<?php

namespace App\Services\Stripe;

/**
 * The bit of Stripe we drive ourselves: the catalogue.
 *
 * Everything else about recurring billing — retries, dunning, off-session SCA,
 * invoice numbering — is Stripe's job, and we learn about it through webhooks.
 * Our side owns capability, because Stripe does not know how big the VM should
 * be.
 */
interface StripeClient
{
    /**
     * Settle an upgrade at once: Stripe works out the days left in the term,
     * raises its own invoice for the difference and charges it there and then.
     *
     * Chosen over letting the proration ride on the next cycle invoice because
     * the cycle invoice is the one WE issue a document for, from the contract's
     * frozen price. A renewal invoice that said one figure while Stripe took
     * that figure plus a proration would be a document that does not match the
     * money — see App\Actions\MoveStripeSubscriptionPrice.
     */
    public const PRORATE_IMMEDIATELY = 'always_invoice';

    /**
     * Change the price and settle nothing. What the next cycle is billed at
     * changes; no credit and no charge is raised for the switch itself.
     */
    public const PRORATE_NONE = 'none';

    /**
     * Stop at the end of the term the customer has already paid for.
     *
     * What a CANCELLATION means. They keep the service to the boundary they have
     * been billed to, no further cycle is ever raised, and Stripe ends the
     * subscription itself at that moment — which arrives here as
     * `customer.subscription.deleted` and is what ApplyStripeBillingEvent reads
     * as the end of the contract.
     */
    public const CANCEL_AT_PERIOD_END = 'at_period_end';

    /**
     * Stop now.
     *
     * What a WITHDRAWAL means. The contract is unwound rather than ended, the
     * whole amount goes back, and there is no paid-up term left to run out — see
     * App\Actions\WithdrawContract.
     */
    public const CANCEL_IMMEDIATELY = 'immediately';

    /** Whether an account is actually configured. */
    public function isConfigured(): bool;

    /**
     * Open a hosted checkout for one plan Price and return the URL to send the
     * customer to.
     *
     * Hosted, not a payment form of ours: card details, 3-D Secure and every
     * local payment method are Stripe's problem, and the moment a page of ours
     * touches a card number the whole installation is in PCI scope.
     *
     * `$metadata` is what comes back on the webhook and decides what is built —
     * plan, plan version and datacenter. It is set on the SESSION and on the
     * subscription: the session's copy is what StripeWebhookController reads,
     * the subscription's is what any later billing event carries.
     *
     * `$priceId` is one of the TWO Prices the catalogue sells that package on —
     * the domestic gross or the bare net a reverse-charge business owes — and which
     * one it is has been decided by TaxTreatment before this is called. Nothing
     * here computes tax, and `automatic_tax` is deliberately never enabled: a
     * second rate worked out by Stripe would charge a German consumer 19 % while
     * our own document said 20 %.
     *
     * `$oneOff` is the setup fee: a second line item with no recurrence, whose
     * `amount_cents` is what this same customer is charged for it, formed the same
     * way and by the same authority as the Price above.
     * Stripe allows one-time prices in a subscription-mode session and puts them
     * on the INITIAL invoice only, which is precisely what a setup fee is — so it
     * is charged once, with the first month, and never again. Null means there is
     * no such fee and no second line is sent at all: a zero-amount line on a
     * checkout is a line telling the customer they owe nothing for something.
     *
     * `label` is what that line is CALLED on Stripe's own page and on the receipt
     * Stripe sends. It arrives from the caller rather than being written here
     * because it is customer-facing wording, and that belongs in the language
     * files with the rest of it. `currency` has to match the recurring Price's, so
     * it comes from the same catalogue the Price was formed from.
     *
     * @param  array{amount_cents: int, label: string, currency: string}|null  $oneOff
     */
    public function createCheckoutSession(
        string $priceId,
        string $successUrl,
        string $cancelUrl,
        array $metadata = [],
        ?string $customerEmail = null,
        ?string $idempotencyKey = null,
        ?array $oneOff = null,
    ): string;

    /**
     * Create a Product for a plan family; returns its Stripe id.
     *
     * `$idempotencyKey` is Stripe's own guard: a crash between their creating
     * the object and our storing the id would otherwise mint a second one on
     * the next run, and there is no way to tell duplicates apart afterwards.
     */
    public function createProduct(string $name, array $metadata = [], ?string $idempotencyKey = null): string;

