using System;

using System.Collections.Generic;

using System.Text;

​

public class Program

{ 

    /*

    Complete the function below which takes a dollar value and writes it out in

    words. It's not a trick question but has a few logic details to work out.

    We're interested in:

    * How you solve a problem

    * Clean, concise code, which communicates your ideas clearly

    * Good understanding of unit testing

​

    Some tests are given below, but they aren't complete. Consider other cases and

    how you might handle them.

​

    There isn't any time limit but it shouldn't take more than a couple of hours,

    and if you are really stuck please get in touch for a hint. We work in a team

    in the real world so sensible questions wont be considered a failure!

    */

    public class MoneyTypes

    {

        public int Thousands { get; set; }

        public int Hundreds { get; set; }

        public int Tens { get; set; }

        public int Cents { get; set; }

​

        public MoneyTypes(int thousands, int hundreds, int tens, int cents)

        {

            Thousands = thousands;

            Hundreds = hundreds;

            Tens = tens;

            Cents = cents;

        }

​

    } 

​

    public class WordConversionService

    {

        public  Dictionary<int, string> Singlular => new()

        {

            { 1, "one" },

            { 2, "two" },

            { 3, "three" },

            { 4, "four" },

            { 5, "five" },

            { 6, "six" },

            { 7, "seven" },

            { 8, "eight" },

            { 9, "nine" },

        };

​

        public Dictionary<int, string> DoubleUnderTwenty => new()

        {

​

            { 0, "ten" },

            { 1, "eleven" },

            { 2, "twelve" },

            { 3, "thirteen" },

            { 4, "fourteen" },

            { 5, "fifteen" },

            { 6, "sixteen" },

            { 7, "seventeen" },

            { 8, "eighteen" },

            { 9, "nineteen" }

        };

        public Dictionary<int, string> MultipleOfTens => new()

        {

            { 2, "twenty" },

            { 3, "thirty" },

            { 4, "forty" },

            { 5, "fifty" },

            { 6, "sixty" },

            { 7, "seventy" },

            { 8, "eighty" },

            { 9, "ninety" }

        };

​

​

        public string Execute(decimal number)

        {

            if (number == decimal.Zero)

            {

                return "zero dollars";

            }

            if (number > 1000)

            {

                return "Error: Value too high, enter a value below 1000.";

            }

            var data = MoneyConversion(number);

            return ConvertToWord(data);

​

        }

        private MoneyTypes MoneyConversion(decimal number)

        {

​

            var dollars = decimal.ToInt32(number);

            var cents = 0;

​

            var split = number.ToString()?.Split(".");

            if (split.Length > 1)

            {               

                var centValue = split[1];

                var singularLengthCent  = centValue.Length == 1;

                cents = singularLengthCent ? (int.Parse(centValue) * 10) : int.Parse(centValue.Substring(0,2));

            }

​

​

            var thousands = (dollars % 10000) / 1000;

            var hundreds = (dollars % 1000) / 100;

            var tens = (dollars % 100);

            return new MoneyTypes(thousands, hundreds, tens, cents);

        }

​

        private string ConvertToWord(MoneyTypes moneyTypes)

        {

            var finalString = string.Empty;

            if(moneyTypes.Thousands > 0){

                var thousands = ConvertThousands(moneyTypes.Thousands);

                finalString += thousands;

            }

​

            if (moneyTypes.Hundreds > 0)

            {

                var hundreds = ConvertHundreds(moneyTypes.Hundreds);

                finalString += hundreds;

            }

​

            if (moneyTypes.Tens > 0)

            {

                var tens = ConvertDoubleNumber(moneyTypes.Tens);

                finalString += (finalString == string.Empty) ? tens : $" and {tens}";

            }

​

            finalString += Dollars(moneyTypes);

​

            if (moneyTypes.Cents > 0 )

            {

                var cents = ConvertDoubleNumber(moneyTypes.Cents);

                finalString += finalString == string.Empty ? cents : $" and {cents}";

            }

​

            finalString += Cents(moneyTypes.Cents);

            return finalString;

        }

​

​

        private string ConvertDoubleNumber(int number)

        {

            var tens = (number % 100) / 10;

            var ones = number % 10;

​

            var singleValue = tens == 0;

            if (singleValue) return ConvertSingleNumber(ones);

