DigitalData.Core/DigitalData.Core.Security/DIExtensions.cs

using DigitalData.Core.Abstractions.Security;
using DigitalData.Core.Security.Config;
using DigitalData.Core.Security.Cryptographer;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using System.Security.Claims;

namespace DigitalData.Core.Security
{
    public static class DIExtensions
    {
        private static (bool Added, object Lock) _mappingProfile = (false, new());
        private static IServiceCollection AddMappingProfile(this IServiceCollection services)
        {
            if (_mappingProfile.Added)
                return services;

            lock (_mappingProfile.Lock)
            {
                if (_mappingProfile.Added)
                    return services;

                _mappingProfile.Added = true;
                return services.AddAutoMapper(typeof(MappingProfile).Assembly);
            }
        }

        private static IServiceCollection AddParamsConfigureOptions<TParams>(this IServiceCollection services) where TParams : RSAFactoryParams
            => services.AddSingleton<IConfigureOptions<TParams>, ParamsConfigureOptions<TParams>>();

        private static IServiceCollection AddAsymCryptService<TAsymCryptParams>(this IServiceCollection services, bool setAsDefault = false) where TAsymCryptParams : AsymCryptParams
        {
            services.AddParamsConfigureOptions<TAsymCryptParams>().AddMappingProfile();
            return setAsDefault
                ? services.AddSingleton<IAsymCryptService, AsymCryptService<TAsymCryptParams>>()
                : services.AddSingleton<IAsymCryptService<TAsymCryptParams>, AsymCryptService<TAsymCryptParams>>();
        }

        /// <summary>
        /// Registers a custom asym crypt service with specified parameters from the given configuration section.
        /// </summary>
        /// <typeparam name="TAsymCryptParams"></typeparam>
        /// <param name="services"></param>
        /// <param name="section"></param>
        /// <param name="setAsDefault">If true, the factory is registered as the default <see cref="IRSAFactory"/>. Otherwise, it is registered as <see cref="IRSAFactory{TRSAFactoryParams}"/>.</param>
        /// <returns></returns>
        public static IServiceCollection AddAsymCryptService<TAsymCryptParams>(this IServiceCollection services, IConfigurationSection section, bool setAsDefault = false) where TAsymCryptParams : AsymCryptParams => services
            .Configure<TAsymCryptParams>(section)
            .AddAsymCryptService<TAsymCryptParams>(setAsDefault: setAsDefault);

        /// <summary>
        /// Registers a custom asym crypt service with default parameters from the given configuration section.
        /// </summary>
        /// <param name="services"></param>
        /// <param name="section"></param>
        /// <param name="setAsDefault"></param>
        /// <returns></returns>
        public static IServiceCollection AddAsymCryptService(this IServiceCollection services, IConfigurationSection section, bool setAsDefault = false)
            => services.Configure<AsymCryptParams>(section).AddAsymCryptService<AsymCryptParams>(setAsDefault: setAsDefault);

        /// <summary>
        /// Registers an asym crypt service with the specified parameters from the given instance. Optionally, sets it as the default factory.
        /// </summary>
        /// <typeparam name="TAsymCryptParams"></typeparam>
        /// <param name="services"></param>
        /// <param name="param"></param>
        /// <param name="setAsDefault">If true, the factory is registered as the default <see cref="IRSAFactory"/>. Otherwise, it is registered as <see cref="IRSAFactory{TRSAFactoryParams}"/>.</param>
        /// <returns></returns>
        public static IServiceCollection AddAsymCryptService<TAsymCryptParams>(this IServiceCollection services, TAsymCryptParams param, bool setAsDefault = false) where TAsymCryptParams : AsymCryptParams => services
            .AddSingleton(Options.Create(param))
            .AddAsymCryptService<TAsymCryptParams>(setAsDefault: setAsDefault);

