' 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.Composition
Imports System.Threading
Imports Microsoft.CodeAnalysis
Imports Microsoft.CodeAnalysis.BraceCompletion
Imports Microsoft.CodeAnalysis.Host.Mef
Imports Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax

Namespace Microsoft.CodeAnalysis.VisualBasic.BraceCompletion
    <ExportBraceCompletionService(LanguageNames.VisualBasic), [Shared]>
    Friend NotInheritable Class ParenthesisBraceCompletionService
        Inherits AbstractVisualBasicBraceCompletionService

        <ImportingConstructor>
        <Obsolete(MefConstruction.ImportingConstructorMessage, True)>
        Public Sub New()
            MyBase.New()
        End Sub

        Protected Overrides ReadOnly Property OpeningBrace As Char = Parenthesis.OpenCharacter
        Protected Overrides ReadOnly Property ClosingBrace As Char = Parenthesis.CloseCharacter

        Protected Overrides Function IsValidOpeningBraceToken(token As SyntaxToken) As Boolean
            Return token.IsKind(SyntaxKind.OpenParenToken)
        End Function

        Protected Overrides Function IsValidClosingBraceToken(token As SyntaxToken) As Boolean
            Return token.IsKind(SyntaxKind.CloseParenToken)
        End Function

        Protected Overrides Function IsValidOpenBraceTokenAtPosition(text As SourceText, token As SyntaxToken, position As Integer) As Boolean
            If Not IsValidOpeningBraceToken(token) OrElse
               position <> token.SpanStart Then
                Return False
            End If

            Dim skippedTriviaNode = TryCast(token.Parent, SkippedTokensTriviaSyntax)
            If skippedTriviaNode IsNot Nothing Then
                Dim skippedToken = skippedTriviaNode.ParentTrivia.Token
                ' These checks don't make any sense.  Leaving them in place to avoid breaking something as part of this move.
                If skippedToken.Kind <> SyntaxKind.CloseParenToken OrElse TypeOf skippedToken.Parent IsNot BinaryConditionalExpressionSyntax Then
                    Return False
                End If
            End If

            Return True
        End Function

        Public Overrides Function AllowOverType(context As BraceCompletionContext, cancellationToken As CancellationToken) As Boolean
            Return AllowOverTypeInUserCodeWithValidClosingToken(context, cancellationToken)
        End Function
    End Class
End Namespace