using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.NetworkInformation;
using System.Reflection;

[assembly: AssemblyTitle("ConnectionStat")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("")]
[assembly: AssemblyProduct("ConnectionStat")]
[assembly: AssemblyCopyright("Copyright ©  2022")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]
[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]

namespace ConnectionStat
{
    class Program
    {
        static void Main(string[] args)
        {
            var all = IPGlobalProperties.GetIPGlobalProperties().GetActiveTcpConnections();

            if (all.Length == 0)
            {
                Console.WriteLine("GetActiveTcpConnections return 0 items.");
                return;
            }

            var allDic = all.GroupBy(p => p.State).Select(p => new { State = p.Key, Count = p.Count() }).Where(p => p.Count != 0).ToDictionary(p => p.State, p => p.Count);

            if (args.Length == 0)
            {
                PrintConnectionStat(allDic, "All");
            }
            else
            {
                foreach (var argString in args)
                {
                    if (!int.TryParse(argString, out var port)) continue;

                    var filterByPort = all.Where(p => p.LocalEndPoint.Port == port);
                    var portDic = filterByPort.GroupBy(p => p.State).Select(p => new { State = p.Key, Count = p.Count() }).Where(p => p.Count != 0).ToDictionary(p => p.State, p => p.Count);

                    PrintConnectionStat(portDic, "Port " + port);
                }
            }
        }

        private static void PrintConnectionStat(Dictionary<TcpState, int> allDic, string label)
        {
            Console.WriteLine($" * Connections of {label}");
            foreach (var kvp in allDic)
            {
                Console.Write($"    {kvp.Key}={kvp.Value}");
            }
            Console.WriteLine($"   TOTAL={allDic.Sum(p => p.Value)}");
            Console.WriteLine();
        }
    }
}