' 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
Imports Microsoft.CodeAnalysis.Diagnostics
Imports Microsoft.CodeAnalysis.Formatting
Imports Microsoft.CodeAnalysis.Text
 
Namespace Microsoft.CodeAnalysis.VisualBasic.Formatting
    Partial Friend Class TriviaDataFactory
        ''' <summary>   
        ''' represents a general trivia between two tokens. slightly more expensive than others since it
        ''' needs to calculate stuff unlike other cases
        ''' </summary>
        Private Class ComplexTrivia
            Inherits AbstractComplexTrivia
 
            Public Sub New(options As LineFormattingOptions, treeInfo As TreeData, token1 As SyntaxToken, token2 As SyntaxToken)
                MyBase.New(options, treeInfo, token1, token2)
                Contract.ThrowIfNull(treeInfo)
            End Sub
 
            Protected Overrides Sub ExtractLineAndSpace(text As String, ByRef lines As Integer, ByRef spaces As Integer)
                text.ProcessTextBetweenTokens(Me.TreeInfo, Me.Token1, Me.Options.TabSize, lines, spaces)
            End Sub
 
            Protected Overrides Function CreateComplexTrivia(line As Integer, space As Integer) As TriviaData
                Return New ModifiedComplexTrivia(Me.Options, Me, line, space)
            End Function
 
            Protected Overrides Function CreateComplexTrivia(line As Integer, space As Integer, indentation As Integer) As TriviaData
                ' We cannot always choose indentation over space because sometimes the complex trivia may contain some text, which
                ' are part of the leadingTrivia of the following token, in the same line as the following token.
                ' Case :
                ' _
                ' : Imports
                ' In the above case, the indentation of the Imports token will be '0' but since it contains the colontrivia we cannot take the
                ' new indentation.
 
                ' if given indentation is negative, and actual formatting shows that we can touch the last line (space == 0)
                ' then, keep the negative indentation.
                Return New ModifiedComplexTrivia(Me.Options, Me, line, If(space = 0 AndAlso indentation < 0, indentation, space))
            End Function
 
            Protected Overrides Function Format(context As FormattingContext,
                                                formattingRules As ChainedFormattingRules,
                                                lines As Integer,
                                                spaces As Integer,
                                                cancellationToken As CancellationToken) As TriviaDataWithList
                Return New FormattedComplexTrivia(context, formattingRules, Me.Token1, Me.Token2, lines, spaces, Me.OriginalString, cancellationToken)
            End Function
 
            Protected Overrides Function ContainsSkippedTokensOrText(list As TriviaList) As Boolean
                Return CodeShapeAnalyzer.ContainsSkippedTokensOrText(list)
            End Function
 
            Private Function ShouldFormat(context As FormattingContext) As Boolean
                Dim commonToken1 As SyntaxToken = Me.Token1
                Dim commonToken2 As SyntaxToken = Me.Token2
 
                Dim list As TriviaList = New TriviaList(commonToken1.TrailingTrivia, commonToken2.LeadingTrivia)
                Contract.ThrowIfFalse(list.Count > 0)
 
                ' okay, now, check whether we need or are able to format noisy tokens
                If ContainsSkippedTokensOrText(list) Then
                    Return False
                End If
 
                Dim beginningOfNewLine = Me.Token1.Kind = SyntaxKind.None
 
                If Not Me.SecondTokenIsFirstTokenOnLine AndAlso Not beginningOfNewLine Then
                    Return CodeShapeAnalyzer.ShouldFormatSingleLine(list)
                End If
 
                Debug.Assert(Me.SecondTokenIsFirstTokenOnLine OrElse beginningOfNewLine)
 
                If Me.Options.UseTabs Then
                    Return True
                End If
 
                Return CodeShapeAnalyzer.ShouldFormatMultiLine(context, beginningOfNewLine, list)
            End Function
 
            Public Overrides Sub Format(context As FormattingContext,
                                        formattingRules As ChainedFormattingRules,
                                        formattingResultApplier As Action(Of Integer, TokenStream, TriviaData),
                                        cancellationToken As CancellationToken,
                                        Optional tokenPairIndex As Integer = TokenPairIndexNotNeeded)
                If Not ShouldFormat(context) Then
                    Return
                End If
 
                formattingResultApplier(tokenPairIndex, context.TokenStream, Format(context, formattingRules, Me.LineBreaks, Me.Spaces, cancellationToken))
            End Sub
 
            Public Overrides Function GetTextChanges(span As TextSpan) As IEnumerable(Of TextChange)
                Throw New NotImplementedException()
            End Function
 
            Public Overrides Function GetTriviaList(cancellationToken As CancellationToken) As SyntaxTriviaList
                Throw New NotImplementedException()
            End Function
        End Class
    End Class
End Namespace