netwatch/app/lib/helpers.php

<?php
/**
 * app/lib/helpers.php
 *
 * Zentrale Hilfsfunktionen
 * - Output-Escaping
 * - Redirects
 * - Flash-Messages
 * - Request-Helper
 * - Allgemeine Utilities
 *
 * KEINE Business-Logik
 */

/**
 * Sitzungs-Keys
 */
const FLASH_SESSION_KEY = 'flash_messages';

/* =========================
 * Output / Sicherheit
 * ========================= */

/**
 * HTML-Escaping
 *
 * @param string|null $value
 * @return string
 */
function e(?string $value): string
{
    if ($value === null) {
        return '';
    }

    return htmlspecialchars($value, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
}

/* =========================
 * Redirects
 * ========================= */

/**
 * HTTP Redirect
 *
 * @param string $url
 * @param int $code
 */
function redirect(string $url, int $code = 302): void
{
    if (!headers_sent()) {
        header('Location: ' . $url, true, $code);
    }

    exit;
}

/* =========================
 * Flash Messages
 * ========================= */

/**
 * Flash-Message setzen
 *
 * @param string $type (success, error, info)
 * @param string $message
 */
function flash(string $type, string $message): void
{
    if (session_status() !== PHP_SESSION_ACTIVE) {
        session_start();
    }

    if (!isset($_SESSION[FLASH_SESSION_KEY])) {
        $_SESSION[FLASH_SESSION_KEY] = [];
    }

    $_SESSION[FLASH_SESSION_KEY][] = ['type' => $type, 'message' => $message];
}

/**
 * Flash-Messages abrufen & löschen
 *
 * @return array
 */
function getFlashes(): array
{
    if (session_status() !== PHP_SESSION_ACTIVE) {
        session_start();
    }

    $messages = $_SESSION[FLASH_SESSION_KEY] ?? [];
    unset($_SESSION[FLASH_SESSION_KEY]);

    return $messages;
}

/* =========================
 * Request Helper
 * ========================= */

/**
 * POST-Wert holen
 *
 * @param string $key
 * @param mixed $default
 * @return mixed
 */
function post(string $key, $default = null)
{
    return $_POST[$key] ?? $default;
}

/**
 * GET-Wert holen
 *
 * @param string $key
 * @param mixed $default
 * @return mixed
 */
function get(string $key, $default = null)
{
    return $_GET[$key] ?? $default;
}

/**
 * Prüfen, ob Request POST ist
 *
 * @return bool
 */
function isPost(): bool
{
    return ($_SERVER['REQUEST_METHOD'] ?? '') === 'POST';
}

/* =========================
 * Validierung
 * ========================= */

/**
 * Prüft auf leeren Wert
 *
 * @param mixed $value
 * @return bool
 */
function isEmpty($value): bool
{
    if (is_string($value)) {
        return trim($value) === '';
    }

    return empty($value);
}

/* =========================
 * Pfade / URLs
 * ========================= */

/**
 * Baut eine URL zur App
 *
 * @param string $path
 * @return string
 */
function url(string $path = ''): string
{
    if ($path === '') {
        $path = '/';
    }

    if (preg_match('~^([a-z]+:)?//~i', $path)) {
        return $path;
    }

    $script = $_SERVER['SCRIPT_NAME'] ?? '';
    $baseDir = rtrim(strtr(dirname($script), '\\\\', '/'), '/');

    if ($baseDir === '.' || $baseDir === '\\\\') {
        $baseDir = '';
    }

    $segment = ltrim($path, '/');
    $prefix = $baseDir === '' ? '' : $baseDir;

    if ($segment === '') {
        return $prefix === '' ? '/' : $prefix;
    }

    return ($prefix === '' ? '' : $prefix) . '/' . $segment;
}

/* =========================
 * Debug / Entwicklung
 * ========================= */

/**
 * Dump & Die (nur Dev)
 *
 * @param mixed $value
 */
function dd($value): void
{
    echo '<pre>';
    var_dump($value);
    echo '</pre>';
    exit;
}

/* =========================
 * Sonstiges
 * ========================= */

// TODO: Weitere Helfer nach Bedarf
// - Datum formatieren
// - Bytes → MB
// - UUID erzeugen
// - SVG-Koordinaten normalisieren