/* Copyright (c) Cloud Software Group, Inc. 
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met: 
 * 
 * *   Redistributions of source code must retain the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer. 
 * *   Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading;
using XenAdmin;
using XenAdmin.Core;
using System.Diagnostics;
using System.Web.Script.Serialization;


namespace XenAPI
{
    public partial class Host : IComparable<Host>, IEquatable<Host>
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod()?.DeclaringType);

        public enum Edition
        {
            Free,
            PerSocket,     //Added in Clearwater (PR-1589)
            XenDesktop,    //Added in Clearwater (PR-1589) and is new form of "EnterpriseXD"
            StandardPerSocket,     // Added in Creedence (standard-per-socket)
            Desktop,               // Added in Creedence (desktop)
            Standard,              // Added in Dundee/Violet (standard)
            EnterprisePerSocket,   // Added in Creedence (enterprise-per-socket)
            EnterprisePerUser,     // Added in Creedence (enterprise-per-user)
            DesktopPlus,           // Added in Creedence (desktop-plus)
            DesktopCloud,          // Added in Jura (desktop-cloud)
            Premium                // Added in Indigo (premium)
        }

        public const string LicenseServerWebConsolePort = "8082";

        public override string Name()
        {
            return name_label;
        }

        public static Edition GetEdition(string editionText)
        {
            switch (editionText)
            {
                case "xendesktop":
                    return Edition.XenDesktop;
                case "per-socket":
                    return Edition.PerSocket;
                case "enterprise-per-socket":
                case "premium-per-socket":
                    return Edition.EnterprisePerSocket;
                case "enterprise-per-user":
                case "premium-per-user":
                    return Edition.EnterprisePerUser;
                case "standard-per-socket":
                    return Edition.StandardPerSocket;
                case "desktop":
                    return Edition.Desktop;
                case "desktop-plus":
                    return Edition.DesktopPlus;
                case "desktop-cloud":
                    return Edition.DesktopCloud;
                case "premium":
                    return Edition.Premium;
                case "standard":
                    return Edition.Standard;
                case "basic":
                default:
                    return Edition.Free;
            }
        }

        public bool CanSeeNetwork(XenAPI.Network network)
        {
            System.Diagnostics.Trace.Assert(network != null);

            // Special case for local networks.
            if (network.PIFs.Count == 0)
                return true;

            foreach (var pifRef in network.PIFs)
            {
                PIF pif = network.Connection.Resolve(pifRef);
                if (pif != null && pif.host != null && pif.host.opaque_ref == opaque_ref)
                    return true;
            }

            return false;
        }

        public string GetEditionText(Edition edition)
        {
            switch (edition)
            {
                case Edition.XenDesktop:
                    return "xendesktop";
                case Edition.PerSocket:
                    return "per-socket";
                case Edition.EnterprisePerSocket:
                    return Helpers.NaplesOrGreater(this) ? "premium-per-socket" : "enterprise-per-socket";
                case Edition.EnterprisePerUser:
                    return Helpers.NaplesOrGreater(this) ? "premium-per-user" : "enterprise-per-user";
                case Edition.StandardPerSocket:
                    return "standard-per-socket";
                case Edition.Desktop:
                    return "desktop";
                case Edition.DesktopPlus:
                    return "desktop-plus";
                case Edition.DesktopCloud:
                    return "desktop-cloud";
                case Edition.Premium:
                    return "premium";
                case Edition.Standard:
                    return "standard";
                default:
                    // CP-43000: For some hosts "trial" works, too. However, "express" is valid from Naples onwards
                    return Helpers.NaplesOrGreater(this) ? "express" : "free";
            }
        }

        public string GetIscsiIqn()
        {
            if (Helpers.KolkataOrGreater(this))
            {
                return iscsi_iqn;
            }
            return Get(other_config, "iscsi_iqn") ?? "";
        }

        public void SetIscsiIqn(string value)
        {
            if (Helpers.KolkataOrGreater(this))
            {
                iscsi_iqn = value;
            }
            else
            {
                other_config = SetDictionaryKey(other_config, "iscsi_iqn", value);
            }
        }

        public override string ToString()
        {
            return this.name_label;
        }

        public override string Description()
        {
            // i18n: CA-30372, CA-207273
            if (name_description == "Default install of XenServer" || name_description == "Default install")
                return string.Format(Messages.DEFAULT_INSTALL_OF_XENSERVER,
                    software_version.ContainsKey("product_brand")
                        ? software_version["product_brand"]
                        : BrandManager.ProductBrand);
            
            return name_description ?? "";
        }

        /// <summary>
        /// The expiry date of this host's license in UTC.
        /// Defaults to 2030-01-01 if not found.
        /// </summary>
        public virtual DateTime LicenseExpiryUTC()
        {
            if (license_params != null && license_params.ContainsKey("expiry") &&
                Util.TryParseIso8601DateTime(license_params["expiry"], out var result))
                return result;
            return new DateTime(2030, 1, 1);
        }

        /// <summary>
        /// The CSS expiry date of this host's license.
        /// The time component is always set to midnight.
        /// Returns null if the value doesn't exist.
        /// </summary>
        public virtual DateTime? LicenseCssExpiry()
        {
            if(license_params != null &&
                license_params.TryGetValue("css_expiry", out var cssExpiryValue) && 
                !string.IsNullOrEmpty(cssExpiryValue) &&
                Util.TryParseNonIso8601DateTime(cssExpiryValue, out var result))
            {
                // css_expiry is not a datetime object
                return result.Date;
            }

            return null;
        }

        public static bool RestrictRBAC(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_rbac");
        }

        public static bool RestrictDMC(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_dmc");
        }

        /// <summary>
        /// Added for Clearwater
        /// </summary>
        /// <param name="h"></param>
        /// <returns></returns>
        public static bool RestrictHotfixApply(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_hotfix_apply");
        }

