Function GetNewEngineType

src/autoreplace_cmd.cpp:281–309

* Get the EngineID of the replacement for a vehicle * @param v The vehicle to find a replacement for * @param c The vehicle's owner (it's faster to forward the pointer than refinding it) * @param always_replace Always replace, even if not old. * @param[out] e the EngineID of the replacement. EngineID::Invalid() if no replacement is found * @return Error if the engine to build is not available

 * @return Error if the engine to build is not available
 */
static CommandCost GetNewEngineType(const Vehicle *v, const Company *c, bool always_replace, EngineID &e)
{
	assert(v->type != VEH_TRAIN || !v->IsArticulatedPart());

	e = EngineID::Invalid();

	if (v->type == VEH_TRAIN && Train::From(v)->IsRearDualheaded()) {
		/* we build the rear ends of multiheaded trains with the front ones */
		return CommandCost();
	}

	bool replace_when_old;
	e = EngineReplacementForCompany(c, v->engine_type, v->group_id, &replace_when_old);
	if (!always_replace && replace_when_old && !v->NeedsAutorenewing(c, false)) e = EngineID::Invalid();

	/* Autoreplace, if engine is available */
	if (e != EngineID::Invalid() && IsEngineBuildable(e, v->type, _current_company)) {
		return CommandCost();
	}

	/* Autorenew if needed */
	if (v->NeedsAutorenewing(c)) e = v->engine_type;

	/* Nothing to do or all is fine? */
	if (e == EngineID::Invalid() || IsEngineBuildable(e, v->type, _current_company)) return CommandCost();

	/* The engine we need is not available. Report error to user */
	return CommandCost(STR_ERROR_RAIL_VEHICLE_NOT_AVAILABLE + v->type);
}

/**
 * Builds and refits a replacement vehicle