<?php

namespace App\Services;

use App\Models\User;
use Carbon\CarbonImmutable;
use Illuminate\Http\Client\PendingRequest;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Http;
use RuntimeException;

class RevenueCatService
{
    public function sync(User $user): User
    {
        $response = $this->client()
            ->get('subscribers/'.rawurlencode((string) $user->getKey()))
            ->throw()
            ->json();

        $subscriber = Arr::get($response, 'subscriber', []);

        if (! is_array($subscriber)) {
            throw new RuntimeException('RevenueCat returned an invalid subscriber payload.');
        }

        $subscription = $this->entitlement(
            $subscriber,
            (string) config('billing.revenuecat.subscription_entitlement'),
        );
        $certification = $this->entitlement(
            $subscriber,
            (string) config('billing.revenuecat.certification_entitlement'),
        );

        $subscriptionProductId = $this->stringValue($subscription['product_identifier'] ?? null);
        $subscriptionDetails = $subscriptionProductId
            ? Arr::get($subscriber, "subscriptions.{$subscriptionProductId}", [])
            : [];

        $user->forceFill([
            'subscription_product_id' => $this->entitlementIsActive($subscription)
                ? $subscriptionProductId
                : null,
            'subscription_store' => $this->entitlementIsActive($subscription)
                ? $this->stringValue(is_array($subscriptionDetails) ? ($subscriptionDetails['store'] ?? null) : null)
                : null,
            'subscription_expires_at' => $this->entitlementIsActive($subscription)
                ? $this->effectiveExpiration($subscription)
                : null,
            'subscription_is_trial' => $this->entitlementIsActive($subscription)
                && is_array($subscriptionDetails)
                && strtoupper((string) ($subscriptionDetails['period_type'] ?? '')) === 'TRIAL',
            'certification_purchased_at' => $this->entitlementIsActive($certification)
                ? $this->dateValue($certification['purchase_date'] ?? null) ?? now()
                : null,
        ])->save();

        return $user->fresh();
    }

    public function deleteCustomer(User $user): void
    {
        if (trim((string) config('billing.revenuecat.secret_key')) === '') {
            return;
        }

        $response = $this->client()
            ->delete('subscribers/'.rawurlencode((string) $user->getKey()));

        if (! $response->notFound()) {
            $response->throw();
        }
    }

    private function client(): PendingRequest
    {
        $secretKey = trim((string) config('billing.revenuecat.secret_key'));

        if ($secretKey === '') {
            throw new RuntimeException('REVENUECAT_SECRET_KEY is not configured.');
        }

        return Http::baseUrl(rtrim((string) config('billing.revenuecat.api_url'), '/'))
            ->withToken($secretKey)
            ->acceptJson()
            ->connectTimeout(5)
            ->timeout(12)
            ->retry([200, 500], throw: false);
    }

    /**
     * @param  array<string, mixed>  $subscriber
     * @return array<string, mixed>
     */
    private function entitlement(array $subscriber, string $identifier): array
    {
        $entitlement = Arr::get($subscriber, "entitlements.{$identifier}", []);

        return is_array($entitlement) ? $entitlement : [];
    }

    /**
     * @param  array<string, mixed>  $entitlement
     */
    private function entitlementIsActive(array $entitlement): bool
    {
        if ($entitlement === []) {
            return false;
        }

        $expiration = $this->effectiveExpiration($entitlement);

        return $expiration === null || $expiration->isFuture();
    }

    /**
     * @param  array<string, mixed>  $entitlement
     */
    private function effectiveExpiration(array $entitlement): ?CarbonImmutable
    {
        $expiration = $this->dateValue($entitlement['expires_date'] ?? null);
        $gracePeriodExpiration = $this->dateValue($entitlement['grace_period_expires_date'] ?? null);

        if ($expiration === null) {
            return $gracePeriodExpiration;
        }

        if ($gracePeriodExpiration === null) {
            return $expiration;
        }

        return $gracePeriodExpiration->greaterThan($expiration)
            ? $gracePeriodExpiration
            : $expiration;
    }

    private function dateValue(mixed $value): ?CarbonImmutable
    {
        if (! is_string($value) || $value === '') {
            return null;
        }

        return CarbonImmutable::parse($value);
    }

    private function stringValue(mixed $value): ?string
    {
        return is_string($value) && $value !== '' ? $value : null;
    }
}