<?php

declare(strict_types=1);

namespace App\Services\Academy;

use App\Models\AcademyBillingEvent;
use App\Models\User;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;
use Laravel\Cashier\Subscription;

final class AcademyStripeWebhookAuditService
{
    private const TRACKED_EVENT_TYPES = [
        'checkout.session.completed',
        'customer.subscription.created',
        'customer.subscription.updated',
        'customer.subscription.deleted',
        'invoice.payment_succeeded',
        'invoice.payment_failed',
        'invoice.payment_action_required',
    ];

    public function __construct(
        private readonly AcademyBillingPlanService $plans,
    ) {}

    /**
     * @param  array<string, mixed>  $payload
     */
    public function recordReceived(array $payload): void
    {
        $context = $this->buildContext($payload);
        $tracked = in_array($context['event_type'], self::TRACKED_EVENT_TYPES, true);
        $cacheKeys = [];

        if ($tracked && $context['user'] instanceof User) {
            $cacheKeys = [
                'academy.billing.account.'.$context['user']->id,
                'academy.billing.pricing.'.$context['user']->id,
            ];

            foreach ($cacheKeys as $cacheKey) {
                Cache::forget($cacheKey);
            }
        }

        $event = $this->persistEvent($context, [
            'received' => true,
            'received_at' => now()->toISOString(),
            'tracked' => $tracked,
            'action' => $tracked ? 'received_for_cashier_processing' : 'ignored_untracked_event',
            'user_resolved' => $context['user'] instanceof User,
            'cache_cleared' => $cacheKeys !== [],
            'cache_keys' => $cacheKeys,
            'status' => $context['object']['status'] ?? null,
            'mode' => $context['object']['mode'] ?? null,
            'amount_total' => $context['object']['amount_total'] ?? null,
            'currency' => $context['object']['currency'] ?? null,
            'price_ids' => $this->extractPriceIds($context['object']),
        ]);

        Log::info('academy.stripe.webhook.received', [
            'stripe_event_id' => $context['event_id'],
            'event_type' => $context['event_type'],
            'tracked' => $tracked,
            'user_id' => $context['user']?->id,
            'academy_plan' => $context['plan']['key'] ?? null,
            'academy_tier' => $context['plan']['tier'] ?? null,
            'audit_event_id' => $event->id,
        ]);
    }

    /**
     * @param  array<string, mixed>  $payload
     */
    public function recordHandled(array $payload): void
    {
        $context = $this->buildContext($payload);
        $localSubscription = $this->resolveLocalSubscription($context['subscription_id'], $context['user']);

        $outcome = $localSubscription instanceof Subscription
            ? 'local_subscription_synced'
            : 'handled_without_local_subscription_change';

        $event = $this->persistEvent($context, [
            'handled' => true,
            'handled_at' => now()->toISOString(),
            'outcome' => $outcome,
            'local_subscription_found' => $localSubscription instanceof Subscription,
            'local_subscription_status' => $localSubscription?->stripe_status,
            'local_subscription_active' => $localSubscription?->active(),
            'local_subscription_on_grace_period' => $localSubscription?->onGracePeriod(),
            'local_price_ids' => $localSubscription instanceof Subscription
                ? $localSubscription->items->pluck('stripe_price')->filter()->values()->all()
                : [],
        ]);

        Log::info('academy.stripe.webhook.handled', [
            'stripe_event_id' => $context['event_id'],
            'event_type' => $context['event_type'],
            'user_id' => $context['user']?->id,
            'academy_plan' => $context['plan']['key'] ?? null,
            'academy_tier' => $context['plan']['tier'] ?? null,
            'outcome' => $outcome,
            'audit_event_id' => $event->id,
        ]);
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return array{event_id:string,event_type:string,object:array<string,mixed>,customer_id:?string,subscription_id:?string,plan:?array<string,mixed>,user:?User}
     */
    private function buildContext(array $payload): array
    {
        $eventType = trim((string) ($payload['type'] ?? ''));
        $object = is_array($payload['data']['object'] ?? null)
            ? $payload['data']['object']
            : [];

        $customerId = $this->extractCustomerId($object);
        $subscriptionId = $this->extractSubscriptionId($object);
        $plan = $this->resolvePlan($object);
        $user = $this->resolveUser($customerId, $subscriptionId, $object);

        return [
            'event_id' => trim((string) ($payload['id'] ?? '')),
            'event_type' => $eventType,
            'object' => $object,
            'customer_id' => $customerId,
            'subscription_id' => $subscriptionId,
            'plan' => $plan,
            'user' => $user,
        ];
    }

