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using System;
using System.Collections.Generic;
using XenAdmin.Actions;
using XenAdmin.Dialogs;
using XenAdmin.Dialogs.ScheduledSnapshots;
using XenAdmin.Dialogs.VMAppliances;
using XenAdmin.Network;
using XenAdmin.Wizards;
using XenAdmin.Wizards.NewPolicyWizard;
using XenAdmin.Wizards.NewVMApplianceWizard;

using XenAPI;

namespace XenAdmin.Core
{
    /// <summary>
    /// A helper class for dealing with a group of VMs (currently either a VMSS or a vApp);
    /// it contains all the functions necessary to abstract away what type of group it is.
    /// 
    /// In C++, we would use template specialization for this, but C# generics don't have that, so we
    /// end up switching on T. It's ugly, but it's the way that maximises the amount of shared code.
    /// </summary>

    static class VMGroup<T> where T : XenObject<T>
    {
        // This section covers all the functions that depend on the type of group we're talking about.

        internal static T[] GroupsInCache(ICache cache)
        {
            return typeof(T) == typeof(VMSS)? cache.VMSSs as T[] : cache.VM_appliances as T[];
        }

        internal static XenRef<T> VmToGroup(VM vm)
        {
            return typeof(T) == typeof(VMSS) ? vm.snapshot_schedule as XenRef<T> : vm.appliance as XenRef<T>;
        }

        internal static List<XenRef<VM>> GroupToVMs(T group)
        {
            return typeof(T) == typeof(VMSS) ? (group as VMSS).VMs : (group as VM_appliance).VMs;
        }

        internal static string ChangeOneWarningString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.CHANGE_VM_SNAPSHOT_SCHEDULE_WARNING : Messages.CHANGE_VMS_APPLIANCE_WARNING; }
        }

        internal static string ChangeMultipleWarningString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.CHANGE_VMS_SNAPSHOT_SCHEDULE_WARNING : Messages.CHANGE_VMS_APPLIANCES_WARNING; }
        }

        internal static string NewGroupString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.NEW_SCHEDULE : Messages.NEW_VM_APPLIANCE; }
        }

        internal static string ChangeVMsGroupString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.CHANGE_VMSS_POLICY : Messages.CHANGE_VMS_APPLIANCE; }
        }

        internal static string AssignMainMenuString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.ASSIGN_VMSS_POLICY : Messages.ASSIGN_VM_APPLIANCE; }
        }

        internal static string AssignContextMenuString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.ASSIGN_VMSS_POLICY_CONTEXT_MENU : Messages.ASSIGN_VM_APPLIANCE; }
        }

        internal static string ManageMainMenuString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.VMSS_MAIN_MENU : Messages.VM_APPLIANCES_MENU; }
        }

        internal static string ManageContextMenuString
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.VMSS_CONTEXT_MENU : Messages.VM_APPLIANCES_MENU; }
        }

        internal static string ChooseVMsPage_Text
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.VMSS_VMS : Messages.NEWVMAPPLIANCE_VMSPAGE_TEXT; }
        }

        internal static string ChooseVMsPage_Title
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.VMSS_VMS_TITLE : Messages.NEWVMAPPLIANCE_VMSPAGE_TITLE; }
        }

        internal static string ChooseVMsPage_Rubric
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.CHOOSE_VMS_VMSS_RUBRIC : Messages.CHOOSE_VMS_VAPP_RUBRIC; }
        }

        internal static string ChooseVMsPage_CurrentGroup
        {
            get { return typeof(T) == typeof(VMSS) ? Messages.CURRENT_SCHEDULE : Messages.CURRENT_VAPP; }
        }

        internal static string ChooseVMsPage_HelpID
        {
            get { return "VMs"; } 
        }

        internal static string UpsellBlurb =>
            typeof(T) == typeof(VMSS)
                ? Messages.UPSELL_BLURB_VMSS
                : Messages.UPSELL_BLURB_VM_APPLIANCES;

        internal static AsyncAction AssignVMsToGroupAction(T group, List<XenRef<VM>> vms, bool suppressHistory)
        {
            return typeof(T) == typeof(VMSS) ? (AsyncAction)(new AssignVMsToPolicyAction(group as VMSS, vms, suppressHistory)) :
                (AsyncAction)(new AssignVMsToVMApplianceAction(group as VM_appliance, vms, suppressHistory));
        }

        internal static AsyncAction RemoveVMsFromGroupAction(T group, List<XenRef<VM>> vms)
        {
            return typeof(T) == typeof(VMSS) ? (AsyncAction)(new RemoveVMsFromPolicyAction(group as VMSS, vms)) :
                (AsyncAction)(new RemoveVMsFromVMApplianceAction(group as VM_appliance, vms));
        }

        internal static XenWizardBase NewGroupWizard(Pool pool)
        {
            return typeof(T) == typeof(VMSS) ? (XenWizardBase) new NewPolicyWizard(pool) : new NewVMApplianceWizard(pool);
        }

        internal static XenWizardBase NewGroupWizard(Pool pool, List<VM> vms)
        {
            return typeof(T) == typeof(VMSS) ? new NewPolicyWizard(pool, vms) : (XenWizardBase)new NewVMApplianceWizard(pool, vms);
        }

        internal static XenDialogBase ManageGroupsDialog(Pool pool)
        {
            return typeof(T) == typeof(VMSS) ? (XenDialogBase)(new ScheduledSnapshotsDialog(pool)) : (XenDialogBase)(new VMAppliancesDialog(pool));
        }

        internal static bool FeaturePossible(IXenConnection connection)
        {
            //VMSS is enabled Falcon onwards
            if ((typeof(T) == typeof(VMSS)) && !Helpers.FalconOrGreater(connection))
                return false;
            
            return true;
        }

        internal static Predicate<Host> FeatureRestricted
        {
            get { return typeof(T) == typeof(VMSS) ? ((Predicate<Host>)Host.RestrictVMSnapshotSchedule) : (Predicate<Host>)Host.RestrictVMAppliances; }
        }

        internal static bool IsQuiescingSupported(IXenConnection connection)
        { 
            return typeof(T) == typeof(VMSS) && !Helpers.QuebecOrGreater(connection);
        }
    }
}