Rearrange storage of reserved tracks for railway tiles

[openttd/fttd.git] / src / economy.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 economy.cpp Handling of the economy. */

#include "stdafx.h"
#include "company_func.h"
#include "command_func.h"
#include "industry.h"
#include "town.h"
#include "news_func.h"
#include "network/network.h"
#include "network/network_func.h"
#include "ai/ai.hpp"
#include "aircraft.h"
#include "newgrf_engine.h"
#include "engine_base.h"
#include "ground_vehicle.hpp"
#include "newgrf_cargo.h"
#include "newgrf_sound.h"
#include "newgrf_industrytiles.h"
#include "newgrf_station.h"
#include "newgrf_airporttiles.h"
#include "object.h"
#include "strings_func.h"
#include "date_func.h"
#include "vehicle_func.h"
#include "signal_func.h"
#include "sound_func.h"
#include "autoreplace_func.h"
#include "company_gui.h"
#include "signs_base.h"
#include "subsidy_base.h"
#include "subsidy_func.h"
#include "station_base.h"
#include "waypoint_base.h"
#include "economy_base.h"
#include "core/pool_func.hpp"
#include "core/backup_type.hpp"
#include "cargo_type.h"
#include "water.h"
#include "game/game.hpp"
#include "cargomonitor.h"
#include "goal_base.h"
#include "story_base.h"
#include "linkgraph/refresh.h"

#include "table/strings.h"
#include "table/pricebase.h"


/* Initialize the cargo payment-pool */
CargoPaymentPool _cargo_payment_pool("CargoPayment");
INSTANTIATE_POOL_METHODS(CargoPayment)

/**
 * Multiply two integer values and shift the results to right.
 *
 * This function multiplies two integer values. The result is
 * shifted by the amount of shift to right.
 *
 * @param a The first integer
 * @param b The second integer
 * @param shift The amount to shift the value to right.
 * @return The shifted result
 */
static inline int32 BigMulS(const int32 a, const int32 b, const uint8 shift)
{
        return (int32)((int64)a * (int64)b >> shift);
}

typedef SmallVector<Industry *, 16> SmallIndustryList;

/**
 * Score info, values used for computing the detailed performance rating.
 */
const ScoreInfo _score_info[] = {
        {     120, 100}, // SCORE_VEHICLES
        {      80, 100}, // SCORE_STATIONS
        {   10000, 100}, // SCORE_MIN_PROFIT
        {   50000,  50}, // SCORE_MIN_INCOME
        {  100000, 100}, // SCORE_MAX_INCOME
        {   40000, 400}, // SCORE_DELIVERED
        {       8,  50}, // SCORE_CARGO
        {10000000,  50}, // SCORE_MONEY
        {  250000,  50}, // SCORE_LOAN
        {       0,   0}  // SCORE_TOTAL
};

int _score_part[MAX_COMPANIES][SCORE_END];
Economy _economy;
Prices _price;
Money _additional_cash_required;
static PriceMultipliers _price_base_multiplier;

/**
 * Calculate the value of the company. That is the value of all
 * assets (vehicles, stations, etc) and money minus the loan,
 * except when including_loan is \c false which is useful when
 * we want to calculate the value for bankruptcy.
 * @param c              the company to get the value of.
 * @param including_loan include the loan in the company value.
 * @return the value of the company.
 */
Money CalculateCompanyValue(const Company *c, bool including_loan)
{
        Owner owner = c->index;

        Station *st;
        uint num = 0;

        FOR_ALL_STATIONS(st) {
                if (st->owner == owner) num += CountBits((byte)st->facilities);
        }

        Money value = num * _price[PR_STATION_VALUE] * 25;

        Vehicle *v;
        FOR_ALL_VEHICLES(v) {
                if (v->owner != owner) continue;

                if (v->type == VEH_TRAIN ||
                                v->type == VEH_ROAD ||
                                (v->type == VEH_AIRCRAFT && Aircraft::From(v)->IsNormalAircraft()) ||
                                v->type == VEH_SHIP) {
                        value += v->value * 3 >> 1;
                }
        }

        /* Add real money value */
        if (including_loan) value -= c->current_loan;
        value += c->money;

        return max(value, (Money)1);
}

/**
 * if update is set to true, the economy is updated with this score
 *  (also the house is updated, should only be true in the on-tick event)
 * @param update the economy with calculated score
 * @param c company been evaluated
 * @return actual score of this company
 *
 */
int UpdateCompanyRatingAndValue(Company *c, bool update)
{
        Owner owner = c->index;
        int score = 0;

        memset(_score_part[owner], 0, sizeof(_score_part[owner]));

        /* Count vehicles */
        {
                Vehicle *v;
                Money min_profit = 0;
                bool min_profit_first = true;
                uint num = 0;

                FOR_ALL_VEHICLES(v) {
                        if (v->owner != owner) continue;
                        if (IsCompanyBuildableVehicleType(v->type) && v->IsPrimaryVehicle()) {
                                if (v->profit_last_year > 0) num++; // For the vehicle score only count profitable vehicles
                                if (v->age > 730) {
                                        /* Find the vehicle with the lowest amount of profit */
                                        if (min_profit_first || min_profit > v->profit_last_year) {
                                                min_profit = v->profit_last_year;
                                                min_profit_first = false;
                                        }
                                }
                        }
                }

                min_profit >>= 8; // remove the fract part

                _score_part[owner][SCORE_VEHICLES] = num;
                /* Don't allow negative min_profit to show */
                if (min_profit > 0) {
                        _score_part[owner][SCORE_MIN_PROFIT] = ClampToI32(min_profit);
                }
        }

        /* Count stations */
        {
                uint num = 0;
                const Station *st;

                FOR_ALL_STATIONS(st) {
                        /* Only count stations that are actually serviced */
                        if (st->owner == owner && (st->time_since_load <= 20 || st->time_since_unload <= 20)) num += CountBits((byte)st->facilities);
                }
                _score_part[owner][SCORE_STATIONS] = num;
        }

        /* Generate statistics depending on recent income statistics */
        {
                int numec = min(c->num_valid_stat_ent, 12);
                if (numec != 0) {
                        const CompanyEconomyEntry *cee = c->old_economy;
                        Money min_income = cee->income + cee->expenses;
                        Money max_income = cee->income + cee->expenses;

                        do {
                                min_income = min(min_income, cee->income + cee->expenses);
                                max_income = max(max_income, cee->income + cee->expenses);
                        } while (++cee, --numec);

                        if (min_income > 0) {
                                _score_part[owner][SCORE_MIN_INCOME] = ClampToI32(min_income);
                        }

                        _score_part[owner][SCORE_MAX_INCOME] = ClampToI32(max_income);
                }
        }

        /* Generate score depending on amount of transported cargo */
        {
                int numec = min(c->num_valid_stat_ent, 4);
                if (numec != 0) {
                        const CompanyEconomyEntry *cee = c->old_economy;
                        OverflowSafeInt64 total_delivered = 0;
                        do {
                                total_delivered += cee->delivered_cargo.GetSum<OverflowSafeInt64>();
                        } while (++cee, --numec);

                        _score_part[owner][SCORE_DELIVERED] = ClampToI32(total_delivered);
                }
        }

        /* Generate score for variety of cargo */
        {
                _score_part[owner][SCORE_CARGO] = c->old_economy->delivered_cargo.GetCount();
        }

        /* Generate score for company's money */
        {
                if (c->money > 0) {
                        _score_part[owner][SCORE_MONEY] = ClampToI32(c->money);
                }
        }

        /* Generate score for loan */
        {
                _score_part[owner][SCORE_LOAN] = ClampToI32(_score_info[SCORE_LOAN].needed - c->current_loan);
        }

        /* Now we calculate the score for each item.. */
        {
                int total_score = 0;
                int s;
                score = 0;
                for (ScoreID i = SCORE_BEGIN; i < SCORE_END; i++) {
                        /* Skip the total */
                        if (i == SCORE_TOTAL) continue;
                        /*  Check the score */
                        s = Clamp(_score_part[owner][i], 0, _score_info[i].needed) * _score_info[i].score / _score_info[i].needed;
                        score += s;
                        total_score += _score_info[i].score;
                }

                _score_part[owner][SCORE_TOTAL] = score;

                /*  We always want the score scaled to SCORE_MAX (1000) */
                if (total_score != SCORE_MAX) score = score * SCORE_MAX / total_score;
        }

        if (update) {
                c->old_economy[0].performance_history = score;
                UpdateCompanyHQ(c->location_of_HQ, score);
                c->old_economy[0].company_value = CalculateCompanyValue(c);
        }

        SetWindowDirty(WC_PERFORMANCE_DETAIL, 0);
        return score;
}

/**
 * Change the ownership of all the items of a company.
 * @param old_owner The company that gets removed.
 * @param new_owner The company to merge to, or INVALID_OWNER to remove the company.
 */
void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
{
        /* We need to set _current_company to old_owner before we try to move
         * the client. This is needed as it needs to know whether "you" really
         * are the current local company. */
        Backup<CompanyByte> cur_company(_current_company, old_owner, FILE_LINE);
#ifdef ENABLE_NETWORK
        /* In all cases, make spectators of clients connected to that company */
        if (_networking) NetworkClientsToSpectators(old_owner);
#endif /* ENABLE_NETWORK */
        if (old_owner == _local_company) {
                /* Single player cheated to AI company.
                 * There are no spectators in single player, so we must pick some other company. */
                assert(!_networking);
                Backup<CompanyByte> cur_company(_current_company, FILE_LINE);
                Company *c;
                FOR_ALL_COMPANIES(c) {
                        if (c->index != old_owner) {
                                SetLocalCompany(c->index);
                                break;
                        }
                }
                cur_company.Restore();
                assert(old_owner != _local_company);
        }

