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using System.Collections.Generic;
using System.Linq;
using XenAdmin.Core;
using XenAdmin.Network;
using XenAdmin.Wizards.CrossPoolMigrateWizard.Filters;
using XenAdmin.Wizards.GenericPages;
using XenAPI;


namespace XenAdmin.Wizards.CrossPoolMigrateWizard
{
    internal class CrossPoolMigrateDestinationPage : SelectMultipleVMDestinationPage
    {
        private List<VM> selectedVMs;
        private readonly WizardMode wizardMode = WizardMode.Migrate;

        // A 2-level cache to store the result of CrossPoolMigrateCanMigrateFilter.
        // Cache structure is like: <vm-ref, <host-ref, fault-reason>>.
        private readonly Dictionary<string, Dictionary<string, string>> migrateFilterCache = 
            new Dictionary<string, Dictionary<string, string>>();

        public CrossPoolMigrateDestinationPage(List<VM> selectedVMs, WizardMode wizardMode, List<IXenConnection> ignoredConnections)
        {
            this.selectedVMs = selectedVMs;
            this.wizardMode = wizardMode;
            this.ignoredConnections = ignoredConnections ?? new List<IXenConnection>();

            InitializeText();
        }

        protected override bool ImplementsIsDirty()
        {
            return true;
        }

        /// <summary>
        /// Gets the value by which the help files section for this page is identified
        /// </summary>
        public override string HelpID => wizardMode == WizardMode.Copy ? "DestinationCopyMode" : "Destination";

        /// <summary>
        /// Gets the page's title (headline)
        /// </summary>
        public override string PageTitle => Messages.CPM_WIZARD_DESTINATION_TITLE;

        /// <summary>
        /// Gets the page's label in the (left hand side) wizard progress panel
        /// </summary>
        public override string Text => Messages.CPM_WIZARD_DESTINATION_TAB_TITLE;

        private bool TemplatesOnly { get { return selectedVMs != null && selectedVMs.All(vm => vm.is_a_template); } }

        protected override string InstructionText 
        {
            get
            {
                if (TemplatesOnly)
                    return Messages.CPM_WIZARD_DESTINATION_INSTRUCTIONS_COPY_TEMPLATE;

                if (wizardMode == WizardMode.Copy)
                    return Messages.CPM_WIZARD_DESTINATION_INSTRUCTIONS_COPY;

                if (wizardMode == WizardMode.Move)
                    return Messages.CPM_WIZARD_DESTINATION_INSTRUCTIONS_MOVE;

                return Messages.CPM_WIZARD_DESTINATION_INSTRUCTIONS_MIGRATE;
            }
        }

        protected override string TargetPoolText => Messages.CPM_WIZARD_DESTINATION_DESTINATION;

        protected override string TargetServerSelectionIntroText
        {
            get
            {
                if (TemplatesOnly)
                    return Messages.CPM_WIZARD_DESTINATION_TABLE_INTRO_TEMPLATES;

                if (wizardMode == WizardMode.Copy)
                    return Messages.CPM_WIZARD_DESTINATION_TABLE_INTRO_COPY;

                if (wizardMode == WizardMode.Move)
                    return Messages.CPM_WIZARD_DESTINATION_TABLE_INTRO_MOVE;

                return Messages.CPM_WIZARD_DESTINATION_TABLE_INTRO_MIGRATE;
            }
        }

        protected override string VmColumnHeaderText => TemplatesOnly ? Messages.TEMPLATE : Messages.VM;

        protected override DelayLoadingOptionComboBoxItem CreateDelayLoadingOptionComboBoxItem(IXenObject xenItem)
        {
            var filters = new List<ReasoningFilter>
            {
                new ResidentHostIsSameAsSelectionFilter(xenItem, selectedVMs),
                new CrossPoolMigrateFilter(xenItem, selectedVMs, wizardMode, migrateFilterCache)
            };
            return new DelayLoadingOptionComboBoxItem(xenItem, filters);
        }

        protected override List<ReasoningFilter> CreateTargetServerFilterList(IXenObject xenObject, List<string> vmOpaqueRefs)
        {
            var filters = new List<ReasoningFilter>();

            if (xenObject != null && vmOpaqueRefs != null && selectedVMs != null)
            {
                List<VM> vmList = new List<VM>();
                foreach (string opaqueRef in vmOpaqueRefs)
                    vmList.Add(selectedVMs.Find(vm => vm.opaque_ref == opaqueRef));

                filters.Add(new ResidentHostIsSameAsSelectionFilter(xenObject, vmList));
                filters.Add(new CrossPoolMigrateFilter(xenObject, vmList, wizardMode, migrateFilterCache));
            }

            return filters;
        }

        protected override bool PerformCheck()
        {
            if (SelectedTargetPool != null && (SelectedTargetPool.Connection == null || !SelectedTargetPool.Connection.IsConnected))
            {
                CrossPoolMigrateWizard.ShowWarningMessageBox(Messages.CPM_WIZARD_ERROR_TARGET_DISCONNECTED);
                return false;
            }

            if (selectedVMs == null || selectedVMs.Count == 0 || Connection == null
                || selectedVMs.Any(vm => Connection.Resolve(new XenRef<VM>(vm)) == null))
            {
                CrossPoolMigrateWizard.ShowWarningMessageBox(string.Format(Messages.CPM_WIZARD_VM_MISSING_ERROR, BrandManager.BrandConsole));
                return false;
            }

            return true;
        }
    }
}