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

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);

        public static String GetBetween(String strSource, String strStart, String strEnd)
        {
            int Start, End;
            if (strSource.Contains(strStart) && strSource.Contains(strEnd))
            {
                Start = strSource.IndexOf(strStart, 0) + strStart.Length;
                End = strSource.IndexOf(strEnd, Start);
                return strSource.Substring(Start, End - Start);
            }
            else
            {
                return "";
            }
        }

        public static int GetShift(String tagName)
        {
            int start = tagName.IndexOf("_", 0) + 1;
            return int.Parse(tagName.Substring(start, tagName.Length-start)) - 1;
        }

        public static List<((String, int), String)> Parse(String path="")
        {
            //String[] lines = new String[6]{"<tag_1>", "\t1", "\t<tag_2>", "\t\t2", "\t</tag_2>", "</tag_1>" };
            String[] lines = File.ReadAllLines(path, Encoding.UTF8);
            var tuples = new List<((String, int), String)>();

            //drop empty lines
            int j = -1;
            String emptyName = "";
            do
            {
                j++;
                emptyName = GetBetween(lines[j], "<", ">");
            } while (emptyName == "" && lines.Length != j);

            //fill tags
            for (int i = j; i < lines.Length; i++)
            {
                String tagName = GetBetween(lines[i], "<", ">");
                int shift = GetShift(tagName);
                String tagValue = "";
                if (tagName[0] != '/')
                {
                    String localTagName = "";
                    do
                    {
                        i++;
                        localTagName = GetBetween(lines[i], "<", ">");
                        if (localTagName == "")
                        {
                            if (tagValue != "")
                                tagValue += '\n';
                            tagValue += lines[i];
                        }
                    } while (localTagName == "" && lines.Length != i);
                    i--;
                }
                tuples.Add(((tagName,shift),tagValue));
            }
            return tuples;
        }

    }

    class Program
    {
        static void Main(string[] args)
        {
            //Exercise 1
            Console.WriteLine(CreateTagFile("file.txt"));
            //Exercise 2
            Console.WriteLine(WriteParsedTagsWithInsert("file.txt","file2.txt"));
            Console.WriteLine(WriteParsedValues("file2.txt","file3.txt"));
        }

        static public String CreateTagFile(String path)
        {
            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(path);
            return tagList.Show();
        }

        static public String WriteParsedTagsWithInsert(String read_path, String save_path, int couple_tags=5, String value="insert value")
        {
            Console.WriteLine("WriteParsedTagsWithInsert");
            Console.WriteLine(new String('-', 20));
            TagList tagList = new TagList();
            var tuples = TagList.Parse(read_path);
            for (int i = 0; i < tuples.Count; i++)
            {
                String tagName = tuples[i].Item1.Item1;
                int level = tuples[i].Item1.Item2;
                String tagValeus = tuples[i].Item2;
                if (tagName[0] != '/')
                {
                    tagList.Open(tagName, level);
                    tagList.Value(tagValeus);
                    if (i+1 == couple_tags)
                    {
                        tagList.Value(value, level+1);
                    }
                }
                else
                {
                    tagList.Close(tagName.Substring(1,tagName.Length-1), level);
                }
            }
            tagList.Write(save_path);
            return tagList.Show();
        }

        static public String WriteParsedValues(String read_path, String save_path)
        {
            Console.WriteLine("WriteParsedValues");
            Console.WriteLine(new String('-', 20));
            TagList tagList = new TagList();
            var tuples = TagList.Parse(read_path);
            for (int i = 0; i < tuples.Count; i++)
            {
                String tagName = tuples[i].Item1.Item1;
                int level = tuples[i].Item1.Item2;
                String tagValeus = tuples[i].Item2;
                if (tagName[0] != '/')
                {
                    tagList.Value(tagValeus);
                }
            }
            tagList.Write(save_path);
            return tagList.Show();
        }
    }
}