Codechange: migrate all game-time-related timers to the new framework

src/airport_gui.cpp

@@ -31,6 +31,8 @@
 #include "airport_cmd.h"
 #include "station_cmd.h"
 #include "zoom_func.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "widgets/airport_widget.h"
 
@@ -581,6 +583,10 @@ public:
 	{
 		CheckRedrawStationCoverage(this);
 	}
+
+	IntervalTimer<TimerGameCalendar> yearly_interval = {{TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->InvalidateData();
+	}};
 };
 
 static const NWidgetPart _nested_build_airport_widgets[] = {

src/cheat_gui.cpp

@@ -30,6 +30,8 @@
 #include "error.h"
 #include "misc_cmd.h"
 #include "core/geometry_func.hpp"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "widgets/cheat_widget.h"
 
@@ -417,6 +419,10 @@ struct CheatWindow : Window {
 		if (value != oldvalue) WriteValue(ce->variable, ce->type, (int64)value);
 		this->SetDirty();
 	}
+
+	IntervalTimer<TimerGameCalendar> daily_interval = {{TimerGameCalendar::MONTH, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->SetDirty();
+	}};
 };
 
 /** Window description of the cheats GUI. */

src/company_cmd.cpp

@@ -36,6 +36,8 @@
 #include "story_base.h"
 #include "widgets/statusbar_widget.h"
 #include "company_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -743,7 +745,7 @@ void OnTick_Companies()
  * A year has passed, update the economic data of all companies, and perhaps show the
  * financial overview window of the local company.
  */
-void CompaniesYearlyLoop()
+static IntervalTimer<TimerGameCalendar> _companies_yearly({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::COMPANY}, [](auto)
 {
 	/* Copy statistics */
 	for (Company *c : Company::Iterate()) {
@@ -761,7 +763,7 @@ void CompaniesYearlyLoop()
 			if (_settings_client.sound.new_year) SndPlayFx(SND_00_GOOD_YEAR);
 		}
 	}
-}
+});
 
 /**
  * Fill the CompanyNewsInformation struct with the required data.

src/currency.cpp

@@ -15,6 +15,8 @@
 #include "settings_type.h"
 #include "date_func.h"
 #include "string_type.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -138,7 +140,7 @@ uint64 GetMaskOfAllowedCurrencies()
 /**
  * Verify if the currency chosen by the user is about to be converted to Euro
  */
-void CheckSwitchToEuro()
+static IntervalTimer<TimerGameCalendar> _check_switch_to_euro({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [](auto)
 {
 	if (_currency_specs[_settings_game.locale.currency].to_euro != CF_NOEURO &&
 			_currency_specs[_settings_game.locale.currency].to_euro != CF_ISEURO &&
@@ -146,7 +148,7 @@ void CheckSwitchToEuro()
 		_settings_game.locale.currency = 2; // this is the index of euro above.
 		AddNewsItem(STR_NEWS_EURO_INTRODUCTION, NT_ECONOMY, NF_NORMAL);
 	}
-}
+});
 
 /**
  * Will fill _currency_specs array with

src/currency.h

@@ -102,7 +102,6 @@ extern CurrencySpec _currency_specs[CURRENCY_END];
 #define _currency ((const CurrencySpec*)&_currency_specs[GetGameSettings().locale.currency])
 
 uint64 GetMaskOfAllowedCurrencies();
-void CheckSwitchToEuro();
 void ResetCurrencies(bool preserve_custom = true);
 StringID *BuildCurrencyDropdown();
 byte GetNewgrfCurrencyIdConverted(byte grfcurr_id);

src/date.cpp

@@ -158,111 +158,3 @@ Date ConvertYMDToDate(Year year, Month month, Day day)
 
