<?php

namespace App\Services\Intune;

class SnapshotValidator
{
    /**
     * @return array{isValid: bool, warnings: array<int, string>, errors: array<int, string>}
     */
    public function validate(array $snapshot): array
    {
        $warnings = [];
        $errors = [];

        if ($snapshot === []) {
            $warnings[] = 'Snapshot is empty';
        }

        if (array_is_list($snapshot)) {
            $warnings[] = 'This snapshot may be incomplete or malformed';
        }

        foreach ($snapshot as $value) {
            if (is_string($value) && $this->looksSerializedJson($value)) {
                $warnings[] = 'Snapshot may have been stored as a serialized string';
                break;
            }
        }

        return [
            'isValid' => empty($errors),
            'warnings' => array_values(array_unique($warnings)),
            'errors' => array_values(array_unique($errors)),
        ];
    }

    private function looksSerializedJson(string $value): bool
    {
        $trimmed = trim($value);

        return str_starts_with($trimmed, '{') || str_starts_with($trimmed, '[');
    }
}