        /// <summary>
        /// Restrict Automated Updates
        /// </summary>
        /// <param name="h">host</param>
        /// <returns></returns>
        public static bool RestrictBatchHotfixApply(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_batch_hotfix_apply");
        }

        public static bool RestrictCheckpoint(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_checkpoint");
        }

        public static bool RestrictCifs(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_cifs");
        }

        public static bool RestrictVendorDevice(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_pci_device_for_auto_update");
        }

        public static bool RestrictWLB(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_wlb");
        }

        public static bool RestrictVSwitchController(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_vswitch_controller"); 
        }
   
        public static bool RestrictSriovNetwork(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_network_sriov");
        }

        public static bool RestrictPooling(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_pooling");
        }

        public static bool RestrictVMSnapshotSchedule(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_vmss");
        }

        public static bool RestrictVMAppliances(Host h)
        {
            return false;
        }

        public static bool RestrictDR(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_dr");
        }

        public static bool RestrictConversion(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_xcm");
        }

        public static bool RestrictCrossPoolMigrate(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_storage_xen_motion");
        }

        public static bool RestrictChangedBlockTracking(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_cbt");
        }

        public virtual bool IsFreeLicense()
        {
            return edition == "free" || edition == "express" || edition == "trial";
        }

        public virtual bool IsExpired()
        {
            if (Connection != null && Connection.CacheIsPopulated)
                return LicenseExpiryUTC() < DateTime.UtcNow - Connection.ServerTimeOffset;
            return true;
        }

        /// <summary>
        /// True if host qualifies for showing an upselling message based on its license and version.
        /// <br />
        /// Used to decide whether or not to show the upselling message from trial or express edition.
        /// <br />
        /// See CP-43000 for more info.
        /// </summary>
        public virtual bool CanShowTrialEditionUpsell()
        {
            return Helpers.NileOrGreater(this) && IsFreeLicense() && !IsInPreviewRelease();
        }

        /// <summary>
        /// Return true if the is_preview_release value in host.software_version is present and set to true.
        /// </summary>
        public virtual bool IsInPreviewRelease()
        {
            return software_version.TryGetValue("is_preview_release", out var isPreviewReleaseString) &&
                   bool.TryParse(isPreviewReleaseString, out var isPreviewRelease) && isPreviewRelease;
        }

        /// <summary>
        /// Returns true if the CSS license has expired, regardless of what edition is shown.
        /// <br />
        /// Do not rely on this method for enforcing restrictions as the user can circumvent this method
        /// by updating the system date.
        /// </summary>
        public virtual bool CssLicenseHasExpired()
        {
            var cssExpiry = LicenseCssExpiry();

            if (cssExpiry.HasValue)
            {
                // User can circumvent this by changing system date
                return DateTime.UtcNow < cssExpiry;
            }

            return false;
        }

        public static bool RestrictHA(Host h)
        {
            return !BoolKey(h.license_params, "enable_xha");
        }

        public static bool RestrictPoolSecretRotation(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_pool_secret_rotation");
        }

        public static bool RestrictCertificateVerification(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_certificate_verification");
        }

        public static bool RestrictAlerts(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_email_alerting");
        }

        public static bool RestrictStorageChoices(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_netapp");
        }

        public static bool RestrictPerformanceGraphs(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_historical_performance");
        }

        public static bool RestrictCpuMasking(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_cpu_masking");
        }

        public static bool RestrictGpu(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_gpu");
        }

        public static bool RestrictUsbPassthrough(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_usb_passthrough");
        }

        public static bool RestrictVgpu(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_vgpu");
        }

        public static bool RestrictManagementOnVLAN(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_management_on_vlan");
        }

        public static bool RestrictIntegratedGpuPassthrough(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_integrated_gpu_passthrough");
        }

        public static bool RestrictExportResourceData(Host h)
        {
                return BoolKeyPreferTrue(h.license_params, "restrict_export_resource_data");
            }

        public static bool RestrictIntraPoolMigrate(Host h)
        {
            return BoolKey(h.license_params, "restrict_xen_motion"); 
        }

        /// <summary>
        /// Active directory is restricted only if the "restrict_ad" key exists and it is true
        /// </summary>
        public static bool RestrictAD(Host h)
        {
            return BoolKey(h.license_params, "restrict_ad");
        }

        public static bool RestrictReadCaching(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_read_caching");
        }

        public static bool RestrictHealthCheck(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_health_check"); 
        }

        /// <summary>
        /// Vss feature is restricted only if the "restrict_vss" key exists and it is true
        /// </summary>
        public static bool RestrictVss(Host h)
        {
            return BoolKey(h.license_params, "restrict_vss"); 
        }

        public static bool RestrictPoolSize(Host h)
        {
            return BoolKey(h.license_params, "restrict_pool_size");
        }

        public static bool RestrictPvsCache(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_pvs_proxy");
        }

        /// <summary>
        /// For Dundee and greater hosts: the feature is restricted only if the "restrict_ssl_legacy_switch" key exists and it is true
        /// For pre-Dundee hosts: the feature is restricted if the "restrict_ssl_legacy_switch" key is absent or it is true
        /// </summary>
        public static bool RestrictSslLegacySwitch(Host h)
        {
            return BoolKey(h.license_params, "restrict_ssl_legacy_switch");
        }

        public static bool RestrictLivePatching(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_live_patching");
        }

        public static bool RestrictIGMPSnooping(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_igmp_snooping");
        }

        public static bool RestrictVcpuHotplug(Host h)
        {
            if (Helpers.ElyOrGreater(h.Connection))
            {
                return BoolKeyPreferTrue(h.license_params, "restrict_set_vcpus_number_live");
            }
            // Pre-Ely hosts:
            // allowed on Premium edition only
            var hostEdition = GetEdition(h.edition);
            if (hostEdition == Edition.Premium)
            {
                return h.LicenseExpiryUTC() < DateTime.UtcNow - h.Connection.ServerTimeOffset; // restrict if the license has expired
            }
            return true;
        }

