// 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.
 
using System;
using System.Composition;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.MetadataAsSource;
using Microsoft.CodeAnalysis.PdbSourceDocument;
using Microsoft.CodeAnalysis.Structure;
 
namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.PdbSourceDocument;
 
/// <summary>
/// IMetadataAsSourceFileService has to always return a result, but for our testing
/// we remove the decompilation provider that would normally ensure that. This provider
/// takes it place to ensure we always return a known null result, so we can also verify
/// against it in tests.
/// </summary>
[ExportMetadataAsSourceFileProvider("Dummy"), Shared]
[ExtensionOrder(After = PdbSourceDocumentMetadataAsSourceFileProvider.ProviderName)]
internal class NullResultMetadataAsSourceFileProvider : IMetadataAsSourceFileProvider
{
    // Represents a null result
    public static MetadataAsSourceFile NullResult = new("", null, null, null);
 
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public NullResultMetadataAsSourceFileProvider()
    {
    }
 
    public void CleanupGeneratedFiles(MetadataAsSourceWorkspace workspace)
    {
    }
 
    public Task<MetadataAsSourceFile?> GetGeneratedFileAsync(MetadataAsSourceWorkspace metadataWorkspace, Workspace sourceWorkspace, Project sourceProject, ISymbol symbol, bool signaturesOnly, MetadataAsSourceOptions options, string tempPath, TelemetryMessage? telemetry, CancellationToken cancellationToken)
    {
        return Task.FromResult<MetadataAsSourceFile?>(NullResult);
    }
 
    public Project? MapDocument(Document document)
    {
        return null;
    }
 
    public bool TryAddDocumentToWorkspace(MetadataAsSourceWorkspace workspace, string filePath, Text.SourceTextContainer sourceTextContainer, [NotNullWhen(true)] out DocumentId? documentId)
    {
        documentId = null!;
        return true;
    }
 
    public bool TryRemoveDocumentFromWorkspace(MetadataAsSourceWorkspace workspace, string filePath)
    {
        return true;
    }
 
    public bool ShouldCollapseOnOpen(MetadataAsSourceWorkspace workspace, string filePath, BlockStructureOptions options)
    {
        return true;
    }
}