 	return DAYS_TILL(year) + days;
 }
-
-/** Functions used by the IncreaseDate function */
-
-extern void EnginesDailyLoop();
-extern void DisasterDailyLoop();
-extern void IndustryDailyLoop();
-
-extern void CompaniesMonthlyLoop();
-extern void EnginesMonthlyLoop();
-extern void TownsMonthlyLoop();
-extern void IndustryMonthlyLoop();
-extern void StationMonthlyLoop();
-extern void SubsidyMonthlyLoop();
-
-extern void CompaniesYearlyLoop();
-extern void VehiclesYearlyLoop();
-extern void TownsYearlyLoop();
-
-extern void ShowEndGameChart();
-
-
-/** Available settings for autosave intervals. */
-static const Month _autosave_months[] = {
-	 0, ///< never
-	 1, ///< every month
-	 3, ///< every 3 months
-	 6, ///< every 6 months
-	12, ///< every 12 months
-};
-
-/**
- * Runs various procedures that have to be done yearly
- */
-static IntervalTimer<TimerGameCalendar> _on_new_year({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [](auto)
-{
-	CompaniesYearlyLoop();
-	VehiclesYearlyLoop();
-	TownsYearlyLoop();
-	InvalidateWindowClassesData(WC_BUILD_STATION);
-	InvalidateWindowClassesData(WC_BUS_STATION);
-	InvalidateWindowClassesData(WC_TRUCK_STATION);
-	if (_network_server) NetworkServerYearlyLoop();
-
-	if (_cur_year == _settings_client.gui.semaphore_build_before) ResetSignalVariant();
-
-	/* check if we reached end of the game (end of ending year); 0 = never */
-	if (_cur_year == _settings_game.game_creation.ending_year + 1 && _settings_game.game_creation.ending_year != 0) {
-		ShowEndGameChart();
-	}
-
-	/* check if we reached the maximum year, decrement dates by a year */
-	if (_cur_year == MAX_YEAR + 1) {
-		int days_this_year;
-
-		_cur_year--;
-		days_this_year = IsLeapYear(_cur_year) ? DAYS_IN_LEAP_YEAR : DAYS_IN_YEAR;
-		_date -= days_this_year;
-		for (Vehicle *v : Vehicle::Iterate()) v->ShiftDates(-days_this_year);
-		for (LinkGraph *lg : LinkGraph::Iterate()) lg->ShiftDates(-days_this_year);
-
-		/* Because the _date wraps here, and text-messages expire by game-days, we have to clean out
-		 *  all of them if the date is set back, else those messages will hang for ever */
-		NetworkInitChatMessage();
-	}
-
-	if (_settings_client.gui.auto_euro) CheckSwitchToEuro();
-});
-
-/**
- * Runs various procedures that have to be done monthly
- */
-static IntervalTimer<TimerGameCalendar> _on_new_month({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::NONE}, [](auto)
-{
-	if (_settings_client.gui.autosave != 0 && (_cur_month % _autosave_months[_settings_client.gui.autosave]) == 0) {
-		_do_autosave = true;
-		SetWindowDirty(WC_STATUS_BAR, 0);
-	}
-
-	SetWindowClassesDirty(WC_CHEATS);
-	CompaniesMonthlyLoop();
-	EnginesMonthlyLoop();
-	TownsMonthlyLoop();
-	IndustryMonthlyLoop();
-	SubsidyMonthlyLoop();
-	StationMonthlyLoop();
-	if (_network_server) NetworkServerMonthlyLoop();
-});
-
-/**
- * Runs various procedures that have to be done daily
- */
-static IntervalTimer<TimerGameCalendar> _on_new_day({TimerGameCalendar::DAY, TimerGameCalendar::Priority::NONE}, [](auto)
-{
-	if (!_newgrf_profilers.empty() && _newgrf_profile_end_date <= _date) {
-		NewGRFProfiler::FinishAll();
-	}
-
-	if (_network_server) NetworkServerDailyLoop();
-
-	DisasterDailyLoop();
-	IndustryDailyLoop();
-
-	SetWindowWidgetDirty(WC_STATUS_BAR, 0, WID_S_LEFT);
-	EnginesDailyLoop();
-
-	/* Refresh after possible snowline change */
-	SetWindowClassesDirty(WC_TOWN_VIEW);
-});

src/disaster_vehicle.cpp

@@ -47,6 +47,8 @@
 #include "core/random_func.hpp"
 #include "core/backup_type.hpp"
 #include "landscape_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -935,14 +937,14 @@ static void ResetDisasterDelay()
 	_disaster_delay = GB(Random(), 0, 9) + 730;
 }
 
-void DisasterDailyLoop()
+static IntervalTimer<TimerGameCalendar> _disaster_daily({TimerGameCalendar::DAY, TimerGameCalendar::Priority::DISASTER}, [](auto)
 {
 	if (--_disaster_delay != 0) return;
 
