/* 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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using System;
using System.Collections.Generic;
using System.Linq;
using XenAPI;
using System.IO;
using System.Xml;
using XenAdmin.Core;
using System.Diagnostics;


namespace XenAdmin.Actions
{
    public class DownloadUpdatesXmlAction : AsyncAction
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
        private const string XenCenterVersionsNode = "xencenterversions";
        private const string XenServerVersionsNode = "serverversions";
        private const string PatchesNode = "patches";
        private const string ConflictingPatchesNode = "conflictingpatches";
        private const string RequiredPatchesNode = "requiredpatches";
        private const string ConflictingPatchNode = "conflictingpatch";
        private const string RequiredPatchNode = "requiredpatch";


        public List<XenCenterVersion> XenCenterVersions { get; private set; }
        public List<XenServerVersion> XenServerVersions { get; private set; }
        public List<XenServerPatch> XenServerPatches { get; private set; }

        public List<XenServerVersion> XenServerVersionsForAutoCheck
        {
            get
            {
                if(_checkForServerVersion)
                {
                    return XenServerVersions;
                }
                return new List<XenServerVersion>();
            }
        }

        private readonly bool _checkForXenCenter;
        private readonly bool _checkForServerVersion;
        private readonly bool _checkForPatches;
        private readonly string _checkForUpdatesUrl;

        public DownloadUpdatesXmlAction(bool checkForXenCenter, bool checkForServerVersion, bool checkForPatches, string checkForUpdatesUrl = null)
            : base(null, "_get_updates", "_get_updates", true)
        {
            Debug.Assert(checkForUpdatesUrl != null, "Parameter checkForUpdatesUrl should not be null. This class does not default its value anymore.");

            XenServerPatches = new List<XenServerPatch>();
            XenServerVersions = new List<XenServerVersion>();
            XenCenterVersions = new List<XenCenterVersion>();

            _checkForXenCenter = checkForXenCenter;
            _checkForServerVersion = checkForServerVersion;
            _checkForPatches = checkForPatches;
            _checkForUpdatesUrl = checkForUpdatesUrl;
        }

        protected override void Run()
        {
            this.Description = Messages.AVAILABLE_UPDATES_SEARCHING;

            XmlDocument xdoc = FetchCheckForUpdatesXml(_checkForUpdatesUrl);

            GetXenCenterVersions(xdoc);
            GetXenServerPatches(xdoc);
            GetXenServerVersions(xdoc);

        }

        private void GetXenCenterVersions(XmlDocument xdoc)
        {
            if (!_checkForXenCenter)
                return;

            foreach (XmlNode versions in xdoc.GetElementsByTagName(XenCenterVersionsNode))
            {
                foreach (XmlNode version in versions.ChildNodes)
                {
                    string version_lang = "";
                    string name = "";
                    bool is_latest = false;
                    string url = "";
                    string timestamp = "";

                    foreach (XmlAttribute attrib in version.Attributes)
                    {
                        if (attrib.Name == "value")
                            version_lang = attrib.Value;
                        else if (attrib.Name == "name")
                            name = attrib.Value;
                        else if (attrib.Name == "latest")
                            is_latest = attrib.Value.ToUpperInvariant() == bool.TrueString.ToUpperInvariant();
                        else if (attrib.Name == "url")
                            url = attrib.Value;
                        else if (attrib.Name == "timestamp")
                            timestamp = attrib.Value;
                    }

                    XenCenterVersions.Add(new XenCenterVersion(version_lang, name, is_latest, url, timestamp));
                }
            }
        }

        private void GetXenServerPatches(XmlDocument xdoc)
        {
            if (!_checkForPatches)
                return;

            foreach (XmlNode versions in xdoc.GetElementsByTagName(PatchesNode))
            {
                foreach (XmlNode version in versions.ChildNodes)
                {
                    string uuid = "";
                    string name = "";
                    string description = "";
                    string guidance = "";
                    string guidance_mandatory = "";
                    string patchVersion = "";
                    string url = "";
                    string patchUrl = "";
                    string timestamp = "";
                    string priority = "";
                    string installationSize = "";

                    foreach (XmlAttribute attrib in version.Attributes)
                    {
                        if (attrib.Name == "uuid")
                            uuid = attrib.Value;
                        else if (attrib.Name == "name-label")
                            name = attrib.Value;
                        else if (attrib.Name == "name-description")
                            description = attrib.Value;
                        else if (attrib.Name == "after-apply-guidance")
                            guidance = attrib.Value;
                        else if (attrib.Name == "guidance-mandatory")
                            guidance_mandatory = attrib.Value;
                        else if (attrib.Name == "version")
                            patchVersion = attrib.Value;
                        else if (attrib.Name == "url")
                            url = attrib.Value;
                        else if (attrib.Name == "patch-url")
                            patchUrl = attrib.Value;
                        else if (attrib.Name == "timestamp")
                            timestamp = attrib.Value;
                        else if (attrib.Name == "priority")
                            priority = attrib.Value;
                        else if (attrib.Name == "installation-size")
                            installationSize = attrib.Value;
                    }

                    var conflictingPatches = GetPatchDependencies(version, ConflictingPatchesNode, ConflictingPatchNode);
                    var requiredPatches = GetPatchDependencies(version, RequiredPatchesNode, RequiredPatchNode);

