_T_REFIT_AIRCRAFT,
};
 
const StringID _send_to_depot_msg_table[] = {
  STR_ERROR_CAN_T_SEND_TRAIN_TO_DEPOT,
  STR_ERROR_CAN_T_SEND_ROAD_VEHICLE_TO_DEPOT,
  STR_ERROR_CAN_T_SEND_SHIP_TO_DEPOT,
  STR_ERROR_CAN_T_SEND_AIRCRAFT_TO_HANGAR,
};
 
 
std::tuple<CommandCost, VehicleID, uint, uint16, CargoArray> CmdBuildVehicle(DoCommandFlag flags, TileIndex tile, EngineID eid, bool use_free_vehicles, CargoID cargo, ClientID client_id)
{
  /* Elementary check for valid location. */
  if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return { CMD_ERROR, INVALID_VEHICLE, 0, 0, {} };
 
  VehicleType type = GetDepotVehicleType(tile);
 
  /* Validate the engine type. */
  if (!IsEngineBuildable(eid, type, _current_company)) return { CommandCost(STR_ERROR_RAIL_VEHICLE_NOT_AVAILABLE + type), INVALID_VEHICLE, 0, 0, {} };
 
  /* Validate the cargo type. */
  if (cargo >= NUM_CARGO && cargo != CT_INVALID) return { CMD_ERROR, INVALID_VEHICLE, 0, 0, {} };
 
  const Engine *e = Engine::Get(eid);
  CommandCost value(EXPENSES_NEW_VEHICLES, e->GetCost());
 
  /* Engines without valid cargo should not be available */
  CargoID default_cargo = e->GetDefaultCargoType();
  if (default_cargo == CT_INVALID) return { CMD_ERROR, INVALID_VEHICLE, 0, 0, {} };
 
  bool refitting = cargo != CT_INVALID && cargo != default_cargo;
 
  /* Check whether the number of vehicles we need to build can be built according to pool space. */
  uint num_vehicles;
  switch (type) {
    case VEH_TRAIN:    num_vehicles = (e->u.rail.railveh_type == RAILVEH_MULTIHEAD ? 2 : 1) + CountArticulatedParts(eid, false); break;
    case VEH_ROAD:     num_vehicles = 1 + CountArticulatedParts(eid, false); break;
    case VEH_SHIP:     num_vehicles = 1; break;
    case VEH_AIRCRAFT: num_vehicles = e->u.air.subtype & AIR_CTOL ? 2 : 3; break;
    default: NOT_REACHED(); // Safe due to IsDepotTile()
  }
  if (!Vehicle::CanAllocateItem(num_vehicles)) return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), INVALID_VEHICLE, 0, 0, {} };
 
  /* Check whether we can allocate a unit number. Autoreplace does not allocate
   * an unit number as it will (always) reuse the one of the replaced vehicle
   * and (train) wagons don't have an unit number in any scenario. */
  UnitID unit_num = (flags & DC_QUERY_COST || flags & DC_AUTOREPLACE || (type == VEH_TRAIN && e->u.rail.railveh_type == RAILVEH_WAGON)) ? 0 : GetFreeUnitNumber(type);
  if (unit_num == UINT16_MAX) return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), INVALID_VEHICLE, 0, 0, {} };
 
  /* If we are refitting we need to temporarily purchase the vehicle to be able to
   * test it. */
  DoCommandFlag subflags = flags;
  if (refitting && !(flags & DC_EXEC)) subflags |= DC_EXEC | DC_AUTOREPLACE;
 
  /* Vehicle construction needs random bits, so we have to save the random
   * seeds to prevent desyncs. */
  SavedRandomSeeds saved_seeds;
  SaveRandomSeeds(&saved_seeds);
 
  Vehicle *v = nullptr;
  switch (type) {
    case VEH_TRAIN:    value.AddCost(CmdBuildRailVehicle(subflags, tile, e, &v)); break;
    case VEH_ROAD:     value.AddCost(CmdBuildRoadVehicle(subflags, tile, e, &v)); break;
    case VEH_SHIP:     value.AddCost(CmdBuildShip       (subflags, tile, e, &v)); break;
    case VEH_AIRCRAFT: value.AddCost(CmdBuildAircraft   (subflags, tile, e, &v)); break;
    default: NOT_REACHED(); // Safe due to IsDepotTile()
  }
 
