LoadMarkdown.cs

using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Waher.Script;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Content.Markdown.Functions
{
    public class LoadMarkdown : FunctionMultiVariate
    {
        public LoadMarkdown(ScriptNode FileName, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { FileName }, argumentTypes1Scalar, Start, Length, Expression)
        {
        }
 
        public LoadMarkdown(ScriptNode FileName, ScriptNode Headers, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { FileName, Headers }, argumentTypes2Scalar, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(LoadMarkdown);
 
        public override string[] DefaultArgumentNames => new string[] { "FileName", "Headers" };
 
        public override bool IsAsynchronous => true;
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            return this.EvaluateAsync(Arguments, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateAsync(IElement[] Arguments, Variables Variables)
        {
            if (!(Arguments[0].AssociatedObjectValue is string FileName))
                throw new ScriptRuntimeException("Expected first argument to be a string file name.", this);
 
            bool IncludeHeaders;
 
            if (Arguments.Length > 1)
            {
                if (!(Arguments[1].AssociatedObjectValue is bool b))
                    throw new ScriptRuntimeException("Expected second argument to be a Boolean value.", this);
 
                IncludeHeaders = b;
            }
            else
                IncludeHeaders = false;
 
            string Markdown = await Resources.ReadAllTextAsync(FileName);
            MarkdownSettings Settings = new MarkdownSettings()
            {
                Variables = Variables,
                ParseMetaData = true
            };
 
            if (Variables.TryGetVariable(MarkdownDocument.MarkdownSettingsVariableName, out Variable v) &&
                v.ValueObject is MarkdownSettings ParentSettings)
            {
                Settings.AllowScriptTag = ParentSettings.AllowScriptTag;
                Settings.AudioAutoplay = ParentSettings.AudioAutoplay;
                Settings.AudioControls = ParentSettings.AudioControls;
                Settings.EmbedEmojis = ParentSettings.EmbedEmojis;
                Settings.EmojiSource = ParentSettings.EmojiSource;
                Settings.HttpxProxy = ParentSettings.HttpxProxy;
                Settings.LocalHttpxResourcePath = ParentSettings.LocalHttpxResourcePath;
                Settings.RootFolder = ParentSettings.RootFolder;
                Settings.VideoAutoplay = ParentSettings.VideoAutoplay;
                Settings.VideoControls = ParentSettings.VideoControls;
            }
 
            KeyValuePair<string, bool> P = await MarkdownDocument.Preprocess(Markdown, Settings, FileName, true);
            Markdown = P.Key;
 
            if (!IncludeHeaders)
            {
                int? Pos = MarkdownDocument.HeaderEndPosition(Markdown);
 
                if (Pos.HasValue)
                    Markdown = Markdown.Substring(Pos.Value).TrimStart();
            }
 
            return new StringValue(Markdown);
        }
    }
}