// 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.Composition;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Host.Mef;
 
namespace Microsoft.CodeAnalysis.LanguageServer.HostWorkspace;
 
[ExportWorkspaceServiceFactory(typeof(IMetadataService), ServiceLayer.Host), Shared]
internal sealed class MetadataServiceFactory : IWorkspaceServiceFactory
{
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public MetadataServiceFactory()
    {
    }
 
    public IWorkspaceService CreateService(HostWorkspaceServices workspaceServices)
    {
        return new MetadataService(workspaceServices.GetRequiredService<IDocumentationProviderService>());
    }
 
    internal sealed class MetadataService : IMetadataService
    {
        private readonly MetadataReferenceCache _metadataCache;
 
        public MetadataService(IDocumentationProviderService documentationProviderService)
        {
            _metadataCache = new MetadataReferenceCache((path, properties) =>
                MetadataReference.CreateFromFile(path, properties, documentationProviderService.GetDocumentationProvider(path)));
        }
 
        public PortableExecutableReference GetReference(string resolvedPath, MetadataReferenceProperties properties)
        {
            try
            {
                return (PortableExecutableReference)_metadataCache.GetReference(resolvedPath, properties);
            }
            catch (IOException ex)
            {
                return new ThrowingExecutableReference(resolvedPath, properties, ex);
            }
        }
 
        private class ThrowingExecutableReference : PortableExecutableReference
        {
            private readonly IOException _ex;
 
            public ThrowingExecutableReference(string resolvedPath, MetadataReferenceProperties properties, IOException ex) : base(properties, resolvedPath)
            {
                _ex = ex;
            }
 
            protected override DocumentationProvider CreateDocumentationProvider()
            {
                throw new NotImplementedException();
            }
 
            protected override Metadata GetMetadataImpl()
            {
                throw _ex;
            }
 
            protected override PortableExecutableReference WithPropertiesImpl(MetadataReferenceProperties properties)
            {
                return new ThrowingExecutableReference(FilePath!, properties, _ex);
            }
        }
    }
}