função para converter steam ids

SteamIDConverter.class.php

<?php
class SteamIDConverter
{
    private const V = "76561197960265728"; // Offset para contas individuais

    /**
     * Converte entre formatos de SteamID (STEAM_X:Y:Z, [U:1:W], SteamID64).
     *
     * @param string $input O valor do SteamID a ser convertido
     * @param int $type Tipo de SteamID (0 = steamID, 1 = steam3ID, 2 = steamID64)
     * @return array|bool Retorna um array com 'steamID', 'steam3ID' e 'steamID64' ou false em caso de erro
     */
    public static function convert($input, $type)
    {
        $W = null;
        $Y = null;
        $Z = null;
        $universe = 1; // padrão (Public)

        switch ($type) {
            case 0: // SteamID (STEAM_X:Y:Z)
                $parsed = self::parseSteamID($input);
                if ($parsed === false) {
                    return false;
                }
                $universe = $parsed['X'];
                $Y = $parsed['Y'];
                $Z = $parsed['Z'];
                $W = $Z * 2 + $Y;
                break;

            case 1: // Steam3 ID ([U:1:W])
                $W = self::parseSteam3ID($input);
                if ($W === false) {
                    return false;
                }
                $Y = $W % 2;
                $Z = ($W - $Y) / 2;
                break;

            case 2: // SteamID64
                $steamID64 = self::validateSteamID64($input);
                if ($steamID64 === false) {
                    return false;
                }
                $W = bcsub($steamID64, self::V);
                $Y = bcmod($W, "2");
                $Z = bcdiv(bcsub($W, $Y), "2");
                break;

            default:
                return false;
        }

        $steamID = "STEAM_{$universe}:{$Y}:{$Z}";
        $steam3ID = "[U:1:{$W}]";
        $steamID64 = bcadd(bcadd(bcmul($Z, "2"), $Y), self::V);

        return [
            'steamID'   => $steamID,
            'steam3ID'  => $steam3ID,
            'steamID64' => $steamID64
        ];
    }

    // --- Funções auxiliares privadas ---

    private static function parseSteamID($input)
    {
        if (!preg_match('/^STEAM_([0-5]):([0-1]):(\d+)$/', $input, $matches)) {
            return false;
        }
        return [
            'X' => (int)$matches[1],
            'Y' => (int)$matches[2],
            'Z' => (int)$matches[3]
        ];
    }

    private static function parseSteam3ID($input)
    {
        if (!preg_match('/^\[U:1:(\d+)\]$/', $input, $matches)) {
            return false;
        }
        return (int)$matches[1];
    }

    private static function validateSteamID64($input)
    {
        if (!ctype_digit($input) || bccomp($input, self::V) < 0) {
            return false;
        }
        return $input;
    }
}

teste-conversao.php

<?php
$inputs = [
    ['value' => 'STEAM_0:0:12574760', 'type' => 0],
    ['value' => '[U:1:25149520]', 'type' => 1],
    ['value' => '76561197985415248', 'type' => 2]
];

foreach ($inputs as $input) {
    $result = SteamIDConverter::convert($input['value'], $input['type']);
    if ($result) {
        echo "Entrada: {$input['value']} (Tipo: {$input['type']})\n";
        echo "SteamID: {$result['steamID']}\n";
        echo "Steam3 ID: {$result['steam3ID']}\n";
        echo "SteamID64: {$result['steamID64']}\n\n";
    } else {
        echo "Erro: Entrada inválida para {$input['value']} (Tipo: {$input['type']})\n\n";
    }
}