// 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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host.Mef;
using Roslyn.LanguageServer.Protocol;
 
namespace Microsoft.CodeAnalysis.LanguageServer.Handler.TextDocumentContent;
 
[ExportCSharpVisualBasicStatelessLspService(typeof(TextDocumentContentHandler)), Shared]
[Method(Methods.WorkspaceTextDocumentContentName)]
[method: ImportingConstructor]
[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
internal sealed class TextDocumentContentHandler() : ILspServiceDocumentRequestHandler<TextDocumentContentParams, TextDocumentContentResult>
{
    public bool MutatesSolutionState => false;
 
    public bool RequiresLSPSolution => true;
 
    public TextDocumentIdentifier GetTextDocumentIdentifier(TextDocumentContentParams request) => new() { DocumentUri = request.Uri };
 
    public async Task<TextDocumentContentResult> HandleRequestAsync(TextDocumentContentParams request, RequestContext context, CancellationToken cancellationToken)
    {
        Contract.ThrowIfNull(context.TextDocument, $"{request.Uri} was not found in any workspace, cannot provide content");
 
        var scheme = request.Uri.ParsedUri?.Scheme;
        if (scheme is not null)
        {
            var provider = context.GetRequiredServices<ITextDocumentContentProvider>().Single(p => p.Scheme == scheme);
 
            var contentText = await provider.GetTextAsync(context.TextDocument, cancellationToken).ConfigureAwait(false);
            return new TextDocumentContentResult { Text = contentText };
        }
 
        var text = await context.TextDocument.GetTextAsync(cancellationToken).ConfigureAwait(false);
        return new TextDocumentContentResult
        {
            Text = text.ToString()
        };
    }
}