/* Copyright (c) Citrix Systems Inc. 
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 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
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 * 
 * *   Redistributions of source code must retain the above 
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 *     following disclaimer. 
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 *     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 
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 * SUCH DAMAGE.
 */

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


namespace XenAdmin.Actions
{

    public abstract class PatchAction : AsyncAction
    {
        public PatchAction(IXenConnection conn, string title) : base(conn, title) { }
        public PatchAction(IXenConnection conn, string title, bool suppress) : base(conn, title, suppress) { }


        protected XenRef<Pool_patch> BringPatchToPoolForHost(Host host, Pool_patch patch)
        {
            // Check the patch exists on the pool this host is connected to
            XenRef<Pool_patch> patch_ref = host.Connection.Cache.FindRef(patch);
            if (patch_ref != null)
                return patch_ref;

            Description = String.Format(Messages.DOWNLOADING_PATCH_FROM, patch.Connection.Name);

            // 1st download patch from the pool that has it (the connection on the xenobject)

            string filename = Path.GetTempFileName();

            try
            {
                Connection = patch.Connection;
                Session = patch.Connection.DuplicateSession();

                try
                {
                    HTTPHelper.Get(this, true, filename, patch.Connection.Hostname,
                        (HTTP_actions.get_sss)HTTP_actions.get_pool_patch_download,
                        Session.uuid, patch.uuid);
                }
                catch (Exception e)
                {
                    throw new PatchDownloadFailedException(string.Format(Messages.PATCH_DOWNLOAD_FAILED, patch.name_label, patch.Connection.Name), e);
                }
                finally
                {
                    Connection = null;
                    Session = null;
                }

                // Then, put it on the pool that doesn't have it

                Description = String.Format(Messages.UPLOADING_PATCH_TO, host.Name);

                Connection = host.Connection;
                Session = host.Connection.DuplicateSession();

                try
                {
                    string result = HTTPHelper.Put(this, true, filename, host.Connection.Hostname,
                        (HTTP_actions.put_ss)HTTP_actions.put_pool_patch_upload, Session.uuid);

                    return new XenRef<Pool_patch>(result);
                }
                finally
                {
                    Connection = null;
                    Session = null;
                    Description = String.Format(Messages.PATCH_UPLOADED, host.Name);
                }
            }
            finally
            {
                File.Delete(filename);
            }
        }
    }

    public class ApplyPatchAction : PatchAction
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private readonly List<Pool_patch> patches;
        private readonly List<Host> hosts; //do we need a generic list in action for hosts rather than specifying 1 host there and many here?

        private string output = "";

        public ApplyPatchAction(List<Pool_patch> patches, List<Host> hosts)
            : base(null, string.Format(Messages.APPLYING_UPDATES, patches.Count, hosts.Count))
        {
            this.patches = patches;
            this.hosts = hosts;
        }

        protected override void Run()
        {
            SafeToExit = false;

            foreach (Pool_patch patch in patches)
            {
                foreach (Host host in hosts)
                {
                    if (patch.AppliedOn(host) == DateTime.MaxValue)
                        ApplyPatch(host, patch);
                }
            }
        
            if (hosts.Count > 1 || patches.Count > 1)
                this.Description = Messages.ALL_UPDATES_APPLIED;
        }

        private void ApplyPatch(Host host, Pool_patch patch)
        {
            // Set the correct connection object, for RecomputeCanCancel
            Connection = host.Connection;
            Session session = host.Connection.DuplicateSession();

            XenRef<Pool_patch> patchRef = BringPatchToPoolForHost(host, patch);

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

                output += String.Format(Messages.APPLY_PATCH_LOG_MESSAGE, patch.Name, host.Name);
                output += Pool_patch.apply(session, patchRef, host.opaque_ref);

                this.Description = String.Format(Messages.PATCH_APPLIED, patch.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];
                }
                    
                throw;
            }
            finally
            {
                Connection = null;
            }
        }

        
    }

    public class PatchDownloadFailedException : ApplicationException
    {
        public PatchDownloadFailedException(string message, Exception innerException) :
            base(message, innerException) { }
    }
}