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

namespace XenAdmin.Commands
{
    class MigrateVirtualDiskCommand : Command
    {
        /// <summary>
        /// Initializes a new instance of this Command. The parameter-less constructor is required in the derived
        /// class if it is to be attached to a ToolStrip menu item or button. It should not be used in any other scenario.
        /// </summary>
        public MigrateVirtualDiskCommand()
        {
        }

        public MigrateVirtualDiskCommand(IMainWindow mainWindow, IEnumerable<SelectedItem> selection)
            : base(mainWindow, selection)
        {
        }

        public override string ContextMenuText
        {
            get { return GetSelection().Count > 1 ? Messages.MAINWINDOW_MOVE_OBJECTS : Messages.MOVE_VDI_CONTEXT_MENU; }
        }

        protected override void RunCore(SelectedItemCollection selection)
        {
            List<VDI> vdis = selection.AsXenObjects<VDI>();

            bool featureForbidden = vdis.TrueForAll(vdi => Helpers.FeatureForbidden(vdi.Connection, Host.RestrictCrossPoolMigrate));
            if (featureForbidden)
            {
                UpsellDialog.ShowUpsellDialog(Messages.UPSELL_BLURB_MIGRATE_VDI, Parent);
            }
            else
            {
                new MigrateVirtualDiskDialog(selection.FirstAsXenObject.Connection, vdis).Show(Program.MainWindow);
            }
        }

        protected override bool CanRunCore(SelectedItemCollection selection)
        {
            return selection.Count > 0 && selection.All(v => CanBeMigrated(v.XenObject as VDI));
        }

        private bool CanBeMigrated(VDI vdi)
        {
            if (vdi == null || vdi.is_a_snapshot || vdi.Locked || vdi.IsHaType() || vdi.cbt_enabled)
                return false;

            if(vdi.Connection.ResolveAll(vdi.VBDs).Count == 0)
                return false;
            if (vdi.GetVMs().Any(vm => !vm.IsRunning()) && !Helpers.DundeeOrGreater(vdi.Connection))
                return false;

            SR sr = vdi.Connection.Resolve(vdi.SR);
            if (sr == null || sr.HBALunPerVDI())
                return false;
            if (!sr.SupportsStorageMigration())
                return false;

            return true;
        }

        protected override string GetCantRunReasonCore(IXenObject item)
        {
            VDI vdi = item as VDI;
            if (vdi == null)
                return base.GetCantRunReasonCore(item);

            if (vdi.is_a_snapshot)
                return Messages.CANNOT_MOVE_VDI_IS_SNAPSHOT;
            if (vdi.Locked)
                return Messages.CANNOT_MOVE_VDI_IN_USE;
            if (vdi.IsHaType())
                return Messages.CANNOT_MOVE_HA_VD;
            if (vdi.cbt_enabled)
                return Messages.CANNOT_MOVE_CBT_ENABLED_VDI;
            if (vdi.IsMetadataForDR())
                return Messages.CANNOT_MOVE_DR_VD;
            if (vdi.GetVMs().Any(vm => !vm.IsRunning()) && !Helpers.DundeeOrGreater(vdi.Connection))
                return Messages.CANNOT_MIGRATE_VDI_NON_RUNNING_VM;

            SR sr = vdi.Connection.Resolve(vdi.SR);
            if (sr == null)
                return base.GetCantRunReasonCore(item);
            if (sr.HBALunPerVDI())
                return Messages.UNSUPPORTED_SR_TYPE;
            if (!sr.SupportsStorageMigration())
                return Messages.UNSUPPORTED_SR_TYPE;

            return base.GetCantRunReasonCore(item);
        }
    }
}