SemanticGraph.cs

using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using Waher.Content.Semantic.Model;
using Waher.Content.Semantic.Ontologies;
 
namespace Waher.Content.Semantic
{
    public class SemanticGraph : InMemorySemanticCube
    {
        private readonly Dictionary<ISemanticElement, bool> nodes = new Dictionary<ISemanticElement, bool>();
        private ISemanticElement lastSubject = null;
        private ISemanticElement[] nodesStatic = null;
 
        public SemanticGraph()
            : base()
        {
        }
 
        public override void Add(ISemanticTriple Triple)
        {
            base.Add(Triple);
 
            if (this.lastSubject is null || !this.lastSubject.Equals(Triple.Subject))
            {
                this.nodes[Triple.Subject] = true;
                this.lastSubject = Triple.Subject;
                this.nodesStatic = null;
            }
 
            if (!Triple.Object.IsLiteral &&
                Triple.Predicate is UriNode Predicate &&
                Predicate.Uri != Rdf.Type)
            {
                this.nodes[Triple.Object] = true;
                this.nodesStatic = null;
            }
        }
 
        public ISemanticElement[] Nodes
        {
            get
            {
                if (this.nodesStatic is null)
                {
                    ISemanticElement[] Result = new ISemanticElement[this.nodes.Count];
                    this.nodes.Keys.CopyTo(Result, 0);
                    this.nodesStatic = Result;
                }
 
                return this.nodesStatic;
            }
        }
 
        public async Task<string> ExportPlantUml()
        {
            StringBuilder Output = new StringBuilder();
            await this.ExportPlantUml(Output);
            return Output.ToString();
        }
 
        public async Task ExportPlantUml(StringBuilder Output)
        {
            Output.AppendLine("@startuml");
 
            Dictionary<ISemanticElement, string> NodeIds = new Dictionary<ISemanticElement, string>();
            Dictionary<string, LinkedList<LinkInfo>> LinksByNodeId = new Dictionary<string, LinkedList<LinkInfo>>();
            int i = 0;
 
            foreach (ISemanticElement Node in this.Nodes)
            {
                if (!NodeIds.TryGetValue(Node, out string NodeId))
                {
                    NodeId = "n" + (++i).ToString();
                    NodeIds[Node] = NodeId;
                }
            }
 
            foreach (ISemanticElement Node in this.Nodes)
            {
                string NodeId = NodeIds[Node];
                ISemanticPlane Plane = await this.GetTriplesBySubject(Node);
                LinkedList<KeyValuePair<string, object>> Properties = null;
                LinkedList<LinkInfo> Links = null;
                string StereoType = null;
                bool IsRdfType;
 
                if (!(Plane is null))
                {
                    IEnumerator<ISemanticElement> Predicates = await Plane.GetXAxisEnumerator();
 
                    while (Predicates.MoveNext())
                    {
                        ISemanticLine Line = await Plane.GetTriplesByX(Predicates.Current);
                        string PropertyName;
 
                        if (Predicates.Current is UriNode UriNode)
                        {
                            PropertyName = UriNode.ShortName;
                            IsRdfType = UriNode.Uri == Rdf.Type;
                        }
                        else
                        {
                            PropertyName = Predicates.Current.ToString();
                            IsRdfType = false;
                        }
 
                        if (!(Line is null))
                        {
                            IEnumerator<ISemanticElement> Values = await Line.GetValueEnumerator();
 
                            while (Values.MoveNext())
                            {
                                if (IsRdfType && StereoType is null)
                                {
                                    if (Values.Current is UriNode UriNode2)
                                        StereoType = UriNode2.ShortName;
                                    else
                                        StereoType = Values.Current.ToString();
                                }
                                else if (Values.Current is ISemanticLiteral Literal)
                                {
                                    if (Properties is null)
                                        Properties = new LinkedList<KeyValuePair<string, object>>();
 
                                    Properties.AddLast(new KeyValuePair<string, object>(PropertyName, Literal.StringValue));
                                }
                                else if (NodeIds.TryGetValue(Values.Current, out string ObjectId))
                                {
                                    if (Links is null)
                                        Links = new LinkedList<LinkInfo>();
 
                                    Links.AddLast(new LinkInfo()
                                    {
                                        From = NodeId,
                                        To = ObjectId,
                                        Type = Node is BlankNode ? "*--" : "-->",
                                        Label = PropertyName
                                    });
                                }
                                else
                                {
                                    if (Properties is null)
                                        Properties = new LinkedList<KeyValuePair<string, object>>();
 
                                    string ValueString;
 
                                    if (Values.Current is UriNode UriNode2)
                                        ValueString = UriNode2.ShortName;
                                    else
                                        ValueString = Values.Current.ToString();
 
                                    Properties.AddLast(new KeyValuePair<string, object>(PropertyName, ValueString));
                                }
                            }
                        }
                    }
                }
 
                if (Properties is null)
                {
                    Output.Append("object \"");
 
                    if (Node is UriNode UriNode)
                        Output.Append(JSON.Encode(UriNode.ShortName));
                    else
                        Output.Append(JSON.Encode(Node.ToString()));
 
                    Output.Append("\" as ");
                    Output.Append(NodeId);
 
                    if (!string.IsNullOrEmpty(StereoType))
                    {
                        Output.Append("<<");
                        Output.Append(StereoType);
                        Output.Append(">>");
                    }
 
                    Output.AppendLine();
                }
                else
                {
                    Output.Append("map \"");
 
                    if (Node is UriNode UriNode)
                        Output.Append(JSON.Encode(UriNode.ShortName));
                    else
                        Output.Append(JSON.Encode(Node.ToString()));
 
                    Output.Append("\" as ");
                    Output.Append(NodeId);
 
                    if (!string.IsNullOrEmpty(StereoType))
                    {
                        Output.Append("<<");
                        Output.Append(StereoType);
                        Output.Append(">>");
                    }
 
                    Output.AppendLine(" {");
 
                    foreach (KeyValuePair<string, object> P in Properties)
                    {
                        Output.Append('\t');
                        Output.Append(P.Key);
                        Output.Append(" => ");
                        Output.AppendLine(P.Value?.ToString());
                    }
 
                    Output.AppendLine("}");
                }
 
                if (!(Links is null))
                    LinksByNodeId[NodeId] = Links;
            }
 
            foreach (LinkedList<LinkInfo> Links in LinksByNodeId.Values)
            {
                foreach (LinkInfo Link in Links)
                {
                    Output.Append(Link.From);
                    Output.Append(' ');
                    Output.Append(Link.Type);
                    Output.Append(' ');
                    Output.Append(Link.To);
                    Output.Append(" : ");
                    Output.AppendLine(Link.Label);
                }
            }
 
            Output.AppendLine("@enduml");
        }
 
        private class LinkInfo
        {
            public string From;
            public string To;
            public string Type;
            public string Label;
        }
 
    }
}