using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ScadaLink.Communication.Grpc;
using ScadaLink.Commons.Interfaces.Repositories;
using ScadaLink.SiteRuntime.Persistence;
using ScadaLink.SiteRuntime.Repositories;
using ScadaLink.SiteRuntime.Scripts;
using ScadaLink.SiteRuntime.Streaming;

namespace ScadaLink.SiteRuntime;

public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Registers Site Runtime services including SiteStorageService for SQLite persistence.
    /// The caller must register an <see cref="ISiteStorageConnectionProvider"/> or call the
    /// overload with an explicit connection string.
    /// </summary>
    public static IServiceCollection AddSiteRuntime(this IServiceCollection services)
    {
        // SiteStorageService is registered by the Host using AddSiteRuntime(connectionString)
        // This overload is for backward compatibility / skeleton placeholder
        return services;
    }

    /// <summary>
    /// Registers Site Runtime services with an explicit SQLite connection string.
    /// </summary>
    public static IServiceCollection AddSiteRuntime(this IServiceCollection services, string siteDbConnectionString)
    {
        services.AddSingleton(sp =>
        {
            var logger = sp.GetRequiredService<ILogger<SiteStorageService>>();
            return new SiteStorageService(siteDbConnectionString, logger);
        });

        services.AddHostedService<SiteStorageInitializer>();

        // WP-19: Script compilation service
        services.AddSingleton<ScriptCompilationService>();

        // WP-17: Shared script library
        services.AddSingleton<SharedScriptLibrary>();

        // WP-23: Site stream manager — registered as singleton and exposed as ISiteStreamSubscriber
        // so the gRPC server can subscribe relay actors to instance events.
        // ActorSystem is injected later via Initialize() after AkkaHostedService starts.
        services.AddSingleton(sp =>
        {
            var options = sp.GetRequiredService<IOptions<SiteRuntimeOptions>>().Value;
            var logger = sp.GetRequiredService<ILogger<SiteStreamManager>>();
            return new SiteStreamManager(options, logger);
        });
        services.AddSingleton<ISiteStreamSubscriber>(sp => sp.GetRequiredService<SiteStreamManager>());

        // Site-local repository implementations backed by SQLite
        services.AddScoped<IExternalSystemRepository, SiteExternalSystemRepository>();
        services.AddScoped<INotificationRepository, SiteNotificationRepository>();

        return services;
    }

    public static IServiceCollection AddSiteRuntimeActors(this IServiceCollection services)
    {
        // Actor registration is handled by AkkaHostedService.RegisterSiteActors()
        // which creates the DeploymentManager singleton and proxy
        return services;
    }
}