// 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.
 
#nullable disable
 
using System;
using System.Composition;
using System.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.DocumentHighlighting;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.ExternalAccess.FSharp.DocumentHighlighting;
 
namespace Microsoft.CodeAnalysis.ExternalAccess.FSharp.Internal.DocumentHighlighting;
 
internal static class FSharpHighlightSpanKindHelpers
{
    public static HighlightSpanKind ConvertTo(FSharpHighlightSpanKind kind)
    {
        switch (kind)
        {
            case FSharpHighlightSpanKind.None:
                {
                    return HighlightSpanKind.None;
                }
 
            case FSharpHighlightSpanKind.Definition:
                {
                    return HighlightSpanKind.Definition;
                }
 
            case FSharpHighlightSpanKind.Reference:
                {
                    return HighlightSpanKind.Reference;
                }
 
            case FSharpHighlightSpanKind.WrittenReference:
                {
                    return HighlightSpanKind.WrittenReference;
                }
 
            default:
                {
                    throw ExceptionUtilities.UnexpectedValue(kind);
                }
        }
    }
}
 
[Shared]
[ExportLanguageService(typeof(IDocumentHighlightsService), LanguageNames.FSharp)]
internal class FSharpDocumentHighlightsService : IDocumentHighlightsService
{
    private readonly IFSharpDocumentHighlightsService _service;
 
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public FSharpDocumentHighlightsService(IFSharpDocumentHighlightsService service)
    {
        _service = service;
    }
 
    private static ImmutableArray<HighlightSpan> MapHighlightSpans(ImmutableArray<FSharpHighlightSpan> highlightSpans)
    {
        return highlightSpans.SelectAsArray(x => new HighlightSpan(x.TextSpan, FSharpHighlightSpanKindHelpers.ConvertTo(x.Kind)));
    }
 
    public async Task<ImmutableArray<DocumentHighlights>> GetDocumentHighlightsAsync(Document document, int position, IImmutableSet<Document> documentsToSearch, HighlightingOptions options, CancellationToken cancellationToken)
    {
        var highlights = await _service.GetDocumentHighlightsAsync(document, position, documentsToSearch, cancellationToken).ConfigureAwait(false);
        return highlights.SelectAsArray(x => new DocumentHighlights(x.Document, MapHighlightSpans(x.HighlightSpans)));
    }
}