  VehicleID veh_id = INVALID_VEHICLE;
  uint refitted_capacity = 0;
  uint16 refitted_mail_capacity = 0;
  CargoArray cargo_capacities;
  if (value.Succeeded()) {
    if (subflags & DC_EXEC) {
      v->unitnumber = unit_num;
      v->value      = value.GetCost();
      veh_id        = v->index;
    }
 
    if (refitting) {
      /* Refit only one vehicle. If we purchased an engine, it may have gained free wagons. */
      CommandCost cc;
      std::tie(cc, refitted_capacity, refitted_mail_capacity, cargo_capacities) = CmdRefitVehicle(flags, v->index, cargo, 0, false, false, 1);
      value.AddCost(cc);
    } else {
      /* Fill in non-refitted capacities */
      if (e->type == VEH_TRAIN || e->type == VEH_ROAD) {
        cargo_capacities = GetCapacityOfArticulatedParts(eid);
        refitted_capacity = cargo_capacities[default_cargo];
        refitted_mail_capacity = 0;
      } else {
        refitted_capacity = e->GetDisplayDefaultCapacity(&refitted_mail_capacity);
        cargo_capacities.Clear();
        cargo_capacities[default_cargo] = refitted_capacity;
        cargo_capacities[CT_MAIL] = refitted_mail_capacity;
      }
    }
 
    if (flags & DC_EXEC) {
      if (type == VEH_TRAIN && use_free_vehicles && !(flags & DC_AUTOREPLACE)) {
        /* Move any free wagons to the new vehicle. */
        NormalizeTrainVehInDepot(Train::From(v));
      }
 
      InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
      InvalidateWindowClassesData(GetWindowClassForVehicleType(type), 0);
      SetWindowDirty(WC_COMPANY, _current_company);
      if (IsLocalCompany()) {
        InvalidateAutoreplaceWindow(v->engine_type, v->group_id); // updates the auto replace window (must be called before incrementing num_engines)
      }
    }
 
    if (subflags & DC_EXEC) {
      GroupStatistics::CountEngine(v, 1);
      GroupStatistics::UpdateAutoreplace(_current_company);
 
      if (v->IsPrimaryVehicle()) {
        GroupStatistics::CountVehicle(v, 1);
        if (!(subflags & DC_AUTOREPLACE)) OrderBackup::Restore(v, client_id);
      }
    }
 
 
    /* If we are not in DC_EXEC undo everything */
    if (flags != subflags) {
      Command<CMD_SELL_VEHICLE>::Do(DC_EXEC, v->index, false, false, INVALID_CLIENT_ID);
    }
  }
 
  /* Only restore if we actually did some refitting */
  if (flags != subflags) RestoreRandomSeeds(saved_seeds);
 
  return { value, veh_id, refitted_capacity, refitted_mail_capacity, cargo_capacities };
}
 
CommandCost CmdSellVehicle(DoCommandFlag flags, VehicleID v_id, bool sell_chain, bool backup_order, ClientID client_id)
{
  Vehicle *v = Vehicle::GetIfValid(v_id);
  if (v == nullptr) return CMD_ERROR;
 
  Vehicle *front = v->First();
 
  CommandCost ret = CheckOwnership(front->owner);
  if (ret.Failed()) return ret;
 
  if (front->vehstatus & VS_CRASHED) return_cmd_error(STR_ERROR_VEHICLE_IS_DESTROYED);
 
  if (!front->IsStoppedInDepot()) return_cmd_error(STR_ERROR_TRAIN_MUST_BE_STOPPED_INSIDE_DEPOT + front->type);
 
  /* Can we actually make the order backup, i.e. are there enough orders? */
  if (backup_order &&
      front->orders != nullptr &&
      !front->orders->IsShared() &&
      !Order::CanAllocateItem(front->orders->GetNumOrders())) {
    /* Only happens in exceptional cases when there aren't enough orders anyhow.
     * Thus it should be safe to just drop the orders in that case. */
    backup_order = false;
  }
 
  if (v->type == VEH_TRAIN) {
    ret = CmdSellRailWagon(flags, v, sell_chain, backup_order, client_id);
  } else {
    ret = CommandCost(EXPENSES_NEW_VEHICLES, -front->value);
 
    if (flags & DC_EXEC) {
      if (front->IsPrimaryVehicle() && backup_order) OrderBackup::Backup(front, client_id);
      delete front;
    }
  }
 
  return ret;
}
 
static int GetRefitCostFactor(const Vehicle *v, EngineID engine_type, CargoID new_cid, byte new_subtype, bool *auto_refit_allowed)
{
  /* Prepare callback param with info about the new cargo type. */
  const Engine *e = Engine::Get(engine_type);
 
  /* Is this vehicle a NewGRF vehicle? */
  if (e->GetGRF() != nullptr) {
    const CargoSpec *cs = CargoSpec::Get(new_cid);
    uint32 param1 = (cs->classes << 16) | (new_subtype << 8) | e->GetGRF()->cargo_map[new_cid];
 
    uint16 cb_res = GetVehicleCallback(CBID_VEHICLE_REFIT_COST, param1, 0, engine_type, v);
    if (cb_res != CALLBACK_FAILED) {
      *auto_refit_allowed = HasBit(cb_res, 14);
      int factor = GB(cb_res, 0, 14);
      if (factor >= 0x2000) factor -= 0x4000; // Treat as signed integer.
      return factor;
    }
  }
 
