using System;

namespace Lesson2
{
    class Program
    {
        static void Main(string[] args)
        {
            // Названия валют
            const string FirstCurrencyName = "золото";
            const string SecondCurrencyName = "серебро";
            const string ThirdCurrencyName = "медь";

            // Валюта в кармане клиента
            float firstCurrencyAmount;
            float secondCurrencyAmount;
            float thirdCurrencyAmount;

            // Курс валют
            float firstInSecond = 10f;
            float firstInThird = 20f;
            float secondInFirst = 1 / firstInSecond;
            float thirdInFirst = 1 / firstInThird;
            float secondInThird = firstInThird / firstInSecond;
            float thirdInSecond = 1 / secondInThird;

            bool quit = false;
            string nextAction;

            Console.WriteLine("Введите ваше количество денег");
            Console.Write($"{FirstCurrencyName}: ");
            firstCurrencyAmount = Convert.ToSingle(Console.ReadLine());

            Console.Write($"{SecondCurrencyName}: ");
            secondCurrencyAmount = Convert.ToSingle(Console.ReadLine());

            Console.Write($"{ThirdCurrencyName}: ");
            thirdCurrencyAmount = Convert.ToSingle(Console.ReadLine());

            Console.WriteLine();

            do
            {
                Console.Write("Доступные действия: обмен валюты (1), узнать свой баланс (2), выйти из программы (q) ");
                nextAction = Console.ReadLine().ToLower();
                Console.WriteLine();

                Console.Clear();

                if (nextAction == "1")
                {
                    string sourceCurrency;
                    string targetCurrency;
                    float sourceAmount;
                    float pocketAmount;
                    float targetAmount;

                    Console.WriteLine($"Обмен валюты: {FirstCurrencyName}, {SecondCurrencyName}, {ThirdCurrencyName}");

                    Console.Write("Введите название валюты, которую будете обменивать: ");
                    sourceCurrency = Console.ReadLine().ToLower();

                    bool isCurrencyCorrect = sourceCurrency == FirstCurrencyName ||
                                             sourceCurrency == SecondCurrencyName ||
                                             sourceCurrency == ThirdCurrencyName;

                    // Сразу проверяем правильность ввода названия
                    if (isCurrencyCorrect)
                    {
                        Console.Write("Введите сумму валюты, которую будете обменивать: ");
                        sourceAmount = Convert.ToSingle(Console.ReadLine());

                        bool isAmountCorrect = false;

                        switch (sourceCurrency)
                        {
                            case FirstCurrencyName:
                                pocketAmount = firstCurrencyAmount;
                                break;
                            case SecondCurrencyName:
                                pocketAmount = secondCurrencyAmount;
                                break;
                            case ThirdCurrencyName:
                                pocketAmount = thirdCurrencyAmount;
                                break;
                            default:
                                pocketAmount = 0f;
                                break;
                        }

                        isAmountCorrect = sourceAmount <= pocketAmount;

                        if (isAmountCorrect)
                        {
                            Console.Write("Введите название валюты, на которую будете обменивать: ");
                            targetCurrency = Console.ReadLine().ToLower();

                            isCurrencyCorrect = targetCurrency == FirstCurrencyName ||
                                                targetCurrency == SecondCurrencyName ||
                                                targetCurrency == ThirdCurrencyName;

                            if (targetCurrency == sourceCurrency)
                            {
                                Console.WriteLine($"Вы собираетесь обменять {sourceCurrency} на {targetCurrency}. Это бессмысленно.");
                                Console.ReadLine();
                            }
                            else if (isCurrencyCorrect)
                            {
                                float exchangeRate;

                                if ((sourceCurrency == FirstCurrencyName) && (targetCurrency == SecondCurrencyName))
                                {
                                    exchangeRate = firstInSecond;
                                }
                                else if ((sourceCurrency == FirstCurrencyName) && (targetCurrency == ThirdCurrencyName))
                                {
                                    exchangeRate = firstInThird;
                                }
                                else if ((sourceCurrency == SecondCurrencyName) && (targetCurrency == FirstCurrencyName))
                                {
                                    exchangeRate = secondInFirst;
                                }
                                else if ((sourceCurrency == SecondCurrencyName) && (targetCurrency == ThirdCurrencyName))
                                {
                                    exchangeRate = secondInThird;
                                }
                                else if ((sourceCurrency == ThirdCurrencyName) && (targetCurrency == FirstCurrencyName))
                                {
                                    exchangeRate = thirdInFirst;
                                }
                                else if ((sourceCurrency == ThirdCurrencyName) && (targetCurrency == SecondCurrencyName))
                                {
                                    exchangeRate = thirdInSecond;
                                }
                                else
                                {
                                    exchangeRate = 0f;
                                }

                                targetAmount = sourceAmount * exchangeRate;

                                switch (targetCurrency)
                                {
                                    case FirstCurrencyName:
                                        firstCurrencyAmount += targetAmount;
                                        break;
                                    case SecondCurrencyName:
                                        secondCurrencyAmount += targetAmount;
                                        break;
                                    case ThirdCurrencyName:
                                        thirdCurrencyAmount += targetAmount;
                                        break;
                                }
                                switch (sourceCurrency)
                                {
                                    case FirstCurrencyName:
                                        firstCurrencyAmount -= sourceAmount;
                                        break;
                                    case SecondCurrencyName:
                                        secondCurrencyAmount -= sourceAmount;
                                        break;
                                    case ThirdCurrencyName:
                                        thirdCurrencyAmount -= sourceAmount;
                                        break;
                                }

                                Console.WriteLine($"Вы поменяли {sourceCurrency} в количестве {sourceAmount}" +
                                                  $" на {targetCurrency} в количестве {targetAmount}");
                                Console.ReadLine();
                            }
                            else
                            {
                                Console.WriteLine("Введено неверное название валюты, на которую хотите обменять.");
                                Console.ReadLine();
                            }
                        }
                        else
                        {
                            Console.WriteLine($"У вас недостаточно валюты {sourceCurrency}.");
                            Console.ReadLine();
                        }
                    }
                    else
                    {
                        Console.WriteLine("Введено неверное название валюты, которую хотите обменять.");
                        Console.ReadLine();
                    }
                }
                else if (nextAction == "2")
                {
                    Console.WriteLine($"Ваш баланс:\nВалюта\t\tСумма");
                    Console.WriteLine($"{FirstCurrencyName}\t\t{firstCurrencyAmount:f2}\n" +
                                      $"{SecondCurrencyName}\t\t{secondCurrencyAmount:f2}\n" +
                                      $"{ThirdCurrencyName}\t\t{thirdCurrencyAmount:f2}");
                    Console.WriteLine();
                }
                else if (nextAction == "q")
                {
                    quit = true;
                }
                else
                {
                    Console.WriteLine("Введена неверная команда, повторите ввод.");
                    Console.WriteLine();
                }
            } while (!quit);
        }
    }
}