<?php

namespace App\Services\PayPal;

use App\Models\CheckoutSession;
use App\Services\Checkout\CheckoutAssignmentService;
use App\Services\Checkout\CheckoutSessionService;
use App\Services\Coupons\CouponRedemptionService;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;

class PayPalWebhookService
{
    public function __construct(
        private readonly CheckoutSessionService $sessions,
        private readonly CheckoutAssignmentService $assignment,
        private readonly CouponRedemptionService $couponRedemptions,
    ) {}

    /**
     * @param  array<string, mixed>  $event
     */
    public function handle(array $event): bool
    {
        $eventType = $event['event_type'] ?? null;
        $resource = $event['resource'] ?? null;

        if (! is_string($eventType) || ! is_array($resource)) {
            return false;
        }

        $orderId = $this->resolveOrderId($eventType, $resource);
        $session = $this->locateSession($orderId, $resource);

        if (! $session) {
            Log::info('[PayPalWebhook] session not resolved', [
                'event_type' => $eventType,
                'order_id' => $orderId,
            ]);

            return false;
        }

        $lockKey = 'checkout:webhook:paypal:'.($orderId ?: $session->id);
        $lock = Cache::lock($lockKey, 30);

        if (! $lock->get()) {
            Log::info('[PayPalWebhook] lock busy', [
                'order_id' => $orderId,
                'session_id' => $session->id,
            ]);

            return true;
        }

        try {
            if ($orderId && $session->paypal_order_id !== $orderId) {
                $session->forceFill([
                    'paypal_order_id' => $orderId,
                    'provider' => CheckoutSession::PROVIDER_PAYPAL,
                ])->save();
            } elseif ($session->provider !== CheckoutSession::PROVIDER_PAYPAL) {
                $session->forceFill(['provider' => CheckoutSession::PROVIDER_PAYPAL])->save();
            }

            $this->mergeProviderMetadata($session, [
                'paypal_last_event' => $eventType,
                'paypal_status' => $this->resolveStatus($resource),
                'paypal_last_update_at' => now()->toIso8601String(),
            ]);

            return $this->applyEvent($session, $eventType, $resource, $event);
        } finally {
            $lock->release();
        }
    }

    /**
     * @param  array<string, mixed>  $resource
     * @param  array<string, mixed>  $event
     */
    protected function applyEvent(CheckoutSession $session, string $eventType, array $resource, array $event): bool
    {
        $normalized = strtoupper($eventType);

        if (in_array($normalized, ['PAYMENT.CAPTURE.COMPLETED', 'CHECKOUT.ORDER.COMPLETED'], true)) {
            $captureId = $this->resolveCaptureId($resource, $normalized);
            $totals = $this->resolveTotals($resource);
            $status = strtoupper((string) ($resource['status'] ?? 'COMPLETED'));

            $session->forceFill([
                'paypal_capture_id' => $captureId ?: $session->paypal_capture_id,
                'provider_metadata' => array_merge($session->provider_metadata ?? [], array_filter([
                    'paypal_capture_id' => $captureId,
                    'paypal_status' => $status,
                    'paypal_totals' => $totals !== [] ? $totals : null,
                    'paypal_captured_at' => now()->toIso8601String(),
                ])),
            ])->save();

            if ($session->status !== CheckoutSession::STATUS_COMPLETED) {
                $this->sessions->markProcessing($session, [
                    'paypal_status' => $status,
                    'paypal_capture_id' => $captureId,
                ]);

                $this->assignment->finalise($session, [
                    'source' => 'paypal_webhook',
                    'provider' => CheckoutSession::PROVIDER_PAYPAL,
                    'provider_reference' => $captureId ?: $session->paypal_order_id,
                    'payload' => $resource,
                ]);

