scream/src/Program.cs

using System.Text;

namespace scream
{
    /// <summary>
    /// Implements the Scream Cipher, encoding messages using diacritics on the letter 'A'.
    /// </summary>
    class Program
    {
        /// <summary>
        /// The base character 'A' used for encoding messages with diacritics.
        /// </summary>
        private const char BASE_CHARACTER = 'A';

        /// <summary>
        /// The starting ASCII value of printable characters.
        /// </summary>
        private const int ASCII_START = 0x20;

        /// <summary>
        /// The ending ASCII value of printable characters.
        /// </summary>
        /// <remarks>
        /// Not used, but included for reference
        /// </remarks>
        private const int ASCII_END = 0x7E;

        /// <summary>
        /// The starting Unicode code point for diacritic marks.
        /// </summary>
        private const int DIACRITIC_START = 0x300;

        /// <summary>
        /// The ending Unicode code point for diacritic marks.
        /// </summary>
        /// <remarks>
        /// Not used, but included for reference
        /// </remarks>
        private const int DIACRITIC_END = 0x36F; // Not needed, but here for reference.

        /// <summary> Main entry-point for this application. </summary>
        /// <param name="args"> The component parts of the message. </param>
        static void Main(string[] args)
        {
            if (args[0].Equals("-q") || args[0].Equals("--quiet"))
            {
                QuietDown(args);
            }
            else if (args.Length > 0)
            {
                var scream = Scream(args);
                Console.OutputEncoding = System.Text.Encoding.UTF8;
                Console.WriteLine(scream);
            }
            else
            {
                return;
            }
        }

        /// <summary> Quiets the given message as defined by the string arry. </summary>
        /// <param name="messageComponents"> The component parts of the message. </param>
        /// <returns> A string representing the quiet message. </returns>
        private static string QuietDown(string[] messageComponents)
        {
            var concat = string.Concat(messageComponents.Skip(1));
            StringBuilder sb = new StringBuilder();

            foreach (var c in concat)
            {
                var index = GetAsciiIndex(c);
                var ascii = GetAscii(index);

                sb.Append(ascii);
            }

            return sb.ToString();
        }

        /// <summary> Screams the given message as defined by the string array. </summary>
        /// <param name="messageComponents"> The component parts of the message. </param>
        /// <returns> A string representing the screamed message. </returns>
        private static string Scream(string[] messageComponents)
        {
            var concat = string.Concat(messageComponents);
            StringBuilder sb = new StringBuilder();

            foreach (var c in concat)
            {
                var index = GetDiacriticIndex(c);
                var diacritic = GetDiacritic(index);

                sb.Append(BASE_CHARACTER);
                sb.Append(diacritic);
            }

            return sb.ToString();
        }

        /// <summary> Gets the zero-based index of the diacritic character. </summary>
        /// <param name="character"> The diacritic character to index. </param>
        /// <returns> The diacritic character index. </returns>
        private static int GetDiacriticIndex(char character)
        {
            var index = character - ASCII_START;

            return index;
        }

        /// <summary> Gets the zero-based index of the viewable ASCII character. </summary>
        /// <param name="character"> The ASCII character to index. </param>
        /// <returns> The ASCII character index. </returns>
        private static int GetAsciiIndex(char character)
        {
            var index = character - DIACRITIC_START;

            return index;
        }

        /// <summary> Gets a diacritic character given an index offset. </summary>
        /// <param name="index"> Zero-based index of the Diacritic character. </param>
        /// <returns> The diacritic character. </returns>
        private static char GetDiacritic(int index)
        {
            var diacritic = (char)(DIACRITIC_START + index);

            return diacritic;
        }

        /// <summary> Gets an ASCII character given an index offset. </summary>
        /// <param name="index"> Zero-based index of the ASCII character. </param>
        /// <returns> The ASCII character. </returns>
        private static char GetAscii(int index)
        {
            var character = (char)(ASCII_START + index);

            return character;
        }
    }
}