using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;

public class Table
{
    List<string[]> Entries;
    public Table(string path)
    {
        Entries = new List<string[]>();

        using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read))
        using (StreamReader sr = new StreamReader(fs))
        {
            string line;
            while ((line = sr.ReadLine()) != null)
            {
                Entries.Add(new string[4]);
                string[] words = line.Split(',');
                for (int i = 0; i < words.Length; i++)
                {
                    words[i] = words[i].Trim(' ');
                }
                Entries[Entries.Count - 1] = words;
            }
        }

    }

    public double FindAnnualFeatureValueInRegion(string request)
    {
        string[] words = request.ToLower().Split(',');
        if (words.Length != 2) throw new ArgumentException("incorrect request");
        for (int i = 0; i < words.Length; i++)
        {
            words[i] = words[i].Trim(' ');
        }
        List<string[]> result = Entries.Where(x => x[0].ToLower() == words[0] && x[1].ToLower() == words[1]).ToList();
        if (result.Count == 0) throw new ArgumentException("no rows with such data in table");
        double sum = 0;
        foreach (var entry in result)
        {
            sum += double.Parse(entry[3]);
        }
        return sum;
    }

    public double FindAverageAnnualFeatureValueInRegion(string request)
    {
        string[] words = request.ToLower().Split(',');
        if (words.Length != 2) throw new ArgumentException();
        for (int i = 0; i < words.Length; i++)
        {
            words[i] = words[i].Trim(' ');
        }
        List<string[]> result = Entries.Where(x => x[0].ToLower() == words[0] && x[1].ToLower() == words[1]).ToList();
        if (result.Count == 0) throw new ArgumentException("no rows with such data in table");
        double sum = 0;
        foreach (var entry in result)
        {
            sum += double.Parse(entry[3]);
        }
        return double.Parse(string.Format("{0:f3}", sum / result.Count));
    }

    public string FindRegionWithMonthlyMaxOrMinFeatureValue(string request)
    {
        string[] words = request.ToLower().Split(',');
        if (words.Length != 3) throw new ArgumentException("incorrect request");
        for (int i = 0; i < words.Length; i++)
        {
            words[i] = words[i].Trim(' ');
        }

        Console.WriteLine(DateTime.Parse(Entries[Entries.Count - 1][2]).Month);
        List<string[]> result = Entries.Where(x => x[0].ToLower() == words[0] && DateTime.ParseExact(x[2], "d.M.yyyy", CultureInfo.InvariantCulture).Month == int.Parse(words[1])).ToList();
        if (result.Count == 0) throw new ArgumentException("incorrect request");
        string[] region = result[0];
        if (words[2] == "max")
        {
            foreach (var entry in result)
            {
                if (double.Parse(entry[3]) > double.Parse(region[3])) region = entry;
            }
        }
        else if (words[2] == "min")
        {
            foreach (var entry in result)
            {
                if (double.Parse(entry[3]) < double.Parse(region[3])) region = entry;
            }
        }
        else
        {
            throw new ArgumentException("no rows with such data in table");
        }

        return region[1];
    }

    public double FindMonthlyAverageFeatureValueInAllRegions(string request)
    {
        string[] words = request.ToLower().Split(',');
        if (words.Length != 2) throw new ArgumentException("incorrect request");
        for (int i = 0; i < words.Length; i++)
        {
            words[i] = words[i].Trim(' ');
        }
        List<string[]> result = Entries.Where(x => x[0].ToLower() == words[0] && DateTime.ParseExact(x[2], "d.M.yyyy", CultureInfo.InvariantCulture).Month == int.Parse(words[1])).ToList();
        if (result.Count == 0) throw new ArgumentException("no rows with such data in table");
        double number = 0;
        foreach (var entry in result)
        {
            number += double.Parse(entry[3]);
        }
        return double.Parse(string.Format("{0:f3}", number / result.Count));
    }
}