// 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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.LanguageServer;
using Microsoft.CodeAnalysis.LanguageServer.Handler;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Text;
using Roslyn.LanguageServer.Protocol;
using Microsoft.VisualStudio.LanguageServices.Xaml.Features.Formatting;
using LSP = Roslyn.LanguageServer.Protocol;
 
namespace Microsoft.VisualStudio.LanguageServices.Xaml.LanguageServer.Handler;
 
internal abstract class AbstractFormatDocumentHandlerBase<RequestType, ResponseType> : ILspServiceRequestHandler<RequestType, ResponseType>
{
    public bool MutatesSolutionState => false;
    public bool RequiresLSPSolution => true;
 
    public abstract TextDocumentIdentifier GetTextDocumentIdentifier(RequestType request);
    public abstract Task<ResponseType> HandleRequestAsync(RequestType request, RequestContext context, CancellationToken cancellationToken);
 
    protected async Task<LSP.TextEdit[]> GetTextEditsAsync(LSP.FormattingOptions formattingOptions, RequestContext context, CancellationToken cancellationToken, LSP.Range? range = null)
    {
        using var _ = ArrayBuilder<LSP.TextEdit>.GetInstance(out var edits);
 
        var document = context.Document;
        var formattingService = document?.Project.Services.GetService<IXamlFormattingService>();
 
        if (document != null && formattingService != null)
        {
            var text = await document.GetValueTextAsync(cancellationToken).ConfigureAwait(false);
            TextSpan? textSpan = null;
            if (range != null)
            {
                textSpan = ProtocolConversions.RangeToTextSpan(range, text);
            }
 
            var options = new XamlFormattingOptions
            {
                InsertSpaces = formattingOptions.InsertSpaces,
                TabSize = formattingOptions.TabSize,
                OtherOptions = formattingOptions.OtherOptions?.AsUntyped()
            };
            var textChanges = await formattingService.GetFormattingChangesAsync(document, options, textSpan, cancellationToken).ConfigureAwait(false);
            edits.AddRange(textChanges.Select(change => ProtocolConversions.TextChangeToTextEdit(change, text)));
        }
 
        return edits.ToArray();
    }
}