        /// <summary>
        /// The feature is restricted if the "restrict_rpu" key exists and it is true
        /// or if the key is absent and the host is unlicensed
        /// </summary>
        public static bool RestrictRpu(Host h)
        {
            return h.license_params.ContainsKey("restrict_rpu")
                ? BoolKey(h.license_params, "restrict_rpu")
                : h.IsExpired(); // restrict if the license has expired
        }

        public static bool RestrictCorosync(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_corosync");
        }

        public static bool RestrictVtpm(Host h)
        {
            return BoolKeyPreferTrue(h.license_params, "restrict_vtpm");
        }

        #region Experimental Features

        //public static bool CorosyncDisabled(Host h)
        //{
        //    return  RestrictCorosync(h) && FeatureDisabled(h, "corosync");
        //}

        //public static bool SriovNetworkDisabled(Host h)
        //{
        //    return RestrictSriovNetwork(h) && FeatureDisabled(h, "network_sriov");
        //}

        public static bool UefiBootDisabled(Host h)
        {
            return FeatureDisabled(h, "guefi");
        }

        public static bool UefiSecureBootDisabled(Host h)
        {
            return FeatureDisabled(h, "guefi-secureboot");
        }

        public static bool FeatureDisabled(Host h, string featureName)
        {
            foreach (var feature in h.Connection.ResolveAll(h.features))
            {
                if (feature.name_label.Equals(featureName, StringComparison.OrdinalIgnoreCase))
                    return !feature.enabled;
            }
            return false;
        }

        #endregion

        public bool HasPBDTo(SR sr)
        {
            foreach (XenRef<PBD> pbd in PBDs)
            {
                PBD thePBD = sr.Connection.Resolve<PBD>(pbd);
                if (thePBD != null && thePBD.SR.opaque_ref == sr.opaque_ref)
                {
                    return true;
                }
            }
            return false;
        }

        public PBD GetPBDTo(SR sr)
        {
            foreach (XenRef<PBD> pbd in PBDs)
            {
                PBD thePBD = sr.Connection.Resolve<PBD>(pbd);
                if (thePBD != null && thePBD.SR.opaque_ref == sr.opaque_ref)
                {
                    return thePBD;
                }
            }
            return null;
        }

        // Constants for other-config from CP-329
        public const String MULTIPATH = "multipathing";
        public const String MULTIPATH_HANDLE = "multipathhandle";
        public const String DMP = "dmp";

        public bool MultipathEnabled()
        {
            if (Helpers.KolkataOrGreater(this))
            {
                return multipathing;
            }
            return BoolKey(other_config, MULTIPATH);
        }

        public String MultipathHandle()
        {
           return Get(other_config, MULTIPATH_HANDLE);
        }

        public override int CompareTo(Host other)
        {
            // CA-20865 Sort in the following order:
            // * Coordinators first
            // * Then connected supporters
            // * Then disconnected servers
            // Within each group, in NaturalCompare order

            bool thisConnected = (Connection.IsConnected && Helpers.GetCoordinator(Connection) != null);
            bool otherConnected = (other.Connection.IsConnected && Helpers.GetCoordinator(other.Connection) != null);

            if (thisConnected && !otherConnected)
                return -1;
            else if (!thisConnected && otherConnected)
                return 1;
            else if (thisConnected)
            {
                bool thisIsCoordinator = IsCoordinator();
                bool otherIsCoordinator = other.IsCoordinator();

                if (thisIsCoordinator && !otherIsCoordinator)
                    return -1;
                else if (!thisIsCoordinator && otherIsCoordinator)
                    return 1;
            }

            return base.CompareTo(other);
        }

        public virtual bool IsCoordinator()
        {
            Pool pool = Helpers.GetPoolOfOne(Connection);
            if (pool == null)
                return false;

            Host coordinator = Connection.Resolve<Host>(pool.master);
            return coordinator != null && coordinator.uuid == this.uuid;
        }

        /// <summary>
        /// Return this host's product version triplet (e.g. 5.6.100), or null if it can't be found.
        /// </summary>
        public virtual string ProductVersion()
        {
            return Get(software_version, "product_version");
        }

        /// <summary>
        /// Return this host's marketing version number (e.g. 5.6 Feature Pack 1),
        /// or ProductVersion (which can still be null) if it can't be found, including pre-Cowley hosts.
        /// </summary>
        public string ProductVersionText()
        {
            string s = Get(software_version, "product_version_text");
            return string.IsNullOrEmpty(s) ? ProductVersion() : s;
        }

        /// <summary>
        /// Return this host's marketing version number in short form (e.g. 5.6 FP1),
        /// or ProductVersion (which can still be null) if it can't be found, including pre-Cowley hosts.
        /// </summary>
        public string ProductVersionTextShort()
        {
            string s = Get(software_version, "product_version_text_short");
            return string.IsNullOrEmpty(s) ? ProductVersion() : s;
        }

        /// <summary>
        /// Return this host's XCP version triplet (e.g. 1.0.50), or null if it can't be found,
        /// including all pre-Tampa hosts.
        /// </summary>
        public virtual string PlatformVersion()
        {
            return Get(software_version, "platform_version");
        }

        public string GetXapiVersion()
        {
            return Get(software_version, "xapi_build") ?? Get(software_version, "xapi");
        }

