// <copyright file="ServiceCollectionExtensions.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under the BUSL-1.1.
// </copyright>

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using StellaOps.Evidence.Pack.Resolvers;
using StellaOps.Evidence.Pack.Storage;

namespace StellaOps.Evidence.Pack;

/// <summary>
/// Extension methods for configuring Evidence Pack services.
/// Sprint: SPRINT_20260109_011_005 Task: EVPK-005
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Adds Evidence Pack services with default configuration.
    /// </summary>
    public static IServiceCollection AddEvidencePack(this IServiceCollection services)
    {
        return services.AddEvidencePack(_ => { });
    }

    /// <summary>
    /// Adds Evidence Pack services with custom configuration.
    /// </summary>
    public static IServiceCollection AddEvidencePack(
        this IServiceCollection services,
        Action<EvidencePackOptions> configure)
    {
        var options = new EvidencePackOptions();
        configure(options);

        // Core services
        services.TryAddSingleton(TimeProvider.System);
        services.TryAddScoped<IEvidencePackService, EvidencePackService>();
        services.TryAddScoped<IEvidenceResolver, EvidenceResolver>();

        // Default to in-memory store if not configured
        services.TryAddSingleton<IEvidencePackStore, InMemoryEvidencePackStore>();

        // Add null type resolver if none configured
        services.TryAddEnumerable(ServiceDescriptor.Singleton<ITypeResolver, NullTypeResolver>());

        return services;
    }

    /// <summary>
    /// Adds a custom type resolver for evidence resolution.
    /// </summary>
    public static IServiceCollection AddEvidenceTypeResolver<TResolver>(
        this IServiceCollection services)
        where TResolver : class, ITypeResolver
    {
        services.AddSingleton<ITypeResolver, TResolver>();
        return services;
    }

    /// <summary>
    /// Adds a custom type resolver factory for evidence resolution.
    /// </summary>
    public static IServiceCollection AddEvidenceTypeResolver(
        this IServiceCollection services,
        Func<IServiceProvider, ITypeResolver> factory)
    {
        services.AddSingleton(factory);
        return services;
    }

    /// <summary>
    /// Adds a passthrough type resolver for testing.
    /// </summary>
    public static IServiceCollection AddPassthroughResolver(
        this IServiceCollection services,
        params string[] types)
    {
        services.AddSingleton<ITypeResolver>(sp =>
            new PassthroughTypeResolver(types, sp.GetRequiredService<TimeProvider>()));
        return services;
    }

    /// <summary>
    /// Uses in-memory storage for Evidence Packs.
    /// </summary>
    public static IServiceCollection UseInMemoryEvidencePackStore(
        this IServiceCollection services)
    {
        services.RemoveAll<IEvidencePackStore>();
        services.AddSingleton<IEvidencePackStore, InMemoryEvidencePackStore>();
        return services;
    }
}

/// <summary>
/// Configuration options for Evidence Pack services.
/// </summary>
public sealed class EvidencePackOptions
{
    /// <summary>
    /// Gets or sets whether to auto-create packs from grounding results.
    /// </summary>
    public bool AutoCreateEnabled { get; set; } = true;

    /// <summary>
    /// Gets or sets the minimum grounding score for auto-creation.
    /// </summary>
    public double MinGroundingScore { get; set; } = 0.7;

    /// <summary>
    /// Gets or sets whether to auto-sign created packs.
    /// </summary>
    public bool AutoSign { get; set; }

    /// <summary>
    /// Gets or sets the signing key identifier.
    /// </summary>
    public string? SigningKeyId { get; set; }

    /// <summary>
    /// Gets or sets the retention period for unsigned packs in days.
    /// </summary>
    public int RetentionDays { get; set; } = 365;

    /// <summary>
    /// Gets or sets the retention period for signed packs in days.
    /// </summary>
    public int SignedRetentionDays { get; set; } = 2555; // 7 years
}