using System;
using System.IO.Pipes;
using System.Threading;

namespace NumeralSystems
{
    public static class Converter
    {
        /// <summary>
        /// Gets the value of a positive integer to its equivalent string representation in the octal numeral systems.
        /// </summary>
        /// <param name="number">Source number.</param>
        /// <returns>The equivalent string representation of the number in the octal numeral systems.</returns>
        /// <exception cref="ArgumentException">Thrown if number is less than zero.</exception>
        public static string GetPositiveOctal(this int number)
        {
            if (number < 0)
            {
                throw new ArgumentException("number is less than zero", nameof(number));
            }

            return GetRadix(number, 8);
        }

        /// <summary>
        /// Gets the value of a positive integer to its equivalent string representation in the decimal numeral systems.
        /// </summary>
        /// <param name="number">Source number.</param>
        /// <returns>The equivalent string representation of the number in the decimal numeral systems.</returns>
        /// <exception cref="ArgumentException">Thrown if number is less than zero.</exception>
        public static string GetPositiveDecimal(this int number)
        {
            if (number < 0)
            {
                throw new ArgumentException("number is less than zero", nameof(number));
            }

            return GetRadix(number, 10);
        }

        /// <summary>
        /// Gets the value of a positive integer to its equivalent string representation in the hexadecimal numeral systems.
        /// </summary>
        /// <param name="number">Source number.</param>
        /// <returns>The equivalent string representation of the number in the hexadecimal numeral systems.</returns>
        /// <exception cref="ArgumentException">Thrown if number is less than zero.</exception>
        public static string GetPositiveHex(this int number)
        {
            if (number < 0)
            {
                throw new ArgumentException("number is less than zero", nameof(number));
            }

            return GetRadix(number, 16);
        }

        /// <summary>
        /// Gets the value of a positive integer to its equivalent string representation in a specified radix.
        /// </summary>
        /// <param name="number">Source number.</param>
        /// <param name="radix">Base of the numeral systems.</param>
        /// <returns>The equivalent string representation of the number in a specified radix.</returns>
        /// <exception cref="ArgumentException">Thrown if radix is not equal 8, 10 or 16.</exception>
        /// <exception cref="ArgumentException">Thrown if number is less than zero.</exception>
        public static string GetPositiveRadix(this int number, int radix)
        {
            if (number < 0)
            {
                throw new ArgumentException("number is less than zero", nameof(number));
            }

            return GetRadix(number, radix);
        }

        /// <summary>
        /// Gets the value of a signed integer to its equivalent string representation in a specified radix.
        /// </summary>
        /// <param name="number">Source number.</param>
        /// <param name="radix">Base of the numeral systems.</param>
        /// <returns>The equivalent string representation of the number in a specified radix.</returns>
        /// <exception cref="ArgumentException">Thrown if radix is not equal 8, 10 or 16.</exception>
        public static string GetRadix(this int number, int radix)
        {
            if (radix != 8 && radix != 10 && radix != 16)
            {
                throw new ArgumentException("radix is not equal 8, 10 or 16", nameof(radix));
            }

            string s = string.Empty;

            uint uNumber = (uint)number;

            while (uNumber > 0)
            {
                switch (uNumber % radix)
                {
                    case 0:
                        s = '0' + s;
                        break;
                    case 1:
                        s = '1' + s;
                        break;
                    case 2:
                        s = '2' + s;
                        break;
                    case 3:
                        s = '3' + s;
                        break;
                    case 4:
                        s = '4' + s;
                        break;
                    case 5:
                        s = '5' + s;
                        break;
                    case 6:
                        s = '6' + s;
                        break;
                    case 7:
                        s = '7' + s;
                        break;
                    case 8:
                        s = '8' + s;
                        break;
                    case 9:
                        s = '9' + s;
                        break;
                    case 10:
                        s = 'A' + s;
                        break;
                    case 11:
                        s = 'B' + s;
                        break;
                    case 12:
                        s = 'C' + s;
                        break;
                    case 13:
                        s = 'D' + s;
                        break;
                    case 14:
                        s = 'E' + s;
                        break;
                    case 15:
                        s = 'F' + s;
                        break;
                }

                uNumber /= (uint)radix;
            }

            return s;
        }
    }
}