using System;
using System.Collections.Generic;

namespace StaticDependencyRegistration
{
    public static class Program
    {
        public static void Main()
        {
            var rand = Register.PerCaller(() => new Random(Guid.NewGuid().GetHashCode()));

            var intBasedRegistrations =
                rand.AndPerCaller(_ => _.Get<Random>().Next())
                    .AndPerCaller(_ => new List<int> { _.Get<int>() })
                    .AndPerCaller(_ => _.Get<List<int>>().ToArray());

            var doubleBasedRegistrations =
                rand.AndPerCaller(_ => _.Get<Random>().NextDouble())
                    .AndSingle(_ => new List<double> { _.Get<double>() })
                    .AndSingle(_ => _.Get<List<double>>().ToArray());

            var registrations = intBasedRegistrations.Combine(doubleBasedRegistrations);

            // ints create a new array each time:
            Console.WriteLine(string.Join(", ", registrations.Get<int[]>()));
            Console.WriteLine(string.Join(", ", registrations.Get<int[]>()));

            // doubles create only one array (used "Single" registration):
            Console.WriteLine(string.Join(", ", registrations.Get<double[]>()));
            Console.WriteLine(string.Join(", ", registrations.Get<double[]>()));
        }
    }

    public static class Register
    {
        public static InstanceRegistration<T> Instance<T>(T it) => new InstanceRegistration<T>(it);

        public static Registration<T> PerCaller<T>(Func<T> f) => new Registration<T>(f);

        public static Registration<T> SingleInstance<T>(Func<T> f)
        {
            var lazy = new Lazy<T>(f);
            return new Registration<T>(() => lazy.Value);
        }
    }

    public static class Extensions
    {
        public static InstanceRegistration<TLeft, TRight> AndInstance<TLeft, TRight>(this TLeft left, TRight right)
            => new InstanceRegistration<TLeft, TRight>(left, right);

        public static Registration<TLeft, TRight> AndSingle<TLeft, TRight>(this TLeft left, Func<TLeft, TRight> right)
        {
            var lazy = new Lazy<TRight>(() => right(left));
            return new Registration<TLeft, TRight>(left, () => lazy.Value);
        }

        public static Registration<TLeft, TRight> AndPerCaller<TLeft, TRight>(this TLeft left, Func<TLeft, TRight> right)
            => new Registration<TLeft, TRight>(left, () => right(left));

        public static InstanceRegistration<TLeft, TRight> Combine<TLeft, TRight>(this TLeft left, TRight right) => left.AndInstance(right);

        public static T Get<T>(this IGet<T> it) => it.Get;
        public static T Get<T>(this IGet<IGet<T>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<T>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<T>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<T>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>>>>>> it) => it.Get.Get();
        public static T Get<T>(this IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<IGet<T>>>>>>>>>>>>>>>>> it) => it.Get.Get();
    }

    public interface IGet<out T>
    {
        T Get { get; }
    }

    public class Registration<T> : IGet<T>
    {
        private readonly Func<T> _factory;

        public Registration(Func<T> factory)
        {
            _factory = factory;
        }

        T IGet<T>.Get => _factory();
    }

    public class InstanceRegistration<T> : IGet<T>
    {
        private readonly T _instance;

        public InstanceRegistration(T instance)
        {
            _instance = instance;
        }

        T IGet<T>.Get => _instance;
    }

    public class InstanceRegistration<TLeft, TRight> : InstanceRegistration<TLeft>, IGet<TRight>
    {
        private readonly TRight _right;

        public InstanceRegistration(TLeft left, TRight right) : base(left)
        {
            _right = right;
        }

        TRight IGet<TRight>.Get => _right;
    }

    public class Registration<TLeft, TRight> : InstanceRegistration<TLeft>, IGet<TRight>
    {
        private readonly Func<TRight> _right;

        public Registration(TLeft left, Func<TRight> right) : base(left)
        {
            _right = right;
        }

        TRight IGet<TRight>.Get => _right();
    }
}