 	ResetDisasterDelay();
 
 	if (_settings_game.difficulty.disasters != 0) DoDisaster();
-}
+});
 
 void StartupDisasters()
 {

src/dock_gui.cpp

@@ -30,6 +30,8 @@
 #include "station_cmd.h"
 #include "water_cmd.h"
 #include "waypoint_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "widgets/dock_widget.h"
 
@@ -477,6 +479,10 @@ public:
 	{
 		CheckRedrawStationCoverage(this);
 	}
+
+	IntervalTimer<TimerGameCalendar> yearly_interval = {{TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->InvalidateData();
+	}};
 };
 
 /** Nested widget parts of a build dock station window. */

src/economy.cpp

@@ -52,6 +52,8 @@
 #include "company_cmd.h"
 #include "economy_cmd.h"
 #include "vehicle_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 #include "table/pricebase.h"
@@ -1983,7 +1985,7 @@ void LoadUnloadStation(Station *st)
 /**
  * Monthly update of the economic data (of the companies as well as economic fluctuations).
  */
-void CompaniesMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _companies_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::COMPANY}, [](auto)
 {
 	CompaniesGenStatistics();
 	if (_settings_game.economy.inflation) {
@@ -1992,7 +1994,7 @@ void CompaniesMonthlyLoop()
 	}
 	CompaniesPayInterest();
 	HandleEconomyFluctuations();
-}
+});
 
 static void DoAcquireCompany(Company *c)
 {

src/engine.cpp

@@ -30,6 +30,8 @@
 #include "articulated_vehicles.h"
 #include "error.h"
 #include "engine_base.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 #include "table/engines.h"
@@ -878,7 +880,7 @@ static bool IsVehicleTypeDisabled(VehicleType type, bool ai)
 }
 
 /** Daily check to offer an exclusive engine preview to the companies. */
-void EnginesDailyLoop()
+static IntervalTimer<TimerGameCalendar> _engines_daily({TimerGameCalendar::DAY, TimerGameCalendar::Priority::ENGINE}, [](auto)
 {
 	for (Company *c : Company::Iterate()) {
 		c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes, _date);
@@ -915,7 +917,7 @@ void EnginesDailyLoop()
 			}
 		}
 	}
-}
+});
 
 /**
  * Clear the 'hidden' flag for all engines of a new company.
@@ -1110,6 +1112,11 @@ void EnginesMonthlyLoop()
 	}
 }
 
+static IntervalTimer<TimerGameCalendar> _engines_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::ENGINE}, [](auto)
+{
+	EnginesMonthlyLoop();
+});
+
 /**
  * Is \a name still free as name for an engine?
  * @param name New name of an engine.

src/highscore_gui.cpp

@@ -22,6 +22,9 @@
 #include "hotkeys.h"
 #include "zoom_func.h"
 #include "misc_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
+#include "date_func.h"
 
 #include "widgets/highscore_widget.h"
 
@@ -250,3 +253,14 @@ void ShowEndGameChart()
 	CloseWindowByClass(WC_ENDSCREEN);
 	new EndGameWindow(&_endgame_desc);
 }
+
+static IntervalTimer<TimerGameCalendar> _check_end_game({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [](auto)
+{
+	/* 0 = never */
+	if (_settings_game.game_creation.ending_year == 0) return;
+
+	/* Show the end-game chart at the end of the ending year (hence the + 1). */
+	if (_cur_year == _settings_game.game_creation.ending_year + 1) {
+		ShowEndGameChart();
+	}
+});

src/industry_cmd.cpp

@@ -44,6 +44,8 @@
 #include "industry_cmd.h"
 #include "landscape_cmd.h"
 #include "terraform_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 #include "table/industry_land.h"
@@ -2947,7 +2949,7 @@ static void ChangeIndustryProduction(Industry *i, bool monthly)
  * For small maps, it implies that less than one change per month is required, while on bigger maps,
  * it would be way more. The daily loop handles those changes.
  */
-void IndustryDailyLoop()
+static IntervalTimer<TimerGameCalendar> _industries_daily({TimerGameCalendar::DAY, TimerGameCalendar::Priority::INDUSTRY}, [](auto)
 {
 	_economy.industry_daily_change_counter += _economy.industry_daily_increment;
 
@@ -2987,9 +2989,9 @@ void IndustryDailyLoop()
 
