Guards
tilttek/exchangeWhat members give each other — transfers of points, trades of items — passes through Guards, one for each:
| Guard | Rule | Refusal |
|---|---|---|
| Self-exchange | A member never exchanges with themselves; always on. | Refusal::SelfExchange |
| New accounts | Both members joined at least the delay before now. | Refusal::NewMember |
| Allowance | What a member gives over a period stays within the limit: points for transfers, offers for trades. | Refusal::AllowanceReached |
use Tilttek\Exchange\Allowance;
use Tilttek\Exchange\Guards;
use Tilttek\Points\Rule\Period;
$transferGuards = new Guards(new Allowance(500, Period::Week), 'P7D', 'America/Toronto', $memberSince);
$tradeGuards = new Guards(new Allowance(10, Period::Day), timezone: 'America/Toronto');The periods are those of the earning caps of tilttek/points — a calendar day, an ISO week from Monday, a calendar
month or year, or ever —, counted in the guards' timezone. The joining dates come from the application's
MemberSince; a member it does not know is refused while a delay is set, and NoMemberSince knows no one.
The allowance is checked against what the stores hold before the exchange is written: two exchanges of the same member at the very same moment may both pass. It is a guard against abuse, not a balance — the balance of points itself never goes negative.