using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Options;
using StellaOps.Policy.Determinization.Scoring;

namespace StellaOps.Policy.Determinization;

/// <summary>
/// Service registration for Determinization subsystem.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Registers determinization services with default options.
    /// </summary>
    /// <param name="services">Service collection</param>
    /// <returns>Service collection for chaining</returns>
    public static IServiceCollection AddDeterminization(this IServiceCollection services)
    {
        return services.AddDeterminization(_ => { });
    }

    /// <summary>
    /// Registers determinization services with the DI container.
    /// </summary>
    /// <param name="services">Service collection</param>
    /// <param name="configuration">Configuration root (for options binding)</param>
    /// <returns>Service collection for chaining</returns>
    public static IServiceCollection AddDeterminization(
        this IServiceCollection services,
        IConfiguration configuration)
    {
        // Register options
        services.AddOptions<DeterminizationOptions>()
            .Bind(configuration.GetSection(DeterminizationOptions.SectionName))
            .ValidateOnStart();

        // Register scoring calculators (both interface and concrete for flexibility)
        services.TryAddSingleton<UncertaintyScoreCalculator>();
        services.TryAddSingleton<IUncertaintyScoreCalculator>(sp => sp.GetRequiredService<UncertaintyScoreCalculator>());

        services.TryAddSingleton<DecayedConfidenceCalculator>();
        services.TryAddSingleton<IDecayedConfidenceCalculator>(sp => sp.GetRequiredService<DecayedConfidenceCalculator>());

        services.TryAddSingleton<TrustScoreAggregator>();

        return services;
    }

    /// <summary>
    /// Registers determinization services with custom options.
    /// </summary>
    public static IServiceCollection AddDeterminization(
        this IServiceCollection services,
        Action<DeterminizationOptions> configureOptions)
    {
        services.AddOptions<DeterminizationOptions>()
            .Configure(configureOptions)
            .ValidateOnStart();

        // Register scoring calculators (both interface and concrete for flexibility)
        services.TryAddSingleton<UncertaintyScoreCalculator>();
        services.TryAddSingleton<IUncertaintyScoreCalculator>(sp => sp.GetRequiredService<UncertaintyScoreCalculator>());

        services.TryAddSingleton<DecayedConfidenceCalculator>();
        services.TryAddSingleton<IDecayedConfidenceCalculator>(sp => sp.GetRequiredService<DecayedConfidenceCalculator>());

        services.TryAddSingleton<TrustScoreAggregator>();

        return services;
    }
}