Function ChangeTownRating

src/town_cmd.cpp:4040–4068

* Changes town rating of the current company * @param t Town to affect * @param add Value to add * @param max Minimum (add < 0) resp. maximum (add > 0) rating that should be achievable with this change. * @param flags Command flags, especially DoCommandFlag::NoModifyTownRating is tested */

 * @param flags Command flags, especially DoCommandFlag::NoModifyTownRating is tested
 */
void ChangeTownRating(Town *t, int add, int max, DoCommandFlags flags)
{
	/* if magic_bulldozer cheat is active, town doesn't penalize for removing stuff */
	if (t == nullptr || flags.Test(DoCommandFlag::NoModifyTownRating) ||
			!Company::IsValidID(_current_company) ||
			(_cheats.magic_bulldozer.value && add < 0)) {
		return;
	}

	int rating = GetRating(t);
	if (add < 0) {
		if (rating > max) {
			rating += add;
			if (rating < max) rating = max;
		}
	} else {
		if (rating < max) {
			rating += add;
			if (rating > max) rating = max;
		}
	}
	if (_town_rating_test) {
		_town_test_ratings[t] = rating;
	} else {
		t->have_ratings.Set(_current_company);
		t->ratings[_current_company] = rating;
		SetWindowDirty(WC_TOWN_AUTHORITY, t->index);
	}
}

/**
 * Does the town authority allow the (destructive) action of the current company?