<?php

namespace App\Services;

use App\Enums\PaymentProvider;
use App\Models\UserAbo;
use App\Services\Payment\PaymentProviderManager;
use App\Services\Payment\Payone\DTOs\CardUpdateResult;
use App\Services\Payment\Payone\DTOs\CreditCardCheckData;
use App\Services\Payment\Payone\PayonePaymentService;
use App\Services\Payment\Stripe\StripePaymentService;
use Illuminate\Support\Facades\DB;
use Throwable;

/**
 * Orchestrates updating the payment method of an existing Abo. The card data /
 * payment method is chosen exclusively by the Abo owner; guard-/owner-specific
 * authorization happens in the calling controller, the invariant in
 * {@see UserAbo::canUpdatePaymentMethod()}.
 *
 * Two flows:
 *  - PAYONE (legacy, CC only): creditcardcheck + preauthorization, no charge
 *    (Phase-1 plan dev/2026-06-25-kreditkarte-update/).
 *  - Stripe (Plan S5, dev/2026-07-08-stripe/): hosted Checkout Session in
 *    setup mode — free choice of any reusable payment method, no charge.
 *    Applies to PAYONE legacy abos too: changing the payment method moves the
 *    abo to Stripe (§7.2 no. 3, soft migration).
 */
class AboPaymentMethodService
{
    public function __construct(private readonly PayonePaymentService $payone) {}

    /**
     * Der Stripe-Setup-Flow gilt, sobald der Anbieter-Schalter auf Stripe
     * steht — unabhängig vom Provider des Abos (PAYONE-Abos ziehen beim
     * Wechsel auf Stripe um).
     */
    public function usesStripeChange(): bool
    {
        return app(PaymentProviderManager::class)->providerForNewCheckout() === PaymentProvider::Stripe;
    }

    /**
     * Zentrale Einstiegs-Prüfung für Controller/Views: Im Stripe-Setup-Flow
     * ist jede Zahlart wechselbar, im PAYONE-Legacy-Flow nur Kreditkarten.
     */
    public function canStartChange(UserAbo $abo): bool
    {
        return $this->usesStripeChange()
            ? $abo->canChangePaymentMethodAnyType()
            : $abo->canUpdatePaymentMethod();
    }

    /**
     * Runs the card update. On success the new token is written atomically; a 3-D Secure
     * challenge is surfaced as a REDIRECT outcome (finalized after return via
     * {@see applyNewCard()}); failures leave the stored card untouched.
     *
     * @param  array<string, string>  $returnUrls  successurl/errorurl/backurl for the 3DS redirect.
     */
    public function updateCreditCard(UserAbo $abo, CreditCardCheckData $card, array $returnUrls, ?string $source = null): CardUpdateResult
    {
        if (app(PaymentProviderManager::class)->aboPaymentsFrozen()) {
            return CardUpdateResult::error(__('payment.abo_payments_frozen'));
        }

        if (! $abo->canUpdatePaymentMethod()) {
            return CardUpdateResult::error(__('abo.card_update_not_allowed'));
        }

        $shoppingUser = $abo->shopping_user;
        if (! $shoppingUser) {
            return CardUpdateResult::error(__('abo.card_update_failed'));
        }

        $mode = $this->resolveMode($abo);

        // Konsistenz-Spur: vor externem PAYONE-Call + DB-Write setzen, damit ein Crash
        // zwischen erfolgreichem PAYONE-Call und DB-Write auffindbar bleibt.
        $abo->forceFill(['card_update_pending_at' => now()])->save();

        $result = $this->payone->refreshAboCardToken($shoppingUser, $card, $returnUrls, $mode);

        if ($result->isApproved()) {
            $this->applyNewCard($abo, $result->carddata, $result->userid, $source);
            // 1-Cent-Reservierung freigeben; Fehler hier ist unkritisch (verfällt sonst).
            $this->safelyReleasePreauth($result->txid, $mode);

            return $result;
        }

        if ($result->isRedirect()) {
            // Pending-Spur bleibt bestehen; Finalisierung nach 3DS-Rückkehr (Controller).
            return $result;
        }

