Inventory/app/Helpers/functions.php

<?php
/**
 * Helper Functions
 */

/**
 * Escape HTML output
 */
function e(string $value): string
{
    return htmlspecialchars($value, ENT_QUOTES, 'UTF-8');
}

/**
 * Generate CSRF token
 */
function csrf_token(): string
{
    $session = new \App\Core\Session();
    return $session->getCsrfToken();
}

/**
 * Generate CSRF field
 */
function csrf_field(): string
{
    return '<input type="hidden" name="csrf_token" value="' . csrf_token() . '">';
}

/**
 * Format date
 */
function format_date(string $date, string $format = 'd.m.Y'): string
{
    return date($format, strtotime($date));
}

/**
 * Format datetime
 */
function format_datetime(string $date, string $format = 'd.m.Y H:i'): string
{
    return date($format, strtotime($date));
}

/**
 * Format currency
 */
function format_currency(float $amount): string
{
    return number_format($amount, 2, ',', '.') . ' €';
}

/**
 * Generate asset number
 */
function generate_asset_number(string $prefix = 'ASSET'): string
{
    return $prefix . '-' . date('Y') . '-' . str_pad(rand(1, 9999), 4, '0', STR_PAD_LEFT);
}

/**
 * Validate file upload
 */
function validate_file_upload(array $file, array $allowedTypes = [], int $maxSize = 52428800): array
{
    $errors = [];

    if ($file['error'] !== UPLOAD_ERR_OK) {
        $errors[] = 'Upload error: ' . $file['error'];
        return $errors;
    }

    if ($file['size'] > $maxSize) {
        $errors[] = 'File too large. Maximum size: ' . format_bytes($maxSize);
    }

    if (!empty($allowedTypes)) {
        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        $mimeType = finfo_file($finfo, $file['tmp_name']);
        finfo_close($finfo);

        if (!in_array($mimeType, $allowedTypes)) {
            $errors[] = 'File type not allowed. Allowed types: ' . implode(', ', $allowedTypes);
        }
    }

    return $errors;
}

/**
 * Format bytes to human readable
 */
function format_bytes(int $bytes): string
{
    $units = ['B', 'KB', 'MB', 'GB', 'TB'];
    
    for ($i = 0; $bytes > 1024 && $i < count($units) - 1; $i++) {
        $bytes /= 1024;
    }
    
    return round($bytes, 2) . ' ' . $units[$i];
}

/**
 * Generate random string
 */
function random_string(int $length = 32): string
{
    return bin2hex(random_bytes($length / 2));
}

/**
 * Check if user has permission
 */
function has_permission(string $permission): bool
{
    $session = new \App\Core\Session();
    $role = $session->getUserRole();
    
    switch ($permission) {
        case 'admin':
            return $role === 'admin';
        case 'auditor':
            return in_array($role, ['admin', 'auditor']);
        case 'employee':
            return in_array($role, ['admin', 'auditor', 'employee']);
        default:
            return false;
    }
}

/**
 * Get user role name
 */
function get_role_name(string $role): string
{
    $roles = [
        'admin' => 'Administrator',
        'auditor' => 'Auditor',
        'employee' => 'Mitarbeiter'
    ];
    
    return $roles[$role] ?? $role;
}

/**
 * Get asset status name
 */
function get_asset_status_name(string $status): string
{
    $statuses = [
        'aktiv' => 'Aktiv',
        'inaktiv' => 'Inaktiv',
        'ausgemustert' => 'Ausgemustert'
    ];
    
    return $statuses[$status] ?? $status;
}

/**
 * Get asset condition name
 */
function get_asset_condition_name(string $condition): string
{
    $conditions = [
        'neu' => 'Neu',
        'gut' => 'Gut',
        'befriedigend' => 'Befriedigend',
        'schlecht' => 'Schlecht',
        'defekt' => 'Defekt'
    ];
    
    return $conditions[$condition] ?? $condition;
}

/**
 * Get inventory status name
 */
function get_inventory_status_name(string $status): string
{
    $statuses = [
        'offen' => 'Offen',
        'abgeschlossen' => 'Abgeschlossen'
    ];
    