  *auto_refit_allowed = e->info.refit_cost == 0;
  return (v == nullptr || v->cargo_type != new_cid) ? e->info.refit_cost : 0;
}
 
static CommandCost GetRefitCost(const Vehicle *v, EngineID engine_type, CargoID new_cid, byte new_subtype, bool *auto_refit_allowed)
{
  ExpensesType expense_type;
  const Engine *e = Engine::Get(engine_type);
  Price base_price;
  int cost_factor = GetRefitCostFactor(v, engine_type, new_cid, new_subtype, auto_refit_allowed);
  switch (e->type) {
    case VEH_SHIP:
      base_price = PR_BUILD_VEHICLE_SHIP;
      expense_type = EXPENSES_SHIP_RUN;
      break;
 
    case VEH_ROAD:
      base_price = PR_BUILD_VEHICLE_ROAD;
      expense_type = EXPENSES_ROADVEH_RUN;
      break;
 
    case VEH_AIRCRAFT:
      base_price = PR_BUILD_VEHICLE_AIRCRAFT;
      expense_type = EXPENSES_AIRCRAFT_RUN;
      break;
 
    case VEH_TRAIN:
      base_price = (e->u.rail.railveh_type == RAILVEH_WAGON) ? PR_BUILD_VEHICLE_WAGON : PR_BUILD_VEHICLE_TRAIN;
      cost_factor <<= 1;
      expense_type = EXPENSES_TRAIN_RUN;
      break;
 
    default: NOT_REACHED();
  }
  if (cost_factor < 0) {
    return CommandCost(expense_type, -GetPrice(base_price, -cost_factor, e->GetGRF(), -10));
  } else {
    return CommandCost(expense_type, GetPrice(base_price, cost_factor, e->GetGRF(), -10));
  }
}
 
struct RefitResult {
  Vehicle *v;         
  uint capacity;      
  uint mail_capacity; 
  byte subtype;       
};
 
static std::tuple<CommandCost, uint, uint16, CargoArray> RefitVehicle(Vehicle *v, bool only_this, uint8 num_vehicles, CargoID new_cid, byte new_subtype, DoCommandFlag flags, bool auto_refit)
{
  CommandCost cost(v->GetExpenseType(false));
  uint total_capacity = 0;
  uint total_mail_capacity = 0;
  num_vehicles = num_vehicles == 0 ? UINT8_MAX : num_vehicles;
  CargoArray cargo_capacities;
 
  VehicleSet vehicles_to_refit;
  if (!only_this) {
    GetVehicleSet(vehicles_to_refit, v, num_vehicles);
    /* In this case, we need to check the whole chain. */
    v = v->First();
  }
 
  std::vector<RefitResult> refit_result;
 
  v->InvalidateNewGRFCacheOfChain();
  byte actual_subtype = new_subtype;
  for (; v != nullptr; v = (only_this ? nullptr : v->Next())) {
    /* Reset actual_subtype for every new vehicle */
    if (!v->IsArticulatedPart()) actual_subtype = new_subtype;
 
    if (v->type == VEH_TRAIN && std::find(vehicles_to_refit.begin(), vehicles_to_refit.end(), v->index) == vehicles_to_refit.end() && !only_this) continue;
 
    const Engine *e = v->GetEngine();
    if (!e->CanCarryCargo()) continue;
 
    /* If the vehicle is not refittable, or does not allow automatic refitting,
     * count its capacity nevertheless if the cargo matches */
    bool refittable = HasBit(e->info.refit_mask, new_cid) && (!auto_refit || HasBit(e->info.misc_flags, EF_AUTO_REFIT));
    if (!refittable && v->cargo_type != new_cid) {
      uint amount = e->DetermineCapacity(v, nullptr);
      if (amount > 0) cargo_capacities[v->cargo_type] += amount;
      continue;
    }
 
    /* Determine best fitting subtype if requested */
    if (actual_subtype == 0xFF) {
      actual_subtype = GetBestFittingSubType(v, v, new_cid);
    }
 
    /* Back up the vehicle's cargo type */
    CargoID temp_cid = v->cargo_type;
    byte temp_subtype = v->cargo_subtype;
    if (refittable) {
      v->cargo_type = new_cid;
      v->cargo_subtype = actual_subtype;
    }
 
    uint16 mail_capacity = 0;
    uint amount = e->DetermineCapacity(v, &mail_capacity);
    total_capacity += amount;
    /* mail_capacity will always be zero if the vehicle is not an aircraft. */
    total_mail_capacity += mail_capacity;
 
    cargo_capacities[new_cid] += amount;
    cargo_capacities[CT_MAIL] += mail_capacity;
 
    if (!refittable) continue;
 
    /* Restore the original cargo type */
    v->cargo_type = temp_cid;
    v->cargo_subtype = temp_subtype;
 
    bool auto_refit_allowed;
    CommandCost refit_cost = GetRefitCost(v, v->engine_type, new_cid, actual_subtype, &auto_refit_allowed);
    if (auto_refit && (flags & DC_QUERY_COST) == 0 && !auto_refit_allowed) {
      /* Sorry, auto-refitting not allowed, subtract the cargo amount again from the total.
       * When querrying cost/capacity (for example in order refit GUI), we always assume 'allowed'.
       * It is not predictable. */
      total_capacity -= amount;
      total_mail_capacity -= mail_capacity;
 
      if (v->cargo_type == new_cid) {
        /* Add the old capacity nevertheless, if the cargo matches */
        total_capacity += v->cargo_cap;
        if (v->type == VEH_AIRCRAFT) total_mail_capacity += v->Next()->cargo_cap;
      }
      continue;
    }
    cost.AddCost(refit_cost);
 