        Town *t;

        assert(old_owner != new_owner);

        {
                Company *c;
                uint i;

                /* See if the old_owner had shares in other companies */
                FOR_ALL_COMPANIES(c) {
                        for (i = 0; i < 4; i++) {
                                if (c->share_owners[i] == old_owner) {
                                        /* Sell his shares */
                                        CommandCost res = DoCommand(0, c->index, 0, DC_EXEC | DC_BANKRUPT, CMD_SELL_SHARE_IN_COMPANY);
                                        /* Because we are in a DoCommand, we can't just execute another one and
                                         *  expect the money to be removed. We need to do it ourself! */
                                        SubtractMoneyFromCompany(res);
                                }
                        }
                }

                /* Sell all the shares that people have on this company */
                Backup<CompanyByte> cur_company2(_current_company, FILE_LINE);
                c = Company::Get(old_owner);
                for (i = 0; i < 4; i++) {
                        cur_company2.Change(c->share_owners[i]);
                        if (_current_company != INVALID_OWNER) {
                                /* Sell the shares */
                                CommandCost res = DoCommand(0, old_owner, 0, DC_EXEC | DC_BANKRUPT, CMD_SELL_SHARE_IN_COMPANY);
                                /* Because we are in a DoCommand, we can't just execute another one and
                                 *  expect the money to be removed. We need to do it ourself! */
                                SubtractMoneyFromCompany(res);
                        }
                }
                cur_company2.Restore();
        }

        /* Temporarily increase the company's money, to be sure that
         * removing his/her property doesn't fail because of lack of money.
         * Not too drastically though, because it could overflow */
        if (new_owner == INVALID_OWNER) {
                Company::Get(old_owner)->money = UINT64_MAX >> 2; // jackpot ;p
        }

        Subsidy *s;
        FOR_ALL_SUBSIDIES(s) {
                if (s->awarded == old_owner) {
                        if (new_owner == INVALID_OWNER) {
                                delete s;
                        } else {
                                s->awarded = new_owner;
                        }
                }
        }
        if (new_owner == INVALID_OWNER) RebuildSubsidisedSourceAndDestinationCache();

        /* Take care of rating and transport rights in towns */
        FOR_ALL_TOWNS(t) {
                /* If a company takes over, give the ratings to that company. */
                if (new_owner != INVALID_OWNER) {
                        if (HasBit(t->have_ratings, old_owner)) {
                                if (HasBit(t->have_ratings, new_owner)) {
                                        /* use max of the two ratings. */
                                        t->ratings[new_owner] = max(t->ratings[new_owner], t->ratings[old_owner]);
                                } else {
                                        SetBit(t->have_ratings, new_owner);
                                        t->ratings[new_owner] = t->ratings[old_owner];
                                }
                        }
                }

                /* Reset the ratings for the old owner */
                t->ratings[old_owner] = RATING_INITIAL;
                ClrBit(t->have_ratings, old_owner);

                /* Transfer exclusive rights */
                if (t->exclusive_counter > 0 && t->exclusivity == old_owner) {
                        if (new_owner != INVALID_OWNER) {
                                t->exclusivity = new_owner;
                        } else {
                                t->exclusive_counter = 0;
                                t->exclusivity = INVALID_COMPANY;
                        }
                }
        }

        {
                Vehicle *v;
                FOR_ALL_VEHICLES(v) {
                        if (v->owner == old_owner && IsCompanyBuildableVehicleType(v->type)) {
                                if (new_owner == INVALID_OWNER) {
                                        if (v->Previous() == NULL) delete v;
                                } else {
                                        if (v->IsEngineCountable()) GroupStatistics::CountEngine(v, -1);
                                        if (v->IsPrimaryVehicle()) GroupStatistics::CountVehicle(v, -1);
                                }
                        }
                }
        }

        /* In all cases clear replace engine rules.
         * Even if it was copied, it could interfere with new owner's rules */
        RemoveAllEngineReplacementForCompany(Company::Get(old_owner));

        if (new_owner == INVALID_OWNER) {
                RemoveAllGroupsForCompany(old_owner);
        } else {
                Group *g;
                FOR_ALL_GROUPS(g) {
                        if (g->owner == old_owner) g->owner = new_owner;
                }
        }

        {
                FreeUnitIDGenerator unitidgen[] = {
                        FreeUnitIDGenerator(VEH_TRAIN, new_owner), FreeUnitIDGenerator(VEH_ROAD,     new_owner),
                        FreeUnitIDGenerator(VEH_SHIP,  new_owner), FreeUnitIDGenerator(VEH_AIRCRAFT, new_owner)
                };

                Vehicle *v;
                FOR_ALL_VEHICLES(v) {
                        if (v->owner == old_owner && IsCompanyBuildableVehicleType(v->type)) {
                                assert(new_owner != INVALID_OWNER);

                                v->owner = new_owner;

                                /* Owner changes, clear cache */
                                v->colourmap = PAL_NONE;
                                v->InvalidateNewGRFCache();

                                if (v->IsEngineCountable()) {
                                        GroupStatistics::CountEngine(v, 1);
                                }
                                if (v->IsPrimaryVehicle()) {
                                        GroupStatistics::CountVehicle(v, 1);
                                        v->unitnumber = unitidgen[v->type].NextID();
                                }

                                /* Invalidate the vehicle's cargo payment "owner cache". */
                                if (v->cargo_payment != NULL) v->cargo_payment->owner = NULL;
                        }
                }

                if (new_owner != INVALID_OWNER) GroupStatistics::UpdateAutoreplace(new_owner);
        }

        /*  Change ownership of tiles */
        {
                TileIndex tile = 0;
                do {
                        ChangeTileOwner(tile, old_owner, new_owner);
                } while (++tile != MapSize());

                if (new_owner != INVALID_OWNER) {
                        /* Update all signals because there can be new segment that was owned by two companies
                         * and signals were not propagated
                         * Similar with crossings - it is needed to bar crossings that weren't before
                         * because of different owner of crossing and approaching train */
                        tile = 0;

                        do {
                                if (IsRailwayTile(tile) && IsTileOwner(tile, new_owner)) {
                                        TrackBits tracks = GetTrackBits(tile);
                                        do { // there may be two tracks with signals for TRACK_BIT_HORZ and TRACK_BIT_VERT
                                                Track track = RemoveFirstTrack(&tracks);
                                                if (HasSignalOnTrack(tile, track)) AddTrackToSignalBuffer(tile, track, new_owner);
                                        } while (tracks != TRACK_BIT_NONE);
                                } else if (IsLevelCrossingTile(tile) && IsTileOwner(tile, new_owner)) {
                                        UpdateLevelCrossing(tile);
                                }
                        } while (++tile != MapSize());
                }

                /* update signals in buffer */
                UpdateSignalsInBuffer();
        }

        /* Add airport infrastructure count of the old company to the new one. */
        if (new_owner != INVALID_OWNER) Company::Get(new_owner)->infrastructure.airport += Company::Get(old_owner)->infrastructure.airport;

        /* convert owner of stations (including deleted ones, but excluding buoys) */
        Station *st;
        FOR_ALL_STATIONS(st) {
                if (st->owner == old_owner) {
                        /* if a company goes bankrupt, set owner to OWNER_NONE so the sign doesn't disappear immediately
                         * also, drawing station window would cause reading invalid company's colour */
                        st->owner = new_owner == INVALID_OWNER ? OWNER_NONE : new_owner;
                }
        }

        /* do the same for waypoints (we need to do this here so deleted waypoints are converted too) */
        Waypoint *wp;
        FOR_ALL_WAYPOINTS(wp) {
                if (wp->owner == old_owner) {
                        wp->owner = new_owner == INVALID_OWNER ? OWNER_NONE : new_owner;
                }
        }

        Sign *si;
        FOR_ALL_SIGNS(si) {
                if (si->owner == old_owner) si->owner = new_owner == INVALID_OWNER ? OWNER_NONE : new_owner;
        }

        /* Remove Game Script created Goals, CargoMonitors and Story pages. */
        Goal *g;
        FOR_ALL_GOALS(g) {
                if (g->company == old_owner) delete g;
        }

        ClearCargoPickupMonitoring(old_owner);
        ClearCargoDeliveryMonitoring(old_owner);

        StoryPage *sp;
        FOR_ALL_STORY_PAGES(sp) {
                if (sp->company == old_owner) delete sp;
        }

        /* Change colour of existing windows */
        if (new_owner != INVALID_OWNER) ChangeWindowOwner(old_owner, new_owner);

        cur_company.Restore();

        MarkWholeScreenDirty();
}

/**
 * Check for bankruptcy of a company. Called every three months.
 * @param c Company to check.
 */
static void CompanyCheckBankrupt(Company *c)
{
        /*  If the company has money again, it does not go bankrupt */
        if (c->money - c->current_loan >= -_economy.max_loan) {
                c->months_of_bankruptcy = 0;
                c->bankrupt_asked = 0;
                return;
        }

        c->months_of_bankruptcy++;

        switch (c->months_of_bankruptcy) {
                /* All the boring cases (months) with a bad balance where no action is taken */
                case 0:
                case 1:
                case 2:
                case 3:

                case 5:
                case 6:

                case 8:
                case 9:
                        break;

                /* Warn about bankruptcy after 3 months */
                case 4: {
                        CompanyNewsInformation *cni = MallocT<CompanyNewsInformation>(1);
                        cni->FillData(c);
                        SetDParam(0, STR_NEWS_COMPANY_IN_TROUBLE_TITLE);
                        SetDParam(1, STR_NEWS_COMPANY_IN_TROUBLE_DESCRIPTION);
                        SetDParamStr(2, cni->company_name);
                        AddCompanyNewsItem(STR_MESSAGE_NEWS_FORMAT, cni);
                        AI::BroadcastNewEvent(new ScriptEventCompanyInTrouble(c->index));
                        Game::NewEvent(new ScriptEventCompanyInTrouble(c->index));
                        break;
                }

