ServiceCollectionExtensions.cs

using System.Diagnostics;
using MediatR;
using Microsoft.Extensions.DependencyInjection;
using OmniSharp.Extensions.LanguageServer.Protocol.Models;
using Reqnroll.IdeSupport.Common;
using Reqnroll.IdeSupport.Common.Configuration;
using Reqnroll.IdeSupport.Common.Diagnostics;
using Reqnroll.IdeSupport.Common.ProjectSystem.Configuration;
using Reqnroll.IdeSupport.LSP.Core.Diagnostics;
using Reqnroll.IdeSupport.LSP.Core.Completions;
using Reqnroll.IdeSupport.LSP.Core.Completions.Matching;
using Reqnroll.IdeSupport.LSP.Core.Scaffolding;
using Reqnroll.IdeSupport.LSP.Core.DocumentOutline;
using Reqnroll.IdeSupport.LSP.Core.Folding;
using Reqnroll.IdeSupport.LSP.Core.Commenting;
using Reqnroll.IdeSupport.LSP.Core.InlayHints;
using Reqnroll.IdeSupport.LSP.Core.Gherkin.Parsing;


using Reqnroll.IdeSupport.LSP.Core.Matching;
using Reqnroll.IdeSupport.LSP.Core.Rename;
using Reqnroll.IdeSupport.LSP.Server.Configuration;
using Reqnroll.IdeSupport.LSP.Server.Diagnostics.Performance;
using Reqnroll.IdeSupport.LSP.Server.Logging;
using Reqnroll.IdeSupport.LSP.Server.Discovery;
using Reqnroll.IdeSupport.LSP.Server.Pipeline;
using Reqnroll.IdeSupport.LSP.Server.Features.CodeActions;
using Reqnroll.IdeSupport.LSP.Server.Features.Commenting;
using Reqnroll.IdeSupport.LSP.Server.Features.DocumentOutline;
using Reqnroll.IdeSupport.LSP.Server.Features.Folding;
using Reqnroll.IdeSupport.LSP.Server.Features.Formatting;
using Reqnroll.IdeSupport.LSP.Server.Features.TextSync;
using Reqnroll.IdeSupport.LSP.Server.Features.CodeLens;
using Reqnroll.IdeSupport.LSP.Server.Features.FindUnusedStepDefs;
using Reqnroll.IdeSupport.LSP.Server.Features.References;
using Reqnroll.IdeSupport.LSP.Server.Features.Rename;
using Reqnroll.IdeSupport.LSP.Server.Features.Completions;
using Reqnroll.IdeSupport.LSP.Server.Features.Definition;
using Reqnroll.IdeSupport.LSP.Server.Features.InlayHints;
using Reqnroll.IdeSupport.LSP.Server.Features.SemanticTokens;
using Reqnroll.IdeSupport.LSP.Server.Telemetry;
using Reqnroll.IdeSupport.LSP.Server.Tagging;
using Reqnroll.IdeSupport.LSP.Server.Tracing;
using Reqnroll.IdeSupport.LSP.Server.Workspace;

namespace Reqnroll.IdeSupport.LSP.Server.Hosting;

/// <summary>
/// Extension methods for configuring the Dependency Injection container for the Reqnroll LSP Server.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Registers core infrastructure and cross-cutting services.
    /// </summary>
    public static IServiceCollection AddReqnrollLspCoreServices(this IServiceCollection services, string? clientIde,
        TraceLevel logLevel = TraceLevel.Warning, InitializeTrace initialTrace = InitializeTrace.Off)
    {
        return services
            .AddSingleton(new ClientIdeContext(clientIde, logLevel))
            .AddSingleton<IDeveroomLogger, LspDeveroomLogger>()
            .AddSingleton<IIdeScope, LspIdeScope>()
            .AddSingleton<IMonitoringService>(sp => NullMonitoringService.Instance)
            // Telemetry: emit telemetry/event notifications, optionally mirrored to a local JSONL
            // debug log (REQNROLL_TELEMETRY_DEBUG_LOG). The decorator wraps the real emitter; when
            // the debug log is unconfigured the sink is a no-op and it simply forwards.
            .AddSingleton<ITelemetryDebugLog>(_ => TelemetryDebugLog.FromEnvironment())
            .AddSingleton<LspTelemetryService>()
            .AddSingleton<ILspTelemetryService>(sp => new FileLoggingLspTelemetryService(
                sp.GetRequiredService<LspTelemetryService>(),
                sp.GetRequiredService<ITelemetryDebugLog>()))
            .AddSingleton<IDeveroomConfigurationProvider, ProjectSystemDeveroomConfigurationProvider>()
            .AddSingleton<IEditorConfigOptionsProvider>(sp =>
                new FileSystemEditorConfigOptionsProvider(sp.GetRequiredService<IIdeScope>().FileSystem))
            // Performance Verification, Layer 4: field instrumentation. The recorder writes
            // PERF lines to the log and (when REQNROLL_PERF_TELEMETRY_SAMPLE is set) emits sampled
            // PerfSample telemetry. Singleton so the sampler's RNG is shared across handlers.
            .AddSingleton<IPerfTelemetrySampler>(_ => PerfTelemetrySampler.FromEnvironment())
            // F41: tracks the LSP `trace` level (--trace / InitializeParams.Trace / $/setTrace) and
            // issues $/logTrace notifications. Singleton so the level set by $/setTrace is visible
            // to every consumer (currently OperationDurationRecorder's PERF lines).
            .AddSingleton<ITraceService>(sp => new TraceService(
                sp.GetRequiredService<OmniSharp.Extensions.LanguageServer.Protocol.Server.ILanguageServerFacade>(),
                initialTrace))
            .AddSingleton<IOperationDurationRecorder>(sp => new OperationDurationRecorder(
                sp.GetRequiredService<IDeveroomLogger>(),
                sp.GetRequiredService<ClientIdeContext>(),
                sp.GetRequiredService<ILspTelemetryService>(),
                sp.GetRequiredService<IPerfTelemetrySampler>(),
                sp.GetRequiredService<ITraceService>()));
    }

