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

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

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

            PrintConnectionStat(allDic, "<ALL IN THIS HOST>");

            var topRemote = all.GroupBy(p => p.RemoteEndPoint.Address)
               .Select(p => new { Address = p.Key, Count = p.Count() })
               .OrderByDescending(p => p.Count)
               .FirstOrDefault();

            if(topRemote!=null) Console.WriteLine($"   Top Remote Address:　{topRemote.Address}, Connections: {topRemote.Count}");

            if (args.Length != 0)
            {
                var dicTotal = new Dictionary<TcpState, int>();

                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);

                    foreach (var kvp in portDic)
                    {
                        if (dicTotal.ContainsKey(kvp.Key)) dicTotal[kvp.Key] += kvp.Value;
                        else dicTotal[kvp.Key] = kvp.Value;
                    }
                }

                if (dicTotal.Count > 1) PrintConnectionStat(dicTotal, "<SUM OF LISTED PORTS>");
            }
        }

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

            Console.WriteLine();
        }
    }
}