					XenServerPatches.Add(new XenServerPatch(uuid, name, description, guidance, guidance_mandatory, patchVersion, url,
                                                            patchUrl, timestamp, priority, installationSize, conflictingPatches, requiredPatches));
                }
            }
        }

        // dependencies patches are listed in the xml as below:
        // <conflictingpatches>
        //    <conflictingpatch uuid="00000000-0000-0000-0000-000000000000">
        //    </conflictingpatch>
        // </conflictingpatches>
        // <requiredpatches>
        //    <requiredgpatch uuid="00000000-0000-0000-0000-000000000000">
        //    </requiredgpatch>
        // </requiredpatches>
        private static List<string> GetPatchDependencies(XmlNode patchsNode, string dependenciesNodeName, string dependencyNodeName)
                    {
            var dependenciesNode = patchsNode.ChildNodes.Cast<XmlNode>().FirstOrDefault(childNode => childNode.Name == dependenciesNodeName);

            if (dependenciesNode == null)
                return null;

            var dependencies = new List<string>();

            dependencies.AddRange(from XmlNode node in dependenciesNode.ChildNodes
                                  where node.Attributes != null
                                  from XmlAttribute attrib in node.Attributes
                                  where node.Name == dependencyNodeName && node.Attributes != null && attrib.Name == "uuid"
                                  select attrib.Value);
            return dependencies;
        }

        private void GetXenServerVersions(XmlDocument xdoc)
        {
            if (!_checkForServerVersion && !_checkForPatches)
                return;

            foreach (XmlNode versions in xdoc.GetElementsByTagName(XenServerVersionsNode))
            {
                foreach (XmlNode version in versions.ChildNodes)
                {
                    string version_oem = "";
                    string name = "";
                    bool is_latest = false;
                    string url = "";
                    string timestamp = "";
                    string buildNumber = "";

                    foreach (XmlAttribute attrib in version.Attributes)
                    {
                        if (attrib.Name == "value")
                            version_oem = attrib.Value;
                        else if (attrib.Name == "name")
                            name = attrib.Value;
                        else if (attrib.Name == "latest")
                            is_latest = attrib.Value.ToUpperInvariant() == bool.TrueString.ToUpperInvariant();
                        else if (attrib.Name == "url")
                            url = attrib.Value;
                        else if (attrib.Name == "timestamp")
                            timestamp = attrib.Value;
                        else if (attrib.Name == "build-number")
                            buildNumber = attrib.Value;
                    }

                    List<XenServerPatch> patches = new List<XenServerPatch>();
                    List<XenServerPatch> minimalPatches = null; //keep it null to indicate that there is no a minimalpatches tag

                    foreach (XmlNode childnode in version.ChildNodes)
                    {
                        if (childnode.Name == "minimalpatches")
                        {
                            minimalPatches = new List<XenServerPatch>();

                            foreach (XmlNode minimalpatch in childnode.ChildNodes)
                            {
                                if (minimalpatch.Name != "patch")
                                    continue;

                                XenServerPatch mp = XenServerPatches.Find(p => string.Equals(p.Uuid, minimalpatch.Attributes["uuid"].Value, StringComparison.OrdinalIgnoreCase));
                                if (mp == null)
                                    continue;
                                minimalPatches.Add(mp);
                            }
                        }

                        if (childnode.Name == "patch")
                        {

                            XenServerPatch patch = XenServerPatches.Find(item => string.Equals(item.Uuid, childnode.Attributes["uuid"].Value, StringComparison.OrdinalIgnoreCase));
                            if (patch == null)
                                continue;
                            patches.Add(patch);
                        }

                    }

                    XenServerVersions.Add(new XenServerVersion(version_oem, name, is_latest, url, patches, minimalPatches, timestamp,
                                                               buildNumber));
                }
            }
        }

        protected virtual XmlDocument FetchCheckForUpdatesXml(string location)
        {
            var xdoc = new XmlDocument();
            var uri = new Uri(location);
            
            if (uri.IsFile)
            {
                xdoc.Load(location);
            }
            else
            {
                using (Stream xmlstream = HTTPHelper.GET(new Uri(location), Connection, false, true))
                {
                    xdoc = Helpers.LoadXmlDocument(xmlstream);
                }
            }
            return xdoc;
        }
    }
}