<?php

declare(strict_types=1);

namespace App\Jobs\FormBuilder;

use App\Enums\FormBuilder\FormWebhookDeliveryStatus;
use App\Models\FormBuilder\FormWebhookDelivery;
use App\Support\Json\JsonCanonicalizer;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

/**
 * HTTP delivery with HMAC signing, SSRF protection, exponential backoff
 * retries, and dead-letter on exhaustion (ARCH §17.5.3–§17.5.4, §22.10).
 */
final class DeliverFormWebhookJob implements ShouldQueue
{
    use Dispatchable;
    use InteractsWithQueue;
    use Queueable;
    use SerializesModels;

    /** @var array<int, int> Retry delays in seconds per attempt. */
    public array $backoff = [60, 300, 1800, 7200, 28800];

    public int $timeout = 30;

    public int $tries = 5;

    public function __construct(public readonly string $deliveryId) {}

    public function handle(): void
    {
        /** @var FormWebhookDelivery|null $delivery */
        $delivery = FormWebhookDelivery::query()->find($this->deliveryId);
        if ($delivery === null) {
            return;
        }

        $webhook = $delivery->webhook;
        if ($webhook === null || ! $webhook->is_active) {
            $delivery->status = FormWebhookDeliveryStatus::FAILED->value;
            $delivery->failed_permanently_at = now();
            $delivery->save();

            return;
        }

        $url = (string) $webhook->url;
        if (! $this->urlIsSafe($url)) {
            $delivery->status = FormWebhookDeliveryStatus::FAILED->value;
            $delivery->failed_permanently_at = now();
            $delivery->response_body_excerpt = 'SSRF protection: URL rejected.';
            $delivery->save();

            return;
        }

        // RFC-WS-6 session 2.7 — canonical JSON for HMAC signing.
        // payload_snapshot was read from a MySQL JSON column whose key
        // order may not match what we wrote. Canonicalize so the
        // signature is byte-stable across re-deliveries and matches what
        // a verifying receiver computes from the same logical payload.
        $payload = (array) ($delivery->payload_snapshot ?? []);
        $body = JsonCanonicalizer::encode($payload);

        $headers = ['Content-Type' => 'application/json'];
        if (! empty($webhook->secret)) {
            $headers['X-Crewli-Signature'] = 'sha256='.hash_hmac('sha256', $body, (string) $webhook->secret);
        }

        $delivery->attempts = (int) $delivery->attempts + 1;
        $delivery->last_attempt_at = now();

        try {
            $response = Http::withHeaders($headers)
                ->timeout((int) config('form_builder.webhooks.timeout_seconds', 10))
                ->withBody($body, 'application/json')
                ->post($url);

            $delivery->response_status = $response->status();
            $delivery->response_body_excerpt = mb_substr((string) $response->body(), 0, 1000);

            if ($response->successful()) {
                $delivery->status = FormWebhookDeliveryStatus::DELIVERED->value;
                $delivery->delivered_at = now();
                $delivery->save();

                return;
            }

            if ($this->isRetriable($response->status()) && $delivery->attempts < $this->tries) {
                $delivery->status = FormWebhookDeliveryStatus::PENDING->value;
                $delivery->next_retry_at = now()->addSeconds($this->backoff[$delivery->attempts - 1] ?? 28800);
                $delivery->save();
                $this->release($this->backoff[$delivery->attempts - 1] ?? 28800);

                return;
            }

            $delivery->status = $delivery->attempts >= $this->tries
                ? FormWebhookDeliveryStatus::DEAD_LETTER->value
                : FormWebhookDeliveryStatus::FAILED->value;
            $delivery->failed_permanently_at = now();
            $delivery->save();
        } catch (\Throwable $e) {
            Log::warning('form-webhook.delivery.exception', [
                'delivery_id' => $delivery->id,
                'message' => $e->getMessage(),
            ]);

            if ($delivery->attempts < $this->tries) {
                $delivery->status = FormWebhookDeliveryStatus::PENDING->value;
                $delivery->next_retry_at = now()->addSeconds($this->backoff[$delivery->attempts - 1] ?? 28800);
                $delivery->save();
                $this->release($this->backoff[$delivery->attempts - 1] ?? 28800);

                return;
            }

            $delivery->status = FormWebhookDeliveryStatus::DEAD_LETTER->value;
            $delivery->failed_permanently_at = now();
            $delivery->save();
        }
    }

    private function urlIsSafe(string $url): bool
    {
        $parts = parse_url($url);
        if ($parts === false || ! isset($parts['host'], $parts['scheme'])) {
            return false;
        }

        if (! in_array(strtolower($parts['scheme']), ['http', 'https'], true)) {
            return false;
        }

        $host = (string) $parts['host'];
        $allowlist = (array) config('form_builder.webhooks.allowlist_domains', []);
        if ($allowlist !== [] && ! in_array(strtolower($host), array_map('strtolower', $allowlist), true)) {
            return false;
        }

        $ips = @gethostbynamel($host) ?: [$host];
        $blocklist = (array) config('form_builder.webhooks.blocklist_ips', []);
        foreach ($ips as $ip) {
            if (! filter_var($ip, FILTER_VALIDATE_IP)) {
                continue;
            }
            foreach ($blocklist as $cidr) {
                if ($this->ipInCidr($ip, (string) $cidr)) {
                    return false;
                }
            }
            if (! filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
                return false;
            }
        }

        return true;
    }

    private function ipInCidr(string $ip, string $cidr): bool
    {
        if (! str_contains($cidr, '/')) {
            return $ip === $cidr;
        }
        [$subnet, $mask] = explode('/', $cidr, 2);
        $ipLong = ip2long($ip);
        $subnetLong = ip2long($subnet);
        if ($ipLong === false || $subnetLong === false) {
            return false;
        }
        $maskLong = -1 << (32 - (int) $mask);

        return ($ipLong & $maskLong) === ($subnetLong & $maskLong);
    }

    private function isRetriable(int $status): bool
    {
        if ($status >= 500) {
            return true;
        }

        return in_array($status, [408, 425, 429], true);
    }
}