// 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.Collections.Immutable;
using System.Threading;
using Microsoft.CodeAnalysis.Completion.Providers;
using Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery;

namespace Microsoft.CodeAnalysis.CSharp.Completion.KeywordRecommenders;

internal sealed class VarKeywordRecommender : IKeywordRecommender<CSharpSyntaxContext>
{
    private static bool IsValidContext(CSharpSyntaxContext context)
    {
        if (context.IsStatementContext ||
            context.IsGlobalStatementContext ||
            context.IsPossibleTupleContext ||
            context.IsAtStartOfPattern)
        {
            return true;
        }

        return context.IsLocalVariableDeclarationContext;
    }

    public ImmutableArray<RecommendedKeyword> RecommendKeywords(int position, CSharpSyntaxContext context, CancellationToken cancellationToken)
    {
        return IsValidContext(context)
            ? [new RecommendedKeyword("var")]
            : [];
    }
}