    /* Record the refitting.
     * Do not execute the refitting immediately, so DetermineCapacity and GetRefitCost do the same in test and exec run.
     * (weird NewGRFs)
     * Note:
     *  - If the capacity of vehicles depends on other vehicles in the chain, the actual capacity is
     *    set after RefitVehicle() via ConsistChanged() and friends. The estimation via _returned_refit_capacity will be wrong.
     *  - We have to call the refit cost callback with the pre-refit configuration of the chain because we want refit and
     *    autorefit to behave the same, and we need its result for auto_refit_allowed.
     */
    refit_result.push_back({v, amount, mail_capacity, actual_subtype});
  }
 
  if (flags & DC_EXEC) {
    /* Store the result */
    for (RefitResult &result : refit_result) {
      Vehicle *u = result.v;
      u->refit_cap = (u->cargo_type == new_cid) ? std::min<uint16>(result.capacity, u->refit_cap) : 0;
      if (u->cargo.TotalCount() > u->refit_cap) u->cargo.Truncate(u->cargo.TotalCount() - u->refit_cap);
      u->cargo_type = new_cid;
      u->cargo_cap = result.capacity;
      u->cargo_subtype = result.subtype;
      if (u->type == VEH_AIRCRAFT) {
        Vehicle *w = u->Next();
        w->refit_cap = std::min<uint16>(w->refit_cap, result.mail_capacity);
        w->cargo_cap = result.mail_capacity;
        if (w->cargo.TotalCount() > w->refit_cap) w->cargo.Truncate(w->cargo.TotalCount() - w->refit_cap);
      }
    }
  }
 
  refit_result.clear();
  return { cost, total_capacity, total_mail_capacity, cargo_capacities };
}
 
std::tuple<CommandCost, uint, uint16, CargoArray> CmdRefitVehicle(DoCommandFlag flags, VehicleID veh_id, CargoID new_cid, byte new_subtype, bool auto_refit, bool only_this, uint8 num_vehicles)
{
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr) return { CMD_ERROR, 0, 0, {} };
 
  /* Don't allow disasters and sparks and such to be refitted.
   * We cannot check for IsPrimaryVehicle as autoreplace also refits in free wagon chains. */
  if (!IsCompanyBuildableVehicleType(v->type)) return { CMD_ERROR, 0, 0, {} };
 
  Vehicle *front = v->First();
 
  CommandCost ret = CheckOwnership(front->owner);
  if (ret.Failed()) return { ret, 0, 0, {} };
 
  bool free_wagon = v->type == VEH_TRAIN && Train::From(front)->IsFreeWagon(); // used by autoreplace/renew
 
  /* Don't allow shadows and such to be refitted. */
  if (v != front && (v->type == VEH_SHIP || v->type == VEH_AIRCRAFT)) return { CMD_ERROR, 0, 0, {} };
 
  /* Allow auto-refitting only during loading and normal refitting only in a depot. */
  if ((flags & DC_QUERY_COST) == 0 && // used by the refit GUI, including the order refit GUI.
      !free_wagon && // used by autoreplace/renew
      (!auto_refit || !front->current_order.IsType(OT_LOADING)) && // refit inside stations
      !front->IsStoppedInDepot()) { // refit inside depots
    return { CommandCost(STR_ERROR_TRAIN_MUST_BE_STOPPED_INSIDE_DEPOT + front->type), 0, 0, {} };
  }
 
  if (front->vehstatus & VS_CRASHED) return { CommandCost(STR_ERROR_VEHICLE_IS_DESTROYED), 0, 0, {} };
 
  /* Check cargo */
  if (new_cid >= NUM_CARGO) return { CMD_ERROR, 0, 0, {} };
 
  /* For ships and aircraft there is always only one. */
  only_this |= front->type == VEH_SHIP || front->type == VEH_AIRCRAFT;
 
  auto [cost, refit_capacity, mail_capacity, cargo_capacities] = RefitVehicle(v, only_this, num_vehicles, new_cid, new_subtype, flags, auto_refit);
 
  if (flags & DC_EXEC) {
    /* Update the cached variables */
    switch (v->type) {
      case VEH_TRAIN:
        Train::From(front)->ConsistChanged(auto_refit ? CCF_AUTOREFIT : CCF_REFIT);
        break;
      case VEH_ROAD:
        RoadVehUpdateCache(RoadVehicle::From(front), auto_refit);
        if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) RoadVehicle::From(front)->CargoChanged();
        break;
 
      case VEH_SHIP:
        v->InvalidateNewGRFCacheOfChain();
        Ship::From(v)->UpdateCache();
        break;
 
      case VEH_AIRCRAFT:
        v->InvalidateNewGRFCacheOfChain();
        UpdateAircraftCache(Aircraft::From(v), true);
        break;
 
      default: NOT_REACHED();
    }
    front->MarkDirty();
 