 	/* production-change */
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, IDIWD_PRODUCTION_CHANGE);
-}
+});
 
-void IndustryMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _industries_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::INDUSTRY}, [](auto)
 {
 	Backup<CompanyID> cur_company(_current_company, OWNER_NONE, FILE_LINE);
 
@@ -3009,7 +3011,7 @@ void IndustryMonthlyLoop()
 
 	/* production-change */
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, IDIWD_PRODUCTION_CHANGE);
-}
+});
 
 
 void InitializeIndustries()

src/network/network_func.h

@@ -65,9 +65,6 @@ void NetworkPrintClients();
 void NetworkHandlePauseChange(PauseMode prev_mode, PauseMode changed_mode);
 
 /*** Commands ran by the server ***/
-void NetworkServerDailyLoop();
-void NetworkServerMonthlyLoop();
-void NetworkServerYearlyLoop();
 void NetworkServerSendConfigUpdate();
 void NetworkServerUpdateGameInfo();
 void NetworkServerShowStatusToConsole();

src/network/network_server.cpp

@@ -31,6 +31,8 @@
 #include "../core/random_func.hpp"
 #include "../company_cmd.h"
 #include "../rev.h"
+#include "../timer/timer.h"
+#include "../timer/timer_game_calendar.h"
 #include <mutex>
 #include <condition_variable>
 
@@ -1812,26 +1814,32 @@ void NetworkServer_Tick(bool send_frame)
 }
 
 /** Yearly "callback". Called whenever the year changes. */
-void NetworkServerYearlyLoop()
+static IntervalTimer<TimerGameCalendar> _network_yearly({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [](auto)
 {
+	if (!_network_server) return;
+
 	NetworkCheckRestartMap();
 	NetworkAdminUpdate(ADMIN_FREQUENCY_ANUALLY);
-}
+});
 
 /** Monthly "callback". Called whenever the month changes. */
-void NetworkServerMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _network_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::NONE}, [](auto)
 {
+	if (!_network_server) return;
+
 	NetworkAutoCleanCompanies();
 	NetworkAdminUpdate(ADMIN_FREQUENCY_MONTHLY);
 	if ((_cur_month % 3) == 0) NetworkAdminUpdate(ADMIN_FREQUENCY_QUARTERLY);
-}
+});
 
 /** Daily "callback". Called whenever the date changes. */
-void NetworkServerDailyLoop()
+static IntervalTimer<TimerGameCalendar> _network_daily({TimerGameCalendar::DAY, TimerGameCalendar::Priority::NONE}, [](auto)
 {
+	if (!_network_server) return;
+
 	NetworkAdminUpdate(ADMIN_FREQUENCY_DAILY);
 	if ((_date % 7) == 3) NetworkAdminUpdate(ADMIN_FREQUENCY_WEEKLY);
-}
+});
 
 /**
  * Get the IP address/hostname of the connected client.

src/newgrf_profiling.cpp

@@ -14,6 +14,8 @@
 #include "console_func.h"
 #include "spritecache.h"
 #include "walltime_func.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include <chrono>
 
@@ -158,3 +160,13 @@ uint32 NewGRFProfiler::FinishAll()
 
 	return total_microseconds;
 }
+
+/**
+ * Check whether profiling is active and should be finished.
+ */
+static IntervalTimer<TimerGameCalendar> _check_profiling_finished({TimerGameCalendar::DAY, TimerGameCalendar::Priority::NONE}, [](auto)
+{
+	if (_newgrf_profilers.empty() || _newgrf_profile_end_date > _date) return;
+
+	NewGRFProfiler::FinishAll();
+});

src/openttd.cpp

@@ -101,6 +101,15 @@ bool _save_config = false;
 bool _request_newgrf_scan = false;
 NewGRFScanCallback *_request_newgrf_scan_callback = nullptr;
 
+/** Available settings for autosave intervals. */
+static const Month _autosave_months[] = {
+	 0, ///< never
+	 1, ///< every month
+	 3, ///< every 3 months
+	 6, ///< every 6 months
+	12, ///< every 12 months
+};
+
 /**
  * Error handling for fatal user errors.
  * @param s the string to print.
@@ -1432,6 +1441,15 @@ void StateGameLoop()
 	assert(IsLocalCompany());
 }
 
