<?php

namespace App\Osint\Runners;

use App\Models\Target;
use App\Osint\Runner;
use App\Osint\RunnerException;
use App\Osint\RunnerResult;

class DnsRunner implements Runner
{
    /**
     * @var array<string, int>
     */
    private const RECORD_TYPES = [
        'A' => DNS_A,
        'AAAA' => DNS_AAAA,
        'MX' => DNS_MX,
        'NS' => DNS_NS,
        'TXT' => DNS_TXT,
        'CNAME' => DNS_CNAME,
    ];

    public function run(Target $target): RunnerResult
    {
        if ($target->type !== 'domain') {
            throw new RunnerException('DNS lookup only supports "domain" targets.');
        }

        if (! preg_match('/^([a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/', $target->value)) {
            throw new RunnerException('Domain contains characters that are not safe to look up.');
        }

        $records = [];

        foreach (self::RECORD_TYPES as $label => $type) {
            // dns_get_record() emits a warning (not an exception) when a
            // record type doesn't resolve for the domain — expected for
            // most domains on most types, not a real error.
            $found = @dns_get_record($target->value, $type);

            if ($found === false || empty($found)) {
                continue;
            }

            $records[$label] = array_values(array_unique(array_map(
                fn (array $record) => $this->formatRecord($label, $record),
                $found
            )));
        }

        $total = array_sum(array_map('count', $records));

        $summary = $total > 0
            ? sprintf('Found %d DNS record%s across %d type%s (%s).',
                $total, $total === 1 ? '' : 's',
                count($records), count($records) === 1 ? '' : 's',
                implode(', ', array_keys($records)))
            : 'No DNS records found.';

        return new RunnerResult(raw: $records, summary: $summary);
    }

    private function formatRecord(string $label, array $record): string
    {
        return match ($label) {
            'A', 'AAAA' => $record['ip'] ?? '',
            'MX' => sprintf('%d %s', $record['pri'] ?? 0, $record['target'] ?? ''),
            'NS', 'CNAME' => $record['target'] ?? '',
            'TXT' => $record['txt'] ?? '',
            default => '',
        };
    }
}