Currency and Coupon Hooks

Hook::add('gate:money.coupon_apply', 10, function ($coupon, $uid, $context) {
    // A guest arrives as 0: split the account rule on that first.
    if ($uid === 0) return 'Please sign in to use this coupon.';

    if (Acme::alreadyUsed($uid, $coupon['code'] ?? '')) return 'The coupon was used already.';

    return null;
});

Hook::add('gate:money.coupon.save', 10, function ($code, $state, $isEdit, $id) {
    // A discount above 90 per cent is usually a typing slip.
    if (($state['type'] ?? '') === 'percent' && (float) ($state['rate'] ?? 0) > 90)
        return 'A discount above 90 per cent wants approval.';

    return null;
});

Hook::add('filter:money.coupon.save_data', 10, function (&$data, $isEdit, $id) {
    // Do not write status on a new record: it is overwritten AFTER this filter.
    $data['code'] = strtoupper((string) ($data['code'] ?? ''));
});

Hook::add('action:money.coupon.status_changed', 10,
    function ($coupon_id, $source_id, $status) {
        // A filled source means this coupon is a copy.
        if ($source_id > 0) Acme::linkCopy($coupon_id, $source_id);
    });

Hook::add('filter:money.exchange_rate', 10,
    function (&$converted, $amount, $from, $to) {
        // It runs on EVERY conversion: no queries, no remote calls here.
        $converted = round($converted * (1 + Acme::MARGIN), 4);
    });

Hook::add('filter:money.format_output', 10, function (&$output, $amount) {
    // Where the browser side formats differently, the figure flickers on load.
    if ((float) $amount === 0.0) $output = Acme::freeLabel();
});

Hook::add('action:money.exchange_rates_updated', 10, function ($changes, $localCode) {
    if (!$changes) return;                        // nothing moved this run

    Ops::note('fx', $localCode . ': ' . implode(',', array_keys($changes)));
});

Hook::add('gate:money.currency.status_change', 10, function ($currency, $status) {
    // Switching off a currency in use leaves prices with nowhere to resolve.
    if ($status !== 'active' && Acme::inUse($currency['id'] ?? 0))
        return 'Live services use this currency; it cannot be switched off.';

    return null;
});

Hook::add('action:coupon.saved', 10, function ($id, $code, $isEdit, $data) {
    // Announce only a new coupon to the campaign system.
    if (!$isEdit) Acme::publishCampaign($code, $data);
});

Hook::add('action:money.coupon.deleted', 10, function ($coupon_id, $coupon) {
    Acme::retireCampaign($coupon['code'] ?? '');
});

Hook::add('action:money.currency.local_changed', 10, function ($id, $currency) {
    // Every rate is now read against the new unit.
    Acme::rebaseReports($id);
});

Hook::add('gate:money.tax_rule.save', 10, function ($country_id, $state_id, $rate) {
    // A rate outside the sane range is usually a typing slip.
    if ($rate < 0 || $rate > 40) return 'The tax rate falls outside the expected range.';

    return null;
});

Hook::add('gate:money.tax_rule.delete', 10, function ($country_id, $state) {
    // A rule kept in step with an outside tax service is removed there, not here.
    if (Acme::managesTaxRule((int) $country_id, (string) $state)) return 'This tax rule is managed by the tax service.';

    return null;
});

Hook::add('action:money.tax_rates_changed', 10, function ($country_id, $state_id, $rate) {
    // A zero rate is a deleted rule (or a rule saved at zero).
    if ((float) $rate === 0.0) {
        Acme::removeTaxRule($country_id, (string) $state_id);
        return;
    }

    Acme::syncTaxTable($country_id, $state_id, $rate);
});

Hook::add('filter:money.currency.save_data', 10, function (&$sets, $id, $currency) {
    // The difference can be empty: look first.
    if (!$sets) return;

    // Pin the rate to your own source.
    if (isset($sets['rate'])) $sets['rate'] = Acme::officialRate($currency['code'] ?? '');
});

Hook::add('filter:money.digit', 10, function ($amount, $currency, $symbol, $exchange) {
    if (($currency['code'] ?? '') !== 'BTC') return;   // do NOT return '': it blanks the amount

    return number_format($amount, 8, '.', '');
});

Hook::add('filter:money.exchange_rates_fetch', 10,
    function (&$rates, $localCode, $targets) {
        // Write your own official source over the outside service.
        $own = Acme::officialRates($localCode);
        foreach ($own as $code => $rate) $rates[$code] = $rate;
    });

Hook::add('action:expense.recurring_recorded', 10, function ($entries, $recorded) {
    // One call per round: send them to accounting in one batch.
    Acme::pushExpenses($entries);
});