using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Management;

namespace Test_Form
{
    class Manager
    {
        public TimeSpan uptime { get; set; }
        public string host { get; set; }
        // Q: Add new attributes and init they in constructor

        public Manager(string host, string username = null, string password = null)
        {
            ManagementObject mgnobj = GetServerInfo(host, username, password);

            this.host = host;

            if (mgnobj != null)
            {
                ulong iUptimeInSec = ((ulong) mgnobj["Timestamp_Object"] - (ulong)(mgnobj["SystemUpTime"])) / (ulong) mgnobj["Frequency_Object"];
                double sUptime = Convert.ToDouble(iUptimeInSec);
                this.uptime = TimeSpan.FromSeconds(sUptime);

                // Q: init other memeber attributes from mgnobj
            }
        }

        public ManagementObject GetServerInfo(string host, string username = null, string password = null)
        {
            ConnectionOptions options = new ConnectionOptions();
            if (username != null)
            {
                options.Username = username;
            }

            if (password != null)
            {
                options.Password = password;
            }

            ManagementScope scope = new ManagementScope(String.Format("\\\\{0}\\root\\cimv2", host), options);

            try
            {
                options.Authentication = AuthenticationLevel.Packet;
                scope.Connect();
            }
            catch (Exception e) { }

            if (!scope.IsConnected)
            {
                // Change the AuthenticationLevel for windows 2000 of lower
                try
                {
                    options.Authentication = AuthenticationLevel.Connect;
                    scope.Connect();
                }
                catch (Exception e) { }
            }

            ObjectQuery query = new ObjectQuery("SELECT * FROM Win32_PerfRawData_PerfOS_System");
            ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query);

            ManagementObjectCollection queryCollection = searcher.Get();

            if (queryCollection.Count <= 0)
            {
                return null;
            }

            foreach (ManagementObject m in queryCollection)
            {
                foreach (PropertyData prop in m.Properties)
                {
                    Console.WriteLine("{0}: {1}", prop.Name, prop.Value);
                }
                return m;
            }

            return null;
        }
    }
}