<?php

namespace App\Support;

use Illuminate\Support\Facades\Cache;

class NetProbe
{
    public static function resolve(bool $force = false): array
    {
        return [
            'ipv4' => self::getIPv4($force),
            'ipv6' => self::getIPv6($force),
        ];
    }

    public static function getIPv4(bool $force = false): ?string
    {
        // 1) ENV zuerst
        $env = trim((string) env('SERVER_PUBLIC_IPV4', ''));
        if ($env !== '' && filter_var($env, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
            return $env;
        }

        // 2) Cache
        if (!$force) {
            $c = Cache::get('netprobe:ipv4');
            if ($c) return $c === 'none' ? null : $c;
        }

        // 3) Probe (einmalig)
        $ip = self::probeIPv4();
        Cache::put('netprobe:ipv4', $ip ?: 'none', now()->addDay());

        return $ip;
    }

    public static function getIPv6(bool $force = false): ?string
    {
        // 1) ENV zuerst
        $env = trim((string) env('SERVER_PUBLIC_IPV6', ''));
        if ($env !== '' && filter_var($env, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
            return $env;
        }

        // 2) Cache mit Sentinel „none“ (verhindert Endlossuche)
        if (!$force) {
            $c = Cache::get('netprobe:ipv6');
            if ($c) return $c === 'none' ? null : $c;
        }

        // 3) Probe (einmalig)
        $ip = self::probeIPv6();
        Cache::put('netprobe:ipv6', $ip ?: 'none', now()->addDay());

        return $ip;
    }

    // — intern —

    protected static function probeIPv4(): ?string
    {
        $out = @shell_exec("ip -4 route get 1.1.1.1 2>/dev/null | awk '{for(i=1;i<=NF;i++) if(\$i==\"src\"){print \$(i+1); exit}}'");
        $ip  = trim((string) $out);
        if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) return $ip;

        $ip = trim($_SERVER['SERVER_ADDR'] ?? '');
        return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) ? $ip : null;
    }

    protected static function probeIPv6(): ?string
    {
        // Variante 1: „Standard“-Weg über Routing
        $out = @shell_exec("ip -6 route get 2001:4860:4860::8888 2>/dev/null | awk '{for(i=1;i<=NF;i++) if(\$i==\"src\"){print \$(i+1); exit}}'");
        $ip  = trim((string) $out);
        if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) return $ip;

        // Variante 2: irgendeine globale v6 vom Interface nehmen (keine ::1, keine link-local fe80:)
        $out = @shell_exec("ip -6 addr show scope global 2>/dev/null | awk '/inet6/ && $2 !~ /::1/ && $2 !~ /^fe80:/ {print $2; exit}'");
        $ip  = trim((string) $out);
        if ($ip !== '') $ip = strtok($ip, '/'); // Prefix entfernen
        return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) ? $ip : null;
    }

}