CodeBlock.cs

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Threading.Tasks;
using System.Xml;
using Waher.Content.Markdown.Rendering;
using Waher.Events;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Markdown.Model.BlockElements
{
    public class CodeBlock : BlockElement
    {
        private ICodeContent handler;
        private Type handlerType = null;
        private readonly string[] rows;
        private readonly string indentString;
        private readonly string language;
        private readonly int start, end, indent;
 
        public CodeBlock(MarkdownDocument Document, string[] Rows, int Start, int End, int Indent)
            : this(Document, Rows, Start, End, Indent, null)
        {
        }
 
        public CodeBlock(MarkdownDocument Document, string[] Rows, int Start, int End, int Indent, string Language)
            : base(Document)
        {
            this.rows = Rows;
            this.start = Start;
            this.end = End;
            this.indent = Indent;
            this.indentString = this.indent <= 0 ? string.Empty : new string('\t', this.indent);
            this.language = Language;
        }
 
        public string Language => this.language;
 
        public string[] Rows => this.rows;
 
        public T CodeContentHandler<T>()
            where T : ICodeContentRenderer
        {
            if (this.handlerType is null || this.handlerType != typeof(T))
            {
                this.handler = GetCodeBlockHandler<T>(this.language, this.Document.Settings.AllowInlineScript);
                this.handlerType = typeof(T);
            }
 
            return (T)this.handler;
        }
 
        private static IXmlVisualizer[] xmlVisualizers = null;
        private readonly static Dictionary<Type, Dictionary<string, ICodeContentRenderer[]>> codeContentHandlers = new Dictionary<Type, Dictionary<string, ICodeContentRenderer[]>>();
        private readonly static Dictionary<string, IXmlVisualizer[]> xmlVisualizerHandlers = new Dictionary<string, IXmlVisualizer[]>(StringComparer.CurrentCultureIgnoreCase);
 
        static CodeBlock()
        {
            Init();
            Types.OnInvalidated += (Sender, e) => Init();
        }
 
        private static void Init()
        {
            List<ICodeContentRenderer> CodeContents = new List<ICodeContentRenderer>();
            List<IXmlVisualizer> XmlVisualizers = new List<IXmlVisualizer>();
 
            foreach (Type T in Types.GetTypesImplementingInterface(typeof(ICodeContentRenderer)))
            {
                ConstructorInfo CI = Types.GetDefaultConstructor(T);
                if (CI is null)
                    continue;
 
                try
                {
                    ICodeContentRenderer CodeContent = (ICodeContentRenderer)CI.Invoke(Types.NoParameters);
                    CodeContents.Add(CodeContent);
                }
                catch (Exception ex)
                {
                    Log.Exception(ex);
                }
            }
 
            foreach (Type T in Types.GetTypesImplementingInterface(typeof(IXmlVisualizer)))
            {
                ConstructorInfo CI = Types.GetDefaultConstructor(T);
                if (CI is null)
                    continue;
 
                try
                {
                    IXmlVisualizer XmlVisualizer = (IXmlVisualizer)CI.Invoke(Types.NoParameters);
                    XmlVisualizers.Add(XmlVisualizer);
                }
                catch (Exception ex)
                {
                    Log.Exception(ex);
                }
            }
 
            lock (codeContentHandlers)
            {
                codeContentHandlers.Clear();
            }
 
            lock (xmlVisualizerHandlers)
            {
                xmlVisualizers = XmlVisualizers.ToArray();
                xmlVisualizerHandlers.Clear();
            }
        }
 
        internal static T GetCodeBlockHandler<T>(string Language, bool AllowScript)
            where T : ICodeContentRenderer
        {
            ICodeContentRenderer[] Handlers;
 
            if (string.IsNullOrEmpty(Language))
                return default;
 
            lock (codeContentHandlers)
            {
                if (!codeContentHandlers.TryGetValue(typeof(T), out Dictionary<string, ICodeContentRenderer[]> PerLanguage))
                {
                    PerLanguage = new Dictionary<string, ICodeContentRenderer[]>();
                    codeContentHandlers[typeof(T)] = PerLanguage;
                }
 
                if (!PerLanguage.TryGetValue(Language, out Handlers))
                {
                    List<ICodeContentRenderer> List = new List<ICodeContentRenderer>();
 
                    foreach (Type T2 in Types.GetTypesImplementingInterface(typeof(T)))
                    {
                        ConstructorInfo CI = Types.GetDefaultConstructor(T2);
                        if (CI is null)
                            continue;
 
