<?php

namespace App\Services\Billing;

use App\Support\CompanyProfile;

/**
 * The one-off charge for setting a customer up — and the one place it is turned
 * into money.
 *
 * The fee had been advertised for months and charged to nobody. It was on the
 * public price sheet ("Einrichtung kostet einmalig 118,80 €"), on the booking page
 * ("zzgl. Einrichtung einmalig"), and the operator set the figure in the console —
 * and CompanyProfile::setupFeeCents() had no reader outside those two sentences
 * and the form that wrote it. Nothing put it on a checkout, on an invoice item or
 * on any bill at all.
 *
 * It is charged now. The two sentences and the money read the same figure through
 * this class, so a change of rate or of fee cannot move one without moving the
 * others.
 *
 * **The figure is GROSS, like every other price this platform charges.** The
 * console asks the operator for the net amount, because that is the commercial
 * number and the field says so; what a customer pays is that with the domestic
 * rate on it, formed by TaxTreatment::chargedCents(), which is the single place a
 * gross is formed. That is also why the fee is the same for a consumer in Vienna
 * and for a reverse-charge business in Rotterdam: the price on the page is the
 * price at the till, for everybody, and the invoice is where the split differs.
 *
 * Zero means there is no such fee. Every reader has to treat that as "no line at
 * all" rather than "a line of nought" — a checkout that itemises nothing owed is
 * worse than one that says nothing.
 */
final class SetupFee
{
    /** The net figure an operator typed, in cents. Zero when there is no fee. */
    public static function netCents(): int
    {
        return CompanyProfile::setupFeeCents();
    }

    /** What a customer is actually charged for it, tax included. */
    public static function chargedCents(): int
    {
        $net = self::netCents();

        return $net === 0 ? 0 : TaxTreatment::chargedCents($net);
    }

    /**
     * The fee as the extra, non-recurring line of a checkout session — or null
     * when the operator has set none.
     *
     * `$currency` is the recurring Price's own, not the catalogue default: Stripe
     * requires every line of one session to share a currency, and reading two
     * sources for it is how a checkout ends up refused for a mismatch nobody can
     * see from either page.
     *
     * @return array{amount_cents: int, label: string, currency: string}|null
     */
    public static function checkoutLine(string $currency): ?array
    {
        $charged = self::chargedCents();

        if ($charged === 0) {
            return null;
        }

        return [
            'amount_cents' => $charged,
            // What the customer reads on Stripe's page and on Stripe's receipt.
            // The same words the price sheet uses, because meeting a different
            // name for the same charge at the till is exactly the moment somebody
            // abandons a checkout.
            'label' => __('checkout.setup_fee_line'),
            'currency' => strtoupper($currency),
        ];
    }
}