/* Copyright (c) Citrix Systems Inc. 
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 * 
 * 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 
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 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
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 */

using System;
using System.Collections.Generic;
using System.IO;
using XenAPI;
using XenAdmin.Network;
using System.Linq;


namespace XenAdmin.Actions
{
    public class ApplyUpdateAction : AsyncAction
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private readonly List<Pool_update> updates;
        private readonly List<Host> hosts;

        private string output = "";

        public ApplyUpdateAction(List<Pool_update> updates, List<Host> hosts)
            : base(null, string.Format(Messages.APPLYING_UPDATES, updates.Count, hosts.Count))
        {
            this.updates = updates;
            this.hosts = hosts;
        }

        protected override void Run()
        {
            SafeToExit = false;

            foreach (Pool_update update in updates)
            {
                foreach (Host host in hosts)
                {
                    if (!update.AppliedOn(host))
                        ApplyUpdate(host, update);
                }
            }
        
            if (hosts.Count > 1 || updates.Count > 1)
                this.Description = Messages.ALL_UPDATES_APPLIED;
        }

        private void ApplyUpdate(Host host, Pool_update update)
        {
            // Set the correct connection object, for RecomputeCanCancel
            Connection = host.Connection;
            Session session = host.Connection.DuplicateSession();

            try
            {
                this.Description = String.Format(Messages.APPLYING_PATCH, update.Name, host.Name);

                output += String.Format(Messages.APPLY_PATCH_LOG_MESSAGE, update.Name, host.Name);
                
                var poolUpdates = new List<Pool_update>(session.Connection.Cache.Pool_updates);
                var poolUpdate = poolUpdates.FirstOrDefault(u => u != null && string.Equals(u.uuid, update.uuid, StringComparison.OrdinalIgnoreCase));

                if (poolUpdate == null)
                    throw new Exception("Pool_update not found");

                if (!poolUpdate.AppliedOn(host))
                {
                    Pool_update.apply(session, poolUpdate.opaque_ref, host.opaque_ref);

                    this.Description = String.Format(Messages.PATCH_APPLIED, update.Name, host.Name);
                }
                else
                {
                    this.Description = String.Format(Messages.PATCH_APPLIED, update.Name, host.Name);
                }
            }
            catch (Failure f)
            {
                if (f.ErrorDescription.Count > 1 && f.ErrorDescription[0] == XenAPI.Failure.PATCH_APPLY_FAILED)
                {
                    output += Messages.APPLY_PATCH_FAILED_LOG_MESSAGE;
                    output += f.ErrorDescription[1];
                }

                log.Error(output, f);

                throw;
            }
            finally
            {
                Connection = null;
            }
        }
    }

}