        /// <summary>
        /// Registers default asym crypt service with the specified parameters from the given instance.
        /// </summary>
        /// <param name="services"></param>
        /// <param name="param"></param>
        /// <returns></returns>
        public static IServiceCollection AddAsymCryptService(this IServiceCollection services, AsymCryptParams param) => services
            .AddAsymCryptService(param: param, setAsDefault: true);

        /// <summary>
        /// Registers default RSA Factory instance with default params
        /// </summary>
        /// <param name="services"></param>
        /// <param name="factoryParams"></param>
        /// <returns>The updated <see cref="IServiceCollection"/> with the RSA Factory registered.</returns>
        public static IServiceCollection AddRSAFactory(this IServiceCollection services, RSAFactoryParams? factoryParams = null) => services
            .AddParamsConfigureOptions<RSAFactoryParams>()
            .AddMappingProfile()
            .AddScoped<IRSAFactory>(_ => new RSAFactory<RSAFactoryParams>(Options.Create(factoryParams ?? new())));

        /// <summary>
        /// Registers a custom RSA Factory with specified parameters from the given configuration section.
        /// </summary>
        /// <typeparam name="TRSAFactoryParams"></typeparam>
        /// <param name="services"></param>
        /// <param name="section"></param>
        /// <param name="setAsDefault">If true, the factory is registered as the default <see cref="IRSAFactory"/>. Otherwise, it is registered as <see cref="IRSAFactory{TRSAFactoryParams}"/>.</param>
        /// <returns>The updated <see cref="IServiceCollection"/> with the RSA Factory registered.</returns>
        public static IServiceCollection AddRSAFactory<TRSAFactoryParams>(this IServiceCollection services, IConfigurationSection section, bool setAsDefault = false)
            where TRSAFactoryParams : RSAFactoryParams
        {
            services.AddMappingProfile().AddParamsConfigureOptions<TRSAFactoryParams>().Configure<TRSAFactoryParams>(section);
            return setAsDefault
                ? services.AddSingleton<IRSAFactory, RSAFactory<TRSAFactoryParams>>()
                : services.AddSingleton<IRSAFactory<TRSAFactoryParams>, RSAFactory<TRSAFactoryParams>>();
        }

        /// <summary>
        /// Registers an RSA Factory with the specified parameters from the given instance. Optionally, sets it as the default factory.
        /// </summary>
        /// <typeparam name="TRSAFactoryParams">The type of the RSA factory parameters.</typeparam>
        /// <param name="services"></param>
        /// <param name="rsaParams"></param>
        /// <param name="setAsDefault">If true, the factory is registered as the default <see cref="IRSAFactory"/>. Otherwise, it is registered as <see cref="IRSAFactory{TRSAFactoryParams}"/>.</param>
        /// <returns>The updated <see cref="IServiceCollection"/> with the RSA Factory registered.</returns>
        public static IServiceCollection AddRSAFactory<TRSAFactoryParams>(this IServiceCollection services, TRSAFactoryParams rsaParams, bool setAsDefault = false)
            where TRSAFactoryParams : RSAFactoryParams
        {
            services.AddMappingProfile().AddSingleton(Options.Create(rsaParams));
            return setAsDefault
                ? services.AddParamsConfigureOptions<TRSAFactoryParams>().AddSingleton<IRSAFactory, RSAFactory<TRSAFactoryParams>>()
                : services.AddParamsConfigureOptions<TRSAFactoryParams>().AddSingleton<IRSAFactory<TRSAFactoryParams>, RSAFactory<TRSAFactoryParams>>();
        }

        private static IServiceCollection AddClaimDescriptor<TPrincipal>(this IServiceCollection services,
            Func<TPrincipal, IDictionary<string, object>>? claimsMapper = null,
            Func<TPrincipal, ClaimsIdentity>? subjectMapper = null)
        {
            var descriptor = new ClaimDescriptor<TPrincipal>
            {
                CreateClaims = claimsMapper,
                CreateSubject = subjectMapper
            };

            return services.AddSingleton(sp => Options.Create(descriptor));
        }
    }
}