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using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Threading;
using XenAdmin;
using XenAdmin.Core;
using XenAdmin.Network;


namespace XenAPI
{
    partial class PBD
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private static bool WaitForPlug(Session session, string pbdOpaqueRef)
        {
            int timeout = 120; //Wait 2 min for PBD to plug

            while (timeout > 0)
            {
                if (PBD.get_currently_attached(session, pbdOpaqueRef))
                    return true;
                Thread.Sleep(1000);
                timeout--;
            }

            return false;
        }

        public static List<PBD> GetPBDsFor(IEnumerable<VM> vms)
        {
            List<PBD> pbds = new List<PBD>();

            // Find all the PBDs this vm relies on

            foreach (VM vm in vms)
            {
                foreach (VBD vbd in vm.Connection.ResolveAll<VBD>(vm.VBDs))
                {
                    VDI vdi = vbd.Connection.Resolve<VDI>(vbd.VDI);
                    if (vdi == null)
                        continue;

                    SR sr = vdi.Connection.Resolve<SR>(vdi.SR);
                    if (sr == null)
                        continue;

                    foreach (PBD pbd in vm.Connection.ResolveAll<PBD>(sr.PBDs))
                    {
                        if (!pbds.Contains(pbd))
                            pbds.Add(pbd);
                    }
                }
            }

            return pbds;
        }

        private enum PlugMode
        {
            NORMAL,     //Exception raised in the plug are propagated
            NONCHALANT  //Exceptions raised in the plug are masked
        }

        public static void CheckAndPlugPBDsFor(IXenConnection connection, List<XenRef<VM>> vmRefs)
        {
            CheckAndPlugPBDsFor(connection, vmRefs, PlugMode.NORMAL);
        }

        public static void CheckAndBestEffortPlugPBDsFor(IXenConnection connection, List<XenRef<VM>> vmRefs)
        {
            CheckAndPlugPBDsFor(connection, vmRefs, PlugMode.NONCHALANT);
        }

        private static void CheckAndPlugPBDsFor(IXenConnection connection, List<XenRef<VM>> vmRefs, PlugMode plugMode)
        {
            //Program.AssertOffEventThread();

            List<VM> vms = new List<VM>();

            foreach (XenRef<VM> vmRef in vmRefs)
            {
                VM vm = null;
                while ((vm = connection.Resolve<VM>(vmRef)) == null)
                    Thread.Sleep(100);

                vms.Add(vm);
            }
            
            CheckAndPlugPBDsFor(vms, plugMode);
        }

        public static void CheckAndPlugPBDsFor(List<VM> vms)
        {
            CheckAndPlugPBDsFor( vms, PlugMode.NORMAL );
        }

        private static void CheckAndPlugPBDsFor(List<VM> vms, PlugMode plugMode)
        {
            List<PBD> pbds = PBD.GetPBDsFor(vms);

            // Now lets see if they're all plugged
            CheckAndPlugPBDs(pbds, plugMode);
        }

        public static void CheckAndPlugPBDs(IList<PBD> pbds)
        {
            CheckAndPlugPBDs(pbds, PlugMode.NORMAL);
        }

        private static void CheckAndPlugPBDs(IList<PBD> pbds, PlugMode plugMode)
        {
            foreach (PBD pbd in pbds)
            {
                Session session = pbd.Connection.DuplicateSession();

                log.DebugFormat("Waiting for PBDs {0} to become plugged", pbd.Name);
                // Wait 2 min for PBD to become plugged
                if (WaitForPlug(session, pbd.opaque_ref))
                    continue;

                // If we still havent 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}", pbd.Name);
                    plug(session, pbd.opaque_ref);
                }
                catch (Exception e)
                {
                    log.Debug(string.Format("Error plugging PBD {0}", pbd.Name), e);

                    if (plugMode != PlugMode.NONCHALANT)
                        throw;
                }
            }
        }

        public static List<PBD> GetUnpluggedPBDsFor(IEnumerable<VM> vms)
        {
            List<PBD> unpluggedPBDs = new List<PBD>();

            foreach (PBD pbd in PBD.GetPBDsFor(vms))
            {
                if (!pbd.currently_attached)
                    unpluggedPBDs.Add(pbd);
            }

            return unpluggedPBDs;
        }

        public static IEnumerable<SR> GetSRs(IEnumerable<PBD> pbds)
        {
            List<SR> result = new List<SR>();
            foreach (PBD pbd in pbds)
            {
                SR sr = pbd.Connection.Resolve(pbd.SR);
                if (sr != null)
                    result.Add(sr);
            }
            return result;
        }

        public bool MultipathActive
        {
            get
            {
                return BoolKey(other_config, "multipathed");
            }
        }

        /// <summary>
        /// The number of iSCSI sessions in use, as advertised by the SR backend, or -1 if the value is missing.
        /// </summary>
        public int ISCSISessions
        {
            get
            {
                return IntKey(other_config, "iscsi_sessions", -1);
            }
        }

        private static readonly Regex multipathCountRegex = new Regex(@"\[(\d+)L?,\s(\d+)L?");

        public static bool ParsePathCounts(String input, out int currentPaths, out int maxPaths)
        {
            currentPaths = 0;
            maxPaths = 0;

            Match match = multipathCountRegex.Match(input);

            return match.Success && match.Groups.Count == 3 &&
                int.TryParse(match.Groups[1].Value, out currentPaths) &&
                int.TryParse(match.Groups[2].Value, out maxPaths);
        }

        /// <summary>
        /// The status of the PBD as a friendly string (unplugged, host down, connected)
        /// </summary>
        public string StatusString
        {
            get
            {
                Host h = Connection.Resolve(host);
                if ((!currently_attached) || (h == null))
                {
                    return Messages.REPAIR_SR_DIALOG_UNPLUGGED;
                }
                else if (!h.IsLive)
                    return Messages.HOST_NOT_LIVE;
                else
                    return Messages.CONNECTED;
            }
        }

        public StorageLinkCredentials GetStorageLinkCredentials()
        {
            var deviceConfig = new Dictionary<string, string>(device_config);
            
            SR sr = Connection.Resolve<SR>(SR);
            
            if (sr != null && sr.type == "cslg")
            {
                string host, username, passwordSecret;

                deviceConfig.TryGetValue("target", out host);
                deviceConfig.TryGetValue("username", out username);
                deviceConfig.TryGetValue("password_secret", out passwordSecret);

                return new StorageLinkCredentials(Connection, host, username, null, passwordSecret);
            }
            return null;
        }
    }
}