                /* Offer company for sale after 6 months */
                case 7: {
                        /* Don't consider the loan */
                        Money val = CalculateCompanyValue(c, false);

                        c->bankrupt_value = val;
                        c->bankrupt_asked = 1 << c->index; // Don't ask the owner
                        c->bankrupt_timeout = 0;

                        /* The company assets should always have some value */
                        assert(c->bankrupt_value > 0);
                        break;
                }

                /* Bankrupt company after 6 months (if the company has no value) or latest
                 * after 9 months (if it still had value after 6 months) */
                default:
                case 10: {
                        if (!_networking && _local_company == c->index) {
                                /* If we are in offline mode, leave the company playing. Eg. there
                                 * is no THE-END, otherwise mark the client as spectator to make sure
                                 * he/she is no long in control of this company. However... when you
                                 * join another company (cheat) the "unowned" company can bankrupt. */
                                c->bankrupt_asked = MAX_UVALUE(CompanyMask);
                                break;
                        }

                        /* Actually remove the company, but not when we're a network client.
                         * In case of network clients we will be getting a command from the
                         * server. It is done in this way as we are called from the
                         * StateGameLoop which can't change the current company, and thus
                         * updating the local company triggers an assert later on. In the
                         * case of a network game the command will be processed at a time
                         * that changing the current company is okay. In case of single
                         * player we are sure (the above check) that we are not the local
                         * company and thus we won't be moved. */
                        if (!_networking || _network_server) DoCommandP(0, 2 | (c->index << 16), CRR_BANKRUPT, CMD_COMPANY_CTRL);
                        break;
                }
        }
}

/**
 * Update the finances of all companies.
 * Pay for the stations, update the history graph, update ratings and company values, and deal with bankruptcy.
 */
static void CompaniesGenStatistics()
{
        Station *st;

        Backup<CompanyByte> cur_company(_current_company, FILE_LINE);
        Company *c;

        if (!_settings_game.economy.infrastructure_maintenance) {
                FOR_ALL_STATIONS(st) {
                        cur_company.Change(st->owner);
                        CommandCost cost(EXPENSES_PROPERTY, _price[PR_STATION_VALUE] >> 1);
                        SubtractMoneyFromCompany(cost);
                }
        } else {
                /* Improved monthly infrastructure costs. */
                FOR_ALL_COMPANIES(c) {
                        cur_company.Change(c->index);

                        CommandCost cost(EXPENSES_PROPERTY);
                        uint32 rail_total = c->infrastructure.GetRailTotal();
                        for (RailType rt = RAILTYPE_BEGIN; rt < RAILTYPE_END; rt++) {
                                if (c->infrastructure.rail[rt] != 0) cost.AddCost(RailMaintenanceCost(rt, c->infrastructure.rail[rt], rail_total));
                        }
                        cost.AddCost(SignalMaintenanceCost(c->infrastructure.signal));
                        for (RoadType rt = ROADTYPE_BEGIN; rt < ROADTYPE_END; rt++) {
                                if (c->infrastructure.road[rt] != 0) cost.AddCost(RoadMaintenanceCost(rt, c->infrastructure.road[rt]));
                        }
                        cost.AddCost(CanalMaintenanceCost(c->infrastructure.water));
                        cost.AddCost(StationMaintenanceCost(c->infrastructure.station));
                        cost.AddCost(AirportMaintenanceCost(c->index));

                        SubtractMoneyFromCompany(cost);
                }
        }
        cur_company.Restore();

        /* Check for bankruptcy each month */
        FOR_ALL_COMPANIES(c) {
                CompanyCheckBankrupt(c);
        }

        /* Only run the economic statics and update company stats every 3rd month (1st of quarter). */
        if (!HasBit(1 << 0 | 1 << 3 | 1 << 6 | 1 << 9, _cur_month)) return;

        FOR_ALL_COMPANIES(c) {
                memmove(&c->old_economy[1], &c->old_economy[0], sizeof(c->old_economy) - sizeof(c->old_economy[0]));
                c->old_economy[0] = c->cur_economy;
                memset(&c->cur_economy, 0, sizeof(c->cur_economy));

                if (c->num_valid_stat_ent != MAX_HISTORY_QUARTERS) c->num_valid_stat_ent++;

                UpdateCompanyRatingAndValue(c, true);
                if (c->block_preview != 0) c->block_preview--;
        }

        SetWindowDirty(WC_INCOME_GRAPH, 0);
        SetWindowDirty(WC_OPERATING_PROFIT, 0);
        SetWindowDirty(WC_DELIVERED_CARGO, 0);
        SetWindowDirty(WC_PERFORMANCE_HISTORY, 0);
        SetWindowDirty(WC_COMPANY_VALUE, 0);
        SetWindowDirty(WC_COMPANY_LEAGUE, 0);
}

/**
 * Add monthly inflation
 * @param check_year Shall the inflation get stopped after 170 years?
 * @return true if inflation is maxed and nothing was changed
 */
bool AddInflation(bool check_year)
{
        /* The cargo payment inflation differs from the normal inflation, so the
         * relative amount of money you make with a transport decreases slowly over
         * the 170 years. After a few hundred years we reach a level in which the
         * games will become unplayable as the maximum income will be less than
         * the minimum running cost.
         *
         * Furthermore there are a lot of inflation related overflows all over the
         * place. Solving them is hardly possible because inflation will always
         * reach the overflow threshold some day. So we'll just perform the
         * inflation mechanism during the first 170 years (the amount of years that
         * one had in the original TTD) and stop doing the inflation after that
         * because it only causes problems that can't be solved nicely and the
         * inflation doesn't add anything after that either; it even makes playing
         * it impossible due to the diverging cost and income rates.
         */
        if (check_year && (_cur_year - _settings_game.game_creation.starting_year) >= (ORIGINAL_MAX_YEAR - ORIGINAL_BASE_YEAR)) return true;

        if (_economy.inflation_prices == MAX_INFLATION || _economy.inflation_payment == MAX_INFLATION) return true;

        /* Approximation for (100 + infl_amount)% ** (1 / 12) - 100%
         * scaled by 65536
         * 12 -> months per year
         * This is only a good approximation for small values
         */
        _economy.inflation_prices  += (_economy.inflation_prices  * _economy.infl_amount    * 54) >> 16;
        _economy.inflation_payment += (_economy.inflation_payment * _economy.infl_amount_pr * 54) >> 16;

        if (_economy.inflation_prices > MAX_INFLATION) _economy.inflation_prices = MAX_INFLATION;
        if (_economy.inflation_payment > MAX_INFLATION) _economy.inflation_payment = MAX_INFLATION;

        return false;
}

/**
 * Computes all prices, payments and maximum loan.
 */
void RecomputePrices()
{
        /* Setup maximum loan */
        _economy.max_loan = (_settings_game.difficulty.max_loan * _economy.inflation_prices >> 16) / 50000 * 50000;

        /* Setup price bases */
        for (Price i = PR_BEGIN; i < PR_END; i++) {
                Money price = _price_base_specs[i].start_price;

                /* Apply difficulty settings */
                uint mod = 1;
                switch (_price_base_specs[i].category) {
                        case PCAT_RUNNING:
                                mod = _settings_game.difficulty.vehicle_costs;
                                break;

                        case PCAT_CONSTRUCTION:
                                mod = _settings_game.difficulty.construction_cost;
                                break;

                        default: break;
                }
                switch (mod) {
                        case 0: price *= 6; break;
                        case 1: price *= 8; break; // normalised to 1 below
                        case 2: price *= 9; break;
                        default: NOT_REACHED();
                }

                /* Apply inflation */
                price = (int64)price * _economy.inflation_prices;

                /* Apply newgrf modifiers, remove fractional part of inflation, and normalise on medium difficulty. */
                int shift = _price_base_multiplier[i] - 16 - 3;
                if (shift >= 0) {
                        price <<= shift;
                } else {
                        price >>= -shift;
                }

                /* Make sure the price does not get reduced to zero.
                 * Zero breaks quite a few commands that use a zero
                 * cost to see whether something got changed or not
                 * and based on that cause an error. When the price
                 * is zero that fails even when things are done. */
                if (price == 0) {
                        price = Clamp(_price_base_specs[i].start_price, -1, 1);
                        /* No base price should be zero, but be sure. */
                        assert(price != 0);
                }
                /* Store value */
                _price[i] = price;
        }

        /* Setup cargo payment */
        CargoSpec *cs;
        FOR_ALL_CARGOSPECS(cs) {
                cs->current_payment = ((int64)cs->initial_payment * _economy.inflation_payment) >> 16;
        }

        SetWindowClassesDirty(WC_BUILD_VEHICLE);
        SetWindowClassesDirty(WC_REPLACE_VEHICLE);
        SetWindowClassesDirty(WC_VEHICLE_DETAILS);
        SetWindowClassesDirty(WC_COMPANY_INFRASTRUCTURE);
        InvalidateWindowData(WC_PAYMENT_RATES, 0);
}

/** Let all companies pay the monthly interest on their loan. */
static void CompaniesPayInterest()
{
        const Company *c;

        Backup<CompanyByte> cur_company(_current_company, FILE_LINE);
        FOR_ALL_COMPANIES(c) {
                cur_company.Change(c->index);

