// 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.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CSharp.CodeGeneration;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CSharp.ExtractMethod;
 
internal partial class CSharpMethodExtractor
{
    private partial class CSharpCodeGenerator
    {
        public sealed class SingleStatementCodeGenerator(
            CSharpSelectionResult selectionResult,
            AnalyzerResult analyzerResult,
            CSharpCodeGenerationOptions options,
            bool localFunction) : CSharpCodeGenerator(selectionResult, analyzerResult, options, localFunction)
        {
            protected override SyntaxToken CreateMethodName() => GenerateMethodNameForStatementGenerators();
 
            protected override ImmutableArray<StatementSyntax> GetInitialStatementsForMethodDefinitions()
            {
                Contract.ThrowIfFalse(this.SelectionResult.IsExtractMethodOnSingleStatement());
 
                return [this.SelectionResult.GetFirstStatement()];
            }
 
            protected override SyntaxNode GetFirstStatementOrInitializerSelectedAtCallSite()
                => this.SelectionResult.GetFirstStatement();
 
            protected override SyntaxNode GetLastStatementOrInitializerSelectedAtCallSite()
            {
                // it is a single statement case. either first statement is same as last statement or
                // last statement belongs (embedded statement) to the first statement.
                return this.SelectionResult.GetFirstStatement();
            }
 
            protected override Task<SyntaxNode> GetStatementOrInitializerContainingInvocationToExtractedMethodAsync(CancellationToken cancellationToken)
            {
                var statement = GetStatementContainingInvocationToExtractedMethodWorker();
                return Task.FromResult<SyntaxNode>(statement.WithAdditionalAnnotations(CallSiteAnnotation));
            }
        }
    }
}