<?php

declare(strict_types=1);

namespace TFGraphics\SmartImport\Knowledge;

final class KnowledgeFingerprint
{
    public function create(string $normalizedIdentifier, string $domain): string
    {
        $identifier = strtoupper(trim($normalizedIdentifier));
        $normalizedDomain = strtolower(trim($domain));
        if ($identifier === '' || $normalizedDomain === '') {
            throw new \InvalidArgumentException('Fingerprint requires normalized identifier and domain.');
        }

        return hash('sha256', $normalizedDomain . '|' . $identifier);
    }

    public function hash(array $payload): string
    {
        $canonical = $this->canonicalize($payload);
        $encoded = json_encode($canonical, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
        if ($encoded === false) {
            throw new \InvalidArgumentException('Knowledge payload cannot be encoded.');
        }

        return hash('sha256', $encoded);
    }

    private function canonicalize(array $payload): array
    {
        if (! $this->isList($payload)) {
            ksort($payload);
        }

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

        return $payload;
    }

    private function isList(array $payload): bool
    {
        return array_keys($payload) === range(0, count($payload) - 1);
    }
}