laatzen/LaaProductionWeb/LaaProductionWeb.Services/ServicesExtensions.cs

namespace LaaProductionWeb.Services
{
    using LaaProductionWeb.Services.Interfaces;

    using Microsoft.Extensions.DependencyInjection;
    
    using System.Linq;

    public static class ServicesExtensions
    {
        public static IServiceCollection AddTransientServices(this IServiceCollection services)
        {
            var transient = typeof(ITransient);
            var assemblyServices = transient
                .Assembly
                .GetTypes()
                .Where(x => !x.IsAbstract 
                         && transient.IsAssignableFrom(x));

            foreach (var service in assemblyServices)
            {
                var interfaces = service
                    .GetInterfaces()
                    .Where(x => x != transient);

                if (!interfaces.Any())
                {
                    services.AddTransient(service);

                    continue;
                }

                foreach (var @interface in interfaces)
                {
                    services.AddTransient(@interface, service);
                }
            }

            return services;
        }

        public static IServiceCollection AddHttpClient(this IServiceCollection services, string baseAddress) 
            => services.AddSingleton<IHttpService>(_ => new HttpService(baseAddress));

        public static IServiceCollection AddSingletonServices(this IServiceCollection services)
        {
            var transient = typeof(ISingleton);
            var assemblyServices = transient
                .Assembly
                .GetTypes()
                .Where(x => !x.IsAbstract
                         && transient.IsAssignableFrom(x));

            foreach (var service in assemblyServices)
            {
                var interfaces = service
                    .GetInterfaces()
                    .Where(x => x != transient);

                if (!interfaces.Any())
                {
                    services.AddTransient(service);

                    continue;
                }

                foreach (var @interface in interfaces)
                {
                    services.AddTransient(@interface, service);
                }
            }

            return services;
        }
    }
}