﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Linq;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.QuickInfo
{
    internal abstract partial class CommonSemanticQuickInfoProvider
    {
        private class ErrorVisitor : SymbolVisitor<bool>
        {
            private static readonly ErrorVisitor s_instance = new();

            public static bool ContainsError(ISymbol? symbol)
                => s_instance.Visit(symbol);

            public override bool DefaultVisit(ISymbol symbol)
                => true;

            public override bool VisitAlias(IAliasSymbol symbol)
                => false;

            public override bool VisitArrayType(IArrayTypeSymbol symbol)
                => Visit(symbol.ElementType);

            public override bool VisitEvent(IEventSymbol symbol)
                => Visit(symbol.Type);

            public override bool VisitField(IFieldSymbol symbol)
                => Visit(symbol.Type);

            public override bool VisitLocal(ILocalSymbol symbol)
                => Visit(symbol.Type);

            public override bool VisitMethod(IMethodSymbol symbol)
            {
                foreach (var parameter in symbol.Parameters)
                {
                    if (!Visit(parameter))
                    {
                        return true;
                    }
                }

                foreach (var typeParameter in symbol.TypeParameters)
                {
                    if (!Visit(typeParameter))
                    {
                        return true;
                    }
                }

                return false;
            }

            public override bool VisitNamedType(INamedTypeSymbol symbol)
            {
                foreach (var typeParameter in symbol.TypeArguments.Concat(symbol.TypeParameters))
                {
                    if (Visit(typeParameter))
                    {
                        return true;
                    }
                }

                return symbol.IsErrorType();
            }

            public override bool VisitParameter(IParameterSymbol symbol)
                => Visit(symbol.Type);

            public override bool VisitProperty(IPropertySymbol symbol)
                => Visit(symbol.Type);

            public override bool VisitPointerType(IPointerTypeSymbol symbol)
                => Visit(symbol.PointedAtType);
        }
    }
}
