using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Text;

namespace UnicodeNormDApp
{
    class Program
    {
        static void Main(string[] args)
        {

            var httpClient = new WebClient();

            var data = httpClient.DownloadString("http://www.unicode.org/Public/UCD/latest/ucd/NormalizationTest.txt");

            var stringReader = new StringReader(data);

            var sep = new char[] {';'};
            var spaceSpec = new char[] {' '};
            string line;
            int count = 0;
            int min = int.MaxValue;
            int max = int.MinValue;
            var values = new Dictionary<char, string>();
            var builder = new StringBuilder();
            while ((line = stringReader.ReadLine()) != null)
            {
                if (line.StartsWith("#") || line.StartsWith("@"))
                {
                    continue;
                }
                var commentIndex = line.IndexOf('#');
                var dataLine = commentIndex > 0 ? line.Substring(0, commentIndex) : line;

                var columns = dataLine.Split(sep, StringSplitOptions.RemoveEmptyEntries);
                if (columns.Length < 4)
                {
                    continue;
                }

                // Skip multi code point
                if (columns[0].IndexOf(' ') > 0)
                {
                    continue;
                }

                var source = Convert.ToInt32(columns[0], 16);
                if (source < min)
                {
                    min = source;
                }
                if (source > max)
                {
                    max = source;
                }

                var column4Space = columns[4].Split(spaceSpec, StringSplitOptions.RemoveEmptyEntries);
                builder.Clear();
                for (int i = 0; i < column4Space.Length; i++)
                {
                    var nfdFirst = Convert.ToInt32(column4Space[i], 16);
                    // We support only single char codepoints
                    string unicodeString = char.ConvertFromUtf32(nfdFirst);
                    // We restrict to ascii only
                    if (unicodeString.Length == 1 && nfdFirst > 32 && nfdFirst < 127)
                    {
                        builder.Append(unicodeString[0]);
                    }
                }
                var str = builder.ToString();
                var sourceString = char.ConvertFromUtf32(source);
                // We don't keep spaces
                if (sourceString.Length == 1 && str.Length > 0 && !values.ContainsKey(sourceString[0]))
                {
                    //Trace.WriteLine(columns[0] + "/" + source + ": " + char.ConvertFromUtf32(source) + " => " + (char)nfdFirst);
                    count++;
                    values.Add(sourceString[0], str);
                }
            }

            //var newValues = new Dictionary<int, char>(values.Count)
            //{
            //    {15, 'a'}
            //}
            Trace.WriteLine($"CodeToAscii = new Dictionary<char, string>({values.Count})");
            Trace.WriteLine("{");
            foreach (var pair in values)
            {
                var escape = pair.Value.Replace("\\", @"\\").Replace("\"", "\\\"");
                Trace.WriteLine($"    {{'{pair.Key}',\"{escape}\"}},");
            }
            Trace.WriteLine("};");

            //Trace.WriteLine("count: " + count);
            //Trace.WriteLine("max: " + max);
            //Trace.WriteLine("min: " + min);
        }

    }
}