    return $statuses[$status] ?? $status;
}

/**
 * Get inventory item status name
 */
function get_inventory_item_status_name(string $status): string
{
    $statuses = [
        'gefunden' => 'Gefunden',
        'nicht_gefunden' => 'Nicht gefunden',
        'defekt' => 'Defekt',
        'verschoben' => 'Verschoben'
    ];
    
    return $statuses[$status] ?? $status;
}

/**
 * Generate QR code data for asset
 */
function generate_qr_data(array $asset): string
{
    return json_encode([
        'id' => $asset['id'],
        'inventarnummer' => $asset['inventarnummer'],
        'bezeichnung' => $asset['bezeichnung']
    ]);
}

/**
 * Check if warranty is expiring soon
 */
function is_warranty_expiring_soon(string $warrantyDate, int $days = 30): bool
{
    if (empty($warrantyDate)) {
        return false;
    }
    
    $warranty = strtotime($warrantyDate);
    $now = time();
    $expiring = strtotime("+{$days} days", $now);
    
    return $warranty <= $expiring && $warranty > $now;
}

/**
 * Calculate asset age in years
 */
function calculate_asset_age(string $purchaseDate): int
{
    if (empty($purchaseDate)) {
        return 0;
    }
    
    $purchase = new DateTime($purchaseDate);
    $now = new DateTime();
    $diff = $now->diff($purchase);
    
    return $diff->y;
}

/**
 * Get asset value depreciation
 */
function calculate_depreciation(float $purchasePrice, string $purchaseDate, float $depreciationRate = 0.1): float
{
    $age = calculate_asset_age($purchaseDate);
    $depreciation = $purchasePrice * $depreciationRate * $age;
    
    return max(0, $purchasePrice - $depreciation);
}

/**
 * Sanitize filename
 */
function sanitize_filename(string $filename): string
{
    // Remove special characters
    $filename = preg_replace('/[^a-zA-Z0-9._-]/', '_', $filename);
    
    // Remove multiple underscores
    $filename = preg_replace('/_+/', '_', $filename);
    
    // Remove leading/trailing underscores
    $filename = trim($filename, '_');
    
    return $filename;
}

/**
 * Get file extension from mime type
 */
function get_extension_from_mime(string $mimeType): string
{
    $extensions = [
        'application/pdf' => 'pdf',
        'image/jpeg' => 'jpg',
        'image/png' => 'png',
        'image/gif' => 'gif',
        'application/msword' => 'doc',
        'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'docx',
        'application/vnd.ms-excel' => 'xls',
        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'xlsx',
        'text/plain' => 'txt',
        'text/csv' => 'csv'
    ];
    
    return $extensions[$mimeType] ?? 'bin';
}

/**
 * Check if string is valid JSON
 */
function is_valid_json(string $string): bool
{
    json_decode($string);
    return json_last_error() === JSON_ERROR_NONE;
}

/**
 * Get current user
 */
function current_user(): ?array
{
    $session = new \App\Core\Session();
    return $session->getUser();
}

/**
 * Get current user ID
 */
function current_user_id(): ?int
{
    $session = new \App\Core\Session();
    return $session->getUserId();
}

/**
 * Check if user is logged in
 */
function is_logged_in(): bool
{
    $session = new \App\Core\Session();
    return $session->isLoggedIn();
}

/**
 * Check if user is admin
 */
function is_admin(): bool
{
    $session = new \App\Core\Session();
    return $session->isAdmin();
}

/**
 * Redirect to URL
 */
function redirect(string $url): void
{
    header("Location: {$url}");
    exit;
}

/**
 * Get base URL
 */
function base_url(string $path = ''): string
{
    $baseUrl = rtrim(APP_URL, '/');
    $path = ltrim($path, '/');
    
    return $baseUrl . '/' . $path;
}

/**
 * Asset URL
 */
function asset_url(string $path): string
{
    return base_url('assets/' . ltrim($path, '/'));
}

/**
 * Storage URL
 */
function storage_url(string $path): string
{
    return base_url('storage/' . ltrim($path, '/'));
}