    if (!free_wagon) {
      InvalidateWindowData(WC_VEHICLE_DETAILS, front->index);
      InvalidateWindowClassesData(GetWindowClassForVehicleType(v->type), 0);
    }
    SetWindowDirty(WC_VEHICLE_DEPOT, front->tile);
  } else {
    /* Always invalidate the cache; querycost might have filled it. */
    v->InvalidateNewGRFCacheOfChain();
  }
 
  return { cost, refit_capacity, mail_capacity, cargo_capacities };
}
 
CommandCost CmdStartStopVehicle(DoCommandFlag flags, VehicleID veh_id, bool evaluate_startstop_cb)
{
  /* Disable the effect of p2 bit 0, when DC_AUTOREPLACE is not set */
  if ((flags & DC_AUTOREPLACE) == 0) evaluate_startstop_cb = true;
 
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
  CommandCost ret = CheckOwnership(v->owner);
  if (ret.Failed()) return ret;
 
  if (v->vehstatus & VS_CRASHED) return_cmd_error(STR_ERROR_VEHICLE_IS_DESTROYED);
 
  switch (v->type) {
    case VEH_TRAIN:
      if ((v->vehstatus & VS_STOPPED) && Train::From(v)->gcache.cached_power == 0) return_cmd_error(STR_ERROR_TRAIN_START_NO_POWER);
      break;
 
    case VEH_SHIP:
    case VEH_ROAD:
      break;
 
    case VEH_AIRCRAFT: {
      Aircraft *a = Aircraft::From(v);
      /* cannot stop airplane when in flight, or when taking off / landing */
      if (a->state >= STARTTAKEOFF && a->state < TERM7) return_cmd_error(STR_ERROR_AIRCRAFT_IS_IN_FLIGHT);
      if (HasBit(a->flags, VAF_HELI_DIRECT_DESCENT)) return_cmd_error(STR_ERROR_AIRCRAFT_IS_IN_FLIGHT);
      break;
    }
 
    default: return CMD_ERROR;
  }
 
  if (evaluate_startstop_cb) {
    /* Check if this vehicle can be started/stopped. Failure means 'allow'. */
    uint16 callback = GetVehicleCallback(CBID_VEHICLE_START_STOP_CHECK, 0, 0, v->engine_type, v);
    StringID error = STR_NULL;
    if (callback != CALLBACK_FAILED) {
      if (v->GetGRF()->grf_version < 8) {
        /* 8 bit result 0xFF means 'allow' */
        if (callback < 0x400 && GB(callback, 0, 8) != 0xFF) error = GetGRFStringID(v->GetGRFID(), 0xD000 + callback);
      } else {
        if (callback < 0x400) {
          error = GetGRFStringID(v->GetGRFID(), 0xD000 + callback);
        } else {
          switch (callback) {
            case 0x400: // allow
              break;
 
            default: // unknown reason -> disallow
              error = STR_ERROR_INCOMPATIBLE_RAIL_TYPES;
              break;
          }
        }
      }
    }
    if (error != STR_NULL) return_cmd_error(error);
  }
 
  if (flags & DC_EXEC) {
    if (v->IsStoppedInDepot() && (flags & DC_AUTOREPLACE) == 0) DeleteVehicleNews(veh_id, STR_NEWS_TRAIN_IS_WAITING + v->type);
 
    v->vehstatus ^= VS_STOPPED;
    if (v->type != VEH_TRAIN) v->cur_speed = 0; // trains can stop 'slowly'
    v->MarkDirty();
    SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
    SetWindowDirty(WC_VEHICLE_DEPOT, v->tile);
    SetWindowClassesDirty(GetWindowClassForVehicleType(v->type));
    InvalidateWindowData(WC_VEHICLE_VIEW, v->index);
  }
  return CommandCost();
}
 
CommandCost CmdMassStartStopVehicle(DoCommandFlag flags, TileIndex tile, bool do_start, bool vehicle_list_window, const VehicleListIdentifier &vli)
{
  VehicleList list;
 
  if (!vli.Valid()) return CMD_ERROR;
  if (!IsCompanyBuildableVehicleType(vli.vtype)) return CMD_ERROR;
 
  if (vehicle_list_window) {
    if (!GenerateVehicleSortList(&list, vli)) return CMD_ERROR;
  } else {
    if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
    /* Get the list of vehicles in the depot */
    BuildDepotVehicleList(vli.vtype, tile, &list, nullptr);
  }
 
  for (uint i = 0; i < list.size(); i++) {
    const Vehicle *v = list[i];
 
    if (!!(v->vehstatus & VS_STOPPED) != do_start) continue;
 
    if (!vehicle_list_window && !v->IsChainInDepot()) continue;
 
    /* Just try and don't care if some vehicle's can't be stopped. */
    Command<CMD_START_STOP_VEHICLE>::Do(flags, v->index, false);
  }
 
  return CommandCost();
}
 
CommandCost CmdDepotSellAllVehicles(DoCommandFlag flags, TileIndex tile, VehicleType vehicle_type)
{
  VehicleList list;
 
  CommandCost cost(EXPENSES_NEW_VEHICLES);
 
  if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
  if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
 
