' 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.Collections.Immutable
Imports System.Threading
Imports Microsoft.CodeAnalysis.Completion.Providers
Imports Microsoft.CodeAnalysis.VisualBasic.Extensions.ContextQuery
Imports Microsoft.CodeAnalysis.VisualBasic.Utilities

Namespace Microsoft.CodeAnalysis.VisualBasic.Completion.KeywordRecommenders.Declarations
    ''' <summary>
    ''' Recommends the "Custom Event" keyword in type declaration contexts
    ''' </summary>
    Friend Class CustomEventKeywordRecommender
        Inherits AbstractKeywordRecommender

        Private Shared ReadOnly s_keywords As ImmutableArray(Of RecommendedKeyword) =
            ImmutableArray.Create(New RecommendedKeyword("Custom Event", VBFeaturesResources.Specifies_that_an_event_has_additional_specialized_code_for_adding_handlers_removing_handlers_and_raising_events))

        Protected Overrides Function RecommendKeywords(context As VisualBasicSyntaxContext, CancellationToken As CancellationToken) As ImmutableArray(Of RecommendedKeyword)
            ' Custom Event cannot appear in interfaces
            If context.IsTypeMemberDeclarationKeywordContext Then
                Dim modifiers = context.ModifierCollectionFacts
                If modifiers.CouldApplyToOneOf(PossibleDeclarationTypes.Event) AndAlso
                   modifiers.CustomKeyword.Kind = SyntaxKind.None Then
                    Return s_keywords
                End If
            End If

            Return ImmutableArray(Of RecommendedKeyword).Empty
        End Function
    End Class
End Namespace