Code.cs

// ReSharper disable InvertIf
namespace Atc.Wpf.Controls.Documents.TextFormatters.SourceCode.Format;

/// <summary>
/// Provides a base class for formatting most programming languages.
/// </summary>
[SuppressMessage("Design", "MA0056:Do not call overridable members in constructor", Justification = "OK.")]
[SuppressMessage("Naming", "CA1711:Identifiers should not have incorrect suffix", Justification = "OK.")]
public abstract class Code : Source
{
    /// <summary>
    /// Initializes a new instance of the <see cref="Code"/> class.
    /// </summary>
    protected Code()
    {
        // generate the keyword and preprocessor regexes from the keyword lists
        var r = new Regex(@"\w+|-\w+|#\w+|@@\w+|#(?:\\(?:s|w)(?:\*|\+)?\w+)+|@\\w\*+", RegexOptions.None, TimeSpan.FromSeconds(5));
        var regKeyword = r.Replace(Keywords, @"(?<=^|\W)$0(?=\W)");
        var regPreproc = r.Replace(Preprocessors, @"(?<=^|\s)$0(?=\s|$)");
        r = new Regex(@" +", RegexOptions.None, TimeSpan.FromSeconds(5));
        regKeyword = r.Replace(regKeyword, @"|");
        regPreproc = r.Replace(regPreproc, @"|");

        if (regPreproc.Length == 0)
        {
            // use something quite impossible...
            regPreproc = "(?!.*)_{37}(?<!.*)";
        }

        // build a master regex with capturing groups
        var regAll = new StringBuilder();
        regAll.Append('(');
        regAll.Append(CommentRegEx);
        regAll.Append(")|(");
        regAll.Append(StringRegEx);
        if (regPreproc.Length > 0)
        {
            regAll.Append(")|(");
            regAll.Append(regPreproc);
        }

        regAll.Append(")|(");
        regAll.Append(regKeyword);
        regAll.Append(')');

        // ReSharper disable once DoNotCallOverridableMethodsInConstructor
        var caseInsensitive = CaseSensitive
            ? RegexOptions.None
            : RegexOptions.IgnoreCase;
        CodeRegex = new Regex(regAll.ToString(), RegexOptions.Singleline | caseInsensitive, TimeSpan.FromSeconds(5));
        CodeParagraphGlobal = new List<Run>();
    }

    /// <summary>
    /// Determines if the language is case-sensitive.
    /// </summary>
    /// <value><b>true</b> if the language is case-sensitive, <b>false</b>
    /// otherwise. The default is true.</value>
    /// <remarks>
    /// A case-insensitive language formatter must override this
    /// property to return false.
    /// </remarks>
    public virtual bool CaseSensitive => true;

    /// <summary>
    /// Must be overridden to provide a list of keywords defined in
    /// each language.
    /// </summary>
    /// <remarks>
    /// Keywords must be separated with spaces.
    /// </remarks>
    protected abstract string Keywords { get; }

    /// <summary>
    /// Can be overridden to provide a list of preprocessors defined in
    /// each language.
    /// </summary>
    /// <remarks>
    /// Preprocessors must be separated with spaces.
    /// </remarks>
    protected virtual string Preprocessors => string.Empty;

    /// <summary>
    /// Must be overridden to provide a regular expression string
    /// to match strings literals.
    /// </summary>
    protected abstract string StringRegEx { get; }

    /// <summary>
    /// Must be overridden to provide a regular expression string
    /// to match comments.
    /// </summary>
    protected abstract string CommentRegEx { get; }

    /// <summary>
    /// Called to evaluate the HTML fragment corresponding to each
    /// matching token in the code.
    /// </summary>
    /// <param name="match">The <see cref="Match" /> resulting from a
    /// single regular expression match.</param>
    /// <param name="themeMode">The ThemeMode.</param>
    /// <returns>A string containing the HTML code fragment.</returns>
    [SuppressMessage("Design", "MA0051:Method is too long", Justification = "OK.")]
    protected override string MatchEval(Match match, ThemeMode themeMode)
    {
        ArgumentNullException.ThrowIfNull(match);

        if (match.Groups[1].Success)
        {
            var reader = new StringReader(match.ToString());
            var sb = new StringBuilder();
            var firstLineRead = false;
            while (reader.ReadLine() is { } line)
            {
                if (firstLineRead)
                {
                    sb.Append('\r');
                }

                sb.Append(line);
                firstLineRead = true;
            }

            if (!string.IsNullOrEmpty(sb.ToString()))
            {
                var run = new Run(sb.ToString())
                {
                    Foreground = new SolidColorBrush(
                        themeMode == ThemeMode.Light
                            ? Color.FromRgb(0, 128, 0)
                            : Color.FromRgb(87, 166, 74)),
                };

                CodeParagraphGlobal.Add(run);
            }

            return FormattingMarker;
        }

        // string literal
        if (match.Groups[2].Success)
        {
            var run = new Run(match.ToString())
            {
                Foreground = new SolidColorBrush(
                    themeMode == ThemeMode.Light
                        ? Color.FromRgb(179, 90, 45)
                        : Color.FromRgb(214, 157, 133)),
            };

            CodeParagraphGlobal.Add(run);
            return FormattingMarker;
        }

        // preprocessor keyword
        if (match.Groups[3].Success)
        {
            var run = new Run(match.ToString())
            {
                Foreground = new SolidColorBrush(Color.FromRgb(155, 155, 143)),
            };

            CodeParagraphGlobal.Add(run);
            return FormattingMarker;
        }

        // keyword
        if (match.Groups[4].Success)
        {
            var run = new Run(match.ToString())
            {
                Foreground = new SolidColorBrush(
                    themeMode == ThemeMode.Light
                        ? Color.FromRgb(0, 0, 255)
                        : Color.FromRgb(86, 156, 214)),
            };

            CodeParagraphGlobal.Add(run);
            return FormattingMarker;
        }

        return string.Empty;
    }
}