// 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.Collections.Immutable;
using System.ComponentModel.Composition;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.LanguageServer;
using Microsoft.CodeAnalysis.LanguageServer.Handler;
using Microsoft.CodeAnalysis.Options;
using Microsoft.CodeAnalysis.Shared.TestHooks;
using Microsoft.VisualStudio.Composition;
using Microsoft.VisualStudio.LanguageServer.Client;
using Microsoft.VisualStudio.LanguageServer.Protocol;
using Microsoft.VisualStudio.Utilities;
 
namespace Microsoft.CodeAnalysis.Editor.Implementation.LanguageClient
{
    // The C# and VB ILanguageClient should not activate on the host. When LiveShare mirrors the C# ILC to the guest,
    // they will not copy the DisableUserExperience attribute, so guests will still use the C# ILC.
    [DisableUserExperience(true)]
    [ContentType(ContentTypeNames.CSharpContentType)]
    [ContentType(ContentTypeNames.VisualBasicContentType)]
    [Export(typeof(ILanguageClient))]
    internal class LiveShareInProcLanguageClient : AbstractInProcLanguageClient
    {
        private readonly ExperimentalCapabilitiesProvider _experimentalCapabilitiesProvider;
 
        [ImportingConstructor]
        [Obsolete(MefConstruction.ImportingConstructorMessage, true)]
        public LiveShareInProcLanguageClient(
            CSharpVisualBasicLspServiceProvider lspServiceProvider,
            IGlobalOptionService globalOptions,
            ExperimentalCapabilitiesProvider experimentalCapabilitiesProvider,
            ILspServiceLoggerFactory lspLoggerFactory,
            IThreadingContext threadingContext,
            ExportProvider exportProvider)
            : base(lspServiceProvider, globalOptions, lspLoggerFactory, threadingContext, exportProvider)
        {
            _experimentalCapabilitiesProvider = experimentalCapabilitiesProvider;
        }
 
        protected override ImmutableArray<string> SupportedLanguages => ProtocolConstants.RoslynLspLanguages;
 
        public override ServerCapabilities GetCapabilities(ClientCapabilities clientCapabilities)
        {
            var isLspEditorEnabled = GlobalOptions.GetOption(LspOptionsStorage.LspEditorFeatureFlag);
 
            // If the preview feature flag to turn on the LSP editor in local scenarios is on, advertise no capabilities for this Live Share
            // LSP server as LSP requests will be serviced by the AlwaysActiveInProcLanguageClient in both local and remote scenarios.
            if (isLspEditorEnabled)
            {
                return new VSServerCapabilities
                {
                    TextDocumentSync = new TextDocumentSyncOptions
                    {
                        OpenClose = false,
                        Change = TextDocumentSyncKind.None,
                    }
                };
            }
 
            var defaultCapabilities = _experimentalCapabilitiesProvider.GetCapabilities(clientCapabilities);
 
            // If the LSP semantic tokens feature flag is enabled, advertise no semantic tokens capabilities for this Live Share
            // LSP server as LSP semantic tokens requests will be serviced by the AlwaysActiveInProcLanguageClient in both local and
            // remote scenarios.
            var isLspSemanticTokenEnabled = GlobalOptions.GetOption(LspOptionsStorage.LspSemanticTokensFeatureFlag);
            if (isLspSemanticTokenEnabled)
            {
                defaultCapabilities.SemanticTokensOptions = null;
            }
 
            // When the lsp pull diagnostics feature flag is enabled we do not advertise pull diagnostics capabilities from here
            // as the AlwaysActivateInProcLanguageClient will provide pull diagnostics both locally and remote.
            var isPullDiagnosticsEnabled = GlobalOptions.IsLspPullDiagnostics();
            if (!isPullDiagnosticsEnabled)
            {
                // Pull diagnostics isn't enabled, let the live share server provide pull diagnostics.
                ((VSInternalServerCapabilities)defaultCapabilities).SupportsDiagnosticRequests = true;
            }
 
            return defaultCapabilities;
        }
 
        /// <summary>
        /// Failures are catastrophic as liveshare guests will not have language features without this server.
        /// </summary>
        public override bool ShowNotificationOnInitializeFailed => true;
 
        public override WellKnownLspServerKinds ServerKind => WellKnownLspServerKinds.LiveShareLspServer;
    }
}