using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
namespace MostConnected
{
    class Program
    {
        static void Main(string[] args)
        {
            //get full path to the CSV
            string listPath = Environment.CurrentDirectory + @"\all.csv";
            //just for convenience
            int column = 2;
            //but does it even exist?
            if (!System.IO.File.Exists(listPath))
            {
                Console.WriteLine("Execution can not continue: \"all.csv\" not found.");
                Console.ReadLine();
                return;
            }
            //nevermind, it exists, create a nice dictionary then
            Dictionary<int, int> connections = new Dictionary<int, int>();
            //and here stuff might start to fail
            try
            {
                //init a reader
                StreamReader read = System.IO.File.OpenText(listPath);
                //lets ensure we always close the stream
                using (read)
                {
                    string line;
                    int linei = 1;
                    //read till end
                    while (!read.EndOfStream)
                    {
                        line = read.ReadLine();
                        //split the row in 3, by columns
                        string[] values = line.Split(new string[] { "," }, 3, StringSplitOptions.None);
                        //if columns are under 3, something has failed, return
                        if (values.Length < 3)
                        {
                            Console.WriteLine("Execution can not continue: invalid entry at line {0}, column count under than 3.", linei.ToString());
                            Console.ReadLine();
                            return;
                        }
                        int personID;
                        //if this isnt a number or something, we can't continue either
                        try
                        {
                            personID = int.Parse(values[column - 1]);
                        }
                        catch (FormatException)
                        {
                            Console.WriteLine("Execution can not continue: invalid entry at line {0}, column {1}.", linei.ToString(), column.ToString());
                            Console.ReadLine();
                            return;
                        }
                        //if key doesnt exists, lets add it
                        if (!connections.ContainsKey(personID))
                        {
                            connections.Add(personID, 0);
                        }
                        //increase value at the specified key
                        connections[personID]++;
                        linei++;
                    }
                }

                int max = -1;
                //get highest count
                foreach (int key in connections.Keys)
                {
                    if (max == -1) max = key;
                    if (connections[key] > connections[max])
                    {
                        max = key;
                    }
                }
                //print out
                Console.WriteLine("Most connected person: {0} with {1} connections.", max.ToString(), connections[max].ToString());
            }
            catch (Exception ex)
            {
                Console.WriteLine("An exception unfortunately got thrown while trying to access/read the Excell workbook. This exception info could prove useful: {0}{1}", Environment.NewLine, ex.ToString());

            }
            Console.ReadLine();
        }
    }
}