KycApplicationItem.cs

namespace NeuroAccessMaui.Services.Kyc
{
    using System;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Globalization;
    using System.Xml;
    using Waher.Networking.XMPP.PubSub;
 
    public sealed class KycApplicationItem
    {
        private const string XmlLanguageNamespace = "http://www.w3.org/XML/1998/namespace";
        private readonly IReadOnlyDictionary<string, string> localizedNames;
        private readonly string? primaryDisplayName;
 
        private KycApplicationItem(
            string nodeId,
            string itemId,
            string processXml,
            string? serviceAddress,
            string? publisher,
            DateTime? published,
            IReadOnlyDictionary<string, string> localizedNames,
            string? primaryDisplayName)
        {
            this.NodeId = nodeId;
            this.ItemId = itemId;
            this.ProcessXml = processXml;
            this.ServiceAddress = serviceAddress;
            this.Publisher = publisher;
            this.Published = published;
            this.localizedNames = localizedNames;
            this.primaryDisplayName = primaryDisplayName;
        }
 
        public string NodeId { get; }
 
        public string ItemId { get; }
 
        public string ProcessXml { get; }
 
        public string? ServiceAddress { get; }
 
        public string? Publisher { get; }
 
        public DateTime? Published { get; }
 
        public IReadOnlyDictionary<string, string> LocalizedNames => this.localizedNames;
 
        public string DisplayName
        {
            get
            {
                if (!string.IsNullOrEmpty(this.primaryDisplayName))
                {
                    return this.primaryDisplayName;
                }
                string Preferred = CultureInfo.CurrentUICulture.TwoLetterISOLanguageName;
                string? Value = this.GetLocalizedName(Preferred);
                return Value ?? string.Empty;
            }
        }
 
        public string? PrimaryDisplayName => this.primaryDisplayName;
 
        public static bool TryCreate(PubSubItem Item, out KycApplicationItem? Application)
        {
            Application = null;
            if (Item is null)
                return false;
 
            string? ItemId = Item.ItemId;
            if (string.IsNullOrWhiteSpace(ItemId))
                return false;
 
                XmlElement? Payload = Item.Item;
                if (Payload is null)
                {
                    string? PayloadXml = Item.Payload;
                    if (string.IsNullOrWhiteSpace(PayloadXml))
                        return false;
 
                    try
                    {
                        XmlDocument Document = new XmlDocument();
                        Document.LoadXml(PayloadXml);
                        Payload = Document.DocumentElement;
                    }
                    catch (XmlException)
                    {
                        return false;
                    }
                }
 
                    if (Payload is null)
                        return false;
 
                    XmlElement? PayloadElement = NormalizePayload(Payload);
                    if (PayloadElement is null)
                        return false;
 
                    string ProcessXml = PayloadElement.OuterXml;
                if (string.IsNullOrWhiteSpace(ProcessXml))
                    return false;
 
                Dictionary<string, string> NamesDictionary = ExtractLocalizedNames(PayloadElement, out string? PrimaryName);
                ReadOnlyDictionary<string, string> Names = new ReadOnlyDictionary<string, string>(NamesDictionary);
 
            string NodeId = Item.Node ?? string.Empty;
            string? ServiceAddress = Item.ServiceAddress;
            string? Publisher = Item.Publisher;
            DateTime? Published = null;
 
                Application = new KycApplicationItem(NodeId, ItemId, ProcessXml, ServiceAddress, Publisher, Published, Names, PrimaryName);
                return true;
            }
 
        public static IReadOnlyList<KycApplicationItem> CreateMany(IEnumerable<PubSubItem> Items)
        {
            List<KycApplicationItem> Results = new List<KycApplicationItem>();
            foreach (PubSubItem Item in Items)
            {
                if (Item is null)
                    continue;
 
                if (TryCreate(Item, out KycApplicationItem? Application) && Application is not null)
                    Results.Add(Application);
            }
 
            return Results;
        }
 
        public string? GetLocalizedName(string? Language)
        {
            if (Language is not null && this.localizedNames.TryGetValue(Language, out string? Value))
                return Value;
 
            if (this.localizedNames.TryGetValue("en", out string? English))
                return English;
 
            foreach (KeyValuePair<string, string> Pair in this.localizedNames)
                return Pair.Value;
 
            return null;
        }
 
        private static XmlElement? NormalizePayload(XmlElement Payload)
        {
            if (Payload.LocalName == "item" && Payload.NamespaceURI == PubSubClient.NamespacePubSub)
            {
                foreach (XmlNode Child in Payload.ChildNodes)
                {
                    if (Child is XmlElement Element)
                        return Element;
                }
 
                return null;
            }
 
            return Payload;
        }
 
        private static Dictionary<string, string> ExtractLocalizedNames(XmlElement Payload, out string? primaryName)
        {
            Dictionary<string, string> Names = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
            primaryName = null;
            XmlElement? NameElement = SelectChild(Payload, "Name");
            if (NameElement is null)
                return Names;
 
            foreach (XmlNode Child in NameElement.ChildNodes)
            {
                if (Child is not XmlElement TextElement)
                    continue;
 
                if (!string.Equals(TextElement.LocalName, "Text", StringComparison.Ordinal))
                    continue;
 
                string Language = TextElement.GetAttribute("lang", XmlLanguageNamespace);
                if (string.IsNullOrWhiteSpace(Language))
                    Language = "und";
 
                string Value = TextElement.InnerText;
                if (string.IsNullOrWhiteSpace(Value))
                    continue;
 
                Names[Language] = Value.Trim();
                if (primaryName is null)
                    primaryName = Value.Trim();
            }
 
            return Names;
        }
 
        private static XmlElement? SelectChild(XmlElement Parent, string LocalName, string? NamespaceUri = null)
        {
            foreach (XmlNode Child in Parent.ChildNodes)
            {
                if (Child is not XmlElement Candidate)
                    continue;
 
                if (!string.Equals(Candidate.LocalName, LocalName, StringComparison.Ordinal))
                    continue;
 
                if (NamespaceUri is not null && !string.Equals(Candidate.NamespaceURI, NamespaceUri, StringComparison.Ordinal))
                    continue;
 
                return Candidate;
            }
 
            return null;
        }
    }
}