// 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.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Internal.Log;
using Roslyn.LanguageServer.Protocol;
 
namespace Microsoft.CodeAnalysis.LanguageServer.Handler;
 
[Method(Methods.InitializeName)]
internal class InitializeHandler : ILspServiceRequestHandler<InitializeParams, InitializeResult>
{
    public InitializeHandler()
    {
    }
 
    public bool MutatesSolutionState => true;
    public bool RequiresLSPSolution => false;
 
    public Task<InitializeResult> HandleRequestAsync(InitializeParams request, RequestContext context, CancellationToken cancellationToken)
    {
        var clientCapabilitiesManager = context.GetRequiredLspService<IInitializeManager>();
        var clientCapabilities = clientCapabilitiesManager.TryGetClientCapabilities();
        if (clientCapabilities != null)
        {
            throw new InvalidOperationException($"{nameof(Methods.InitializeName)} called multiple times");
        }
 
        clientCapabilities = request.Capabilities;
        clientCapabilitiesManager.SetInitializeParams(request);
 
        var capabilitiesProvider = context.GetRequiredLspService<ICapabilitiesProvider>();
        var serverCapabilities = capabilitiesProvider.GetCapabilities(clientCapabilities);
 
        // Record a telemetry event indicating what capabilities are being provided by the server.
        // Useful for figuring out if a particular session is opted into an LSP feature.
        Logger.Log(FunctionId.LSP_Initialize, KeyValueLogMessage.Create(m =>
        {
            m["serverKind"] = context.ServerKind.ToTelemetryString();
            m["capabilities"] = JsonSerializer.Serialize(serverCapabilities, ProtocolConversions.LspJsonSerializerOptions);
        }));
 
        return Task.FromResult(new InitializeResult
        {
            Capabilities = serverCapabilities,
        });
    }
}