                /* Over a year the paid interest should be "loan * interest percentage",
                 * but... as that number is likely not dividable by 12 (pay each month),
                 * one needs to account for that in the monthly fee calculations.
                 * To easily calculate what one should pay "this" month, you calculate
                 * what (total) should have been paid up to this month and you subtract
                 * whatever has been paid in the previous months. This will mean one month
                 * it'll be a bit more and the other it'll be a bit less than the average
                 * monthly fee, but on average it will be exact.
                 * In order to prevent cheating or abuse (just not paying interest by not
                 * taking a loan we make companies pay interest on negative cash as well
                 */
                Money yearly_fee = c->current_loan * _economy.interest_rate / 100;
                if (c->money < 0) {
                        yearly_fee += -c->money *_economy.interest_rate / 100;
                }
                Money up_to_previous_month = yearly_fee * _cur_month / 12;
                Money up_to_this_month = yearly_fee * (_cur_month + 1) / 12;

                SubtractMoneyFromCompany(CommandCost(EXPENSES_LOAN_INT, up_to_this_month - up_to_previous_month));

                SubtractMoneyFromCompany(CommandCost(EXPENSES_OTHER, _price[PR_STATION_VALUE] >> 2));
        }
        cur_company.Restore();
}

static void HandleEconomyFluctuations()
{
        if (_settings_game.difficulty.economy != 0) {
                /* When economy is Fluctuating, decrease counter */
                _economy.fluct--;
        } else if (EconomyIsInRecession()) {
                /* When it's Steady and we are in recession, end it now */
                _economy.fluct = -12;
        } else {
                /* No need to do anything else in other cases */
                return;
        }

        if (_economy.fluct == 0) {
                _economy.fluct = -(int)GB(Random(), 0, 2);
                AddNewsItem(STR_NEWS_BEGIN_OF_RECESSION, NT_ECONOMY, NF_NORMAL);
        } else if (_economy.fluct == -12) {
                _economy.fluct = GB(Random(), 0, 8) + 312;
                AddNewsItem(STR_NEWS_END_OF_RECESSION, NT_ECONOMY, NF_NORMAL);
        }
}


/**
 * Reset changes to the price base multipliers.
 */
void ResetPriceBaseMultipliers()
{
        memset(_price_base_multiplier, 0, sizeof(_price_base_multiplier));
}

/**
 * Change a price base by the given factor.
 * The price base is altered by factors of two.
 * NewBaseCost = OldBaseCost * 2^n
 * @param price Index of price base to change.
 * @param factor Amount to change by.
 */
void SetPriceBaseMultiplier(Price price, int factor)
{
        assert(price < PR_END);
        _price_base_multiplier[price] = Clamp(factor, MIN_PRICE_MODIFIER, MAX_PRICE_MODIFIER);
}

/**
 * Initialize the variables that will maintain the daily industry change system.
 * @param init_counter specifies if the counter is required to be initialized
 */
void StartupIndustryDailyChanges(bool init_counter)
{
        uint map_size = MapLogX() + MapLogY();
        /* After getting map size, it needs to be scaled appropriately and divided by 31,
         * which stands for the days in a month.
         * Using just 31 will make it so that a monthly reset (based on the real number of days of that month)
         * would not be needed.
         * Since it is based on "fractional parts", the leftover days will not make much of a difference
         * on the overall total number of changes performed */
        _economy.industry_daily_increment = (1 << map_size) / 31;

        if (init_counter) {
                /* A new game or a savegame from an older version will require the counter to be initialized */
                _economy.industry_daily_change_counter = 0;
        }
}

void StartupEconomy()
{
        _economy.interest_rate = _settings_game.difficulty.initial_interest;
        _economy.infl_amount = _settings_game.difficulty.initial_interest;
        _economy.infl_amount_pr = max(0, _settings_game.difficulty.initial_interest - 1);
        _economy.fluct = GB(Random(), 0, 8) + 168;

        /* Set up prices */
        RecomputePrices();

        StartupIndustryDailyChanges(true); // As we are starting a new game, initialize the counter too

}

/**
 * Resets economy to initial values
 */
void InitializeEconomy()
{
        _economy.inflation_prices = _economy.inflation_payment = 1 << 16;
        ClearCargoPickupMonitoring();
        ClearCargoDeliveryMonitoring();
}

/**
 * Determine a certain price
 * @param index Price base
 * @param cost_factor Price factor
 * @param grf_file NewGRF to use local price multipliers from.
 * @param shift Extra bit shifting after the computation
 * @return Price
 */
Money GetPrice(Price index, uint cost_factor, const GRFFile *grf_file, int shift)
{
        if (index >= PR_END) return 0;

        Money cost = _price[index] * cost_factor;
        if (grf_file != NULL) shift += grf_file->price_base_multipliers[index];

        if (shift >= 0) {
                cost <<= shift;
        } else {
                cost >>= -shift;
        }

        return cost;
}

Money GetTransportedGoodsIncome(uint num_pieces, uint dist, byte transit_days, CargoID cargo_type)
{
        const CargoSpec *cs = CargoSpec::Get(cargo_type);
        if (!cs->IsValid()) {
                /* User changed newgrfs and some vehicle still carries some cargo which is no longer available. */
                return 0;
        }

        /* Use callback to calculate cargo profit, if available */
        if (HasBit(cs->callback_mask, CBM_CARGO_PROFIT_CALC)) {
                uint32 var18 = min(dist, 0xFFFF) | (min(num_pieces, 0xFF) << 16) | (transit_days << 24);
                uint16 callback = GetCargoCallback(CBID_CARGO_PROFIT_CALC, 0, var18, cs);
                if (callback != CALLBACK_FAILED) {
                        int result = GB(callback, 0, 14);

                        /* Simulate a 15 bit signed value */
                        if (HasBit(callback, 14)) result -= 0x4000;

                        /* "The result should be a signed multiplier that gets multiplied
                         * by the amount of cargo moved and the price factor, then gets
                         * divided by 8192." */
                        return result * num_pieces * cs->current_payment / 8192;
                }
        }

        static const int MIN_TIME_FACTOR = 31;
        static const int MAX_TIME_FACTOR = 255;

        const int days1 = cs->transit_days[0];
        const int days2 = cs->transit_days[1];
        const int days_over_days1 = max(   transit_days - days1, 0);
        const int days_over_days2 = max(days_over_days1 - days2, 0);

        /*
         * The time factor is calculated based on the time it took
         * (transit_days) compared two cargo-depending values. The
         * range is divided into three parts:
         *
         *  - constant for fast transits
         *  - linear decreasing with time with a slope of -1 for medium transports
         *  - linear decreasing with time with a slope of -2 for slow transports
         *
         */
        const int time_factor = max(MAX_TIME_FACTOR - days_over_days1 - days_over_days2, MIN_TIME_FACTOR);

        return BigMulS(dist * time_factor * num_pieces, cs->current_payment, 21);
}

/** The industries we've currently brought cargo to. */
static SmallIndustryList _cargo_delivery_destinations;

/**
 * Transfer goods from station to industry.
 * All cargo is delivered to the nearest (Manhattan) industry to the station sign, which is inside the acceptance rectangle and actually accepts the cargo.
 * @param st The station that accepted the cargo
 * @param cargo_type Type of cargo delivered
 * @param num_pieces Amount of cargo delivered
 * @param source The source of the cargo
 * @return actually accepted pieces of cargo
 */
static uint DeliverGoodsToIndustry(const Station *st, CargoID cargo_type, uint num_pieces, IndustryID source)
{
        /* Find the nearest industrytile to the station sign inside the catchment area, whose industry accepts the cargo.
         * This fails in three cases:
         *  1) The station accepts the cargo because there are enough houses around it accepting the cargo.
         *  2) The industries in the catchment area temporarily reject the cargo, and the daily station loop has not yet updated station acceptance.
         *  3) The results of callbacks CBID_INDUSTRY_REFUSE_CARGO and CBID_INDTILE_CARGO_ACCEPTANCE are inconsistent. (documented behaviour)
         */

        uint accepted = 0;

        for (uint i = 0; i < st->industries_near.Length() && num_pieces != 0; i++) {
                Industry *ind = st->industries_near[i];
                if (ind->index == source) continue;

                uint cargo_index;
                for (cargo_index = 0; cargo_index < lengthof(ind->accepts_cargo); cargo_index++) {
                        if (cargo_type == ind->accepts_cargo[cargo_index]) break;
                }
                /* Check if matching cargo has been found */
                if (cargo_index >= lengthof(ind->accepts_cargo)) continue;

                /* Check if industry temporarily refuses acceptance */
                if (IndustryTemporarilyRefusesCargo(ind, cargo_type)) continue;

                /* Insert the industry into _cargo_delivery_destinations, if not yet contained */
                _cargo_delivery_destinations.Include(ind);

                uint amount = min(num_pieces, 0xFFFFU - ind->incoming_cargo_waiting[cargo_index]);
                ind->incoming_cargo_waiting[cargo_index] += amount;
                num_pieces -= amount;
                accepted += amount;
        }

        return accepted;
}

/**
 * Delivers goods to industries/towns and calculates the payment
 * @param num_pieces amount of cargo delivered
 * @param cargo_type the type of cargo that is delivered
 * @param dest Station the cargo has been unloaded
 * @param source_tile The origin of the cargo for distance calculation
 * @param days_in_transit Travel time
 * @param company The company delivering the cargo
 * @param src_type Type of source of cargo (industry, town, headquarters)
 * @param src Index of source of cargo
 * @return Revenue for delivering cargo
 * @note The cargo is just added to the stockpile of the industry. It is due to the caller to trigger the industry's production machinery
 */
static Money DeliverGoods(int num_pieces, CargoID cargo_type, StationID dest, TileIndex source_tile, byte days_in_transit, Company *company, SourceType src_type, SourceID src)
{
        assert(num_pieces > 0);

        Station *st = Station::Get(dest);

        /* Give the goods to the industry. */
        uint accepted = DeliverGoodsToIndustry(st, cargo_type, num_pieces, src_type == ST_INDUSTRY ? src : INVALID_INDUSTRY);

