using System;
using System.IO;

namespace _2
{
    public class TagList
    {
        public String list;
        public String filePath;

        public TagList(String path = null) { filePath = path; }

        public String Open(String tagName, int level, String value = null)
        {
            String shift = new String('\t', level);
            list += String.Format("\n{0}<{1}>", shift, tagName);
            if (!(value is null))
                Value(value, level);
            return list;
        }
        public String Close(String tagName, int level)
        {
            String shift = new String('\t', level);
            list += String.Format("\n{0}</{1}>", shift, tagName);
            return list;
        }

        public String Insert(String tagName, int level, String value, bool newLine = false)
        {
            String shift = new String('\t', level);
            String enter = newLine ? "\n" : "";
            list += String.Format("{0}{1}<{2}>{3}</{2}>{0}", enter, shift, tagName, value);
            return list;
        }

        public String Value(String value, int level = 0)
        {
            String shift = new String('\t', level);
            list += '\n' + shift + value;
            return list;
        }

        public void Write(String path = null)
        {
            if (path is null)
                path = this.filePath;
            using (FileStream fs = File.Open(path, FileMode.OpenOrCreate, FileAccess.Write))
            {
                byte[] bytes = System.Text.Encoding.Default.GetBytes(list);
                fs.Write(bytes, 0, bytes.Length);
            }
        }

        public String Show() => list;
        public void Clear() { list = new String(""); }
        public String NewLine(int count = 0) => list += new String('\n', count);

    }

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(CreateTagFile());
        }

        static public String CreateTagFile()
        {
            Console.WriteLine("CreateTagFile");
            Console.WriteLine(new String('-', 20));
            TagList tagList = new TagList();
            for (int i = 0; i < 10; i++)
            {
                tagList.Open($"tag_{i + 1}", i);
                tagList.Value(Convert.ToString(i + 1), i + 1);
            }
            for (int i = 9; i >= 0; i--)
            {
                tagList.Close($"tag_{i + 1}", i);
            }
            tagList.Write("file.txt");
            return tagList.Show();
        }
    }
}