/* Copyright (c) Citrix Systems Inc. 
 * All rights reserved. 
 * 
 * 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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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE.
 */

using System;
using XenAPI;
using XenAdmin.Diagnostics.Problems;
using XenAdmin.Core;
using System.IO;
using XenAdmin.Diagnostics.Problems.HostProblem;
using System.Text.RegularExpressions;
using System.Xml;
using System.Collections.Generic;


namespace XenAdmin.Diagnostics.Checks
{
    class PatchPrecheckCheck : Check
    {
        private readonly Pool_patch _patch;

        private static Regex PrecheckErrorRegex = new Regex("(<error).+(</error>)");



        public PatchPrecheckCheck(Host host, Pool_patch patch)
            : base(host)
        {
            _patch = patch;
        }


        public override Problem RunCheck()
        {
            if (!Host.IsLive)
                return new HostNotLiveWarning(this, Host);

            if (!Host.Connection.IsConnected)
                throw new EndOfStreamException(Helpers.GetName(Host.Connection));

            Session session = Host.Connection.DuplicateSession();

            //
            // Check patch isn't already applied here
            //
            if (Patch.AppliedOn(Host) != DateTime.MaxValue)
            {
                return new PatchAlreadyApplied(this, Host);

            }

            try
            {
                return FindProblem(Pool_patch.precheck(session, Patch.opaque_ref, Host.opaque_ref), Host);

            }
            catch (Failure f)
            {
                log.Error(f.ToString());
                if(f.ErrorDescription.Count>0)
                    log.Error(f.ErrorDescription[0]);
                if (f.ErrorDescription.Count > 1)
                    log.Error(f.ErrorDescription[1]);
                if (f.ErrorDescription.Count > 2)
                    log.Error(f.ErrorDescription[2]);
                return new PrecheckFailed(this,Host, f);
            }
        }

        public override string Description
        {
            get { return Messages.SERVER_SIDE_CHECK_DESCRIPTION; }
        }

        public Pool_patch Patch
        {
            get { return _patch; }
        }

        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
       
        private Problem FindProblem(string result, Host host)
        {
            if (!PrecheckErrorRegex.IsMatch(result.Replace("\n", "")))
                return null;

            Match m = PrecheckErrorRegex.Match(result.Replace("\n", ""));

            XmlDocument doc = new XmlDocument();
            doc.LoadXml(m.ToString());
            log.Error(m.ToString());
            XmlNode errorNode = doc.FirstChild;

            string errorcode = errorNode.Attributes["errorcode"] != null
                                   ? errorNode.Attributes["errorcode"].Value
                                   : string.Empty;

            switch (errorcode)
            {
                case "PATCH_PRECHECK_FAILED_WRONG_SERVER_VERSION":
                    foreach (XmlNode node in errorNode.ChildNodes)
                    {
                        if (node.Name == "required")
                        {
                            return new WrongServerVersion(this, node.InnerXml,host);
                        }
                    }
                    break;
                case "PATCH_PRECHECK_FAILED_OUT_OF_SPACE":
                    long required = 0;
                    long found = 0;
                    foreach (XmlNode node in errorNode.ChildNodes)
                    {
                        if (node.Name == "found")
                        {
                            long.TryParse(node.InnerText, out found);
                        }

                        if (node.Name == "required")
                        {
                            long.TryParse(node.InnerText, out required);
                        }
                    }

                    // get reclaimable disk space (excluding current patch)
                    long reclaimableDiskSpace = 0;
                    try
                    {
                        var args = new Dictionary<string, string>();
                        if (Patch != null)
                            args.Add("exclude", Patch.uuid);
                        var resultReclaimable = Host.call_plugin(host.Connection.Session, host.opaque_ref, "disk-space", "get_reclaimable_disk_space", args);
                        reclaimableDiskSpace = Convert.ToInt64(resultReclaimable);                        
                    }
                    catch (Failure failure)
                    {
                        log.WarnFormat("Plugin call disk-space.get_reclaimable_disk_space on {0} failed with {1}", Host.Name, failure.Message);
                    }

                    var operation = XenAdmin.Actions.DiskSpaceRequirements.OperationTypes.install;

                    var diskSpaceReq = new XenAdmin.Actions.DiskSpaceRequirements(operation, host, Patch.Name, required, found, reclaimableDiskSpace);
                    
                    return new HostOutOfSpaceProblem(this, host, Patch, diskSpaceReq);
                case "":
                    return null;
                default:
                    return new PrecheckFailed(this, host,new Failure(errorcode));
            }
            return null;
        }
    }
}