<?php

namespace Tests\Support;

use AltchaOrg\Altcha\Algorithm\Pbkdf2;
use AltchaOrg\Altcha\Altcha;
use AltchaOrg\Altcha\CreateChallengeOptions;
use AltchaOrg\Altcha\SolveChallengeOptions;

/**
 * Builds a valid altcha payload for tests using the fixed ALTCHA_HMAC_KEY,
 * mirroring the payload shape produced by the browser widget (base64 JSON with
 * a challenge array and a solution array).
 */
final class AltchaPayload
{
    public static function valid(?int $counter = null): string
    {
        $pbkdf2 = new Pbkdf2;
        $altcha = new Altcha(
            hmacSignatureSecret: config('captcha.hmac_key'),
        );

        $counter ??= random_int(1, 100);

        $challenge = $altcha->createChallenge(new CreateChallengeOptions(
            algorithm: $pbkdf2,
            cost: 5000,
            counter: $counter,
            expiresAt: time() + 600,
        ));

        $solution = $altcha->solveChallenge(new SolveChallengeOptions(
            challenge: $challenge,
            algorithm: $pbkdf2,
            start: $counter,
            step: 1,
            timeout: 5,
        ));

        return base64_encode(json_encode([
            'challenge' => $challenge->toArray(),
            'solution' => $solution->toArray(),
        ]));
    }
}