Huffman

using System;

namespace AIKD_01
{
    class Program
    {
        static void Main()
        {
            var huffman = new Huffman("02.txt");
            huffman.Run();

            huffman.PrintPretty();
            Console.ReadKey();
        }
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
namespace AIKD_01
{
    internal class Node
    {
        public char? Char { get; set; }
        public Node Left { get; set; }
        public Node Right { get; set; }
        public string Code { get; set; }
        public string Dir { get; set; }

        private int _Count;
        public int Count
        {
            get
            {
                if (Left != null || Right != null)
                {

                    _Count = 0;
                    if (Left != null)
                        _Count += Left.Count;

                    if (Right != null)
                        _Count += Right.Count;
                }
                return _Count;
            }
        }

        public Node(char? newChar)
        {
            Code = "";
            Char = newChar;
            _Count = 1;
        }

        public void CountAdd()
        {
            _Count++;
        }
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

namespace AIKD_01
{
    internal class Huffman
    {
        private string FileName, FileText;
        private List<Node> AllNodes;
        private List<Node> CodedList;
        private List<Node> Tree;

        public Huffman(string fileName)
        {
            AllNodes = new List<Node>();
            Tree = new List<Node>();
            CodedList = new List<Node>();
            FileName = fileName;
        }

        public void Run()
        {
            if (LoadFile())
            {
                GenerateNodes();
                Tree = AllNodes;
                GenerateTree();
                GenerateCode();
            }

            foreach (var letter in FileText)
            {
                Console.Write(Convert.ToString(letter, 2) + " ");
            }

            Console.WriteLine("\n");

            foreach (var letter in FileText)
            {
                Console.Write(CodedList.FirstOrDefault(a=>a.Char == letter).Code + " ");
            }

            Console.WriteLine("\n\n");

        }

        private void GenerateCode(Node node = null, string code = "")
        {
            if (node == null)
                node = Tree.First();

            if (node.Char != '+')
            {
                node.Code = code;
                CodedList.Add(node);
            }

            if (node.Left != null)
                GenerateCode(node.Left, code + "0");
            if (node.Right != null)
                GenerateCode(node.Right, code + "1");
        }

        private void GenerateTree()
        {
            while (Tree.Count() != 1)
            {
                Tree = Tree.OrderBy(t => t.Count).ToList();

                Tree[0].Dir = "LEWO";
                Tree[1].Dir = "PRAWO";

                var newNode = new Node(null)
                {
                    Left = Tree[0],
                    Right = Tree[1]
                };
                Tree.Add(newNode);

                Tree.RemoveAt(0);
                Tree.RemoveAt(0);
            }
        }

        private void GenerateNodes()
        {
            foreach (var Char in FileText)
            {
                if (AllNodes.All(c => c.Char != Char))
                    AllNodes.Add(new Node(Char));
                else
                    AllNodes.First(a => a.Char == Char).CountAdd();
            }
        }

        private bool LoadFile()
        {
            var textLetters = "";
            try
            {
                using (var sr = new StreamReader(FileName))
                {
                    string line;
                    while ((line = sr.ReadLine()) != null)
                    {
                        textLetters += line.ToUpper();
                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine($"Nie znaleziono pliku ({e.Message})");
                return false;
            }
            //var pattern = new Regex("[^A-Za-z]|[ ]");
            //textLetters = pattern.Replace(textLetters, "");

            FileText = textLetters;
            return true;
        }

        public void PrintPretty(int layer = 0, Node node = null)
        {
            if (node == null && layer == 0)
                node = Tree.First();

            for (var i = 0; i < layer; i++)
                Console.Write(" ");

            if (node.Char != null)
                Console.WriteLine($"|-'{node.Char}':{node.Count} ({node.Code} : {node.Dir})");
            else
                Console.WriteLine($"|- {node.Count} : {node.Dir}");

            if (node.Left != null)
                PrintPretty(layer + 2, node.Left);

            if (node.Right != null)
                PrintPretty(layer + 2, node.Right);
        }
    }
}