        /* If this cargo type is always accepted, accept all */
        if (HasBit(st->always_accepted, cargo_type)) accepted = num_pieces;

        /* Update station statistics */
        if (accepted > 0) {
                SetBit(st->goods[cargo_type].acceptance_pickup, GoodsEntry::GES_EVER_ACCEPTED);
                SetBit(st->goods[cargo_type].acceptance_pickup, GoodsEntry::GES_CURRENT_MONTH);
                SetBit(st->goods[cargo_type].acceptance_pickup, GoodsEntry::GES_ACCEPTED_BIGTICK);
        }

        /* Update company statistics */
        company->cur_economy.delivered_cargo[cargo_type] += accepted;

        /* Increase town's counter for town effects */
        const CargoSpec *cs = CargoSpec::Get(cargo_type);
        st->town->received[cs->town_effect].new_act += accepted;

        /* Determine profit */
        Money profit = GetTransportedGoodsIncome(accepted, DistanceManhattan(source_tile, st->xy), days_in_transit, cargo_type);

        /* Update the cargo monitor. */
        AddCargoDelivery(cargo_type, company->index, accepted, src_type, src, st);

        /* Modify profit if a subsidy is in effect */
        if (CheckSubsidised(cargo_type, company->index, src_type, src, st))  {
                switch (_settings_game.difficulty.subsidy_multiplier) {
                        case 0:  profit += profit >> 1; break;
                        case 1:  profit *= 2; break;
                        case 2:  profit *= 3; break;
                        default: profit *= 4; break;
                }
        }

        return profit;
}

/**
 * Inform the industry about just delivered cargo
 * DeliverGoodsToIndustry() silently incremented incoming_cargo_waiting, now it is time to do something with the new cargo.
 * @param i The industry to process
 */
static void TriggerIndustryProduction(Industry *i)
{
        const IndustrySpec *indspec = GetIndustrySpec(i->type);
        uint16 callback = indspec->callback_mask;

        i->was_cargo_delivered = true;
        i->last_cargo_accepted_at = _date;

        if (HasBit(callback, CBM_IND_PRODUCTION_CARGO_ARRIVAL) || HasBit(callback, CBM_IND_PRODUCTION_256_TICKS)) {
                if (HasBit(callback, CBM_IND_PRODUCTION_CARGO_ARRIVAL)) {
                        IndustryProductionCallback(i, 0);
                } else {
                        SetWindowDirty(WC_INDUSTRY_VIEW, i->index);
                }
        } else {
                for (uint cargo_index = 0; cargo_index < lengthof(i->incoming_cargo_waiting); cargo_index++) {
                        uint cargo_waiting = i->incoming_cargo_waiting[cargo_index];
                        if (cargo_waiting == 0) continue;

                        i->produced_cargo_waiting[0] = min(i->produced_cargo_waiting[0] + (cargo_waiting * indspec->input_cargo_multiplier[cargo_index][0] / 256), 0xFFFF);
                        i->produced_cargo_waiting[1] = min(i->produced_cargo_waiting[1] + (cargo_waiting * indspec->input_cargo_multiplier[cargo_index][1] / 256), 0xFFFF);

                        i->incoming_cargo_waiting[cargo_index] = 0;
                }
        }

        TriggerIndustry(i, INDUSTRY_TRIGGER_RECEIVED_CARGO);
        StartStopIndustryTileAnimation(i, IAT_INDUSTRY_RECEIVED_CARGO);
}

/**
 * Makes us a new cargo payment helper.
 * @param front The front of the train
 */
CargoPayment::CargoPayment(Vehicle *front) :
        front(front),
        current_station(front->last_station_visited)
{
}

CargoPayment::~CargoPayment()
{
        if (this->CleaningPool()) return;

        this->front->cargo_payment = NULL;

        if (this->visual_profit == 0 && this->visual_transfer == 0) return;

        Backup<CompanyByte> cur_company(_current_company, this->front->owner, FILE_LINE);

        SubtractMoneyFromCompany(CommandCost(this->front->GetExpenseType(true), -this->route_profit));
        this->front->profit_this_year += (this->visual_profit + this->visual_transfer) << 8;

        if (this->route_profit != 0 && IsLocalCompany() && !PlayVehicleSound(this->front, VSE_LOAD_UNLOAD)) {
                SndPlayVehicleFx(SND_14_CASHTILL, this->front);
        }

        if (this->visual_transfer != 0) {
                ShowFeederIncomeAnimation(this->front->x_pos, this->front->y_pos,
                                this->front->z_pos, this->visual_transfer, -this->visual_profit);
        } else if (this->visual_profit != 0) {
                ShowCostOrIncomeAnimation(this->front->x_pos, this->front->y_pos,
                                this->front->z_pos, -this->visual_profit);
        }

        cur_company.Restore();
}

/**
 * Handle payment for final delivery of the given cargo packet.
 * @param cp The cargo packet to pay for.
 * @param count The number of packets to pay for.
 */
void CargoPayment::PayFinalDelivery(const CargoPacket *cp, uint count)
{
        if (this->owner == NULL) {
                this->owner = Company::Get(this->front->owner);
        }

        /* Handle end of route payment */
        Money profit = DeliverGoods(count, this->ct, this->current_station, cp->SourceStationXY(), cp->DaysInTransit(), this->owner, cp->SourceSubsidyType(), cp->SourceSubsidyID());
        this->route_profit += profit;

        /* The vehicle's profit is whatever route profit there is minus feeder shares. */
        this->visual_profit += profit - cp->FeederShare(count);
}

/**
 * Handle payment for transfer of the given cargo packet.
 * @param cp The cargo packet to pay for; actual payment won't be made!.
 * @param count The number of packets to pay for.
 * @return The amount of money paid for the transfer.
 */
Money CargoPayment::PayTransfer(const CargoPacket *cp, uint count)
{
        Money profit = GetTransportedGoodsIncome(
                        count,
                        /* pay transfer vehicle for only the part of transfer it has done: ie. cargo_loaded_at_xy to here */
                        DistanceManhattan(cp->LoadedAtXY(), Station::Get(this->current_station)->xy),
                        cp->DaysInTransit(),
                        this->ct);

        profit = profit * _settings_game.economy.feeder_payment_share / 100;

        this->visual_transfer += profit; // accumulate transfer profits for whole vehicle
        return profit; // account for the (virtual) profit already made for the cargo packet
}

/**
 * Prepare the vehicle to be unloaded.
 * @param curr_station the station where the consist is at the moment
 * @param front_v the vehicle to be unloaded
 */
void PrepareUnload(Vehicle *front_v)
{
        Station *curr_station = Station::Get(front_v->last_station_visited);
        curr_station->loading_vehicles.push_back(front_v);

        /* At this moment loading cannot be finished */
        ClrBit(front_v->vehicle_flags, VF_LOADING_FINISHED);

        /* Start unloading at the first possible moment */
        front_v->load_unload_ticks = 1;

        assert(front_v->cargo_payment == NULL);
        /* One CargoPayment per vehicle and the vehicle limit equals the
         * limit in number of CargoPayments. Can't go wrong. */
        assert_compile(CargoPaymentPool::MAX_SIZE == VehiclePool::MAX_SIZE);
        assert(CargoPayment::CanAllocateItem());
        front_v->cargo_payment = new CargoPayment(front_v);

        StationIDStack next_station = front_v->GetNextStoppingStation();
        if (front_v->orders.list == NULL || (front_v->current_order.GetUnloadType() & OUFB_NO_UNLOAD) == 0) {
                Station *st = Station::Get(front_v->last_station_visited);
                for (Vehicle *v = front_v; v != NULL; v = v->Next()) {
                        const GoodsEntry *ge = &st->goods[v->cargo_type];
                        if (v->cargo_cap > 0 && v->cargo.TotalCount() > 0) {
                                v->cargo.Stage(
                                                HasBit(ge->acceptance_pickup, GoodsEntry::GES_ACCEPTANCE),
                                                front_v->last_station_visited, next_station,
                                                front_v->current_order.GetUnloadType(), ge,
                                                front_v->cargo_payment);
                                if (v->cargo.UnloadCount() > 0) SetBit(v->vehicle_flags, VF_CARGO_UNLOADING);
                        }
                }
        }
}

/**
 * Gets the amount of cargo the given vehicle can load in the current tick.
 * This is only about loading speed. The free capacity is ignored.
 * @param v Vehicle to be queried.
 * @return Amount of cargo the vehicle can load at once.
 */
static uint GetLoadAmount(Vehicle *v)
{
        const Engine *e = v->GetEngine();
        uint load_amount = e->info.load_amount;

        /* The default loadamount for mail is 1/4 of the load amount for passengers */
        bool air_mail = v->type == VEH_AIRCRAFT && !Aircraft::From(v)->IsNormalAircraft();
        if (air_mail) load_amount = CeilDiv(load_amount, 4);

        if (_settings_game.order.gradual_loading) {
                uint16 cb_load_amount = CALLBACK_FAILED;
                if (e->GetGRF() != NULL && e->GetGRF()->grf_version >= 8) {
                        /* Use callback 36 */
                        cb_load_amount = GetVehicleProperty(v, PROP_VEHICLE_LOAD_AMOUNT, CALLBACK_FAILED);
                } else if (HasBit(e->info.callback_mask, CBM_VEHICLE_LOAD_AMOUNT)) {
                        /* Use callback 12 */
                        cb_load_amount = GetVehicleCallback(CBID_VEHICLE_LOAD_AMOUNT, 0, 0, v->engine_type, v);
                }
                if (cb_load_amount != CALLBACK_FAILED) {
                        if (e->GetGRF()->grf_version < 8) cb_load_amount = GB(cb_load_amount, 0, 8);
                        if (cb_load_amount >= 0x100) {
                                ErrorUnknownCallbackResult(e->GetGRFID(), CBID_VEHICLE_LOAD_AMOUNT, cb_load_amount);
                        } else if (cb_load_amount != 0) {
                                load_amount = cb_load_amount;
                        }
                }
        }

