spectre.console/src/Spectre.Console.Analyzer/Analyzers/FavorInstanceAnsiConsoleOverStaticAnalyzer.cs

namespace Spectre.Console.Analyzer;

/// <summary>
/// Analyzer to suggest using available instances of AnsiConsole over the static methods.
/// </summary>
[DiagnosticAnalyzer(LanguageNames.CSharp)]
public class FavorInstanceAnsiConsoleOverStaticAnalyzer : SpectreAnalyzer
{
    private static readonly DiagnosticDescriptor _diagnosticDescriptor =
        Descriptors.S1010_FavorInstanceAnsiConsoleOverStatic;

    /// <inheritdoc />
    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics =>
        ImmutableArray.Create(_diagnosticDescriptor);

    /// <inheritdoc />
    protected override void AnalyzeCompilation(CompilationStartAnalysisContext compilationStartContext)
    {
        compilationStartContext.RegisterOperationAction(
            context =>
            {
                var ansiConsoleType = context.Compilation.GetTypeByMetadataName("Spectre.Console.AnsiConsole");

                // if this operation isn't an invocation against one of the System.Console methods
                // defined in _methods then we can safely stop analyzing and return;
                var invocationOperation = (IInvocationOperation)context.Operation;
                if (!SymbolEqualityComparer.Default.Equals(invocationOperation.TargetMethod.ContainingType, ansiConsoleType))
                {
                    return;
                }

                // if we aren't in a method then it might be too complex for us to handle.
                if (!invocationOperation.Syntax.Ancestors().OfType<MethodDeclarationSyntax>().Any())
                {
                    return;
                }

                if (!HasFieldAnsiConsole(invocationOperation.Syntax) &&
                    !HasParameterAnsiConsole(invocationOperation.Syntax))
                {
                    return;
                }

                var methodSymbol = invocationOperation.TargetMethod;

                var displayString = SymbolDisplay.ToDisplayString(
                    methodSymbol,
                    SymbolDisplayFormat.CSharpShortErrorMessageFormat
                        .WithParameterOptions(SymbolDisplayParameterOptions.None)
                        .WithGenericsOptions(SymbolDisplayGenericsOptions.None));

                context.ReportDiagnostic(
                    Diagnostic.Create(
                        _diagnosticDescriptor,
                        invocationOperation.Syntax.GetLocation(),
                        displayString));
            }, OperationKind.Invocation);
    }

    private static bool HasParameterAnsiConsole(SyntaxNode syntaxNode)
    {
        return syntaxNode
            .Ancestors().OfType<MethodDeclarationSyntax>()
            .First()
            .ParameterList.Parameters
            .Any(i => i.Type?.NormalizeWhitespace()?.ToString() == "IAnsiConsole");
    }

    private static bool HasFieldAnsiConsole(SyntaxNode syntaxNode)
    {
        var isStatic = syntaxNode
            .Ancestors()
            .OfType<MethodDeclarationSyntax>()
            .First()
            .Modifiers.Any(i => i.IsKind(SyntaxKind.StaticKeyword));

        return syntaxNode
            .Ancestors().OfType<ClassDeclarationSyntax>()
            .First()
            .Members
            .OfType<FieldDeclarationSyntax>()
            .Any(i =>
                i.Declaration.Type.NormalizeWhitespace().ToString() == "IAnsiConsole" &&
                (!isStatic ^ i.Modifiers.Any(modifier => modifier.IsKind(SyntaxKind.StaticKeyword))));
    }
}