        /// <summary>
        /// For legacy build numbers only (used to be integers + one char at the end)
        /// From Falcon, this property is not used.
        /// </summary>
        /// <remarks>
        /// Return the build number of this host, or -1 if none can be found.  This will often be
        /// 0 or -1 for developer builds, so comparisons should generally treat those numbers as if
        /// they were brand new.
        /// </remarks>
        internal int BuildNumber()
        {
            Debug.Assert(!Helpers.ElyOrGreater(this));

            string bn = BuildNumberRaw();
            if (bn == null)
                return -1;
            while (bn.Length > 0 && !char.IsDigit(bn[bn.Length - 1]))
            {
                bn = bn.Substring(0, bn.Length - 1);
            }
            int result;
            if (int.TryParse(bn, out result))
                return result;
            else
                return -1;
        }

        /// <summary>
        /// Return the exact build_number of this host
        /// </summary>
        /// <remarks>
        /// null if not found
        /// </remarks>
        public virtual string BuildNumberRaw()
        {
            return Get(software_version, "build_number");
        }

        /// <summary>
        /// Return this host's product version and build number (e.g. 5.6.100.72258), or null if product version can't be found.
        /// </summary>
        public virtual string LongProductVersion()
        {
            string productVersion = ProductVersion();
            return productVersion != null ? string.Format("{0}.{1}", productVersion, Helpers.ElyOrGreater(this) ? BuildNumberRaw() : BuildNumber().ToString()) : null;
        }

        /// <summary>
        /// Return the product_brand of this host, or null if none can be found.
        /// </summary>
        public string ProductBrand()
        {
            return Get(software_version, "product_brand");
        }

        /// <summary>
        /// The remote syslog target. May return null if not set on the server.
        /// </summary>
        public string GetSysLogDestination()
        {
            return logging != null && logging.ContainsKey("syslog_destination") ? logging["syslog_destination"] : null;
        }

        /// <summary>
        /// Set to null to unset
        /// </summary>
        public void SetSysLogDestination(string value)
        {
            logging = SetDictionaryKey(logging, "syslog_destination", value);
        }

        public virtual List<Pool_patch> AppliedPatches()
        {
            List<Pool_patch> patches = new List<Pool_patch>();

            foreach (Host_patch hostPatch in Connection.ResolveAll(this.patches))
            {
                Pool_patch patch = Connection.Resolve(hostPatch.pool_patch);
                if (patch != null)
                    patches.Add(patch);
            }

            return patches;
        }

        public virtual List<Pool_update> AppliedUpdates()
        {
            var updates = new List<Pool_update>();

            foreach (var hostUpdate in Connection.ResolveAll(this.updates))
            {
                if (hostUpdate != null)
                    updates.Add(hostUpdate);
            }

            return updates;
        }

        public bool LinuxPackPresent()
        {
            return software_version.ContainsKey("xs:linux");
        }

        public bool HasCrashDumps()
        {
            return crashdumps != null && crashdumps.Count > 0;
        }

        public bool IsLive()
        {
            if (Connection == null)
                return false;

            Host_metrics hm = Connection.Resolve(metrics);
            return hm != null && hm.live;
        }

        public const string MAINTENANCE_MODE = "MAINTENANCE_MODE";

        public bool MaintenanceMode()
        {
            return BoolKey(other_config, MAINTENANCE_MODE);
        }

        private const string BOOT_TIME = "boot_time";

        public double BootTime()
        {
            if (other_config == null)
                return 0.0;

            if (!other_config.ContainsKey(BOOT_TIME))
                return 0.0;

            double bootTime;

            if (!double.TryParse(other_config[BOOT_TIME], NumberStyles.Number,
                CultureInfo.InvariantCulture, out bootTime))
                return 0.0;

            return bootTime;
        }

        public static double BootTime(Session session, string hostOpaqueRef)
        {
            var host = get_record(session, hostOpaqueRef);
            return host.BootTime();
        }

        public PrettyTimeSpan Uptime()
        {
            double bootTime = BootTime();
            if (bootTime == 0.0)
                return null;
            return new PrettyTimeSpan(DateTime.UtcNow - Util.FromUnixTime(bootTime) - Connection.ServerTimeOffset);
        }

        private const string AGENT_START_TIME = "agent_start_time";

        public double AgentStartTime()
        {
            if (other_config == null)
                return 0.0;

            if (!other_config.ContainsKey(AGENT_START_TIME))
                return 0.0;

            double agentStartTime;

            if (!double.TryParse(other_config[AGENT_START_TIME], System.Globalization.NumberStyles.Any, CultureInfo.InvariantCulture, out agentStartTime))
                return 0.0;

            return agentStartTime;
        }

        public static double AgentStartTime(Session session, string hostOpaqueRef)
        {
            var host = get_record(session, hostOpaqueRef);
            return host.AgentStartTime();
        }

        public PrettyTimeSpan AgentUptime()
        {
            double startTime = AgentStartTime();
            if (startTime == 0.0)
                return null;
            return new PrettyTimeSpan(DateTime.UtcNow - Util.FromUnixTime(startTime) - Connection.ServerTimeOffset);
        }

        // Get the path counts from the Multipath Boot From SAN feature (see PR-1034 and CP-1696).
        // Returns true if the Host.other_config contains the multipathed and mpath-boot keys,
        // and the mpath-boot key is parseable. In this case, current and max will contain the result;
        // otherwise they will contain zero.
        public bool GetBootPathCounts(out int current, out int max)
        {
            current = max = 0;
            return (BoolKey(other_config, "multipathed") &&
                other_config.ContainsKey("mpath-boot") &&
                PBD.ParsePathCounts(other_config["mpath-boot"], out current, out max));
        }

        public bool HasRunningVMs()
        {
            // 2 not 1, because the Control Domain doesn't count
            return resident_VMs != null && resident_VMs.Count >= 2;
        }

