' 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 Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
 
Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax
 
    Partial Public Class DirectiveTriviaSyntax
 
        Public Function GetRelatedDirectives() As List(Of DirectiveTriviaSyntax)
            Dim list = New List(Of DirectiveTriviaSyntax)()
            Me.GetRelatedDirectives(list)
            Return list
        End Function
 
        Private Sub GetRelatedDirectives(list As List(Of DirectiveTriviaSyntax))
            list.Clear()
            Dim p = Me.GetPreviousRelatedDirective()
            While p IsNot Nothing
                list.Add(p)
                p = p.GetPreviousRelatedDirective()
            End While
 
            list.Reverse()
            list.Add(Me)
            Dim n = Me.GetNextRelatedDirective()
            While n IsNot Nothing
                list.Add(n)
                n = n.GetNextRelatedDirective()
            End While
        End Sub
 
        Private Function GetNextRelatedDirective() As DirectiveTriviaSyntax
            Dim d As DirectiveTriviaSyntax = Me
            Select Case d.Kind
                Case SyntaxKind.IfDirectiveTrivia
                    While d IsNot Nothing
                        Select Case d.Kind
                            Case SyntaxKind.ElseIfDirectiveTrivia, SyntaxKind.ElseDirectiveTrivia, SyntaxKind.EndIfDirectiveTrivia
                                Return d
                        End Select
 
                        d = d.GetNextPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.ElseIfDirectiveTrivia
                    While d IsNot Nothing
                        Select Case d.Kind
                            Case SyntaxKind.ElseDirectiveTrivia, SyntaxKind.EndIfDirectiveTrivia
                                Return d
                        End Select
 
                        d = d.GetNextPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.ElseDirectiveTrivia
                    While d IsNot Nothing
                        If d.Kind = SyntaxKind.EndIfDirectiveTrivia Then
                            Return d
                        End If
 
                        d = d.GetNextPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.RegionDirectiveTrivia
                    While d IsNot Nothing
                        If d.Kind = SyntaxKind.EndRegionDirectiveTrivia Then
                            Return d
                        End If
 
                        d = d.GetNextPossiblyRelatedDirective()
                    End While
 
            End Select
 
            Return Nothing
        End Function
 
        Private Function GetNextPossiblyRelatedDirective() As DirectiveTriviaSyntax
            Dim d As DirectiveTriviaSyntax = Me
            While d IsNot Nothing
                d = d.GetNextDirective()
                If d IsNot Nothing Then
                    Select Case d.Kind
                        Case SyntaxKind.IfDirectiveTrivia
                            While d IsNot Nothing AndAlso d.Kind <> SyntaxKind.EndIfDirectiveTrivia
                                d = d.GetNextRelatedDirective()
                            End While
 
                            Continue While
                        Case SyntaxKind.RegionDirectiveTrivia
                            While d IsNot Nothing AndAlso d.Kind <> SyntaxKind.EndRegionDirectiveTrivia
                                d = d.GetNextRelatedDirective()
                            End While
 
                            Continue While
                    End Select
                End If
 
                Return d
            End While
 
            Return Nothing
        End Function
 
        Private Function GetPreviousRelatedDirective() As DirectiveTriviaSyntax
            Dim d As DirectiveTriviaSyntax = Me
            Select Case d.Kind
                Case SyntaxKind.EndIfDirectiveTrivia
                    While d IsNot Nothing
                        Select Case d.Kind
                            Case SyntaxKind.IfDirectiveTrivia, SyntaxKind.ElseIfDirectiveTrivia, SyntaxKind.ElseDirectiveTrivia
                                Return d
                        End Select
 
                        d = d.GetPreviousPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.ElseIfDirectiveTrivia
                    While d IsNot Nothing
                        If d.Kind = SyntaxKind.IfDirectiveTrivia Then
                            Return d
                        End If
 
                        d = d.GetPreviousPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.ElseDirectiveTrivia
                    While d IsNot Nothing
                        Select Case d.Kind
                            Case SyntaxKind.IfDirectiveTrivia, SyntaxKind.ElseIfDirectiveTrivia
                                Return d
                        End Select
 
                        d = d.GetPreviousPossiblyRelatedDirective()
                    End While
 
                Case SyntaxKind.EndRegionDirectiveTrivia
                    While d IsNot Nothing
                        If d.Kind = SyntaxKind.RegionDirectiveTrivia Then
                            Return d
                        End If
 
                        d = d.GetPreviousPossiblyRelatedDirective()
                    End While
 
            End Select
 
            Return Nothing
        End Function
 
        Private Function GetPreviousPossiblyRelatedDirective() As DirectiveTriviaSyntax
            Dim d As DirectiveTriviaSyntax = Me
            While d IsNot Nothing
                d = d.GetPreviousDirective()
                If d IsNot Nothing Then
                    Select Case d.Kind
                        Case SyntaxKind.EndIfDirectiveTrivia
                            While d IsNot Nothing AndAlso d.Kind <> SyntaxKind.IfDirectiveTrivia
                                d = d.GetPreviousRelatedDirective()
                            End While
 
                            Continue While
                        Case SyntaxKind.EndRegionDirectiveTrivia
                            While d IsNot Nothing AndAlso d.Kind <> SyntaxKind.RegionDirectiveTrivia
                                d = d.GetPreviousRelatedDirective()
                            End While
 
                            Continue While
                    End Select
                End If
 
                Return d
            End While
 
            Return Nothing
        End Function
 
    End Class
 
End Namespace