SoftUni Course Planning

using System;
using System.Collections.Generic;
using System.Linq;

namespace SoftUniCourse
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            List<string> scheduleList = Console.ReadLine().Split(", ").ToList();
            string command = Console.ReadLine();
            while (command != "course start")
            {
                string[] commandArray = command.Split(':').ToArray();

                if (commandArray[0] == "Add")
                {
                    Add(scheduleList, commandArray);
                }

                else if (commandArray[0] == "Insert")
                {
                    Insert(scheduleList, commandArray);

                }

                else if (commandArray[0] == "Remove")
                {
                    Remove(scheduleList, commandArray);

                }

                else if (commandArray[0] == "Swap")
                {
                    string firstLesson = commandArray[1];
                    string secondLesson = commandArray[2];
                    if (scheduleList.Exists(x => x == firstLesson) && scheduleList.Exists(x => x == secondLesson))
                    {
                        Swap(scheduleList, firstLesson, secondLesson);
                    }

                    else
                    {
                        continue;
                    }
                }

                else if (commandArray[0] == "Exercise")
                {
                    string lessonTitle = commandArray[1];
                    ExerciseCommand(scheduleList, lessonTitle);

                }

                command = Console.ReadLine();
            }

            int counter = 1;
            foreach (var item in scheduleList)
            {
                Console.WriteLine($"{counter}.{item}");
                counter++;
            }
        }

        private static void ExerciseCommand(List<string> scheduleList, string lessonTitle)
        {
            if (scheduleList.Contains(lessonTitle) && (scheduleList.Contains($"{lessonTitle}-Exercise") == false))
            {
                int indexOfLessonTitle = scheduleList.IndexOf(lessonTitle);
                scheduleList.Insert(indexOfLessonTitle + 1, $"{lessonTitle}-Exercise");
            }

            else if (scheduleList.Contains(lessonTitle) == false)
            {
                scheduleList.Add(lessonTitle);
                scheduleList.Add($"{lessonTitle}-Exercise");
            }
        }

        private static void Swap(List<string> scheduleList, string firstLesson, string secondLesson)
        {
            int firstIndex = scheduleList.IndexOf(firstLesson);
            int secondIndex = scheduleList.IndexOf(secondLesson);
            scheduleList[firstIndex] = secondLesson;
            scheduleList[secondIndex] = firstLesson;

            if (scheduleList.Contains($"{firstLesson}-Exercise"))
            {
                scheduleList.Remove($"{firstLesson}-Exercise");
                int indexOfFirstLesson = scheduleList.IndexOf(firstLesson);
                scheduleList.Insert(indexOfFirstLesson + 1, $"{firstLesson}-Exercise");
            }

            if (scheduleList.Contains($"{secondLesson}-Exercise"))
            {
                scheduleList.Remove($"{secondLesson}-Exercise");
                int indexOfSecondLesson = scheduleList.IndexOf(secondLesson);
                scheduleList.Insert(indexOfSecondLesson + 1, $"{secondLesson}-Exercise");
            }
        }

        private static void Remove(List<string> scheduleList, string[] commandArray)
        {
            string lessonTitle = commandArray[1];
            if (scheduleList.Contains(lessonTitle))
            {
                scheduleList.Remove(lessonTitle);
            }
            if (scheduleList.Contains($"{lessonTitle}-Exercise"))
            {
                scheduleList.Remove($"{lessonTitle}-Exercise");
            }
        }

        private static void Insert(List<string> scheduleList, string[] commandArray)
        {
            string lessonTitle = commandArray[1];
            int index = int.Parse(commandArray[2]);

            if (scheduleList.Contains(lessonTitle) == false && index >= 0 && index < scheduleList.Count)
            {
                scheduleList.Insert(index, lessonTitle);
            }
        }

        private static void Add(List<string> scheduleList, string[] commandArray)
        {
            string lessonTitle = commandArray[1];

            if (scheduleList.Contains(lessonTitle) == false)
            {
                scheduleList.Add(lessonTitle);
            }
        }
    }
}