        public List<XenRef<VM>> GetRunningPvVMs()
        {
            var vms = from XenRef<VM> vmref in resident_VMs
                      let vm = Connection.Resolve(vmref)
                      where vm != null && vm.IsRealVm() && !vm.IsHVM()
                      select vmref;

            return vms.ToList();
        }

        public List<XenRef<VM>> GetRunningHvmVMs()
        {
            var vms = from XenRef<VM> vmref in resident_VMs
                      let vm = Connection.Resolve(vmref)
                      where vm != null && vm.IsRealVm() && vm.IsHVM()
                      select vmref;

            return vms.ToList();
        }


        public List<XenRef<VM>> GetRunningVMs()
        {
            var vms = from XenRef<VM> vmref in resident_VMs
                      let vm = Connection.Resolve(vmref)
                      where vm != null && vm.IsRealVm()
                      select vmref;

            return vms.ToList();
        }

        #region Save Evacuated VMs for later

        public const String MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED = "MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED";
        public const String MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED = "MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED";
        public const String MAINTENANCE_MODE_EVACUATED_VMS_HALTED = "MAINTENANCE_MODE_EVACUATED_VMS_HALTED";

        /// <summary>
        /// Save the list of VMs on this host, so we can try and put them back when finished.
        /// This may get run multiple times, after which some vms will have been suspended / shutdown.
        /// </summary>
        /// <param name="session">Pass in the session you want to use for the other config writing</param>
        public void SaveEvacuatedVMs(Session session)
        {
            //Program.AssertOffEventThread();

            XenRef<Host> opaque_ref = get_by_uuid(session, uuid);

            List<VM> migratedVMs = GetVMs(MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED);
            List<VM> suspendedVMs = GetVMs(MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED);
            List<VM> haltedVMs = GetVMs(MAINTENANCE_MODE_EVACUATED_VMS_HALTED);

            List<VM> allVMs = new List<VM>();
            allVMs.AddRange(migratedVMs);
            allVMs.AddRange(suspendedVMs);
            allVMs.AddRange(haltedVMs);

            // First time round there will be no saved VMs, 
            // (or less saved VMs than currently resident)
            // so just save them all as migrated
            // don't forget the control domain

            if (allVMs.Count < resident_VMs.Count - 1)
            {
                SaveVMList(session, opaque_ref, MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED,
                    Connection.ResolveAll(resident_VMs));
                return;
            }

            // We've been round once, so just make sure all the vms are in the correct list
            // and then save the lists again

            migratedVMs.Clear();
            suspendedVMs.Clear();
            haltedVMs.Clear();

            foreach (VM vm in allVMs)
            {
                switch (vm.power_state)
                {
                    case vm_power_state.Halted:
                        haltedVMs.Add(vm);
                        break;

                    case vm_power_state.Running:
                        migratedVMs.Add(vm);
                        break;

                    case vm_power_state.Suspended:
                        suspendedVMs.Add(vm);
                        break;
                }
            }

            SaveVMList(session, opaque_ref, MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED, migratedVMs);
            SaveVMList(session, opaque_ref, MAINTENANCE_MODE_EVACUATED_VMS_HALTED, haltedVMs);
            SaveVMList(session, opaque_ref, MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED, suspendedVMs);
        }

        private static void SaveVMList(Session session, String serverOpaqueRef, String key, List<VM> vms)
        {
            //Program.AssertOffEventThread();

            List<String> vmUUIDs = new List<String>();
            foreach (VM vm in vms)
            {
                if (vm.is_control_domain)
                    continue;

                vmUUIDs.Add(vm.uuid);
            }

            Host.remove_from_other_config(session, serverOpaqueRef, key);
            Host.add_to_other_config(session, serverOpaqueRef, key, String.Join(",", vmUUIDs.ToArray()));
        }

        private List<VM> GetVMs(String key)
        {
            List<VM> vms = new List<VM>();

            if (other_config == null || !other_config.ContainsKey(key))
                return vms;

            String vmUUIDs = other_config[key];
            if (String.IsNullOrEmpty(vmUUIDs))
                return vms;

            foreach (String vmUUID in vmUUIDs.Split(new char[] { ',' }))
                foreach (VM vm in Connection.Cache.VMs)
                    if (vm.uuid == vmUUID)
                    {
                        if (!vms.Contains(vm))
                            vms.Add(vm);

                        break;
                    }

            return vms;
        }

        public void ClearEvacuatedVMs(Session session)
        {
            var hostRef = get_by_uuid(session, uuid);
            ClearEvacuatedVMs(session, hostRef);
        }

        public static void ClearEvacuatedVMs(Session session, XenRef<Host> hostRef)
        {
            remove_from_other_config(session, hostRef, MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED);
            remove_from_other_config(session, hostRef, MAINTENANCE_MODE_EVACUATED_VMS_HALTED);
            remove_from_other_config(session, hostRef, MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED);
        }

        public List<VM> GetMigratedEvacuatedVMs()
        {
            return GetEvacuatedVMs(MAINTENANCE_MODE_EVACUATED_VMS_MIGRATED, vm_power_state.Running);
        }

        public List<VM> GetSuspendedEvacuatedVMs()
        {
            return GetEvacuatedVMs(MAINTENANCE_MODE_EVACUATED_VMS_SUSPENDED, vm_power_state.Suspended);
        }

        public List<VM> GetHaltedEvacuatedVMs()
        {
            return GetEvacuatedVMs(MAINTENANCE_MODE_EVACUATED_VMS_HALTED, vm_power_state.Halted);
        }

        private List<VM> GetEvacuatedVMs(String key, vm_power_state expectedPowerState)
        {
            List<VM> vms = GetVMs(key);
            foreach (VM vm in vms.ToArray())
                if (vm.power_state != expectedPowerState)
                    vms.Remove(vm);

