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using System;
using System.Collections.Generic;
using XenAPI;
using XenAdmin.Core;
using XenAdmin.Dialogs;
using XenAdmin.Actions;

namespace XenAdmin.Commands
{
    class ActivateVBDCommand : Command
    {
        /// <summary>
        /// Deactivates a selection of VBDs
        /// </summary>
        /// <param name="mainWindow"></param>
        /// <param name="selection"></param>
        public ActivateVBDCommand(IMainWindow mainWindow, IEnumerable<SelectedItem> selection)
            : base(mainWindow, selection)
        {
            
        }

        /// <summary>
        /// Deactivates a single VBD
        /// </summary>
        /// <param name="mainWindow"></param>
        /// <param name="vbd"></param>
        public ActivateVBDCommand(IMainWindow mainWindow, VBD vbd)
            : base(mainWindow, vbd)
        {

        }

        public override string ContextMenuText
        {
            get
            {
                return Messages.MESSAGEBOX_ACTIVATE_VD_TITLE;
            }
        }

        protected override bool CanExecuteCore(SelectedItemCollection selection)
        {
            return selection.AllItemsAre<VBD>() && selection.AtLeastOneXenObjectCan<VBD>(CanExecute);
        }

        // We only need to check for IO Drivers for hosts before Ely
        private bool AreIODriversNeededAndMissing(VM vm)
        {
            if (Helpers.ElyOrGreater(vm.Connection))
            {
                return false;
            }

            return !vm.GetVirtualisationStatus.HasFlag(VM.VirtualisationStatus.IO_DRIVERS_INSTALLED);
        }

        private bool CanExecute(VBD vbd)
        {
            VM vm = vbd.Connection.Resolve<VM>(vbd.VM);
            VDI vdi = vbd.Connection.Resolve<VDI>(vbd.VDI);
            if (vm == null || vm.not_a_real_vm || vdi == null)
                return false;
            if (vm.power_state != vm_power_state.Running)
                return false;
            if (vdi.type == vdi_type.system)
                return false;
            if (AreIODriversNeededAndMissing(vm))
                return false;    
            if (vbd.currently_attached)
                return false;

            return vbd.allowed_operations.Contains(vbd_operations.plug);
        }

        protected override string GetCantExecuteReasonCore(SelectedItem item)
        {
            VBD vbd = item.XenObject as VBD;
            if (vbd == null)
                return base.GetCantExecuteReasonCore(item);

            VM vm = vbd.Connection.Resolve<VM>(vbd.VM);
            VDI vdi = vbd.Connection.Resolve<VDI>(vbd.VDI);
            if (vm == null || vm.not_a_real_vm || vdi == null)
                return base.GetCantExecuteReasonCore(item);

            SR sr = vdi.Connection.Resolve<SR>(vdi.SR);
            if (sr == null)
                return Messages.SR_COULD_NOT_BE_CONTACTED;

            if (vdi.Locked)
                return vdi.VDIType == VDI.FriendlyType.SNAPSHOT ? Messages.CANNOT_ACTIVATE_SNAPSHOT_IN_USE
                    : vdi.VDIType == VDI.FriendlyType.ISO ? Messages.CANNOT_ACTIVATE_ISO_IN_USE
                    : Messages.CANNOT_ACTIVATE_VD_IN_USE;

            if (vm.power_state != vm_power_state.Running)
                return string.Format(
                    Messages.CANNOT_ACTIVATE_VD_VM_HALTED, 
                    Helpers.GetName(vm).Ellipsise(50));

            if (vdi.type == vdi_type.system)
                return Messages.TOOLTIP_DEACTIVATE_SYSVDI;

            if (AreIODriversNeededAndMissing(vm))
                return string.Format(
                    vm.HasNewVirtualisationStates ? Messages.CANNOT_ACTIVATE_VD_VM_NEEDS_IO_DRIVERS : Messages.CANNOT_ACTIVATE_VD_VM_NEEDS_TOOLS, 
                    Helpers.GetName(vm).Ellipsise(50));
              
            if (vbd.currently_attached)
                return string.Format(Messages.CANNOT_ACTIVATE_VD_ALREADY_ACTIVE, Helpers.GetName(vm).Ellipsise(50));

            return base.GetCantExecuteReasonCore(item);
        }

        protected override CommandErrorDialog GetErrorDialogCore(IDictionary<SelectedItem, string> cantExecuteReasons)
        {
            return new CommandErrorDialog(Messages.ERROR_ACTIVATING_VDIS_TITLE, Messages.ERROR_ACTIVATING_VDIS_MESSAGE, cantExecuteReasons);
        }

        protected override void ExecuteCore(SelectedItemCollection selection)
        {
            List<AsyncAction> actionsToComplete = new List<AsyncAction>();
            foreach (VBD vbd in selection.AsXenObjects<VBD>())
            {
                if (vbd.Locked)
                    continue;

                actionsToComplete.Add(getActivateVBDAction(vbd));
            }

            if (actionsToComplete.Count == 0)
                return;

            if (actionsToComplete.Count > 1)
                RunMultipleActions(actionsToComplete, Messages.ACTION_ACTIVATING_MULTIPLE_VDIS_TITLE, Messages.ACTION_ACTIVATING_MULTIPLE_VDIS_STATUS, Messages.COMPLETED, true);
            else
                actionsToComplete[0].RunAsync();
        }

        private AsyncAction getActivateVBDAction(VBD vbd)
        {
            VDI vdi = vbd.Connection.Resolve<VDI>(vbd.VDI);
            VM vm = vbd.Connection.Resolve<VM>(vbd.VM);
            String title = String.Format(Messages.ACTION_DISK_ACTIVATING_TITLE, vdi.Name, vm.Name);
            String startDesc = Messages.ACTION_DISK_ACTIVATING;
            String endDesc = Messages.ACTION_DISK_ACTIVATED;

            AsyncAction action = new DelegatedAsyncAction(vbd.Connection,
                title, startDesc, endDesc,session => VBD.plug(session, vbd.opaque_ref),"vbd.plug");
            action.VM = vm;
            return action;
        }
    }
}