                        try
                        {
                            T CodeContent = (T)CI.Invoke(Types.NoParameters);
                            if (CodeContent.Supports(Language) > Grade.NotAtAll)
                                List.Add(CodeContent);
                        }
                        catch (Exception ex)
                        {
                            Log.Exception(ex);
                        }
                    }
 
                    if (List.Count > 0)
                        Handlers = List.ToArray();
                    else
                        Handlers = null;
 
                    PerLanguage[Language] = Handlers;
                }
            }
 
            if (Handlers is null)
                return default;
 
            T Best = default;
            Grade BestGrade = Grade.NotAtAll;
            Grade ContentGrade;
 
            foreach (ICodeContentRenderer Content in Handlers)
            {
                ContentGrade = Content.Supports(Language);
                if (ContentGrade > BestGrade && Content is T TypedContent && (AllowScript || !Content.EvaluatesScript))
                {
                    BestGrade = ContentGrade;
                    Best = TypedContent;
                }
            }
 
            return Best;
        }
 
        internal static IXmlVisualizer GetXmlVisualizerHandler(XmlDocument Xml)
        {
            if (Xml is null || Xml.DocumentElement is null)
                return null;
 
            IXmlVisualizer[] Handlers;
            string Key = Xml.DocumentElement.NamespaceURI + "#" + Xml.DocumentElement.LocalName;
 
            lock (xmlVisualizerHandlers)
            {
                if (!xmlVisualizerHandlers.TryGetValue(Key, out Handlers))
                {
                    List<IXmlVisualizer> List = new List<IXmlVisualizer>();
 
                    foreach (IXmlVisualizer Visualizer in xmlVisualizers)
                    {
                        if (Visualizer.Supports(Xml) > Grade.NotAtAll)
                            List.Add(Visualizer);
                    }
 
                    if (List.Count > 0)
                        Handlers = List.ToArray();
                    else
                        Handlers = null;
 
                    xmlVisualizerHandlers[Key] = Handlers;
                }
            }
 
            if (Handlers is null)
                return null;
 
            IXmlVisualizer Best = null;
            Grade BestGrade = Grade.NotAtAll;
            Grade VisualizerGrade;
 
            foreach (IXmlVisualizer Visualizer in Handlers)
            {
                VisualizerGrade = Visualizer.Supports(Xml);
                if (VisualizerGrade > BestGrade)
                {
                    BestGrade = VisualizerGrade;
                    Best = Visualizer;
                }
            }
 
            return Best;
        }
 
        public override Task Render(IRenderer Output) => Output.Render(this);
 
        public int Indent => this.indent;
 
        public string IndentString => this.indentString;
 
        public override bool InlineSpanElement => false;
 
        public int Start => this.start;
 
        public int End => this.end;
 
        public override bool SameMetaData(MarkdownElement E)
        {
            return E is CodeBlock x &&
                this.indent == x.indent &&
                this.indentString == x.indentString &&
                this.language == x.language &&
                AreEqual(this.rows, x.rows) &&
                base.SameMetaData(E);
        }
 
        public override bool Equals(object obj)
        {
            return obj is CodeBlock x &&
                this.indent == x.indent &&
                this.indentString == x.indentString &&
                this.language == x.language &&
                AreEqual(this.rows, x.rows) &&
                base.Equals(obj);
        }
 
        public override int GetHashCode()
        {
            int h1 = base.GetHashCode();
            int h2 = this.indent.GetHashCode();
 
            h1 = ((h1 << 5) + h1) ^ h2;
            h2 = this.indentString?.GetHashCode() ?? 0;
 
            h1 = ((h1 << 5) + h1) ^ h2;
            h2 = this.language?.GetHashCode() ?? 0;
 
            h1 = ((h1 << 5) + h1) ^ h2;
            h2 = GetHashCode(this.rows);
 
            h1 = ((h1 << 5) + h1) ^ h2;
 
            return h1;
        }
 
        public override void IncrementStatistics(MarkdownStatistics Statistics)
        {
            Statistics.NrCodeBlocks++;
        }
 
    }
}