    /**
     * Create a Price. Stripe Prices are immutable and carry their own interval,
     * which is why one exists per plan version AND term — and, since a
     * reverse-charge business is charged the bare net while everybody else pays
     * the gross, two per priced row on each term.
     */
    public function createPrice(
        string $productId,
        int $amountCents,
        string $currency,
        string $interval,
        array $metadata = [],
        ?string $idempotencyKey = null,
    ): string;

    /**
     * Every active recurring Price of a Product, as Stripe holds them.
     *
     * The half of the catalogue mirror that was missing: nothing here ever asked
     * Stripe what it already had. A run that created a Price and died before the
     * row was written left an orphan our table never learned about, and once the
     * idempotency key expired the next run made a SECOND live Price for the same
     * money — the exact duplicate the key exists to prevent. See
     * App\Services\Billing\AdoptStripePrice, which is the only caller.
     *
     * Active ones only, because the question being asked is "is there something
     * here I can sell on?". `currency` comes back UPPER CASE, the way our own
     * tables hold it.
     *
     * FOUR properties are checked, and they are named because the list is what
     * the contract is: `recurring.interval_count` is 1, `recurring.usage_type`
     * is `licensed`, there is no `transform_quantity`, and `billing_scheme` is
     * `per_unit`. Those are Stripe's own defaults, and createPrice() sets none of
     * the four — so anything else is a Price this platform did not write, and is
     * filtered out here rather than returned.
     *
     * The reason it is filtered at all: AdoptStripePrice compares the amount,
     * currency and interval of the shape below and trusts that triple as the
     * WHOLE of what a Price charges. A Price billed every three months, on
     * metered usage, dividing the quantity before charging, or pricing in tiers
     * would otherwise pass that triple on `interval => 'month'` alone and be
     * adopted as if it charged our figure per unit per month — which is adoption
     * moving money, the one thing nothing here may do.
     *
     * Not a list of everything Stripe can put on a Price: it is the list of
     * fields known to change what one CHARGES. A fifth would have to be added
     * here, at the boundary, before the shape below is handed on.
     *
     * @return array<int, array{id: string, unit_amount: int, currency: string, interval: string, created: int, metadata: array<string, string>}>
     */
    public function activePricesFor(string $productId): array;

    /**
     * Write metadata onto a Price that already exists.
     *
     * Metadata is one of the few fields a Stripe Price lets you change — the
     * same property activatePrice() rests on, and the reason the metadata format
     * is NOT part of a Price's identity. An adopted orphan is brought up to
     * today's metadata rather than replaced, which is exactly what was done by
     * hand after 2026-07-29 and keeps Stripe's own dashboard readable.
     */
    public function updatePriceMetadata(string $priceId, array $metadata): void;

    /** Stop a Price being offered. The Price itself stays, as Stripe requires. */
    public function archivePrice(string $priceId): void;

    /**
     * Offer an archived Price again.
     *
     * The other half of archivePrice(), and it was missing. A rate that moves and
     * then moves back finds the Price for the figure it has come back to already
     * in our register: the sync brings that row back rather than minting a second
     * Price for one amount, which is right — but the Price was archived AT STRIPE,
     * and only this makes it sellable again. Without it the catalogue pointed at
     * an inactive Price and the failure was a customer meeting a refused checkout.
     */
    public function activatePrice(string $priceId): void;

    /**
     * Move a subscription onto another Price.
     *
     * The ITEM is what carries a price, not the subscription, so the swap needs
     * both ids. `$prorationBehaviour` is one of the constants above and is
     * always passed explicitly: Stripe's own default settles a proration
     * silently, and a default deciding what a customer is charged is exactly
     * the kind of thing that must be written down at the call site.
     */
    public function updateSubscriptionPrice(
        string $subscriptionId,
        string $itemId,
        string $priceId,
        string $prorationBehaviour,
    ): void;

    /**
     * The id of the item a subscription bills its PACKAGE through, or null if it
     * has none.
     *
     * For contracts opened before the item id was stored: Stripe knows it, we
     * did not ask, and asking once is cheaper than being unable to move them.
     * The first item is the package, because that is the one the checkout
     * created; modules are added afterwards and carry their own ids, which are
     * stored on the bookings themselves.
     */
    public function subscriptionItemId(string $subscriptionId): ?string;