  /* Get the list of vehicles in the depot */
  BuildDepotVehicleList(vehicle_type, tile, &list, &list);
 
  CommandCost last_error = CMD_ERROR;
  bool had_success = false;
  for (uint i = 0; i < list.size(); i++) {
    CommandCost ret = Command<CMD_SELL_VEHICLE>::Do(flags, list[i]->index, true, false, INVALID_CLIENT_ID);
    if (ret.Succeeded()) {
      cost.AddCost(ret);
      had_success = true;
    } else {
      last_error = ret;
    }
  }
 
  return had_success ? cost : last_error;
}
 
CommandCost CmdDepotMassAutoReplace(DoCommandFlag flags, TileIndex tile, VehicleType vehicle_type)
{
  VehicleList list;
  CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES);
 
  if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
  if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
 
  /* Get the list of vehicles in the depot */
  BuildDepotVehicleList(vehicle_type, tile, &list, &list, true);
 
  for (uint i = 0; i < list.size(); i++) {
    const Vehicle *v = list[i];
 
    /* Ensure that the vehicle completely in the depot */
    if (!v->IsChainInDepot()) continue;
 
    CommandCost ret = Command<CMD_AUTOREPLACE_VEHICLE>::Do(flags, v->index);
 
    if (ret.Succeeded()) cost.AddCost(ret);
  }
  return cost;
}
 
bool IsUniqueVehicleName(const std::string &name)
{
  for (const Vehicle *v : Vehicle::Iterate()) {
    if (!v->name.empty() && v->name == name) return false;
  }
 
  return true;
}
 
static void CloneVehicleName(const Vehicle *src, Vehicle *dst)
{
  std::string buf;
 
  /* Find the position of the first digit in the last group of digits. */
  size_t number_position;
  for (number_position = src->name.length(); number_position > 0; number_position--) {
    /* The design of UTF-8 lets this work simply without having to check
     * for UTF-8 sequences. */
    if (src->name[number_position - 1] < '0' || src->name[number_position - 1] > '9') break;
  }
 
  /* Format buffer and determine starting number. */
  long num;
  byte padding = 0;
  if (number_position == src->name.length()) {
    /* No digit at the end, so start at number 2. */
    buf = src->name;
    buf += " ";
    number_position = buf.length();
    num = 2;
  } else {
    /* Found digits, parse them and start at the next number. */
    buf = src->name.substr(0, number_position);
 
    auto num_str = src->name.substr(number_position);
    padding = (byte)num_str.length();
 
    std::istringstream iss(num_str);
    iss >> num;
    num++;
  }
 
  /* Check if this name is already taken. */
  for (int max_iterations = 1000; max_iterations > 0; max_iterations--, num++) {
    std::ostringstream oss;
 
    /* Attach the number to the temporary name. */
    oss << buf << std::setw(padding) << std::setfill('0') << std::internal << num;
 
    /* Check the name is unique. */
    auto new_name = oss.str();
    if (IsUniqueVehicleName(new_name)) {
      dst->name = new_name;
      break;
    }
  }
 
  /* All done. If we didn't find a name, it'll just use its default. */
}
 
std::tuple<CommandCost, VehicleID> CmdCloneVehicle(DoCommandFlag flags, TileIndex tile, VehicleID veh_id, bool share_orders)
{
  CommandCost total_cost(EXPENSES_NEW_VEHICLES);
 
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr || !v->IsPrimaryVehicle()) return { CMD_ERROR, INVALID_VEHICLE };
  Vehicle *v_front = v;
  Vehicle *w = nullptr;
  Vehicle *w_front = nullptr;
  Vehicle *w_rear = nullptr;
 
  /*
   * v_front is the front engine in the original vehicle
   * v is the car/vehicle of the original vehicle that is currently being copied
   * w_front is the front engine of the cloned vehicle
   * w is the car/vehicle currently being cloned
   * w_rear is the rear end of the cloned train. It's used to add more cars and is only used by trains
   */
 
  CommandCost ret = CheckOwnership(v->owner);
  if (ret.Failed()) return { ret, INVALID_VEHICLE };
 
  if (v->type == VEH_TRAIN && (!v->IsFrontEngine() || Train::From(v)->crash_anim_pos >= 4400)) return { CMD_ERROR, INVALID_VEHICLE };
 
  /* check that we can allocate enough vehicles */
  if (!(flags & DC_EXEC)) {
    int veh_counter = 0;
    do {
      veh_counter++;
    } while ((v = v->Next()) != nullptr);
 
    if (!Vehicle::CanAllocateItem(veh_counter)) {
      return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), INVALID_VEHICLE };
    }
  }
 
  v = v_front;
 
  VehicleID new_veh_id = INVALID_VEHICLE;
  do {
    if (v->type == VEH_TRAIN && Train::From(v)->IsRearDualheaded()) {
      /* we build the rear ends of multiheaded trains with the front ones */
      continue;
    }
 
