<?php

namespace App\Services\Stripe;

use RuntimeException;

/**
 * A Stripe that records what it was asked to do.
 *
 * The catalogue sync has to be exercised for real — it is the thing that must
 * be idempotent and must never mint a second Price for the same row — and that
 * is testable without a network. Ids are deterministic so a test can assert
 * which product a price was attached to.
 */
class FakeStripeClient implements StripeClient
{
    public bool $configured = true;

    /** @var array<int, array{name: string, metadata: array}> */
    public array $products = [];

    /** @var array<int, array{product: string, amount: int, currency: string, interval: string, metadata: array}> */
    public array $prices = [];

    /** @var array<int, string> */
    public array $archived = [];

    /**
     * Every Price that was put back on sale, in order — a rate that moved and
     * moved back reaches for the Price it already has rather than minting a
     * second one for the same amount.
     *
     * @var array<int, string>
     */
    public array $activated = [];

    /** Idempotency key → the id first returned for it. @var array<string, string> */
    public array $keys = [];

    /**
     * What Stripe would answer when asked which item a subscription bills
     * through: subscription id → item id.
     *
     * @var array<string, string>
     */
    public array $items = [];

    /**
     * Every price swap that was asked for, in order, so a test can assert the
     * proration behaviour as well as the price.
     *
     * @var array<int, array{subscription: string, item: string, price: string, proration: string}>
     */
    public array $priceChanges = [];

    /**
     * The items on each subscription as this Stripe sees them: item id → what
     * it bills. Modules are added and removed here, so a test can assert how
     * many items a contract carries and at which quantity.
     *
     * @var array<string, array{subscription: string, price: string, quantity: int}>
     */
    public array $subscriptionItems = [];

    /**
     * Every item call that was made, in order, so a test can assert the
     * proration behaviour as well as the outcome.
     *
     * @var array<int, array<string, mixed>>
     */
    public array $itemCalls = [];

    /**
     * The lines this Stripe would report for an invoice: invoice id → lines.
     * Only for the invoice whose lines an event did not carry in full.
     *
     * @var array<string, array<int, array<string, mixed>>>
     */
    public array $invoiceLines = [];

    /**
     * Every order to stop billing, in order, so a test can assert WHEN a
     * contract was cancelled as well as that it was — the difference between a
     * customer keeping the term they paid for and losing it.
     *
     * @var array<int, array{subscription: string, when: string, key: ?string}>
     */
    public array $cancellations = [];

    /**
     * Every refund that was sent, in order, so a test can assert the amount as
     * well as the fact of it.
     *
     * @var array<int, array{payment: string, amount: ?int, key: ?string}>
     */
    public array $refunds = [];

    /**
     * What this Stripe would answer when asked which payment an invoice was
     * settled by: invoice id → payment reference.
     *
     * @var array<string, ?string>
     */
    public array $invoicePayments = [];

    /**
     * Set to make every call fail, the way an outage, a revoked key or a
     * network without a route out does.
     */
    public ?string $failWith = null;

    /**
     * Every checkout that was opened, in order.
     *
     * `one_off` is the setup-fee line, or null where none was sent — a test has to
     * be able to assert both that it is charged and that it is absent when the
     * operator has set no fee.
     *
     * @var array<int, array{price: string, success: string, cancel: string, metadata: array, email: ?string, one_off: ?array<string, mixed>}>
     */
    public array $checkouts = [];

    public function isConfigured(): bool
    {
        return $this->configured;
    }

    public function createCheckoutSession(
        string $priceId,
        string $successUrl,
        string $cancelUrl,
        array $metadata = [],
        ?string $customerEmail = null,
        ?string $idempotencyKey = null,
        ?array $oneOff = null,
    ): string {
        $this->failIfAsked();

        $this->checkouts[] = [
            'price' => $priceId,
            'success' => $successUrl,
            'cancel' => $cancelUrl,
            'metadata' => $metadata,
            'email' => $customerEmail,
            'one_off' => $oneOff,
        ];

        return 'https://checkout.stripe.test/session/'.count($this->checkouts);
    }

    public function createProduct(string $name, array $metadata = [], ?string $idempotencyKey = null): string
    {
        // Replays the first answer for a repeated key, as Stripe does.
        if ($idempotencyKey !== null && isset($this->keys[$idempotencyKey])) {
            return $this->keys[$idempotencyKey];
        }

        $id = 'prod_'.substr(sha1($name.count($this->products)), 0, 12);
        $this->products[$id] = ['name' => $name, 'metadata' => $metadata];

        if ($idempotencyKey !== null) {
            $this->keys[$idempotencyKey] = $id;
        }

        return $id;
    }

    public function createPrice(
        string $productId,
        int $amountCents,
        string $currency,
        string $interval,
        array $metadata = [],
        ?string $idempotencyKey = null,
    ): string {
        if ($idempotencyKey !== null && isset($this->keys[$idempotencyKey])) {
            return $this->keys[$idempotencyKey];
        }

