<?php

class OCPPTransport
{
    public static function buildEnvelope(OCPPMessage $message, int $targetInstance = 0): array
    {
        return [
            'TargetInstance' => $targetInstance,
            'ChargePointId' => $message->chargePointId,
            'Version' => $message->version,
            'Frame' => $message->toJson(),
            'Timestamp' => time()
        ];
    }

    public static function decodeEnvelope(string $json): array
    {
        $data = json_decode($json, true);
        if (!is_array($data)) {
            return [];
        }
        return [
            'TargetInstance' => (int)($data['TargetInstance'] ?? 0),
            'ChargePointId' => (string)($data['ChargePointId'] ?? ''),
            'Version' => (string)($data['Version'] ?? 'auto'),
            'Frame' => (string)($data['Frame'] ?? ''),
            'Timestamp' => (int)($data['Timestamp'] ?? time())
        ];
    }
}

?>