gaemstone/src/gaemstone.SourceGen/Utility/SymbolExtensions.cs

using System.Linq;
using System.Text;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

namespace gaemstone.SourceGen.Utility;

public static class SymbolExtensions
{
	public static string GetFullName(this ISymbol symbol, bool metadata = false)
	{
		var builder = new StringBuilder();
		AppendFullName(symbol, builder, metadata);
		return builder.ToString();
	}

	public static void AppendFullName(this ISymbol symbol, StringBuilder builder, bool metadata = false)
	{
		if ((symbol.ContainingSymbol is ISymbol parent)
			&& ((parent as INamespaceSymbol)?.IsGlobalNamespace != true))
		{
			AppendFullName(parent, builder, metadata);
			builder.Append(((parent is ITypeSymbol) && metadata) ? '+' : '.');
		}

		if (!metadata && (symbol is INamedTypeSymbol typeSymbol) && typeSymbol.IsGenericType) {
			var length = symbol.MetadataName.IndexOf('`');
			builder.Append(symbol.MetadataName, 0, length);
			builder.Append('<');
			foreach (var genericType in typeSymbol.TypeArguments) {
				AppendFullName(genericType, builder, true);
				builder.Append(',');
			}
			builder.Length--; // Remove the last ',' character.
			builder.Append('>');
		} else builder.Append(symbol.MetadataName);
	}

	public static string? GetNamespace(this ISymbol symbol)
		=> symbol.ContainingNamespace?.GetFullName();

	public static bool HasAttribute(this ISymbol symbol, string attrMetadataName)
		=> symbol.GetAttributes().Any(attr => attr.AttributeClass!.GetFullName(true) == attrMetadataName);

	public static AttributeData? GetAttribute(this ISymbol symbol, string attrMetadataName)
		=> symbol.GetAttributes().FirstOrDefault(attr => attr.AttributeClass!.GetFullName(true) == attrMetadataName);

	public static string ToStringLiteral(this string? input)
		=> (input != null) ? SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression,
			SyntaxFactory.Literal(input)).ToFullString() : "null";
}