    /* In case we're building a multi headed vehicle and the maximum number of
     * vehicles is almost reached (e.g. max trains - 1) not all vehicles would
     * be cloned. When the non-primary engines were build they were seen as
     * 'new' vehicles whereas they would immediately be joined with a primary
     * engine. This caused the vehicle to be not build as 'the limit' had been
     * reached, resulting in partially build vehicles and such. */
    DoCommandFlag build_flags = flags;
    if ((flags & DC_EXEC) && !v->IsPrimaryVehicle()) build_flags |= DC_AUTOREPLACE;
 
    CommandCost cost;
    std::tie(cost, new_veh_id, std::ignore, std::ignore, std::ignore) = Command<CMD_BUILD_VEHICLE>::Do(build_flags, tile, v->engine_type, false, CT_INVALID, INVALID_CLIENT_ID);
 
    if (cost.Failed()) {
      /* Can't build a part, then sell the stuff we already made; clear up the mess */
      if (w_front != nullptr) Command<CMD_SELL_VEHICLE>::Do(flags, w_front->index, true, false, INVALID_CLIENT_ID);
      return { cost, INVALID_VEHICLE };
    }
 
    total_cost.AddCost(cost);
 
    if (flags & DC_EXEC) {
      w = Vehicle::Get(new_veh_id);
 
      if (v->type == VEH_TRAIN && HasBit(Train::From(v)->flags, VRF_REVERSE_DIRECTION)) {
        SetBit(Train::From(w)->flags, VRF_REVERSE_DIRECTION);
      }
 
      if (v->type == VEH_TRAIN && !v->IsFrontEngine()) {
        /* this s a train car
         * add this unit to the end of the train */
        CommandCost result = Command<CMD_MOVE_RAIL_VEHICLE>::Do(flags, w->index, w_rear->index, true);
        if (result.Failed()) {
          /* The train can't be joined to make the same consist as the original.
           * Sell what we already made (clean up) and return an error.           */
          Command<CMD_SELL_VEHICLE>::Do(flags, w_front->index, true, false, INVALID_CLIENT_ID);
          Command<CMD_SELL_VEHICLE>::Do(flags, w->index,       true, false, INVALID_CLIENT_ID);
          return { result, INVALID_VEHICLE }; // return error and the message returned from CMD_MOVE_RAIL_VEHICLE
        }
      } else {
        /* this is a front engine or not a train. */
        w_front = w;
        w->service_interval = v->service_interval;
        w->SetServiceIntervalIsCustom(v->ServiceIntervalIsCustom());
        w->SetServiceIntervalIsPercent(v->ServiceIntervalIsPercent());
      }
      w_rear = w; // trains needs to know the last car in the train, so they can add more in next loop
    }
  } while (v->type == VEH_TRAIN && (v = v->GetNextVehicle()) != nullptr);
 
  if ((flags & DC_EXEC) && v_front->type == VEH_TRAIN) {
    /* for trains this needs to be the front engine due to the callback function */
    new_veh_id = w_front->index;
  }
 
  if (flags & DC_EXEC) {
    /* Cloned vehicles belong to the same group */
    Command<CMD_ADD_VEHICLE_GROUP>::Do(flags, v_front->group_id, w_front->index, false);
  }
 
 
  /* Take care of refitting. */
  w = w_front;
  v = v_front;
 
  /* Both building and refitting are influenced by newgrf callbacks, which
   * makes it impossible to accurately estimate the cloning costs. In
   * particular, it is possible for engines of the same type to be built with
   * different numbers of articulated parts, so when refitting we have to
   * loop over real vehicles first, and then the articulated parts of those
   * vehicles in a different loop. */
  do {
    do {
      if (flags & DC_EXEC) {
        assert(w != nullptr);
 
        /* Find out what's the best sub type */
        byte subtype = GetBestFittingSubType(v, w, v->cargo_type);
        if (w->cargo_type != v->cargo_type || w->cargo_subtype != subtype) {
          CommandCost cost = std::get<0>(Command<CMD_REFIT_VEHICLE>::Do(flags, w->index, v->cargo_type, subtype, false, true, 0));
          if (cost.Succeeded()) total_cost.AddCost(cost);
        }
 
        if (w->IsGroundVehicle() && w->HasArticulatedPart()) {
          w = w->GetNextArticulatedPart();
        } else {
          break;
        }
      } else {
        const Engine *e = v->GetEngine();
        CargoID initial_cargo = (e->CanCarryCargo() ? e->GetDefaultCargoType() : (CargoID)CT_INVALID);
 
        if (v->cargo_type != initial_cargo && initial_cargo != CT_INVALID) {
          bool dummy;
          total_cost.AddCost(GetRefitCost(nullptr, v->engine_type, v->cargo_type, v->cargo_subtype, &dummy));
        }
      }
 
      if (v->IsGroundVehicle() && v->HasArticulatedPart()) {
        v = v->GetNextArticulatedPart();
      } else {
        break;
      }
    } while (v != nullptr);
 
    if ((flags & DC_EXEC) && v->type == VEH_TRAIN) w = w->GetNextVehicle();
  } while (v->type == VEH_TRAIN && (v = v->GetNextVehicle()) != nullptr);
 
  if (flags & DC_EXEC) {
    /*
     * Set the orders of the vehicle. Cannot do it earlier as we need
     * the vehicle refitted before doing this, otherwise the moved
     * cargo types might not match (passenger vs non-passenger)
     */
    CommandCost result = Command<CMD_CLONE_ORDER>::Do(flags, (share_orders ? CO_SHARE : CO_COPY), w_front->index, v_front->index);
    if (result.Failed()) {
      /* The vehicle has already been bought, so now it must be sold again. */
      Command<CMD_SELL_VEHICLE>::Do(flags, w_front->index, true, false, INVALID_CLIENT_ID);
      return { result, INVALID_VEHICLE };
    }
 
