<?php

namespace App\Services\Payments;

use Illuminate\Http\Request;
use RuntimeException;

final class PaddleWebhookVerifier implements WebhookVerifier
{
    public function verify(Request $request, string $rawBody): void
    {
        $secret = (string) config('rsync-studio.paddle.webhook_secret');
        $header = (string) $request->header('Paddle-Signature');
        if ($secret === '' || $header === '') {
            throw new RuntimeException('Paddle webhook verification is not configured.');
        }
        $parts = [];
        foreach (explode(';', $header) as $part) {
            [$k,$v] = array_pad(explode('=', trim($part), 2), 2, null);
            if ($k && $v) {
                $parts[$k][] = $v;
            }
        }
        $ts = isset($parts['ts'][0]) ? (int) $parts['ts'][0] : 0;
        $signatures = $parts['h1'] ?? [];
        $tolerance = max(1, (int) config('rsync-studio.paddle.timestamp_tolerance', 300));
        if (! $ts || abs(time() - $ts) > $tolerance) {
            throw new RuntimeException('Paddle webhook timestamp is outside the allowed tolerance.');
        }
        $expected = hash_hmac('sha256', $ts.':'.$rawBody, $secret);
        foreach ($signatures as $signature) {
            if (hash_equals($expected, $signature)) {
                return;
            }
        }
        throw new RuntimeException('Paddle webhook signature is invalid.');
    }
}