​

            var underTwentyDoubles = tens == 1;

            if (underTwentyDoubles) return ConvertDoubleStartingWithOnes(ones);

            var oneWords = ones > 0 ? $" {ConvertSingleNumber(ones)}" : string.Empty;

            return $"{MultipleOfTens[tens]}{oneWords}";

        }

​

        private string ConvertSingleNumber(int number) => Singlular[number];

        private string ConvertDoubleStartingWithOnes(int number) =>  DoubleUnderTwenty[number];

        private string ConvertThousands(int number) => $"{ConvertSingleNumber(number)} thousand";

        private string ConvertHundreds(int number) => $"{ConvertSingleNumber(number)} hundred";

​

        private string Dollars(MoneyTypes moneyType)

        {

            var totalAmount = moneyType.Thousands + moneyType.Hundreds + moneyType.Tens;

            if (totalAmount == 1 && moneyType.Tens == 1) return " dollar";

            if (totalAmount > 0) return " dollars";

            return string.Empty;

​

        }

​

        private string Cents(int cents)

        {

            if (cents == 0) return string.Empty;

            if (cents == 1) return " cent";

            return " cents";

​

        }

    }

    /// <summary>

    /// Write out a dollar value in words. Handles values less than $1,000, and

    /// up to two decimal places.

    /// </summary>

    static string DollarsToWords(decimal value)

    {

        var wordConversionService = new WordConversionService();

        var words = wordConversionService.Execute(value);

        return words;

    }

    public static void Main()

    {

        Test(0.12m, "twelve cents");

        Test(10.55m, "ten dollars and fifty five cents");

        //The test was wrong, it should be dollar instead of cents

        Test(120, "one hundred and twenty dollars");

        Test(99, "ninety nine dollars");

        Test(91, "ninety one dollars");

        Test(0.99m, "ninety nine cents");

        // use non plurals

        Test(0.01m, "one cent");

        Test(1, "one dollar");

​

        Test(1000, "one thousand dollars");

        Test(901, "nine hundred and one dollars");

        Test(0, "zero dollars");

        Test(10000, "Error: Value too high, enter a value below 1000.");

        // Usually an early return as it's an odd case

        Test(0, "zero dollars");

​

        // Place logic often catches people out, as do the plural vs singular checks

        Test(0.01m, "one cent");

        Test(0.10m, "ten cents");

        Test(1, "one dollar");

        Test(10, "ten dollars");

        Test(100, "one hundred dollars");

        Test(110, "one hundred and ten dollars");

        Test(111, "one hundred and eleven dollars");

        Test(110.01m, "one hundred and ten dollars and one cent");

        Test(110.10m, "one hundred and ten dollars and ten cents");

​

        // Cents

        Test(0.12m, "twelve cents");

        Test(0.09m, "nine cents"); // NB: Frequently treated as ninety for some reason

        Test(0.90m, "ninety cents");

        Test(0.99m, "ninety nine cents");

        Test(0.48m, "forty eight cents"); // Forty rather than Fourty is correct

​

        // Dollars

        Test(4, "four dollars");

        Test(25, "twenty five dollars");

        Test(91, "ninety one dollars");

        Test(99, "ninety nine dollars");

        Test(120, "one hundred and twenty dollars");

        Test(899, "eight hundred and ninety nine dollars");

        Test(901, "nine hundred and one dollars");

​

        // Combinations

        Test(1.01m, "one dollar and one cent");

        Test(1.55m, "one dollar and fifty five cents");

        Test(1.63m, "one dollar and sixty three cents");

        Test(10.55m, "ten dollars and fifty five cents");

        Test(77.01m, "seventy seven dollars and one cent");

        Test(70.40m, "seventy dollars and forty cents");

        Test(500.55m, "five hundred dollars and fifty five cents");

        Test(763.3m, "seven hundred and sixty three dollars and thirty cents");

        Test(763.38m, "seven hundred and sixty three dollars and thirty eight cents");

        Test(999.99m, "nine hundred and ninety nine dollars and ninety nine cents");

    }

​

    static void Test(decimal number, string expected)

    {

        var actual = DollarsToWords(number);

        if (actual == expected)

        {

            Console.WriteLine($"{number}: PASS");

            return;

        }

        Console.WriteLine($"{number}: FAIL");

        Console.WriteLine($"  Expected: {expected}");

        Console.WriteLine($"  Actual:   {actual}");

        Console.WriteLine();

    }

}