        /* Scale load amount the same as capacity */
        if (HasBit(e->info.misc_flags, EF_NO_DEFAULT_CARGO_MULTIPLIER) && !air_mail) load_amount = CeilDiv(load_amount * CargoSpec::Get(v->cargo_type)->multiplier, 0x100);

        return load_amount;
}

/**
 * Reserves cargo if the full load order and improved_load is set or if the
 * current order allows autorefit.
 * @param st Station where the consist is loading at the moment.
 * @param u Front of the loading vehicle consist.
 * @param consist_capleft If given, save free capacities after reserving there.
 * @param next_station Station(s) the vehicle will stop at next.
 */
static void ReserveConsist(Station *st, Vehicle *u, CargoArray *consist_capleft, StationIDStack next_station)
{
        Vehicle *next_cargo = u;
        uint32 seen_cargos = 0;

        while (next_cargo != NULL) {
                if (next_cargo->cargo_cap == 0) {
                        /* No need to reserve for vehicles without capacity. */
                        next_cargo = next_cargo->Next();
                        continue;
                }

                CargoID current_cargo = next_cargo->cargo_type;

                Vehicle *v = next_cargo;
                SetBit(seen_cargos, current_cargo);
                next_cargo = NULL;
                for (; v != NULL; v = v->Next()) {
                        if (v->cargo_type != current_cargo) {
                                /* Save start point for next cargo type. */
                                if (next_cargo == NULL && !HasBit(seen_cargos, v->cargo_type)) next_cargo = v;
                                continue;
                        }

                        assert(v->cargo_cap >= v->cargo.RemainingCount());
                        uint cap = v->cargo_cap - v->cargo.RemainingCount();

                        /* Nothing to do if the vehicle is full */
                        if (cap > 0) {
                                cap -= st->goods[v->cargo_type].cargo.Reserve(cap, &v->cargo, st->xy, next_station);
                        }

                        if (consist_capleft != NULL) {
                                (*consist_capleft)[current_cargo] += cap;
                        }
                }
        }
}

/**
 * Checks whether an articulated vehicle is empty.
 * @param v Vehicle
 * @return true if all parts are empty.
 */
static bool IsArticulatedVehicleEmpty(Vehicle *v)
{
        v = v->GetFirstEnginePart();

        for (; v != NULL; v = v->HasArticulatedPart() ? v->GetNextArticulatedPart() : NULL) {
                if (v->cargo.StoredCount() != 0) return false;
        }

        return true;
}

/**
 * Refit a vehicle in a station.
 * @param v Vehicle to be refitted.
 * @param consist_capleft Added cargo capacities in the consist.
 * @param st Station the vehicle is loading at.
 * @param next_station Possible next stations the vehicle can travel to.
 * @param new_cid Target cargo for refit.
 */
static void HandleStationRefit(Vehicle *v, CargoArray &consist_capleft, Station *st, StationIDStack next_station, CargoID new_cid)
{
        if (v->type == VEH_AIRCRAFT && (!Aircraft::From(v)->IsNormalAircraft() || v->Next()->cargo.StoredCount() > 0)) {
                return;
        }

        bool is_normal_aircraft = (v->type == VEH_AIRCRAFT && Aircraft::From(v)->IsNormalAircraft());
        Vehicle *v_start = v->GetFirstEnginePart();

        /* Remove old capacity from consist capacity */
        consist_capleft[v_start->cargo_type] -= (v_start->cargo_cap - v_start->cargo.ReservedCount());
        for (Vehicle *w = v_start; w->HasArticulatedPart(); ) {
                w = w->GetNextArticulatedPart();
                consist_capleft[w->cargo_type] -= (w->cargo_cap - w->cargo.ReservedCount());
        }
        if (is_normal_aircraft) {
                consist_capleft[v->Next()->cargo_type] -= (v->Next()->cargo_cap - v->Next()->cargo.ReservedCount());
        }

        Backup<CompanyByte> cur_company(_current_company, v->owner, FILE_LINE);

        /* Check if all articulated parts are empty and collect refit mask. */
        uint32 refit_mask = v->GetEngine()->info.refit_mask;
        Vehicle *w = v_start;
        while (w->HasArticulatedPart()) {
                w = w->GetNextArticulatedPart();
                refit_mask |= EngInfo(w->engine_type)->refit_mask;
        }

        if (new_cid == CT_AUTO_REFIT) {
                /* Get a refittable cargo type with waiting cargo for next_station or INVALID_STATION. */
                CargoID cid;
                new_cid = v_start->cargo_type;
                FOR_EACH_SET_CARGO_ID(cid, refit_mask) {
                        if (st->goods[cid].cargo.HasCargoFor(next_station)) {
                                /* Try to find out if auto-refitting would succeed. In case the refit is allowed,
                                 * the returned refit capacity will be greater than zero. */
                                DoCommand(v_start->tile, v_start->index, cid | 1U << 6 | 0xFF << 8 | 1U << 16, DC_QUERY_COST, GetCmdRefitVeh(v_start)); // Auto-refit and only this vehicle including artic parts.
                                /* Try to balance different loadable cargoes between parts of the consist, so that
                                 * all of them can be loaded. Avoid a situation where all vehicles suddenly switch
                                 * to the first loadable cargo for which there is only one packet. */
                                if (_returned_refit_capacity > 0 && consist_capleft[cid] < consist_capleft[new_cid]) {
                                        new_cid = cid;
                                }
                        }
                }
        }

        /* Refit if given a valid cargo. */
        if (new_cid < NUM_CARGO && new_cid != v_start->cargo_type) {
                StationID next_one = StationIDStack(next_station).Pop();
                v_start->cargo.Return(UINT_MAX, &st->goods[v_start->cargo_type].cargo, next_one);
                for (w = v_start; w->HasArticulatedPart();) {
                        w = w->GetNextArticulatedPart();
                        w->cargo.Return(UINT_MAX, &st->goods[w->cargo_type].cargo, next_one);
                }
                if (is_normal_aircraft) {
                        v->Next()->cargo.Return(UINT_MAX, &st->goods[v->Next()->cargo_type].cargo, next_one);
                }
                CommandCost cost = DoCommand(v_start->tile, v_start->index, new_cid | 1U << 6 | 0xFF << 8 | 1U << 16, DC_EXEC, GetCmdRefitVeh(v_start)); // Auto-refit and only this vehicle including artic parts.
                if (cost.Succeeded()) v->First()->profit_this_year -= cost.GetCost() << 8;
        }

        /* Add new capacity to consist capacity and reserve cargo */
        w = v_start;
        do {
                st->goods[w->cargo_type].cargo.Reserve(w->cargo_cap, &w->cargo, st->xy, next_station);
                consist_capleft[w->cargo_type] += w->cargo_cap - w->cargo.RemainingCount();
                w = w->HasArticulatedPart() ? w->GetNextArticulatedPart() : NULL;
        } while (w != NULL);
        if (is_normal_aircraft) {
                consist_capleft[v->Next()->cargo_type] += v->Next()->cargo_cap - v->Next()->cargo.RemainingCount();
        }

        cur_company.Restore();
}

/**
 * Loads/unload the vehicle if possible.
 * @param front the vehicle to be (un)loaded
 */
static void LoadUnloadVehicle(Vehicle *front)
{
        assert(front->current_order.IsType(OT_LOADING));

        StationID last_visited = front->last_station_visited;
        Station *st = Station::Get(last_visited);

        StationIDStack next_station = front->GetNextStoppingStation();
        bool use_autorefit = front->current_order.IsRefit() && front->current_order.GetRefitCargo() == CT_AUTO_REFIT;
        CargoArray consist_capleft;
        if (_settings_game.order.improved_load &&
                        ((front->current_order.GetLoadType() & OLFB_FULL_LOAD) != 0 || use_autorefit)) {
                ReserveConsist(st, front,
                                (use_autorefit && front->load_unload_ticks != 0) ? &consist_capleft : NULL,
                                next_station);
        }

        /* We have not waited enough time till the next round of loading/unloading */
        if (front->load_unload_ticks != 0) return;

        if (front->type == VEH_TRAIN && (!IsStationTile(front->tile) || GetStationIndex(front->tile) != st->index)) {
                /* The train reversed in the station. Take the "easy" way
                 * out and let the train just leave as it always did. */
                SetBit(front->vehicle_flags, VF_LOADING_FINISHED);
                front->load_unload_ticks = 1;
                return;
        }

        int unloading_time = 0;
        bool dirty_vehicle = false;
        bool dirty_station = false;

        bool completely_emptied = true;
        bool anything_unloaded  = false;
        bool anything_loaded    = false;
        uint32 full_load_amount = 0;
        uint32 cargo_not_full   = 0;
        uint32 cargo_full       = 0;
        uint32 reservation_left = 0;

        front->cur_speed = 0;

        CargoPayment *payment = front->cargo_payment;

        uint artic_part = 0; // Articulated part we are currently trying to load. (not counting parts without capacity)
        for (Vehicle *v = front; v != NULL; v = v->Next()) {
                if (v == front || !v->Previous()->HasArticulatedPart()) artic_part = 0;
                if (v->cargo_cap == 0) continue;
                artic_part++;

                uint load_amount = GetLoadAmount(v);

                GoodsEntry *ge = &st->goods[v->cargo_type];

                if (HasBit(v->vehicle_flags, VF_CARGO_UNLOADING) && (front->current_order.GetUnloadType() & OUFB_NO_UNLOAD) == 0) {
                        uint cargo_count = v->cargo.UnloadCount();
                        uint amount_unloaded = _settings_game.order.gradual_loading ? min(cargo_count, load_amount) : cargo_count;
                        bool remaining = false; // Are there cargo entities in this vehicle that can still be unloaded here?

