Function CheckEngines

src/engine.cpp:1313–1337

* Check for engines that have an appropriate availability. */

 * Check for engines that have an appropriate availability.
 */
void CheckEngines()
{
	TimerGameCalendar::Date min_date{INT32_MAX};

	for (const Engine *e : Engine::Iterate()) {
		if (!e->IsEnabled()) continue;

		/* Don't consider train wagons, we need a powered engine available. */
		if (e->type == VEH_TRAIN && e->VehInfo<RailVehicleInfo>().railveh_type == RAILVEH_WAGON) continue;

		/* We have an available engine... yay! */
		if (e->flags.Test(EngineFlag::Available) && e->company_avail.Any()) return;

		/* Okay, try to find the earliest date. */
		min_date = std::min(min_date, e->info.base_intro);
	}

	if (min_date < INT32_MAX) {
		ShowErrorMessage(GetEncodedString(STR_ERROR_NO_VEHICLES_AVAILABLE_YET),
			GetEncodedString(STR_ERROR_NO_VEHICLES_AVAILABLE_YET_EXPLANATION, min_date), WL_WARNING);
	} else {
		ShowErrorMessage(GetEncodedString(STR_ERROR_NO_VEHICLES_AVAILABLE_AT_ALL),
			GetEncodedString(STR_ERROR_NO_VEHICLES_AVAILABLE_AT_ALL_EXPLANATION), WL_WARNING);
	}
}