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;
        }
    }
}