            return vms;
        }

        #endregion

        /// <summary>
        /// Will return null if cannot find connection or any control domain in list of vms
        /// </summary>
        public VM ControlDomainZero()
        {
            if (Connection == null)
                return null;

            if (!Helper.IsNullOrEmptyOpaqueRef(control_domain))
                return Connection.Resolve(control_domain);

            var vms = Connection.ResolveAll(resident_VMs);
            return vms.FirstOrDefault(vm => vm.is_control_domain && vm.domid == 0);
        }

        public IEnumerable<VM> OtherControlDomains()
        {
            if (Connection == null)
                return null;

            var vms = Connection.ResolveAll(resident_VMs);

            if (!Helper.IsNullOrEmptyOpaqueRef(control_domain))
                return vms.Where(v => v.is_control_domain && v.opaque_ref != control_domain);

            return vms.Where(v => v.is_control_domain && v.domid != 0);
        }

        /// <summary>
        /// Interpret a value from the software_version dictionary as a int, or 0 if we couldn't parse it.
        /// </summary>
        private int GetSVAsInt(string key)
        {
            string s = Get(software_version, key);
            if (s == null)
                return 0;
            return (int)Helper.GetAPIVersion(s);
        }

        /// <summary>
        /// The xencenter_min as a int, or 0. if we couldn't parse it.
        /// </summary>
        public int XenCenterMin()
        {
            return GetSVAsInt("xencenter_min");
        }

        /// <summary>
        /// The xencenter_max as a int, or 0 if we couldn't parse it.
        /// </summary>
        public int XenCenterMax()
        {
            return GetSVAsInt("xencenter_max");
        }

        public string GetDatabaseSchema()
        {
            return Get(software_version, "db_schema");
        }

        /// <summary>
        /// The amount of memory free on the host. For George and earlier hosts, we use to use
        /// the obvious Host_metrics.memory_free. Since Midnight Ride, however, we use
        /// the same calculation as xapi, adding the used memory and the virtualisation overheads
        /// on each of the VMs. This is a more conservative estimate (i.e., it reports less memory
        /// free), but it's the one we need to make the memory go down to zero when ballooning
        /// takes place.
        /// </summary>
        public long memory_free_calc()
        {
            Host_metrics host_metrics = Connection.Resolve(this.metrics);
            if (host_metrics == null)
                return 0;

            long used = memory_overhead;
            foreach (VM vm in Connection.ResolveAll(resident_VMs))
            {
                used += vm.memory_overhead;
                VM_metrics vm_metrics = vm.Connection.Resolve(vm.metrics);
                if (vm_metrics != null)
                    used += vm_metrics.memory_actual;
            }

            // This hack is needed because of bug CA-32509. xapi uses a deliberately generous
            // estimate of VM.memory_overhead: but the low-level squeezer code doesn't (and can't)
            // know about the same calculation, and so uses some of this memory_overhead for the
            // VM's memory_actual. This causes up to 1MB of double-counting per VM.
            return ((host_metrics.memory_total > used) ? (host_metrics.memory_total - used) : 0);
        }

        /// <summary>
        /// The total of all the dynamic_minimum memories of all resident VMs other than the control domain.
        /// For non-ballonable VMs, we use the static_maximum instead, because the dynamic_minimum has no effect.
        /// </summary>
        public long tot_dyn_min()
        {
            long ans = 0;
            foreach (VM vm in Connection.ResolveAll(resident_VMs))
            {
                if (!vm.is_control_domain)
                    ans += vm.SupportsBallooning() ? vm.memory_dynamic_min : vm.memory_static_max;
            }
            return ans;
        }

        /// <summary>
        /// The total of all the dynamic_maximum memories of all resident VMs other than the control domain.
        /// For non-ballonable VMs, we use the static_maximum instead, because the dynamic_maximum has no effect.
        /// </summary>
        public long tot_dyn_max()
        {
            long ans = 0;
            foreach (VM vm in Connection.ResolveAll(resident_VMs))
            {
                if (!vm.is_control_domain)
                    ans += vm.SupportsBallooning() ? vm.memory_dynamic_max : vm.memory_static_max;
            }
            return ans;
        }

        /// <summary>
        /// The amount of available memory on the host. This is not the same as the amount of free memory, because
        /// it includes the memory that could be freed by reducing balloonable VMs to their dynamic_minimum memory.
        /// </summary>
        public long memory_available_calc()
        {
            Host_metrics host_metrics = Connection.Resolve(this.metrics);
            if (host_metrics == null)
                return 0;

            long avail = host_metrics.memory_total - tot_dyn_min() - xen_memory_calc();
            if (avail < 0)
                avail = 0; // I don't think this can happen, but I'm nervous about CA-32509: play it safe
            return avail;
        }

        /// <summary>
        /// The amount of memory used by Xen, including the control domain plus host and VM overheads.
        /// Used to calculate this as total - free - tot_vm_mem, but that caused xen_mem to jump around
        /// during VM startup/shutdown because some changes happen before others.
        /// </summary>
        public long xen_memory_calc()
        {
            long xen_mem = memory_overhead;
            foreach (VM vm in Connection.ResolveAll(resident_VMs))
            {
                xen_mem += vm.memory_overhead;
                if (vm.is_control_domain)
                {
                    VM_metrics vmMetrics = vm.Connection.Resolve(vm.metrics);
                    if (vmMetrics != null)
                        xen_mem += vmMetrics.memory_actual;
                }
            }
            return xen_mem;
        }

        public long dom0_memory()
        {
            long dom0_mem = 0;
            VM vm = ControlDomainZero();
            if (vm != null)
            {
                VM_metrics vmMetrics = vm.Connection.Resolve(vm.metrics);
                dom0_mem = vmMetrics != null ? vmMetrics.memory_actual : vm.memory_dynamic_min;
            }
            return dom0_mem;
        }

        public long dom0_memory_extra()
        {
            VM vm = ControlDomainZero();
            return vm != null ? vm.memory_static_max - vm.memory_static_min : 0;
        }

