' 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.

Imports System.Threading
Imports Microsoft.CodeAnalysis.PooledObjects
Imports Microsoft.CodeAnalysis.Simplification
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax

Namespace Microsoft.CodeAnalysis.VisualBasic.Simplification
    Partial Friend Class VisualBasicCallReducer
        Inherits AbstractVisualBasicReducer

        Private Shared ReadOnly s_pool As ObjectPool(Of IReductionRewriter) =
            New ObjectPool(Of IReductionRewriter)(Function() New Rewriter(s_pool))

        Private Shared ReadOnly s_simplifyCallStatement As Func(Of CallStatementSyntax, SemanticModel, SimplifierOptions, CancellationToken, SyntaxNode) = AddressOf SimplifyCallStatement

        Public Sub New()
            MyBase.New(s_pool)
        End Sub

        Public Overrides Function IsApplicable(options As VisualBasicSimplifierOptions) As Boolean
            Return True
        End Function

        Private Shared Function SimplifyCallStatement(
            callStatement As CallStatementSyntax,
            semanticModel As SemanticModel,
            options As SimplifierOptions,
            cancellationToken As CancellationToken
        ) As ExecutableStatementSyntax

            If callStatement.CanRemoveCallKeyword() Then
                Dim leading = callStatement.GetLeadingTrivia()

                Dim resultNode = SyntaxFactory.ExpressionStatement(callStatement.Invocation) _
                             .WithLeadingTrivia(leading)

                resultNode = SimplificationHelpers.CopyAnnotations(callStatement, resultNode)

                Return resultNode
            End If

            ' We don't know how to simplify this.
            Return callStatement
        End Function
    End Class
End Namespace