using System;
using System.Linq;

namespace Calculator
{
    class Control
    {
        /**
         * If input is not int, then throws error. Else returns it.
         *
         * @return int output
         */
        public int Int()
        {
            int output;
            while (!int.TryParse(Console.ReadLine(), out output))
            {
                Render.Error();
            }
            return output;
        }

        /**
         * If input is not float, then throws error. Else returns it.
         *
         * @return float output
         */
        public float Float()
        {
            float output;
            while (!float.TryParse(Console.ReadLine(), out output))
            {
                Render.Error();
            }
            return output;
        }
    }

    class Render : Program
    {
        /**
         * Writes menu.
         */
        public static void Menu()
        {
            Console.WriteLine("1 - Sčítat");
            Console.WriteLine("2 - Odčítat");
            Console.WriteLine("3 - Násobit");
            Console.WriteLine("4 - Dělit");
            Console.WriteLine("5 - Umocnit");
            Console.WriteLine("6 - Odmocnit");
            Console.WriteLine("7 - Historie výsledků");
            Console.WriteLine("Jiné číslo - Konec");
        }

        /**
         * Writes result and gives it to array.
         *
         * @param float result, float[] results
         */
        public static void Result(float result, float[] results)
        {
            Console.WriteLine("Výsledek se rovná {0}.", result);

            for (int i = 0; i < results.Length; i++)
            {
                // Pokud je prázdný, tak se zaplní
                if (results[i] == 0)
                {
                    results[i] = result;
                    break;
                }
                else if (i == results.Length - 1)
                {
                    Console.WriteLine("dd");
                    results = results.Skip(1).ToArray();
                    for (int b = 0; b < results.Length; b++)
                    {
                        Console.Write("{0}; ", results[b]);
                    }
                    break;
                }
            }
        }

        /**
         * Writes error.
         */
        public static void Error()
        {
            Console.WriteLine("Zadejte správnou hodnotu!");
        }

        /**
         * Writes history of results.
         *
         * @param float[] results
         */
        public static void Results(float[] results)
        {
            Console.WriteLine("\n");
            Console.WriteLine("------------------------------");
            for (int i = 0; i < results.Length; i++)
            {
                Console.Write("{0}; ", results[i]);
            }
            Console.WriteLine("\n------------------------------");
            Console.WriteLine("\n");
        }

        /**
         * Writes last message.
         */
        public static void End()
        {
            Console.WriteLine("Ukončil jste program.");
        }

        /**
         * Renders input for number.
         *
         * @return float firstNumber
         */
        public static float Number()
        {
            Control control = new Control();
            Console.WriteLine("Zadejte číslo:\n");
            float number = control.Float();
            return number;
        }
    }

    class Math : Program
    {
        /**
         * Adds inputs.
         *
         * @param float firstNumber, float secondNumber, float[] results
         */
        public static void AddUp(float firstNumber, float secondNumber, float[] results)
        {
            float output = firstNumber + secondNumber;
            Render.Result(output, results);
        }

        /**
         * Subtracts inputs.
         *
         * @param float firstNumber, float secondNumber, float[] results
         */
        public static void Subtract(float firstNumber, float secondNumber, float[] results)
        {
            float output = firstNumber - secondNumber;
            Render.Result(output, results);
        }

        /**
        * Multiplies inputs.
        *
        * @param float firstNumber, float secondNumber, float[] results
        */
        public static void Multiply(float firstNumber, float secondNumber, float[] results)
        {
            float output = firstNumber * secondNumber;
            Render.Result(output, results);
        }

        /**
        * Divides inputs.
        *
        * @param float firstNumber, float secondNumber, float[] results
        */
        public static void Divide(float firstNumber, float secondNumber, float[] results)
        {
            if (secondNumber == 0)
            {
                Render.Error();
            }
            else
            {
                float output = firstNumber / secondNumber;
                Render.Result(output, results);
            }
        }

        /**
        * Roots inputs.
        *
        * @param float firstNumber, float[] results
        */
        public static void Sqrt(float firstNumber, float[] results)
        {
            float output = (float)System.Math.Sqrt(firstNumber);
            Render.Result(output, results);
        }

        /**
        * Raises input.
        *
        * @param float firstNumber, float[] results
        */
        public static void Power(float firstNumber, float[] results)
        {
            float output = (float)System.Math.Pow(firstNumber, 2);
            Render.Result(output, results);
        }
    }

    class Program
    {
        public float[] Results { get; set; } = new float[10];

        /**
        * Runs program and triggers actions.
        *
        * @param string[] args
        */
        public static void Main(string[] args)
        {
            Control control = new Control();
            bool again = true;

            while (again is true)
            {
                Render.Menu();
                Console.WriteLine("Co chcete udělat?:\n");
                int action = control.Int();

                switch (action)
                {
                    case 1:
                        Math.AddUp(Render.Number(), Render.Number(), Results);
                        break;
                    case 2:
                        Math.Subtract(Render.Number(), Render.Number(), Results);
                        break;
                    case 3:
                        Math.Multiply(Render.Number(), Render.Number(), Results);
                        break;
                    case 4:
                        Math.Divide(Render.Number(), Render.Number(), Results);
                        break;
                    case 5:
                        Math.Power(Render.Number(), Results);
                        break;
                    case  6:
                        Math.Sqrt(Render.Number(), Results);
                        break;
                    case 7:
                        Render.Results(Results);
                        break;
                    default:
                        Render.End();
                        again = false;
                        break;
                }
            }
        }
    }
}