        /// <summary>
        /// Friendly string showing memory usage on the host
        /// </summary>
        public string HostMemoryString()
        {
            Host_metrics m = Connection.Resolve(metrics);
            if (m == null)
                return Messages.GENERAL_UNKNOWN;

            long ServerMBAvail = memory_available_calc();
            long ServerMBTotal = m.memory_total;

            return string.Format(Messages.GENERAL_MEMORY_SERVER_FREE,
                Util.MemorySizeStringSuitableUnits(ServerMBAvail, true),
                Util.MemorySizeStringSuitableUnits(ServerMBTotal, true));
        }

        /// <summary>
        /// A friendly string for the XenMemory on this host
        /// </summary>
        public string XenMemoryString()
        {
            if (Connection.Resolve(metrics) == null)
                return Messages.GENERAL_UNKNOWN;

            return Util.MemorySizeStringSuitableUnits(xen_memory_calc(), true);
        }

        /// <summary>
        /// A friendly string of the resident VM's memory usage, with each entry separated by a line break
        /// </summary>
        public string ResidentVMMemoryUsageString()
        {
            Host_metrics m = Connection.Resolve(metrics);

            if (m == null)
                return Messages.GENERAL_UNKNOWN;
            else
            {
                List<string> lines = new List<string>();

                foreach (VM vm in Connection.ResolveAll(resident_VMs))
                {
                    if (vm.is_control_domain)
                        continue;

                    VM_metrics VMMetrics = Connection.Resolve(vm.metrics);
                    if (VMMetrics == null)
                        continue;

                    string message = string.Format(Messages.GENERAL_MEMORY_VM_USED, vm.Name(),
                        Util.MemorySizeStringSuitableUnits(VMMetrics.memory_actual, true));

                    lines.Add(message);
                }

                return string.Join("\n", lines.ToArray());
            }
        }

        /// <summary>
        /// Wait about two minutes for all the PBDs on this host to become plugged:
        /// if they do not, try and plug them. (Refs: CA-41219, CA-41305, CA-66496).
        /// </summary>
        public void CheckAndPlugPBDs()
        {
            bool allPBDsReady = false;
            int timeout = 120;
            log.DebugFormat("Waiting for PBDs on host {0} to become plugged", Name());

            while (timeout > 0)
            {
                if (enabled) // if the Host is not yet enabled, pbd.currently_attached may not be accurate: see CA-66496.
                {
                    allPBDsReady = true;
                    foreach (var pbdRef in PBDs)
                    {
                        var pbd = Connection.Resolve(pbdRef);

                        if (pbd == null || pbd.currently_attached)
                            continue;

                        if (Helpers.StockholmOrGreater(this)) //CA-350406
                        {
                            var sr = Connection.Resolve(pbd.SR);
                            if (sr != null && sr.is_tools_sr)
                                continue;
                        }

                        allPBDsReady = false;
                        break;
                    }
                }

                if (allPBDsReady)
                    return;

                Thread.Sleep(1000);
                timeout--;
            }

            foreach (var pbdRef in PBDs)
            {
                var pbd = Connection.Resolve(pbdRef);
                if (pbd == null || pbd.currently_attached)
                    continue;

                if (Helpers.StockholmOrGreater(this))
                {
                    var sr = Connection.Resolve(pbd.SR);
                    if (sr != null && sr.is_tools_sr)
                        continue;
                }

                Session session = Connection.DuplicateSession();

                // If we still haven't plugged, then try and plug it - this will probably
                // fail, but at least we'll get a better error message.

                try
                {
                    log.DebugFormat("Plugging PBD {0} on host {1}", pbd.Name(), Name());
                    PBD.plug(session, pbd.opaque_ref);
                }
                catch (Exception e)
                {
                    log.Debug(string.Format("Error plugging PBD {0} on host {1}", pbd.Name(), Name()), e);
                }
            }
        }

        /// <summary>
        /// Whether the host is running the vSwitch network stack
        /// </summary>
        public bool vSwitchNetworkBackend()
        {
            return software_version.ContainsKey("network_backend") &&
                   software_version["network_backend"] == "openvswitch";
        }

        /// <summary>
        /// The number of CPU sockets the host has
        /// Return 0 if a problem is found
        /// </summary>
        public virtual int CpuSockets()
        {
            const string key = "socket_count";
            const int defaultSockets = 0;

            if (cpu_info == null || !cpu_info.ContainsKey(key))
                return defaultSockets;

            int sockets;
            bool parsed = int.TryParse(cpu_info[key], out sockets);
            if (!parsed)
                return defaultSockets;

            return sockets;
        }

        /// <summary>
        /// The number of cpus the host has
        /// Return 0 if a problem is found
        /// </summary>
        public int CpuCount()
        {
            const string key = "cpu_count";
            const int defaultCpuCount = 0;

            if (cpu_info == null || !cpu_info.ContainsKey(key))
                return defaultCpuCount;

            int cpuCount;
            bool parsed = int.TryParse(cpu_info[key], out cpuCount);
            if (!parsed)
                return defaultCpuCount;

            return cpuCount;
        }

        /// <summary>
        /// The number of cores per socket the host has
        /// Return 0 if a problem is found
        /// </summary>
        public int CoresPerSocket()
        {
            var sockets = CpuSockets();
            var cpuCount = CpuCount();
            if (sockets > 0 && cpuCount > 0)
                return (cpuCount/sockets);

            return 0;
        }

        /// <summary>
        /// Grace is either upgrade or regular
        /// </summary>
        public virtual bool InGrace()
        {
            return license_params.ContainsKey("grace");
        }