    /**
     * Put a module on the subscription as an item of its own, and return the
     * item's id.
     *
     * `$prorationBehaviour` is passed explicitly for the same reason as above.
     * A module booked in the middle of a term is charged PRORATE_IMMEDIATELY:
     * Stripe works out the days that are left, raises an invoice for exactly
     * that and takes the money there and then — which is the invoice the
     * customer is owed a document for.
     */
    public function addSubscriptionItem(
        string $subscriptionId,
        string $priceId,
        int $quantity,
        string $prorationBehaviour,
        ?string $idempotencyKey = null,
    ): string;

    /**
     * Change how many of a module the subscription bills for.
     *
     * A pack is sold by the unit, so a second one is a quantity of two on one
     * item rather than a second item at the same price — two items on one price
     * is a thing Stripe allows and nothing could later tell apart.
     */
    public function updateSubscriptionItemQuantity(
        string $itemId,
        int $quantity,
        string $prorationBehaviour,
    ): void;

    /**
     * Take a module off the subscription.
     *
     * Removed with PRORATE_NONE by everything that calls it: a cancelled module
     * is kept until the end of the term the customer has already paid for and
     * earns no credit, so nothing is to be settled — only the next cycle is
     * smaller.
     */
    public function removeSubscriptionItem(string $itemId, string $prorationBehaviour): void;

    /**
     * Tell Stripe to stop charging for a contract that is over.
     *
     * The one call this platform could not make. Nothing here cancelled a Stripe
     * subscription at all: a customer's cancellation wrote a date on the
     * instance, a withdrawal marked the contract cancelled and sent the money
     * back, and in both cases Stripe went on taking the next month, and the next,
     * for a service that had ended — and every one of those payments arrived as
     * `invoice.paid` and drew a number out of the gapless Austrian series.
     *
     * `$when` is one of the CANCEL_* constants and is always passed explicitly,
     * for the same reason `$prorationBehaviour` is above: the two are different
     * promises to the customer, and which one a caller means has to be legible at
     * the call site rather than inherited from a default written down here.
     *
     * `$idempotencyKey` because a retry after a timeout cannot tell whether the
     * first attempt landed. Cancelling twice is harmless at Stripe, but the same
     * key makes the retry provably a no-op instead of merely a likely one.
     */
    public function cancelSubscription(
        string $subscriptionId,
        string $when,
        ?string $idempotencyKey = null,
    ): void;

    /**
     * Send money back, against the payment that took it.
     *
     * The only outgoing money movement this platform makes, and it exists
     * because a consumer who withdraws within fourteen days is owed one — see
     * App\Actions\WithdrawContract. `$amountCents` is the whole of what was
     * taken: the owner has decided a withdrawing consumer gets everything back,
     * not the amount less the days the cloud ran. It stays an explicit figure
     * rather than "refund the payment" because a Storno states an amount and the
     * money has to be the amount the Storno states.
     *
     * `$paymentReference` is a PaymentIntent (`pi_…`) or a Charge (`ch_…`) —
     * whichever Stripe reported for the payment. Both are accepted rather than
     * one normalised: which of the two an account produces depends on the API
     * version it is pinned to, and a refund that silently does nothing because
     * the wrong field was read is the worst possible failure here.
     *
     * `$idempotencyKey` is not optional in practice. A refund is the one call
     * whose retry after a timeout would send the customer's money twice.
     *
     * @return string the refund's id
     */
    public function refund(
        string $paymentReference,
        ?int $amountCents = null,
        ?string $idempotencyKey = null,
    ): string;

    /**
     * The payment behind a Stripe invoice, or null if it has none.
     *
     * A subscription checkout charges through an invoice, so the invoice id is
     * usually all we have written down — and a refund cannot be issued against
     * an invoice. This is the one hop between the two.
     */
    public function invoicePaymentReference(string $invoiceId): ?string;

    /**
     * Every line on a Stripe invoice, for the document we owe it.
     *
     * The webhook payload carries the lines already; this is for the invoice
     * that has more of them than Stripe puts in an event. A document missing a
     * line that was charged is worse than one nobody sent, so the complete list
     * is worth an extra call.
     *
     * @return array<int, array<string, mixed>>
     */
    public function invoiceLines(string $invoiceId): array;
}