ProgressBarLib/ProgressBarLib/ProgressBar.cs

using System;
using System.Collections.Generic;
using System.Threading;

namespace ProgressBarLib
{
    public class ProgressBar
    {
        private volatile bool _shouldStop;
        private volatile List<string> _msgList = new List<string>();
        private volatile int _lastCurr;
        private volatile int _lastTotal;
        private volatile string _lastMsg = "";
        private volatile string _mainMsg = "";
        private readonly object _lock = new object();
        private volatile bool _hasStopped;

        public ProgressBar()
        {
            Console.WriteLine();

            new Thread(() =>
            {
                Thread.CurrentThread.IsBackground = true;
                while (!_shouldStop)
                {
                    lock (_lock)
                        if (_msgList.Count > 0)
                        {
                            ClearCurrentConsoleLine();
                            foreach (var msg in _msgList)
                            {
                                Console.WriteLine(msg.Length < Console.WindowWidth
                                    ? msg
                                    : msg.Substring(0, Console.WindowWidth - 1));
                            }

                            _msgList.Clear();
                        }

                    ClearCurrentConsoleLine();
                    Console.Write("\r" + _mainMsg);
                    Thread.Sleep(500);
                }

                if (_msgList.Count > 0)
                {
                    ClearCurrentConsoleLine();
                    foreach (var msg in _msgList)
                    {
                        Console.WriteLine(msg.Length < Console.WindowWidth
                            ? msg
                            : msg.Substring(0, Console.WindowWidth - 1));
                    }

                    _msgList.Clear();
                }
                else
                {
                    ClearCurrentConsoleLine();
                    Console.Write("\r" + _mainMsg);
                }

                _hasStopped = true;
            }).Start();
        }

        public void UpdateMain(int curr, int total, string msg)
        {
            UpdateMainAdv(curr, total, curr.ToString(), msg);
        }

        public void UpdateMainAdv(int curr, int total, string custCurr, string msg)
        {
            var outMsg = $"({custCurr}/{total}) ";
            var progPart = MakeProgressBar(curr, total);
            var msgMaxLength = Console.WindowWidth - outMsg.Length - progPart.Length;

            if (msgMaxLength < 0)
            {
                _mainMsg = "Increase terminal width";
                return;
            }

            if (msg.Length < msgMaxLength)
                for (var i = (msgMaxLength - msg.Length); i > 0; i--)
                    msg += " ";
            else
                msg = msg.Substring(0, msgMaxLength);

            outMsg += msg;
            outMsg += progPart;

            _lastCurr = curr;
            _lastMsg = msg;
            _lastTotal = total;

            _mainMsg = outMsg;
        }

        public void Tick()
        {
            _lastCurr++;
            UpdateMain(_lastCurr, _lastTotal, _lastMsg);
        }

        public void PushMsg(string msg)
        {
            lock (_lock)
                _msgList.Add(msg);
        }

        public void Stop()
        {
            _shouldStop = true;
            while (!_hasStopped) ;
        }

        private static string MakeProgressBar(int curr, int total)
        {
            const string fullChar = "=";
            const string blankChar = "-";

            var progStr = "[";

            var fullCharCount = (int) (15d / total * curr);
            var blankCharCount = 15 - fullCharCount;

            for (var i = fullCharCount; i > 0; i--) progStr += fullChar;
            for (var i = blankCharCount; i > 0; i--) progStr += blankChar;

            progStr += "]";

            return progStr;
        }

        private static void ClearCurrentConsoleLine()
        {
            var currentLineCursor = Console.CursorTop;
            Console.SetCursorPosition(0, Console.CursorTop);
            Console.Write(new string(' ', Console.WindowWidth));
            Console.SetCursorPosition(0, currentLineCursor);
        }
    }
}