using System;

namespace OkePreparing
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            //Console.Write(typeof(string).Assembly.ImageRuntimeVersion);

            var fibbMethod = GetFibbonaciMethod(FibboObject.Normal);

            var result = fibbMethod.CountFibbonaci(10);

            var recursiveMethod = GetFibbonaciMethod(FibboObject.Recursive);

            var recursiveResult = recursiveMethod.CountFibbonaci(10);

            var tailResusive = GetFibbonaciMethod(FibboObject.TailRecursive);

            var tailRecursiveResult = tailResusive.CountFibbonaci(10);

            Console.WriteLine($"{result} for 10 - normal");
            Console.WriteLine($"{recursiveResult} for 10 - recursive");
            Console.WriteLine($"{tailRecursiveResult} for 10 - tail recursive");

            Console.Read();

        }

        public static IFibbonaciFactory GetFibbonaciMethod(FibboObject obj)
        {
            IFibbonaciFactory fibb = null;

            switch (obj)
            {
                case FibboObject.Normal:
                    fibb = new NormalFibbonaci();
                    break;
                case FibboObject.Recursive:
                    fibb = new RecursiveFibbonaci();
                    break;
                case FibboObject.TailRecursive:
                    fibb = new TailRecursiveFibbonaci();
                    break;
            }

            return fibb;
        }
    }

    public interface IFibbonaciFactory
    {
        int CountFibbonaci(int n);
    }

    public class NormalFibbonaci : IFibbonaciFactory
    {
        public int CountFibbonaci(int n)
        {
            if (n <= 1)
            {
                return 1;
            }
            var fibbArray = new int[n];
            fibbArray[0] = 1;
            fibbArray[1] = 1;


            for (int i = 2; i < n; i++)
            {
                fibbArray[i] = fibbArray[i - 1] + fibbArray[i - 2];
            }

            return fibbArray[n - 1];
        }
    }

    public class RecursiveFibbonaci : IFibbonaciFactory
    {
        public int CountFibbonaci(int n)
        {
            if (n == 0)
            {
                return 0;
            }

            if (n == 1)
            {
                return 1;
            }

            return CountFibbonaci(n - 1) + CountFibbonaci(n - 2);
        }
    }

    public class TailRecursiveFibbonaci : IFibbonaciFactory
    {
        public int CountFibbonaci(int n)
        {
            return CountTailRecursiveFibb(n, 0, 1);
        }

        private int CountTailRecursiveFibb(int n, int e1, int e2)
        {
            if (n == 0)
            {
                return e1;
            }

            if (n == 1)
            {
                return e2;
            }

            return CountTailRecursiveFibb(n - 1, e2, e1 + e2);
        }
    }

    public enum FibboObject
    {
        Normal,
        Recursive,
        TailRecursive
    }

    //public interface INameFactory
    //{
    //    void ShowName()
    //    {
    //        Console.WriteLine("name");
    //    }
    //}
}