<?php

declare(strict_types=1);

namespace Apoloz\AlfaBank\Traits;

use Apoloz\AlfaBank\Contracts\SignerInterface;
use Apoloz\AlfaBank\Data\NominalAccounts\Payouts\DigestSignatureData;
use Spatie\LaravelData\DataCollection;

trait SignableData
{
    public function sign(SignerInterface $signer): self
    {
        // 1. Get raw data as array
        $data = $this->toArray();

        // 2. Remove existing signatures if any
        unset($data['digestSignatures']);

        // 3. Canonicalize (RFC 8785 - simple version: sort keys, remove nulls, no spaces)
        $canonicalData = $this->canonicalizeArray($data);

        $jsonToSign = json_encode($canonicalData, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);

        // 4. Sign
        $signature = $signer->sign($jsonToSign);

        // 5. Attach signature to the original object
        if ($this->digestSignatures === null) {
            $this->digestSignatures = new DataCollection(DigestSignatureData::class, []);
        }

        $current = array_values($this->digestSignatures->toCollection()->all());
        $current[] = new DigestSignatureData($signature, 'RSA');

        $this->digestSignatures = new DataCollection(DigestSignatureData::class, $current);

        return $this;
    }

    private function canonicalizeArray(array $array): array
    {
        // Remove nulls and empty strings
        $array = array_filter($array, fn ($v) => $v !== null);

        // Sort keys lexically
        ksort($array);

        foreach ($array as $key => $value) {
            if (is_array($value)) {
                $array[$key] = $this->canonicalizeArray($value);
            }
        }

        return $array;
    }
}