        // Fehler: Spur zurücknehmen, kein DB-Update.
        $abo->forceFill(['card_update_pending_at' => null])->save();

        return $result;
    }

    /**
     * Writes the new card token atomically and idempotently and clears the pending trace.
     * Also used by the 3-D-Secure return path after successful authentication.
     *
     * @param  array<string, mixed>  $carddata
     */
    public function applyNewCard(UserAbo $abo, array $carddata, int $userid, ?string $source = null): void
    {
        try {
            DB::transaction(function () use ($abo, $carddata, $userid, $source) {
                $abo->forceFill([
                    'carddata' => $carddata,
                    'payone_userid' => $userid,
                    'card_update_pending_at' => null,
                ])->save();

                $abo->card_changes()->create([
                    'masked_card' => UserAbo::formatMaskedCard($carddata),
                    'source' => $source,
                ]);
            });
        } catch (Throwable $e) {
            // PAYONE hat die neue Karte, der lokale DB-Write schlug fehl → Inkonsistenz:
            // card_update_pending_at bleibt gesetzt (auffindbare Spur), CRITICAL-Alert.
            MyLog::writeLog(
                'payment',
                'critical',
                'Kreditkarten-Update: DB-Write nach erfolgreichem PAYONE-Call fehlgeschlagen (Abo '.$abo->id.')',
                ['user_abo_id' => $abo->id, 'payone_userid' => $userid, 'exception' => $e->getMessage()],
            );

            throw $e;
        }
    }

    /**
     * Startet den Stripe-Setup-Flow (Plan S5.1/S5.3): Pending-Spur setzen,
     * Setup-Session erstellen, Redirect-URL zurückgeben. Kein Charge.
     *
     * @param  string  $successUrl  Muss den Platzhalter {CHECKOUT_SESSION_ID} enthalten.
     */
    public function beginStripeChange(UserAbo $abo, string $successUrl, string $cancelUrl, ?string $source = null): CardUpdateResult
    {
        if (app(PaymentProviderManager::class)->aboPaymentsFrozen()) {
            return CardUpdateResult::error(__('payment.abo_payments_frozen'));
        }

        if (! $abo->canChangePaymentMethodAnyType()) {
            return CardUpdateResult::error(__('abo.card_update_not_allowed'));
        }

        // Konsistenz-Spur wie beim PAYONE-Flow: vor dem externen Call setzen.
        $abo->forceFill(['card_update_pending_at' => now()])->save();

        try {
            $session = app(StripePaymentService::class)->createPaymentMethodChangeSession(
                $abo,
                $successUrl,
                $cancelUrl,
                $source,
            );
        } catch (Throwable $e) {
            $abo->forceFill(['card_update_pending_at' => null])->save();
            \Log::channel('stripe')->error('Zahlungsart-Wechsel: Setup-Session konnte nicht erstellt werden: '.$e->getMessage(), [
                'user_abo_id' => $abo->id,
            ]);

            return CardUpdateResult::error(__('payment.stripe_unavailable'));
        }

        return CardUpdateResult::redirect((string) $session->url, [], '');
    }

    /**
     * Return-Pfad des Setup-Flows: Session nachladen, SetupIntent prüfen und
     * die neue Zahlungsart verankern. Der setup_intent.succeeded-Webhook macht
     * dasselbe als Sicherheitsnetz — applyStripePaymentMethod() ist idempotent.
     */
    public function finalizeStripeChangeFromSession(UserAbo $abo, string $sessionId, ?string $source = null): bool
    {
        try {
            $session = app(StripePaymentService::class)->retrieveSetupSession($sessionId);
        } catch (Throwable $e) {
            \Log::channel('stripe')->error('Zahlungsart-Wechsel: Setup-Session nicht abrufbar: '.$e->getMessage(), [
                'user_abo_id' => $abo->id,
                'session_id' => $sessionId,
            ]);

            return false;
        }

        // Session muss zu genau diesem Abo gehören (kein fremdes session_id-Query-Param).
        if ((string) ($session->metadata['user_abo_id'] ?? '') !== (string) $abo->id) {
            return false;
        }