    /// <summary>
    /// Registers project system, workspace, and binding discovery services.
    /// </summary>
    public static IServiceCollection AddReqnrollProjectSystem(this IServiceCollection services)
    {
        return services
            .AddSingleton<ILspWorkspaceScopeManager, LspWorkspaceScopeManager>()
            // BindingRegistryProviderRouter creates and owns one ConnectorBindingRegistryProvider
            // per project and routes binding-registry lookups to the correct per-project instance
            // via IProjectBindingRegistryLookup.GetRegistryForUri. Registries are NOT merged —
            // each feature file is resolved against only its own project's bindings.
            .AddSingleton<BindingRegistryProviderRouter>()
            .AddSingleton<IProjectBindingRegistryLookup>(sp => sp.GetRequiredService<BindingRegistryProviderRouter>())
            // Roslyn (source-level) binding discovery for .cs edits (design doc F2).
            .AddSingleton<ICSharpBindingDiscoveryService, CSharpBindingDiscoveryService>()
            .AddSingleton<IDeveroomTagParser, DeveroomTagParser>()
            // Debounces the closed-feature-file rescan triggered by an incremental Roslyn patch
            // whose binding expressions actually changed (BindingRegistryChangedHandler).
            .AddSingleton<IFeatureRescanDebouncer, FeatureRescanDebouncer>();
    }

    /// <summary>
    /// Registers editor services, parsing, and shared caching components.
    /// </summary>
    public static IServiceCollection AddReqnrollEditorServices(this IServiceCollection services)
    {
        return services
            .AddSingleton<IDocumentBufferService, DocumentBufferService>()
            // BindingMatchService holds the per-document match cache; it must be a singleton
            // so the cache survives across requests and is shared by the tagger (writer) and
            // the Go to Definition / diagnostics consumers (readers).
            .AddSingleton<IBindingMatchService, BindingMatchService>()
            .AddSingleton<IGherkinDocumentTaggerService, GherkinDocumentTaggerService>()
            .AddSingleton<ISemanticTokenService, SemanticTokenService>()
            .AddSingleton<IDiagnosticsAggregator, DiagnosticsAggregator>()
            .AddSingleton<IGherkinFoldingRangeService, GherkinFoldingRangeService>()
            .AddSingleton<ICommentToggleService, CommentToggleService>()
            .AddSingleton<IGherkinInlayHintService, GherkinInlayHintService>();
    }

    /// <summary>
    /// Registers OmniSharp LSP protocol handlers as singletons.
    /// 
    /// NOTE: MediatR notification handlers (e.g., SemanticTokensRefreshHandler, DiagnosticsPublishHandler) 
    /// are auto-discovered and registered as transients by the AddMediatR call in ConfigureServer. 
    /// DO NOT add explicit AddSingleton&lt;INotificationHandler&lt;T&gt;&gt; registrations here, as it will 
    /// cause MediatR to dispatch every notification to two handler instances (the transient from the 
    /// scan and the singleton from the explicit call). 
    /// 
    /// The handlers listed below ARE registered explicitly as singletons because OmniSharp resolves 
    /// them from the root DryIoc container (not from a per-request scope), and they hold injected 
    /// ILanguageServer references that must live for the server's lifetime.
    /// </summary>
    public static IServiceCollection AddReqnrollLspHandlers(this IServiceCollection services)
    {
        return services
            .AddSingleton<TextDocumentSyncHandler>()
            .AddSingleton<WorkspaceFoldersHandler>()
            .AddSingleton<WatchedFilesHandler>()
            .AddSingleton<SemanticTokensHandler>()
            .AddSingleton<StepReferencesHandler>()
            .AddSingleton<FindStepUsagesHandler>()
            .AddSingleton<ICompletionContextResolver, CompletionContextResolver>()
            .AddSingleton<ICompletionService, CompletionService>()
            .AddSingleton<ICompletionMatcher, ReturnAllCompletionMatcher>()
            .AddSingleton<FeatureDefinitionHandler>()
            .AddSingleton<GoToStepDefinitionsHandler>()
            .AddSingleton<GoToHooksHandler>()
            .AddSingleton<StepCodeLensHandler>()
            .AddSingleton<GherkinCompletionHandler>()
            .AddSingleton<IStepScaffoldService, StepScaffoldService>()
            .AddSingleton<FeatureCodeActionHandler>()
            .AddSingleton<FindUnusedStepDefinitionsHandler>()
            .AddSingleton<GherkinFormattingHandler>()
            .AddSingleton<IGherkinDocumentSymbolService, GherkinDocumentSymbolService>()
            .AddSingleton<FeatureDocumentSymbolHandler>()
            .AddSingleton<FeatureFoldingRangeHandler>()
            .AddSingleton<CommentToggleHandler>()
            .AddSingleton<StepRenameHandler>()
            .AddSingleton<RenameSessionManager>()
            .AddSingleton<FeatureInlayHintHandler>()
            .AddSingleton<SetTraceNotificationHandler>();
    }
}