    /**
     * @param  array<string, mixed>  $context
     * @param  array<string, mixed>  $summary
     */
    private function persistEvent(array $context, array $summary): AcademyBillingEvent
    {
        $eventId = $context['event_id'];

        $event = $eventId !== ''
            ? AcademyBillingEvent::query()->firstOrNew(['stripe_event_id' => $eventId])
            : new AcademyBillingEvent();

        $existingSummary = is_array($event->payload_summary) ? $event->payload_summary : [];

        $event->fill([
            'user_id' => $context['user']?->id,
            'stripe_event_id' => $eventId !== '' ? $eventId : null,
            'stripe_customer_id' => $context['customer_id'],
            'stripe_subscription_id' => $context['subscription_id'],
            'event_type' => $context['event_type'] !== '' ? $context['event_type'] : 'unknown',
            'academy_tier' => $context['plan']['tier'] ?? null,
            'academy_plan' => $context['plan']['key'] ?? null,
            'payload_summary' => array_merge($existingSummary, $summary),
            'processed_at' => now(),
        ]);

        $event->save();

        return $event;
    }

    /**
     * @param  array<string, mixed>  $object
     * @return array<string, mixed>|null
     */
    private function resolvePlan(array $object): ?array
    {
        $metadataPlan = trim((string) Arr::get($object, 'metadata.academy_plan', ''));

        if ($metadataPlan !== '') {
            return $this->plans->plan($metadataPlan);
        }

        foreach ($this->extractPriceIds($object) as $priceId) {
            $plan = $this->plans->planForPriceId($priceId);

            if ($plan !== null) {
                return $plan;
            }
        }

        return null;
    }

    /**
     * @param  array<string, mixed>  $object
     * @return list<string>
     */
    private function extractPriceIds(array $object): array
    {
        $priceIds = [];

        foreach ((array) Arr::get($object, 'items.data', []) as $item) {
            if (! is_array($item)) {
                continue;
            }

            $priceId = trim((string) Arr::get($item, 'price.id', ''));

            if ($priceId !== '') {
                $priceIds[] = $priceId;
            }
        }

        $lineItemPriceId = trim((string) Arr::get($object, 'display_items.0.price.id', ''));

        if ($lineItemPriceId !== '') {
            $priceIds[] = $lineItemPriceId;
        }

        return array_values(array_unique($priceIds));
    }

    /**
     * @param  array<string, mixed>  $object
     */
    private function extractCustomerId(array $object): ?string
    {
        $value = trim((string) ($object['customer'] ?? ''));

        return $value !== '' ? $value : null;
    }

    /**
     * @param  array<string, mixed>  $object
     */
    private function extractSubscriptionId(array $object): ?string
    {
        $subscriptionId = trim((string) ($object['id'] ?? ''));

        if (str_starts_with($subscriptionId, 'sub_')) {
            return $subscriptionId;
        }

        $nested = trim((string) ($object['subscription'] ?? ''));

        return $nested !== '' ? $nested : null;
    }

    /**
     * @param  array<string, mixed>  $object
     */
    private function resolveUser(?string $customerId, ?string $subscriptionId, array $object): ?User
    {
        $metadataUserId = (int) Arr::get($object, 'metadata.user_id', 0);

        if ($metadataUserId > 0) {
            return User::query()->find($metadataUserId);
        }

        if ($customerId !== null) {
            $user = User::query()->where('stripe_id', $customerId)->first();

            if ($user instanceof User) {
                return $user;
            }
        }

        if ($subscriptionId !== null) {
            $subscription = Subscription::query()->where('stripe_id', $subscriptionId)->first();

            if ($subscription !== null && $subscription->user instanceof User) {
                return $subscription->user;
            }
        }

        return null;
    }

    private function resolveLocalSubscription(?string $subscriptionId, ?User $user): ?Subscription
    {
        if ($subscriptionId !== null) {
            $subscription = Subscription::query()->where('stripe_id', $subscriptionId)->with('items')->first();

            if ($subscription instanceof Subscription) {
                return $subscription;
            }
        }

        if (! $user instanceof User) {
            return null;
        }

        $subscription = $user->subscription($this->plans->subscriptionName());

        return $subscription instanceof Subscription
            ? $subscription->loadMissing('items')
            : null;
    }
}