public class RuleValidator : IRuleValidator
    {
        private readonly Dictionary<Type, object> _map = new Dictionary<Type, object>();

        public IRuleValidator Register<T>(IValidationRule<T> rule)
        {
            if (!_map.ContainsKey(typeof(T)))
            {
                _map.Add(typeof(T), rule);
            }

            return this;
        }

        public IRuleValidator Validate<T>(T input) where T : IValidationRuleInput
        {
            if (!_map.ContainsKey(input.GetType()))
                throw new InvalidOperationException($"No rule defined for input type {input.GetType()}");

            var rule = (IValidationRule<T>)_map[input.GetType()];
            rule.Validate(input);

            return this;
        }
    }