                        payment->SetCargo(v->cargo_type);

                        if (!HasBit(ge->acceptance_pickup, GoodsEntry::GES_ACCEPTANCE) && v->cargo.ActionCount(VehicleCargoList::MTA_DELIVER) > 0) {
                                /* The station does not accept our goods anymore. */
                                if (front->current_order.GetUnloadType() & (OUFB_TRANSFER | OUFB_UNLOAD)) {
                                        /* Transfer instead of delivering. */
                                        v->cargo.Reassign(v->cargo.ActionCount(VehicleCargoList::MTA_DELIVER),
                                                        VehicleCargoList::MTA_DELIVER, VehicleCargoList::MTA_TRANSFER);
                                } else {
                                        uint new_remaining = v->cargo.RemainingCount() + v->cargo.ActionCount(VehicleCargoList::MTA_DELIVER);
                                        if (v->cargo_cap < new_remaining) {
                                                /* Return some of the reserved cargo to not overload the vehicle. */
                                                v->cargo.Return(new_remaining - v->cargo_cap, &ge->cargo, INVALID_STATION);
                                        }

                                        /* Keep instead of delivering. This may lead to no cargo being unloaded, so ...*/
                                        v->cargo.Reassign(v->cargo.ActionCount(VehicleCargoList::MTA_DELIVER),
                                                        VehicleCargoList::MTA_DELIVER, VehicleCargoList::MTA_KEEP);

                                        /* ... say we unloaded something, otherwise we'll think we didn't unload
                                         * something and we didn't load something, so we must be finished
                                         * at this station. Setting the unloaded means that we will get a
                                         * retry for loading in the next cycle. */
                                        anything_unloaded = true;
                                }
                        }

                        /* Mark the station dirty if we transfer, but not if we only deliver. */
                        dirty_station = v->cargo.ActionCount(VehicleCargoList::MTA_TRANSFER) > 0;
                        amount_unloaded = v->cargo.Unload(amount_unloaded, &ge->cargo, payment);
                        remaining = v->cargo.UnloadCount() > 0;
                        if (amount_unloaded > 0) {
                                dirty_vehicle = true;
                                anything_unloaded = true;
                                unloading_time += amount_unloaded;

                                /* Deliver goods to the station */
                                st->time_since_unload = 0;
                        }

                        if (_settings_game.order.gradual_loading && remaining) {
                                completely_emptied = false;
                        } else {
                                /* We have finished unloading (cargo count == 0) */
                                ClrBit(v->vehicle_flags, VF_CARGO_UNLOADING);
                        }

                        continue;
                }

                /* Do not pick up goods when we have no-load set or loading is stopped. */
                if (front->current_order.GetLoadType() & OLFB_NO_LOAD || HasBit(front->vehicle_flags, VF_STOP_LOADING)) continue;

                /* This order has a refit, if this is the first vehicle part carrying cargo and the whole vehicle is empty, try refitting. */
                if (front->current_order.IsRefit() && artic_part == 1 && IsArticulatedVehicleEmpty(v)) {
                        HandleStationRefit(v, consist_capleft, st, next_station, front->current_order.GetRefitCargo());
                        ge = &st->goods[v->cargo_type];
                }

                /* As we're loading here the following link can carry the full capacity of the vehicle. */
                v->refit_cap = v->cargo_cap;

                /* update stats */
                int t;
                switch (front->type) {
                        case VEH_TRAIN: /* FALL THROUGH */
                        case VEH_SHIP:
                                t = front->vcache.cached_max_speed;
                                break;

                        case VEH_ROAD:
                                t = front->vcache.cached_max_speed / 2;
                                break;

                        case VEH_AIRCRAFT:
                                t = Aircraft::From(front)->GetSpeedOldUnits(); // Convert to old units.
                                break;

                        default: NOT_REACHED();
                }

                /* if last speed is 0, we treat that as if no vehicle has ever visited the station. */
                ge->last_speed = min(t, 255);
                ge->last_age = min(_cur_year - front->build_year, 255);
                ge->time_since_pickup = 0;

                assert(v->cargo_cap >= v->cargo.StoredCount());
                /* If there's goods waiting at the station, and the vehicle
                 * has capacity for it, load it on the vehicle. */
                uint cap_left = v->cargo_cap - v->cargo.StoredCount();
                if (cap_left > 0 && (v->cargo.ActionCount(VehicleCargoList::MTA_LOAD) > 0 || ge->cargo.AvailableCount() > 0)) {
                        if (_settings_game.order.gradual_loading) cap_left = min(cap_left, load_amount);
                        if (v->cargo.StoredCount() == 0) TriggerVehicle(v, VEHICLE_TRIGGER_NEW_CARGO);

                        uint loaded = ge->cargo.Load(cap_left, &v->cargo, st->xy, next_station);
                        if (v->cargo.ActionCount(VehicleCargoList::MTA_LOAD) > 0) {
                                /* Remember if there are reservations left so that we don't stop
                                 * loading before they're loaded. */
                                SetBit(reservation_left, v->cargo_type);
                        }

                        /* Store whether the maximum possible load amount was loaded or not.*/
                        if (loaded == cap_left) {
                                SetBit(full_load_amount, v->cargo_type);
                        } else {
                                ClrBit(full_load_amount, v->cargo_type);
                        }

                        /* TODO: Regarding this, when we do gradual loading, we
                         * should first unload all vehicles and then start
                         * loading them. Since this will cause
                         * VEHICLE_TRIGGER_EMPTY to be called at the time when
                         * the whole vehicle chain is really totally empty, the
                         * completely_emptied assignment can then be safely
                         * removed; that's how TTDPatch behaves too. --pasky */
                        if (loaded > 0) {
                                completely_emptied = false;
                                anything_loaded = true;

                                st->time_since_load = 0;
                                st->last_vehicle_type = v->type;

                                if (ge->cargo.TotalCount() == 0) {
                                        TriggerStationRandomisation(st, st->xy, SRT_CARGO_TAKEN, v->cargo_type);
                                        TriggerStationAnimation(st, st->xy, SAT_CARGO_TAKEN, v->cargo_type);
                                        AirportAnimationTrigger(st, AAT_STATION_CARGO_TAKEN, v->cargo_type);
                                }

                                unloading_time += loaded;

                                dirty_vehicle = dirty_station = true;
                        }
                }

                if (v->cargo.StoredCount() >= v->cargo_cap) {
                        SetBit(cargo_full, v->cargo_type);
                } else {
                        SetBit(cargo_not_full, v->cargo_type);
                }
        }

        if (anything_loaded || anything_unloaded) {
                if (front->type == VEH_TRAIN) {
                        TriggerStationRandomisation(st, front->tile, SRT_TRAIN_LOADS);
                        TriggerStationAnimation(st, front->tile, SAT_TRAIN_LOADS);
                }
        }

        /* Only set completely_emptied, if we just unloaded all remaining cargo */
        completely_emptied &= anything_unloaded;

        if (!anything_unloaded) delete payment;

        ClrBit(front->vehicle_flags, VF_STOP_LOADING);
        if (anything_loaded || anything_unloaded) {
                if (_settings_game.order.gradual_loading) {
                        /* The time it takes to load one 'slice' of cargo or passengers depends
                         * on the vehicle type - the values here are those found in TTDPatch */
                        const uint gradual_loading_wait_time[] = { 40, 20, 10, 20 };

                        unloading_time = gradual_loading_wait_time[front->type];
                }
                /* We loaded less cargo than possible for all cargo types and it's not full
                 * load and we're not supposed to wait any longer: stop loading. */
                if (!anything_unloaded && full_load_amount == 0 && reservation_left == 0 && !(front->current_order.GetLoadType() & OLFB_FULL_LOAD) &&
                                front->current_order_time >= (uint)max(front->current_order.wait_time - front->lateness_counter, 0)) {
                        SetBit(front->vehicle_flags, VF_STOP_LOADING);
                }
        } else {
                bool finished_loading = true;
                if (front->current_order.GetLoadType() & OLFB_FULL_LOAD) {
                        if (front->current_order.GetLoadType() == OLF_FULL_LOAD_ANY) {
                                /* if the aircraft carries passengers and is NOT full, then
                                 * continue loading, no matter how much mail is in */
                                if ((front->type == VEH_AIRCRAFT && IsCargoInClass(front->cargo_type, CC_PASSENGERS) && front->cargo_cap > front->cargo.StoredCount()) ||
                                                (cargo_not_full && (cargo_full & ~cargo_not_full) == 0)) { // There are still non-full cargoes
                                        finished_loading = false;
                                }
                        } else if (cargo_not_full != 0) {
                                finished_loading = false;
                        }

                        /* Refresh next hop stats if we're full loading to make the links
                         * known to the distribution algorithm and allow cargo to be sent
                         * along them. Otherwise the vehicle could wait for cargo
                         * indefinitely if it hasn't visited the other links yet, or if the
                         * links die while it's loading. */
                        if (!finished_loading) LinkRefresher::Run(front);
                }
                unloading_time = 20;

                SB(front->vehicle_flags, VF_LOADING_FINISHED, 1, finished_loading);
        }

        if (front->type == VEH_TRAIN) {
                /* Each platform tile is worth 2 rail vehicles. */
                int overhang = front->GetGroundVehicleCache()->cached_total_length - st->GetPlatformLength(front->tile) * TILE_SIZE;
                if (overhang > 0) {
                        unloading_time <<= 1;
                        unloading_time += (overhang * unloading_time) / 8;
                }
        }

