// 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.
 
#nullable disable
 
using System;
using System.Composition;
using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.GenerateMember.GenerateEnumMember;
using Microsoft.CodeAnalysis.Host.Mef;
 
namespace Microsoft.CodeAnalysis.CSharp.GenerateMember.GenerateEnumMember;
 
[ExportLanguageService(typeof(IGenerateEnumMemberService), LanguageNames.CSharp), Shared]
[method: ImportingConstructor]
[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
internal sealed partial class CSharpGenerateEnumMemberService() :
    AbstractGenerateEnumMemberService<CSharpGenerateEnumMemberService, SimpleNameSyntax, ExpressionSyntax>
{
    protected override bool IsIdentifierNameGeneration(SyntaxNode node)
        => node is IdentifierNameSyntax;
 
    protected override bool TryInitializeIdentifierNameState(
        SemanticDocument document, SimpleNameSyntax identifierName, CancellationToken cancellationToken,
        out SyntaxToken identifierToken, out ExpressionSyntax simpleNameOrMemberAccessExpression)
    {
        identifierToken = identifierName.Identifier;
        if (identifierToken.ValueText != string.Empty &&
            !identifierName.IsVar)
        {
            simpleNameOrMemberAccessExpression = identifierName.Parent is MemberAccessExpressionSyntax memberAccess && memberAccess.Name == identifierName
                ? memberAccess
                : identifierName;
 
            // If we're being invoked, then don't offer this, offer generate method instead.
            // Note: we could offer to generate a field with a delegate type.  However, that's
            // very esoteric and probably not what most users want.
            if (simpleNameOrMemberAccessExpression.Parent.Kind()
                    is SyntaxKind.InvocationExpression
                    or SyntaxKind.ObjectCreationExpression
                    or SyntaxKind.GotoStatement
                    or SyntaxKind.AliasQualifiedName)
            {
                return false;
            }
 
            return true;
        }
 
        identifierToken = default;
        simpleNameOrMemberAccessExpression = null;
        return false;
    }
}