using System;
using System.Collections.Generic;
using System.Management;

namespace MyNamespace
{
#region Return Value of RequestStateChange Method of the Msvm_ComputerSystem Class
//Return Value of RequestStateChange Method of the Msvm_ComputerSystem Class 
//This method returns one of the following values.
//Completed with No Error (0)
//DMTF Reserved (7–4095) 
//Method Parameters Checked - Transition Started (4096)
//Failed (32768) 
//Access Denied (32769) 
//Not Supported (32770) 
//Status is unknown (32771) 
//Timeout (32772) 
//Invalid parameter (32773) 
//System is in use (32774) 
//Invalid state for this operation (32775) 
//Incorrect data type (32776) 
//System is not available (32777) 
//Out of memory (32778)
    #endregion

public class VMManagement
    {
private static string hostServer = "hostServer";
private static string userName = "username";
private static string password = "password";

public static string HostServer
        {
get;
set;
        }

public static string UserName
        {
get;
set;
        }

public static string Password
        {
get;
set;
        }

public static VMState GetVMState(string vmName)
        {
            VMState vmState = VMState.Undefined;
            ConnectionOptions co = new ConnectionOptions();
            co.Username = userName;
            co.Password = password;

            ManagementScope manScope = new ManagementScope(string.Format(@"\\{0}\root\virtualization", hostServer), co);
            manScope.Connect();

            ObjectQuery queryObj = new ObjectQuery("SELECT * FROM Msvm_ComputerSystem");
            ManagementObjectSearcher vmSearcher = new ManagementObjectSearcher(manScope, queryObj);
            ManagementObjectCollection vmCollection = vmSearcher.Get();

foreach (ManagementObject vm in vmCollection)
            {
if (string.Compare(vm["ElementName"].ToString(), vmName, true) == 0)
                {
                    vmState = ConvertStrToVMState(vm["EnabledState"].ToString());
break;
                }
            }

return vmState;
        }

public static bool StartUp(string vmName)
        {

return ChangeVMState(vmName, VMState.Enabled);
        }

public static bool ShutDown(string vmName)
        {
return ChangeVMState(vmName, VMState.Disabled);
        }

public static bool RollBack(string vmName, string snapShotName)
        {
            ConnectionOptions co = new ConnectionOptions();
            co.Username = userName;
            co.Password = password;

            ManagementScope manScope = new ManagementScope(string.Format(@"\\{0}\root\virtualization", hostServer), co);
            manScope.Connect();

            ObjectQuery queryObj = new ObjectQuery("SELECT * FROM Msvm_ComputerSystem");
            ManagementObjectSearcher vmSearcher = new ManagementObjectSearcher(manScope, queryObj);
            ManagementObjectCollection vmCollection = vmSearcher.Get();

object opResult = null;
// loop the virtual machines
            foreach (ManagementObject vm in vmCollection)
            {
// find the vmName virtual machine, then get the list of snapshot
                if (string.Compare(vm["ElementName"].ToString(), vmName, true) == 0)
                {
                    ObjectQuery queryObj1 = new ObjectQuery(string.Format("SELECT * FROM Msvm_VirtualSystemSettingData WHERE SystemName='{0}' and SettingType=5", vm["Name"].ToString()));
                    ManagementObjectSearcher vmSearcher1 = new ManagementObjectSearcher(manScope, queryObj1);
                    ManagementObjectCollection vmCollection1 = vmSearcher1.Get();
                    ManagementObject snapshot = null;
// find and record the snapShot object
                    foreach (ManagementObject snap in vmCollection1)
                    {
if (string.Compare(snap["ElementName"].ToString(), snapShotName, true) == 0)
                        {
                            snapshot = snap;
break;
                        }
                    }

                    ObjectQuery queryObj2 = new ObjectQuery("SELECT * FROM Msvm_VirtualSystemManagementService");
                    ManagementObjectSearcher vmSearcher2 = new ManagementObjectSearcher(manScope, queryObj2);
                    ManagementObjectCollection vmCollection2 = vmSearcher2.Get();

                    ManagementObject virtualSystemService = null;
foreach (ManagementObject o in vmCollection2)
                    {
                        virtualSystemService = o;
break;
                    }

if (ConvertStrToVMState(vm["EnabledState"].ToString()) != VMState.Disabled)
                    {
                        ShutDown(vm["ElementName"].ToString());
                    }
                    opResult = virtualSystemService.InvokeMethod("ApplyVirtualSystemSnapShot", new object[] { vm.Path, snapshot.Path });
break;
                }
            }

return "0" == opResult.ToString();
        }

public static List<SnapShot> GetVMSnapShotList(string vmName)
        {
            List<SnapShot> shotList = new List<SnapShot>();
            ConnectionOptions co = new ConnectionOptions();
            co.Username = userName;
            co.Password = password;

            ManagementScope manScope = new ManagementScope(string.Format(@"\\{0}\root\virtualization", hostServer), co);
            manScope.Connect();