    /* Now clone the vehicle's name, if it has one. */
    if (!v_front->name.empty()) CloneVehicleName(v_front, w_front);
 
    /* Since we can't estimate the cost of cloning a vehicle accurately we must
     * check whether the company has enough money manually. */
    if (!CheckCompanyHasMoney(total_cost)) {
      /* The vehicle has already been bought, so now it must be sold again. */
      Command<CMD_SELL_VEHICLE>::Do(flags, w_front->index, true, false, INVALID_CLIENT_ID);
      return { total_cost, INVALID_VEHICLE };
    }
  }
 
  return { total_cost, new_veh_id };
}
 
static CommandCost SendAllVehiclesToDepot(DoCommandFlag flags, bool service, const VehicleListIdentifier &vli)
{
  VehicleList list;
 
  if (!GenerateVehicleSortList(&list, vli)) return CMD_ERROR;
 
  /* Send all the vehicles to a depot */
  bool had_success = false;
  for (uint i = 0; i < list.size(); i++) {
    const Vehicle *v = list[i];
    CommandCost ret = Command<CMD_SEND_VEHICLE_TO_DEPOT>::Do(flags, v->index, (service ? DepotCommand::Service : DepotCommand::None) | DepotCommand::DontCancel, {});
 
    if (ret.Succeeded()) {
      had_success = true;
 
      /* Return 0 if DC_EXEC is not set this is a valid goto depot command)
       * In this case we know that at least one vehicle can be sent to a depot
       * and we will issue the command. We can now safely quit the loop, knowing
       * it will succeed at least once. With DC_EXEC we really need to send them to the depot */
      if (!(flags & DC_EXEC)) break;
    }
  }
 
  return had_success ? CommandCost() : CMD_ERROR;
}
 
CommandCost CmdSendVehicleToDepot(DoCommandFlag flags, VehicleID veh_id, DepotCommand depot_cmd, const VehicleListIdentifier &vli)
{
  if ((depot_cmd & DepotCommand::MassSend) != DepotCommand::None) {
    /* Mass goto depot requested */
    if (!vli.Valid()) return CMD_ERROR;
    return SendAllVehiclesToDepot(flags, (depot_cmd & DepotCommand::Service) != DepotCommand::None, vli);
  }
 
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr) return CMD_ERROR;
  if (!v->IsPrimaryVehicle()) return CMD_ERROR;
 
  return v->SendToDepot(flags, depot_cmd);
}
 
CommandCost CmdRenameVehicle(DoCommandFlag flags, VehicleID veh_id, const std::string &text)
{
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
  CommandCost ret = CheckOwnership(v->owner);
  if (ret.Failed()) return ret;
 
  bool reset = text.empty();
 
  if (!reset) {
    if (Utf8StringLength(text) >= MAX_LENGTH_VEHICLE_NAME_CHARS) return CMD_ERROR;
    if (!(flags & DC_AUTOREPLACE) && !IsUniqueVehicleName(text)) return_cmd_error(STR_ERROR_NAME_MUST_BE_UNIQUE);
  }
 
  if (flags & DC_EXEC) {
    if (reset) {
      v->name.clear();
    } else {
      v->name = text;
    }
    InvalidateWindowClassesData(GetWindowClassForVehicleType(v->type), 1);
    MarkWholeScreenDirty();
  }
 
  return CommandCost();
}
 
 
CommandCost CmdChangeServiceInt(DoCommandFlag flags, VehicleID veh_id, uint16 serv_int, bool is_custom, bool is_percent)
{
  Vehicle *v = Vehicle::GetIfValid(veh_id);
  if (v == nullptr || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
  CommandCost ret = CheckOwnership(v->owner);
  if (ret.Failed()) return ret;
 
  const Company *company = Company::Get(v->owner);
  is_percent = is_custom ? is_percent : company->settings.vehicle.servint_ispercent;
 
  if (is_custom) {
    if (serv_int != GetServiceIntervalClamped(serv_int, is_percent)) return CMD_ERROR;
  } else {
    serv_int = CompanyServiceInterval(company, v->type);
  }
 
  if (flags & DC_EXEC) {
    v->SetServiceInterval(serv_int);
    v->SetServiceIntervalIsCustom(is_custom);
    v->SetServiceIntervalIsPercent(is_percent);
    SetWindowDirty(WC_VEHICLE_DETAILS, v->index);
  }
 
  return CommandCost();
}