using Microsoft.Extensions.DependencyInjection;

namespace ScadaLink.SiteEventLogging;

public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Register site event logging services (recording, purge, query).
    /// </summary>
    public static IServiceCollection AddSiteEventLogging(this IServiceCollection services)
    {
        // The recorder is registered as a concrete singleton and the interface is
        // forwarded to the same instance. The purge and query services depend on the
        // concrete SiteEventLogger directly (they need its lock-guarded WithConnection)
        // rather than downcasting an ISiteEventLogger, which would throw
        // InvalidCastException for any other ISiteEventLogger implementation.
        services.AddSingleton<SiteEventLogger>();
        services.AddSingleton<ISiteEventLogger>(sp => sp.GetRequiredService<SiteEventLogger>());
        services.AddSingleton<IEventLogQueryService, EventLogQueryService>();
        services.AddHostedService<EventLogPurgeService>();
        return services;
    }

    // NOTE: EventLogHandlerActor is wired up directly in
    // ScadaLink.Host/Actors/AkkaHostedService.cs as a cluster singleton, because the
    // actor must be created inside the ActorSystem with the resolved
    // IEventLogQueryService. There is intentionally no DI helper for that here — a
    // former AddSiteEventLoggingActors placeholder was dead code and has been removed.
}