            ObjectQuery queryObj = new ObjectQuery("SELECT * FROM Msvm_ComputerSystem");
            ManagementObjectSearcher vmSearcher = new ManagementObjectSearcher(manScope, queryObj);
            ManagementObjectCollection vmCollection = vmSearcher.Get();

string str = "";
// loop through the machines
            foreach (ManagementObject vm in vmCollection)
            {

                str += "Snapshot of " + vm["ElementName"].ToString() + "\r\n";
//Get the snaplist
                if (string.Compare(vm["ElementName"].ToString(), vmName, true) == 0)
                {
                    ObjectQuery queryObj1 = new ObjectQuery(string.Format("SELECT * FROM Msvm_VirtualSystemSettingData WHERE SystemName='{0}' and SettingType=5", vm["Name"].ToString()));
                    ManagementObjectSearcher vmSearcher1 = new ManagementObjectSearcher(manScope, queryObj1);
                    ManagementObjectCollection vmCollection1 = vmSearcher1.Get();

foreach (ManagementObject snap in vmCollection1)
                    {
                        SnapShot ss = new SnapShot();
                        ss.Name = snap["ElementName"].ToString();
                        ss.CreationTime = DateTime.ParseExact(snap["CreationTime"].ToString().Substring(0, 14), "yyyyMMddHHmmss", null).ToLocalTime();
                        ss.Notes = snap["Notes"].ToString();
                        shotList.Add(ss);
                    }
                }
            }

return shotList;
        }

private static bool ChangeVMState(string vmName, VMState toState)
        {
string toStateCode = ConvertVMStateToStr(toState);
if (toStateCode == string.Empty)
return false;

            ConnectionOptions co = new ConnectionOptions();
            co.Username = userName;
            co.Password = password;

            ManagementScope manScope = new ManagementScope(string.Format(@"\\{0}\root\virtualization", hostServer), co);
            manScope.Connect();

            ObjectQuery queryObj = new ObjectQuery("SELECT * FROM Msvm_ComputerSystem");
            ManagementObjectSearcher vmSearcher = new ManagementObjectSearcher(manScope, queryObj);
            ManagementObjectCollection vmCollection = vmSearcher.Get();

object o = null;
foreach (ManagementObject vm in vmCollection)
            {
if (string.Compare(vm["ElementName"].ToString(), vmName, true) == 0)
                {
                    o = vm.InvokeMethod("RequestStateChange", new object[] { toStateCode });
break;
                }
            }
return "0" == o.ToString();
        }

private static VMState ConvertStrToVMState(string statusCode)
        {
            VMState vmState = VMState.Undefined;

switch (statusCode)
            {
case "0":
                    vmState = VMState.Unknown;
break;
case "2":
                    vmState = VMState.Enabled;
break;
case "3":
                    vmState = VMState.Disabled;
break;
case "32768":
                    vmState = VMState.Paused;
break;
case "32769":
                    vmState = VMState.Suspended;
break;
case "32770":
                    vmState = VMState.Starting;
break;
case "32771":
                    vmState = VMState.Snapshotting;
break;
case "32773":
                    vmState = VMState.Saving;
break;
case "32774":
                    vmState = VMState.Stopping;
break;
case "32776":
                    vmState = VMState.Pausing;
break;
case "32777":
                    vmState = VMState.Resuming;
break;
            }

return vmState;
        }

private static string ConvertVMStateToStr(VMState vmState)
        {
string status = string.Empty;
switch (vmState)
            {
case VMState.Unknown:
                    status = "0";
break;
case VMState.Enabled:
                    status = "2";
break;
case VMState.Disabled:
                    status = "3";
break;
case VMState.Paused:
                    status = "32768";
break;
case VMState.Suspended:
                    status = "32769";
break;
case VMState.Starting:
                    status = "32770";
break;
case VMState.Snapshotting:
                    status = "32771";
break;
case VMState.Saving:
                    status = "32773";
break;
case VMState.Stopping:
                    status = "32774";
break;
case VMState.Pausing:
                    status = "32776";
break;
case VMState.Resuming:
                    status = "32777";
break;
            }

return status;
        }
    }

/// <summary>
///-        Undefined      --> "Not defined"
///0        Unknown        --> "Unknown"
///2        Enabled        --> "Running" 
///3        Diabled        --> "Off"
///32768    Paused         --> "Paused"
///32769    Suspended      --> "Saved"
///32770    Starting       --> "Starting"
///32771    Snapshotting   --> "Snapshooting
///32773    Saving         --> "Saving"
///32774    Stopping       --> "Shuting down
///32776    Pausing        --> "Pausing"
///32777    Resuming       --> "Resuming"
/// </summary>
    public enum VMState
    {
        Undefined,
        Unknown,
        Enabled,
        Disabled,
        Paused,
        Suspended,
        Starting,
        Snapshotting,
        Saving,
        Stopping,
        Pausing,
        Resuming
    }

public class SnapShot
    {
public string Name
        {
get;
set;
        }

public DateTime CreationTime
        {
get;
set;
        }

public string Notes
        {
get;
set;
        }
    }
}