Program.cs

using VModLoader.DynamicNodes;
using VModLoader.Nodes;

namespace VModLoader
{
    internal class Program
    {
        static readonly DecisionNode decisionTree = new
            ("Main Menu",
                [
                    new DynamicDecisionNode("Run Installs", RunInstallGenerator.LoadFromInstallFile),
                    new DynamicDecisionNode("Manage VVVVVV installs", ManageAllInstallsGenerator.LoadFromInstallFile),
                    new ExitNode("Exit VML"),
                ]
            );

        static DecisionNode traverse = decisionTree;
        static readonly List<DecisionNode> backHistory = [ ];

        const int INDEX_OFFSET = 1;
        internal const string BACK_CMD = "back";

        /// <summary>
        /// Writes the VML icon to the console.
        /// </summary>
        public static void WriteIcon()
        {
            Console.WriteLine(@"    _____     _____   ________   _____   _____      ");
            Console.WriteLine(@"   \\\\  \   ////  / ////     | /     | ||||  |     ");
            Console.WriteLine(@"    \\\\  \ ////  / ////  /|  |/  /|  | ||||  |     ");
            Console.WriteLine(@"     \\\\  \///  / ////  /||  |  /||  | ||||  |     ");
            Console.WriteLine(@"      \\\\  \/  / ////  /|||    /|||  | ||||  |___  ");
            Console.WriteLine(@"       \\\\____/ ////__/||||___/||||__| ||||______| ");
            Console.WriteLine(@"                                                    ");
            Console.WriteLine(@"              x-->> VModLoader <<--x                ");
            Console.WriteLine(@"              |   By  MonkeManII   |                ");
            Console.WriteLine(@"  >>----------x--------------------x-------------<< ");
            Console.WriteLine(@"  | A basic modloader for Terry Cavanagh's VVVVVV | ");
            Console.WriteLine(@"  >>---------------------------------------------<< ");
        }

        /// <summary>
        /// Writes the current traversal info to the console.
        /// </summary>
        internal static void WriteTraverse()
        {
            Console.Clear();
            WriteIcon();
            traverse.ConsoleWrite(INDEX_OFFSET);
            if (backHistory.Count > 0)
            {
                Console.WriteLine($"Run '{BACK_CMD}' to go back!");
            }
        }

        /// <summary>
        /// Runs the given user command.
        /// </summary>
        /// <param name="command">The user command.</param>
        internal static void RunCommand(string command)
        {
            // Check for the back command.
            if (command.ToLower() == BACK_CMD.ToLower())
            {
                if (backHistory.Count <= 0)
                {
                    return;
                }

                traverse = backHistory[^1];
                backHistory.RemoveAt(backHistory.Count - 1);
                WriteTraverse();
                return;
            }

            // Try to parse it as a node input.
            if (!traverse.ParseInput(command, INDEX_OFFSET, out string? error, out int index))
            {
                Console.WriteLine(error);
                return;
            }
            else
            {
                // Select it and traverse if applicable.
                DecisionNode? newNode = traverse.GetChild(index);

                if (newNode is not null)
                {
                    if (!newNode.OnSelected())
                    {
                        return;
                    }

                    backHistory.Add(traverse);
                    traverse = newNode;
                }
                WriteTraverse();
            }
        }

        static void Main(string[] args)
        {
            FileUtils.Initialize();
            WriteTraverse();

            while (true)
            {
                // Because this is blocking, while true works fine.
                string? inp = Console.ReadLine();

                if (!string.IsNullOrEmpty(inp))
                {
                    RunCommand(inp);
                }
            }
        }

        /// <summary>
        /// Closes this window.
        /// </summary>
        internal static void Close()
        {
            Environment.Exit(0);
        }

        /// <summary>
        /// Traverses to the given node.
        /// </summary>
        /// <param name="node">The node to traverse to.</param>
        internal static void TraverseTo(DecisionNode node)
        {
            traverse = node;
        }
    }
}