+static IntervalTimer<TimerGameCalendar> _autosave_interval({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::AUTOSAVE}, [](auto)
+{
+	if (_settings_client.gui.autosave == 0) return;
+	if ((_cur_month % _autosave_months[_settings_client.gui.autosave]) != 0) return;
+
+	_do_autosave = true;
+	SetWindowDirty(WC_STATUS_BAR, 0);
+});
+
 /**
  * Create an autosave. The default name is "autosave#.sav". However with
  * the setting 'keep_all_autosave' the name defaults to company-name + date

src/rail_gui.cpp

@@ -40,6 +40,8 @@
 #include "tunnelbridge_cmd.h"
 #include "waypoint_cmd.h"
 #include "rail_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "station_map.h"
 #include "tunnelbridge_map.h"
@@ -1505,6 +1507,10 @@ public:
 		CheckRedrawStationCoverage(this);
 	}
 
+	IntervalTimer<TimerGameCalendar> yearly_interval = {{TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->SetDirty();
+	}};
+
 	static HotkeyList hotkeys;
 };
 
@@ -2201,6 +2207,13 @@ void ResetSignalVariant(int32 new_value)
 	}
 }
 
+static IntervalTimer<TimerGameCalendar> _check_reset_signal({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [](auto)
+{
+	if (_cur_year != _settings_client.gui.semaphore_build_before) return;
+
+	ResetSignalVariant();
+});
+
 /**
  * Resets the rail GUI - sets default railtype to build
  * and resets the signal GUI

src/road_gui.cpp

@@ -39,6 +39,8 @@
 #include "sortlist_type.h"
 #include "stringfilter_type.h"
 #include "string_func.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "widgets/road_widget.h"
 
@@ -1586,6 +1588,10 @@ public:
 		CheckRedrawStationCoverage(this);
 	}
 
+	IntervalTimer<TimerGameCalendar> yearly_interval = {{TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->InvalidateData();
+	}};
+
 	static HotkeyList hotkeys;
 };
 

src/station_cmd.cpp

@@ -60,6 +60,8 @@
 #include "landscape_cmd.h"
 #include "rail_cmd.h"
 #include "newgrf_roadstop.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -4007,7 +4009,7 @@ void OnTick_Station()
 }
 
 /** Monthly loop for stations. */
-void StationMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _stations_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::STATION}, [](auto)
 {
 	for (Station *st : Station::Iterate()) {
 		for (CargoID i = 0; i < NUM_CARGO; i++) {
@@ -4016,8 +4018,7 @@ void StationMonthlyLoop()
 			ClrBit(ge->status, GoodsEntry::GES_CURRENT_MONTH);
 		}
 	}
-}
+});
-
 
 void ModifyStationRatingAround(TileIndex tile, Owner owner, int amount, uint radius)
 {

src/statusbar_gui.cpp

@@ -27,6 +27,7 @@
 #include "core/geometry_func.hpp"
 #include "zoom_func.h"
 #include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 #include "timer/timer_window.h"
 
 #include "widgets/statusbar_widget.h"
@@ -233,6 +234,10 @@ struct StatusBarWindow : Window {
 	TimeoutTimer<TimerWindow> reminder_timeout = {REMINDER_START, [this]() {
 		this->SetWidgetDirty(WID_S_MIDDLE);
 	}};
+
+	IntervalTimer<TimerGameCalendar> daily_interval = {{TimerGameCalendar::DAY, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		this->SetWidgetDirty(WID_S_LEFT);
+	}};
 };
 
 static const NWidgetPart _nested_main_status_widgets[] = {

src/subsidy.cpp

@@ -25,6 +25,8 @@
 #include "string_func.h"
 #include "tile_cmd.h"
 #include "subsidy_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -477,7 +479,7 @@ bool FindSubsidyCargoDestination(CargoID cid, SourceType src_type, SourceID src)
 }
 
 /** Perform the monthly update of open subsidies, and try to create a new one. */
-void SubsidyMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _subsidies_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::SUBSIDY}, [](auto)
 {
 	bool modified = false;
 
@@ -547,7 +549,7 @@ void SubsidyMonthlyLoop()
 	modified |= passenger_subsidy || town_subsidy || industry_subsidy;
 
 	if (modified) InvalidateWindowData(WC_SUBSIDIES_LIST, 0);
-}
+});
 