        $setupIntent = $session->setup_intent;
        if (! $setupIntent || $setupIntent->status !== 'succeeded' || empty($setupIntent->payment_method)) {
            $abo->forceFill(['card_update_pending_at' => null])->save();

            return false;
        }

        $paymentMethodId = is_string($setupIntent->payment_method)
            ? $setupIntent->payment_method
            : $setupIntent->payment_method->id;
        $customerId = is_string($session->customer) ? $session->customer : $session->customer->id;

        $this->applyStripePaymentMethod($abo, $customerId, $paymentMethodId, $source);

        return true;
    }

    /**
     * Verankert die neue Stripe-Zahlungsart atomar und idempotent am Abo und
     * zieht PAYONE-Abos dabei auf Stripe um (§7.2 Nr. 3). Wird vom Return-Pfad
     * UND vom setup_intent.succeeded-Webhook aufgerufen.
     */
    public function applyStripePaymentMethod(UserAbo $abo, string $customerId, string $paymentMethodId, ?string $source = null): void
    {
        // Idempotenz: Webhook und Return-Pfad laufen beide — nur einmal verankern.
        if ($abo->stripe_payment_method_id === $paymentMethodId) {
            if ($abo->card_update_pending_at !== null) {
                $abo->forceFill(['card_update_pending_at' => null])->save();
            }

            return;
        }

        $previousPaymentMethodId = $abo->payment_provider === PaymentProvider::Stripe->value
            ? $abo->stripe_payment_method_id
            : null;

        $summary = app(StripePaymentService::class)->retrievePaymentMethodSummary($paymentMethodId);

        try {
            DB::transaction(function () use ($abo, $customerId, $paymentMethodId, $summary, $source) {
                $abo->forceFill([
                    'payment_provider' => PaymentProvider::Stripe->value,
                    'stripe_customer_id' => $customerId,
                    'stripe_payment_method_id' => $paymentMethodId,
                    'clearingtype' => 'stripe',
                    'wallettype' => null,
                    'carddata' => $summary,
                    'card_update_pending_at' => null,
                ])->save();

                $abo->card_changes()->create([
                    'masked_card' => UserAbo::formatMaskedCard($summary),
                    'source' => $source,
                ]);
            });
        } catch (Throwable $e) {
            // Stripe hat die neue Zahlungsart, der lokale DB-Write schlug fehl → Inkonsistenz:
            // card_update_pending_at bleibt gesetzt (auffindbare Spur), CRITICAL-Alert.
            MyLog::writeLog(
                'payment',
                'critical',
                'Zahlungsart-Wechsel (Stripe): DB-Write nach erfolgreichem Setup fehlgeschlagen (Abo '.$abo->id.')',
                ['user_abo_id' => $abo->id, 'payment_method' => $paymentMethodId, 'exception' => $e->getMessage()],
            );

            throw $e;
        }

        if ($previousPaymentMethodId && $previousPaymentMethodId !== $paymentMethodId) {
            app(StripePaymentService::class)->detachPaymentMethod($previousPaymentMethodId);
        }
    }

    private function safelyReleasePreauth(string $txid, string $mode): void
    {
        if ($txid === '') {
            return;
        }

        try {
            $this->payone->releasePreauth($txid, $mode);
        } catch (Throwable $e) {
            MyLog::writeLog(
                'payone',
                'warning',
                'Preauth-Freigabe (capture amount=0) fehlgeschlagen, Reservierung verfällt',
                ['txid' => $txid, 'error' => $e->getMessage()],
                false,
            );
        }
    }

    private function resolveMode(UserAbo $abo): string
    {
        return $abo->initialShoppingPayment()?->mode ?: config('payone.defaults.mode');
    }
}