<?php
class HealthService {
    
    public static function getHealthReport() {
        return [
            'php_version' => PHP_VERSION,
            'disk_free'   => self::getDiskStatus(),
            'memory'      => self::formatBytes(self::getMemoryLimit()),
            'env_status'  => self::checkEnvFile(),
            'db_status'   => self::checkDatabase(),
            'writable'    => self::checkWritableFolders(['public', 'app'])
        ];
    }

    private static function getMemoryLimit() {
        $limit = ini_get('memory_limit');
        if (preg_match('/^(\d+)(.)$/', $limit, $matches)) {
            $val = (int)$matches[1];
            switch (strtoupper($matches[2])) {
                case 'G': $val *= 1024 * 1024 * 1024; break;
                case 'M': $val *= 1024 * 1024; break;
                case 'K': $val *= 1024; break;
            }
            return $val;
        }
        return (int)$limit;
    }

    private static function formatBytes($bytes, $precision = 2) {
        $units = ['B', 'KB', 'MB', 'GB', 'TB'];
        $bytes = max($bytes, 0);
        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
        $pow = min($pow, count($units) - 1);
        return round($bytes / pow(1024, $pow), $precision) . ' ' . $units[$pow];
    }

    private static function getDiskStatus() {
        if (function_exists('disk_free_space') && function_exists('disk_total_space')) {
            try {
                $free = @disk_free_space("/");
                $total = @disk_total_space("/");
                if ($free !== false && $total > 0) {
                    return round(($free / $total) * 100) . "% frei";
                }
            } catch (Exception $e) {}
        }
        return "Eingeschränkt (Hosting)";
    }

    private static function checkEnvFile() {
        // Springt aus app/services/ zwei Ebenen hoch zum Hauptverzeichnis
        return file_exists(__DIR__ . '/../../.env') ? 'Bereit' : 'Fehlt!';
    }

    private static function checkDatabase() {
        try {
            // Checkt, ob überhaupt ein Name gesetzt ist
            if (empty(Config::get('DB_NAME'))) {
                return 'Deaktiviert';
            }
            
            $db = new Database();
            $db->query("SELECT VERSION() as v");
            $res = $db->single();
            return $res['v'] ?? 'Online';
        } catch (Exception $e) {
            return 'Offline / Fehler';
        }
    }

    private static function checkWritableFolders($folders) {
        foreach ($folders as $folder) {
            // Geht vom aktuellen Verzeichnis (app/services/) zwei Ebenen hoch
            $path = realpath(__DIR__ . '/../../' . $folder);
            if (!$path || !is_dir($path)) return "Fehlt: $folder";
            if (!is_writable($path)) return "Rechte: $folder";
        }
        return "OK";
    }
}