 /**
  * Tests whether given delivery is subsidised and possibly awards the subsidy to delivering company

src/timer/timer_game_calendar.cpp

@@ -86,4 +86,15 @@ void TimerManager<TimerGameCalendar>::Elapsed(TimerGameCalendar::TElapsed delta)
 			timer->Elapsed(TimerGameCalendar::YEAR);
 		}
 	}
+
+	/* check if we reached the maximum year, decrement dates by a year */
+	if (_cur_year == MAX_YEAR + 1) {
+		int days_this_year;
+
+		_cur_year--;
+		days_this_year = IsLeapYear(_cur_year) ? DAYS_IN_LEAP_YEAR : DAYS_IN_YEAR;
+		_date -= days_this_year;
+		for (Vehicle *v : Vehicle::Iterate()) v->ShiftDates(-days_this_year);
+		for (LinkGraph *lg : LinkGraph::Iterate()) lg->ShiftDates(-days_this_year);
+	}
 }

src/town_cmd.cpp

@@ -52,6 +52,8 @@
 #include "road_cmd.h"
 #include "terraform_cmd.h"
 #include "tunnelbridge_cmd.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 #include "table/town_land.h"
@@ -3756,7 +3758,7 @@ CommandCost CheckforTownRating(DoCommandFlag flags, Town *t, TownRatingCheckType
 	return CommandCost();
 }
 
-void TownsMonthlyLoop()
+static IntervalTimer<TimerGameCalendar> _towns_monthly({TimerGameCalendar::MONTH, TimerGameCalendar::Priority::TOWN}, [](auto)
 {
 	for (Town *t : Town::Iterate()) {
 		if (t->road_build_months != 0) t->road_build_months--;
@@ -3770,17 +3772,16 @@ void TownsMonthlyLoop()
 		UpdateTownRating(t);
 		UpdateTownUnwanted(t);
 	}
+});
 
-}
+static IntervalTimer<TimerGameCalendar> _towns_yearly({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::TOWN}, [](auto)
-
-void TownsYearlyLoop()
 {
 	/* Increment house ages */
 	for (TileIndex t = 0; t < Map::Size(); t++) {
 		if (!IsTileType(t, MP_HOUSE)) continue;
 		IncrementHouseAge(t);
 	}
-}
+});
 
 static CommandCost TerraformTile_Town(TileIndex tile, DoCommandFlag flags, int z_new, Slope tileh_new)
 {

src/town_gui.cpp

@@ -35,6 +35,7 @@
 #include "town_kdtree.h"
 #include "town_cmd.h"
 #include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 #include "timer/timer_window.h"
 
 #include "widgets/town_widget.h"
@@ -596,6 +597,11 @@ public:
 
 		Command<CMD_RENAME_TOWN>::Post(STR_ERROR_CAN_T_RENAME_TOWN, this->window_number, str);
 	}
+
+	IntervalTimer<TimerGameCalendar> daily_interval = {{TimerGameCalendar::DAY, TimerGameCalendar::Priority::NONE}, [this](auto) {
+		/* Refresh after possible snowline change */
+		this->SetDirty();
+	}};
 };
 
 static const NWidgetPart _nested_town_game_view_widgets[] = {

src/vehicle.cpp

@@ -56,6 +56,8 @@
 #include "train_cmd.h"
 #include "vehicle_cmd.h"
 #include "newgrf_roadstop.h"
+#include "timer/timer.h"
+#include "timer/timer_game_calendar.h"
 
 #include "table/strings.h"
 
@@ -2826,7 +2828,7 @@ void Vehicle::RemoveFromShared()
 	this->previous_shared = nullptr;
 }
 
-void VehiclesYearlyLoop()
+static IntervalTimer<TimerGameCalendar> _vehicles_yearly({TimerGameCalendar::YEAR, TimerGameCalendar::Priority::VEHICLE}, [](auto)
 {
 	for (Vehicle *v : Vehicle::Iterate()) {
 		if (v->IsPrimaryVehicle()) {
@@ -2851,8 +2853,7 @@ void VehiclesYearlyLoop()
 	SetWindowClassesDirty(WC_SHIPS_LIST);
 	SetWindowClassesDirty(WC_ROADVEH_LIST);
 	SetWindowClassesDirty(WC_AIRCRAFT_LIST);
-}
+});
-
 
 /**
  * Can this station be used by the given engine type?