        /* Calculate the loading indicator fill percent and display
         * In the Game Menu do not display indicators
         * If _settings_client.gui.loading_indicators == 2, show indicators (bool can be promoted to int as 0 or 1 - results in 2 > 0,1 )
         * if _settings_client.gui.loading_indicators == 1, _local_company must be the owner or must be a spectator to show ind., so 1 > 0
         * if _settings_client.gui.loading_indicators == 0, do not display indicators ... 0 is never greater than anything
         */
        if (_game_mode != GM_MENU && (_settings_client.gui.loading_indicators > (uint)(front->owner != _local_company && _local_company != COMPANY_SPECTATOR))) {
                StringID percent_up_down = STR_NULL;
                int percent = CalcPercentVehicleFilled(front, &percent_up_down);
                if (front->fill_percent_te_id == INVALID_TE_ID) {
                        front->fill_percent_te_id = ShowFillingPercent(front->x_pos, front->y_pos, front->z_pos + 20, percent, percent_up_down);
                } else {
                        UpdateFillingPercent(front->fill_percent_te_id, percent, percent_up_down);
                }
        }

        /* Always wait at least 1, otherwise we'll wait 'infinitively' long. */
        front->load_unload_ticks = max(1, unloading_time);

        if (completely_emptied) {
                /* Make sure the vehicle is marked dirty, since we need to update the NewGRF
                 * properties such as weight, power and TE whenever the trigger runs. */
                dirty_vehicle = true;
                TriggerVehicle(front, VEHICLE_TRIGGER_EMPTY);
        }

        if (dirty_vehicle) {
                SetWindowDirty(GetWindowClassForVehicleType(front->type), front->owner);
                SetWindowDirty(WC_VEHICLE_DETAILS, front->index);
                front->MarkDirty();
        }
        if (dirty_station) {
                st->MarkTilesDirty(true);
                SetWindowDirty(WC_STATION_VIEW, last_visited);
        }
}

/**
 * Load/unload the vehicles in this station according to the order
 * they entered.
 * @param st the station to do the loading/unloading for
 */
void LoadUnloadStation(Station *st)
{
        /* No vehicle is here... */
        if (st->loading_vehicles.empty()) return;

        Vehicle *last_loading = NULL;
        std::list<Vehicle *>::iterator iter;

        /* Check if anything will be loaded at all. Otherwise we don't need to reserve either. */
        for (iter = st->loading_vehicles.begin(); iter != st->loading_vehicles.end(); ++iter) {
                Vehicle *v = *iter;

                if ((v->vehstatus & (VS_STOPPED | VS_CRASHED))) continue;

                assert(v->load_unload_ticks != 0);
                if (--v->load_unload_ticks == 0) last_loading = v;
        }

        /* We only need to reserve and load/unload up to the last loading vehicle.
         * Anything else will be forgotten anyway after returning from this function.
         *
         * Especially this means we do _not_ need to reserve cargo for a single
         * consist in a station which is not allowed to load yet because its
         * load_unload_ticks is still not 0.
         */
        if (last_loading == NULL) return;

        for (iter = st->loading_vehicles.begin(); iter != st->loading_vehicles.end(); ++iter) {
                Vehicle *v = *iter;
                if (!(v->vehstatus & (VS_STOPPED | VS_CRASHED))) LoadUnloadVehicle(v);
                if (v == last_loading) break;
        }

        /* Call the production machinery of industries */
        const Industry * const *isend = _cargo_delivery_destinations.End();
        for (Industry **iid = _cargo_delivery_destinations.Begin(); iid != isend; iid++) {
                TriggerIndustryProduction(*iid);
        }
        _cargo_delivery_destinations.Clear();
}

/**
 * Monthly update of the economic data (of the companies as well as economic fluctuations).
 */
void CompaniesMonthlyLoop()
{
        CompaniesGenStatistics();
        if (_settings_game.economy.inflation) {
                AddInflation();
                RecomputePrices();
        }
        CompaniesPayInterest();
        HandleEconomyFluctuations();
}

static void DoAcquireCompany(Company *c)
{
        CompanyID ci = c->index;

        CompanyNewsInformation *cni = MallocT<CompanyNewsInformation>(1);
        cni->FillData(c, Company::Get(_current_company));

        SetDParam(0, STR_NEWS_COMPANY_MERGER_TITLE);
        SetDParam(1, c->bankrupt_value == 0 ? STR_NEWS_MERGER_TAKEOVER_TITLE : STR_NEWS_COMPANY_MERGER_DESCRIPTION);
        SetDParamStr(2, cni->company_name);
        SetDParamStr(3, cni->other_company_name);
        SetDParam(4, c->bankrupt_value);
        AddCompanyNewsItem(STR_MESSAGE_NEWS_FORMAT, cni);
        AI::BroadcastNewEvent(new ScriptEventCompanyMerger(ci, _current_company));
        Game::NewEvent(new ScriptEventCompanyMerger(ci, _current_company));

        ChangeOwnershipOfCompanyItems(ci, _current_company);

        if (c->bankrupt_value == 0) {
                Company *owner = Company::Get(_current_company);
                owner->current_loan += c->current_loan;
        }

        if (c->is_ai) AI::Stop(c->index);

        DeleteCompanyWindows(ci);
        InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
        InvalidateWindowClassesData(WC_SHIPS_LIST, 0);
        InvalidateWindowClassesData(WC_ROADVEH_LIST, 0);
        InvalidateWindowClassesData(WC_AIRCRAFT_LIST, 0);

        delete c;
}

extern int GetAmountOwnedBy(const Company *c, Owner owner);

/**
 * Acquire shares in an opposing company.
 * @param tile unused
 * @param flags type of operation
 * @param p1 company to buy the shares from
 * @param p2 unused
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdBuyShareInCompany(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        CommandCost cost(EXPENSES_OTHER);
        CompanyID target_company = (CompanyID)p1;
        Company *c = Company::GetIfValid(target_company);

        /* Check if buying shares is allowed (protection against modified clients)
         * Cannot buy own shares */
        if (c == NULL || !_settings_game.economy.allow_shares || _current_company == target_company) return CMD_ERROR;

        /* Protect new companies from hostile takeovers */
        if (_cur_year - c->inaugurated_year < 6) return_cmd_error(STR_ERROR_PROTECTED);

        /* Those lines are here for network-protection (clients can be slow) */
        if (GetAmountOwnedBy(c, COMPANY_SPECTATOR) == 0) return cost;

        if (GetAmountOwnedBy(c, COMPANY_SPECTATOR) == 1) {
                if (!c->is_ai) return cost; //  We can not buy out a real company (temporarily). TODO: well, enable it obviously.

                if (GetAmountOwnedBy(c, _current_company) == 3 && !MayCompanyTakeOver(_current_company, target_company)) return_cmd_error(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME);
        }


        cost.AddCost(CalculateCompanyValue(c) >> 2);
        if (flags & DC_EXEC) {
                OwnerByte *b = c->share_owners;

                while (*b != COMPANY_SPECTATOR) b++; // share owners is guaranteed to contain at least one COMPANY_SPECTATOR
                *b = _current_company;

                for (int i = 0; c->share_owners[i] == _current_company;) {
                        if (++i == 4) {
                                c->bankrupt_value = 0;
                                DoAcquireCompany(c);
                                break;
                        }
                }
                InvalidateWindowData(WC_COMPANY, target_company);
                CompanyAdminUpdate(c);
        }
        return cost;
}

/**
 * Sell shares in an opposing company.
 * @param tile unused
 * @param flags type of operation
 * @param p1 company to sell the shares from
 * @param p2 unused
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdSellShareInCompany(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        CompanyID target_company = (CompanyID)p1;
        Company *c = Company::GetIfValid(target_company);

        /* Cannot sell own shares */
        if (c == NULL || _current_company == target_company) return CMD_ERROR;

        /* Check if selling shares is allowed (protection against modified clients).
         * However, we must sell shares of companies being closed down. */
        if (!_settings_game.economy.allow_shares && !(flags & DC_BANKRUPT)) return CMD_ERROR;

        /* Those lines are here for network-protection (clients can be slow) */
        if (GetAmountOwnedBy(c, _current_company) == 0) return CommandCost();

        /* adjust it a little to make it less profitable to sell and buy */
        Money cost = CalculateCompanyValue(c) >> 2;
        cost = -(cost - (cost >> 7));

        if (flags & DC_EXEC) {
                OwnerByte *b = c->share_owners;
                while (*b != _current_company) b++; // share owners is guaranteed to contain company
                *b = COMPANY_SPECTATOR;
                InvalidateWindowData(WC_COMPANY, target_company);
                CompanyAdminUpdate(c);
        }
        return CommandCost(EXPENSES_OTHER, cost);
}

/**
 * Buy up another company.
 * When a competing company is gone bankrupt you get the chance to purchase
 * that company.
 * @todo currently this only works for AI companies
 * @param tile unused
 * @param flags type of operation
 * @param p1 company to buy up
 * @param p2 unused
 * @param text unused
 * @return the cost of this operation or an error
 */
CommandCost CmdBuyCompany(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
        CompanyID target_company = (CompanyID)p1;
        Company *c = Company::GetIfValid(target_company);
        if (c == NULL) return CMD_ERROR;

        /* Disable takeovers when not asked */
        if (!HasBit(c->bankrupt_asked, _current_company)) return CMD_ERROR;

        /* Disable taking over the local company in single player */
        if (!_networking && _local_company == c->index) return CMD_ERROR;

        /* Do not allow companies to take over themselves */
        if (target_company == _current_company) return CMD_ERROR;

        /* Disable taking over when not allowed. */
        if (!MayCompanyTakeOver(_current_company, target_company)) return CMD_ERROR;

        /* Get the cost here as the company is deleted in DoAcquireCompany. */
        CommandCost cost(EXPENSES_OTHER, c->bankrupt_value);

        if (flags & DC_EXEC) {
                DoAcquireCompany(c);
        }
        return cost;
}