                $this->sessions->markCompleted($session, now());
                $this->couponRedemptions->recordSuccess($session, $resource);
            }

            return true;
        }

        if ($normalized === 'CHECKOUT.ORDER.APPROVED') {
            if ($session->status !== CheckoutSession::STATUS_COMPLETED) {
                $this->sessions->markRequiresCustomerAction($session, 'paypal_approved');
            }

            return true;
        }

        if ($normalized === 'PAYMENT.CAPTURE.PENDING') {
            if ($session->status !== CheckoutSession::STATUS_COMPLETED) {
                $this->sessions->markRequiresCustomerAction($session, 'paypal_pending');
            }

            return true;
        }

        if (in_array($normalized, ['PAYMENT.CAPTURE.DENIED', 'PAYMENT.CAPTURE.REFUNDED', 'CHECKOUT.ORDER.VOIDED'], true)) {
            $reason = match ($normalized) {
                'PAYMENT.CAPTURE.DENIED' => 'paypal_capture_denied',
                'PAYMENT.CAPTURE.REFUNDED' => 'paypal_refunded',
                'CHECKOUT.ORDER.VOIDED' => 'paypal_voided',
                default => 'paypal_failed',
            };

            $this->sessions->markFailed($session, $reason);
            $this->couponRedemptions->recordFailure($session, $reason);

            return true;
        }

        return false;
    }

    /**
     * @param  array<string, mixed>  $resource
     */
    protected function resolveOrderId(string $eventType, array $resource): ?string
    {
        if (str_starts_with(strtoupper($eventType), 'PAYMENT.CAPTURE.')) {
            $relatedOrderId = Arr::get($resource, 'supplementary_data.related_ids.order_id');

            return is_string($relatedOrderId) && $relatedOrderId !== '' ? $relatedOrderId : null;
        }

        $orderId = $resource['id'] ?? null;

        return is_string($orderId) && $orderId !== '' ? $orderId : null;
    }

    /**
     * @param  array<string, mixed>  $resource
     */
    protected function locateSession(?string $orderId, array $resource): ?CheckoutSession
    {
        if ($orderId) {
            return CheckoutSession::query()
                ->where('paypal_order_id', $orderId)
                ->first();
        }

        $customId = Arr::get($resource, 'purchase_units.0.custom_id');

        if (is_string($customId) && $customId !== '') {
            return CheckoutSession::query()->find($customId);
        }

        return null;
    }

    /**
     * @param  array<string, mixed>  $resource
     */
    protected function resolveCaptureId(array $resource, string $eventType): ?string
    {
        if (str_starts_with($eventType, 'PAYMENT.CAPTURE.')) {
            $captureId = $resource['id'] ?? null;

            return is_string($captureId) && $captureId !== '' ? $captureId : null;
        }

        $captureId = Arr::get($resource, 'purchase_units.0.payments.captures.0.id');

        return is_string($captureId) && $captureId !== '' ? $captureId : null;
    }

    /**
     * @param  array<string, mixed>  $resource
     * @return array{currency?: string, total?: float}
     */
    protected function resolveTotals(array $resource): array
    {
        $amount = Arr::get($resource, 'amount')
            ?? Arr::get($resource, 'purchase_units.0.payments.captures.0.amount')
            ?? Arr::get($resource, 'purchase_units.0.amount');

        if (! is_array($amount)) {
            return [];
        }

        $currency = Arr::get($amount, 'currency_code');
        $total = Arr::get($amount, 'value');

        return array_filter([
            'currency' => is_string($currency) ? strtoupper($currency) : null,
            'total' => is_numeric($total) ? (float) $total : null,
        ], static fn ($value) => $value !== null);
    }

    /**
     * @param  array<string, mixed>  $resource
     */
    protected function resolveStatus(array $resource): ?string
    {
        $status = $resource['status'] ?? null;

        return is_string($status) && $status !== '' ? strtoupper($status) : null;
    }

    /**
     * @param  array<string, mixed>  $data
     */
    protected function mergeProviderMetadata(CheckoutSession $session, array $data): void
    {
        $session->provider_metadata = array_merge($session->provider_metadata ?? [], $data);
        $session->save();
    }
}