        $id = 'price_'.substr(sha1($productId.$amountCents.$interval.count($this->prices)), 0, 12);
        $this->prices[$id] = [
            'product' => $productId,
            'amount' => $amountCents,
            'currency' => $currency,
            'interval' => $interval,
            'metadata' => $metadata,
        ];

        if ($idempotencyKey !== null) {
            $this->keys[$idempotencyKey] = $id;
        }

        return $id;
    }

    public function archivePrice(string $priceId): void
    {
        $this->archived[] = $priceId;
    }

    public function activatePrice(string $priceId): void
    {
        // Taken off the archived list rather than merely appended to a second
        // one, so a test asking "is this Price still being sold?" gets the
        // answer Stripe would give instead of a history it has to interpret.
        $this->archived = array_values(array_filter(
            $this->archived,
            fn (string $id) => $id !== $priceId,
        ));

        $this->activated[] = $priceId;
    }

    public function updateSubscriptionPrice(
        string $subscriptionId,
        string $itemId,
        string $priceId,
        string $prorationBehaviour,
    ): void {
        $this->failIfAsked();

        $this->priceChanges[] = [
            'subscription' => $subscriptionId,
            'item' => $itemId,
            'price' => $priceId,
            'proration' => $prorationBehaviour,
        ];
    }

    public function subscriptionItemId(string $subscriptionId): ?string
    {
        $this->failIfAsked();

        return $this->items[$subscriptionId] ?? null;
    }

    public function addSubscriptionItem(
        string $subscriptionId,
        string $priceId,
        int $quantity,
        string $prorationBehaviour,
        ?string $idempotencyKey = null,
    ): string {
        $this->failIfAsked();

        $id = 'si_'.substr(sha1($subscriptionId.$priceId.count($this->subscriptionItems)), 0, 12);

        $this->subscriptionItems[$id] = [
            'subscription' => $subscriptionId,
            'price' => $priceId,
            'quantity' => $quantity,
        ];

        $this->itemCalls[] = [
            'call' => 'add',
            'subscription' => $subscriptionId,
            'item' => $id,
            'price' => $priceId,
            'quantity' => $quantity,
            'proration' => $prorationBehaviour,
        ];

        return $id;
    }

    public function updateSubscriptionItemQuantity(
        string $itemId,
        int $quantity,
        string $prorationBehaviour,
    ): void {
        $this->failIfAsked();

        if (isset($this->subscriptionItems[$itemId])) {
            $this->subscriptionItems[$itemId]['quantity'] = $quantity;
        }

        $this->itemCalls[] = [
            'call' => 'quantity',
            'item' => $itemId,
            'quantity' => $quantity,
            'proration' => $prorationBehaviour,
        ];
    }

    public function removeSubscriptionItem(string $itemId, string $prorationBehaviour): void
    {
        $this->failIfAsked();

        unset($this->subscriptionItems[$itemId]);

        $this->itemCalls[] = [
            'call' => 'remove',
            'item' => $itemId,
            'proration' => $prorationBehaviour,
        ];
    }

    public function cancelSubscription(
        string $subscriptionId,
        string $when,
        ?string $idempotencyKey = null,
    ): void {
        $this->failIfAsked();

        // Refused here as well as in HttpStripeClient, so a caller that invents a
        // third timing fails in the tests rather than in production.
        if (! in_array($when, [self::CANCEL_AT_PERIOD_END, self::CANCEL_IMMEDIATELY], true)) {
            throw new RuntimeException("Unknown cancellation timing: {$when}");
        }

        // Replays the first answer for a repeated key, as Stripe does, so a retry
        // after a timeout records one order to stop rather than two.
        if ($idempotencyKey !== null && isset($this->keys[$idempotencyKey])) {
            return;
        }

        $this->cancellations[] = [
            'subscription' => $subscriptionId,
            'when' => $when,
            'key' => $idempotencyKey,
        ];

        if ($idempotencyKey !== null) {
            $this->keys[$idempotencyKey] = $subscriptionId;
        }
    }

    public function refund(
        string $paymentReference,
        ?int $amountCents = null,
        ?string $idempotencyKey = null,
    ): string {
        $this->failIfAsked();

        // Replays the first answer for a repeated key, as Stripe does — which
        // is the whole point of sending one on a refund.
        if ($idempotencyKey !== null && isset($this->keys[$idempotencyKey])) {
            return $this->keys[$idempotencyKey];
        }

        $this->refunds[] = [
            'payment' => $paymentReference,
            'amount' => $amountCents,
            'key' => $idempotencyKey,
        ];

        $id = 're_'.substr(sha1($paymentReference.count($this->refunds)), 0, 12);

        if ($idempotencyKey !== null) {
            $this->keys[$idempotencyKey] = $id;
        }

        return $id;
    }

    public function invoicePaymentReference(string $invoiceId): ?string
    {
        $this->failIfAsked();

        return $this->invoicePayments[$invoiceId] ?? null;
    }

    public function invoiceLines(string $invoiceId): array
    {
        $this->failIfAsked();

        return $this->invoiceLines[$invoiceId] ?? [];
    }

    /** The module items this Stripe holds for one subscription. */
    public function itemsOn(string $subscriptionId): array
    {
        return array_filter(
            $this->subscriptionItems,
            fn (array $item) => $item['subscription'] === $subscriptionId,
        );
    }

    private function failIfAsked(): void
    {
        if ($this->failWith !== null) {
            throw new RuntimeException($this->failWith);
        }
    }
}