        internal override string LocationString()
        {
            //for standalone hosts we do not show redundant location info
            return Helpers.GetPool(Connection) == null ? string.Empty : base.LocationString();
        }

        public bool EnterpriseFeaturesEnabled()
        {
            var hostEdition = GetEdition(edition);
            return EligibleForSupport() && (hostEdition == Edition.EnterprisePerSocket || hostEdition == Edition.EnterprisePerUser
                                          || hostEdition == Edition.PerSocket);
        }

        public bool DesktopPlusFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.DesktopPlus;
        }

        public bool DesktopFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.Desktop;
        }

        public bool DesktopCloudFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.DesktopCloud;
        }

        public bool PremiumFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.Premium;
        }

        public bool StandardFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.Standard;
        }

        public bool FreeFeaturesEnabled()
        {
            return GetEdition(edition) == Edition.Free;
        }

        public bool EligibleForSupport()
        {
            return GetEdition(edition) != Edition.Free;
        }

        #region Supplemental Packs

        // From http://scale.uk.xensource.com/confluence/display/engp/Supplemental+Pack+product+design+notes#SupplementalPackproductdesignnotes-XenAPI:
        // The supplemental packs that are installed on a host are listed in the host's Host.software_version field in the data model.
        // The keys of the entries have the form "<originator>:<name>", the value is "<description>, version <version>", appended by
        // ", build <build>" if the build number is present in the XML file, and further appended by ", homogeneous" if the
        // enforce-homogeneity attribute is present and set to true.
        //
        // Examples:
        // xs:main: Base Pack, version 5.5.900, build 19689c
        // xs:linux: Linux Pack, version 5.5.900, build 19689c, homogeneous

        public class SuppPack
        {
            private string originator, name, description, version, build;
            private bool homogeneous;

            public string Originator { get { return originator; } }
            public string Name { get { return name; } }
            public string Description { get { return description; } }
            public string Version { get { return version; } }
            public string Build { get { return build; } }
            public bool Homogeneous { get { return homogeneous; } }

            public string OriginatorAndName { get { return originator + ":" + name; } }

            private bool parsed = false;
            public bool IsValid { get { return parsed; } }

            public string LongDescription { get { return string.Format(Messages.SUPP_PACK_DESCRIPTION, description, version); } }

            /// <summary>
            /// Try to parse the supp pack information from one key of software_version
            /// </summary>
            public SuppPack(string key, string value)
            {
                // Parse the key
                string[] splitKey = key.Split(':');
                if (splitKey.Length != 2)
                    return;
                originator = splitKey[0];
                name = splitKey[1];

                // Parse the value. The description may contain arbitrary text, so we have to be a bit subtle:
                // we first search from the end to find where the description ends.
                int x = value.LastIndexOf(", version ");
                if (x <= 0)
                    return;

                description = value.Substring(0, x);
                string val = value.Substring(x + 10);

                string[] delims = new string[] {", "};
                string[] splitValue = val.Split(delims, StringSplitOptions.None);
                if (splitValue.Length == 0 || splitValue.Length > 3)
                    return;

                version = splitValue[0];

                if (splitValue.Length >= 2)
                {
                    if (!splitValue[1].StartsWith("build "))
                        return;
                    build = splitValue[1].Substring(6);
                }

                if (splitValue.Length >= 3)
                {
                    if (splitValue[2] != "homogeneous")
                        return;
                    homogeneous = true;
                }
                else
                    homogeneous = false;

                parsed = true;
            }
        }


        /// <summary>
        /// Return a list of the supplemental packs
        /// </summary>
        public List<SuppPack> SuppPacks()
        {
            List<SuppPack> packs = new List<SuppPack>();
            if (software_version == null)
                return packs;
            foreach (string key in software_version.Keys)
            {
                SuppPack pack = new SuppPack(key, software_version[key]);
                if (pack.IsValid)
                    packs.Add(pack);
            }
            return packs;
        }

        #endregion

        /// <summary>
        /// The PGPU that is the system display device or null
        /// </summary>
        public PGPU SystemDisplayDevice()
        {
            var pGpus = Connection.ResolveAll(PGPUs);
            return pGpus.FirstOrDefault(pGpu => pGpu.is_system_display_device);
        }

        /// <summary>
        /// Is the host allowed to enable/disable integrated GPU passthrough or is the feature unavailable/restricted?
        /// </summary>
        public bool CanEnableDisableIntegratedGpu()
        {
            return Helpers.GpuCapability(Connection) &&
                   !Helpers.FeatureForbidden(Connection, RestrictIntegratedGpuPassthrough);
        }

        public static bool TryGetUpgradeVersion(Host host, Dictionary<string, string> installMethodConfig,
            out string platformVersion, out string productVersion)
        {
            platformVersion = productVersion = null;
            
            try
            {
                var result = call_plugin(host.Connection.Session, host.opaque_ref,
                    "prepare_host_upgrade.py", "getVersion", installMethodConfig);
                var serializer = new JavaScriptSerializer();
                var version = (Dictionary<string, object>)serializer.DeserializeObject(result);
                platformVersion = version.ContainsKey("platform-version") ? (string)version["platform-version"] : null;
                productVersion = version.ContainsKey("product-version") ? (string)version["product-version"] : null;
                return platformVersion != null || productVersion != null;
            }
            catch (Exception exception)
            {
                log.WarnFormat("Plugin call prepare_host_upgrade.getVersion on {0} failed with {1}", host.Name(), exception.Message);
                return false;
            }
        }

        #region IEquatable<Host> Members

        /// <summary>
        /// Indicates whether the current object is equal to the specified object. This calls the implementation from XenObject.
        /// This implementation is required for ToStringWrapper.
        /// </summary>
        public virtual bool Equals(Host other)
        {
            return base.Equals(other);
        }

        #endregion
    }
}