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using CommandLine;

namespace Builtins
{
    // Echo command
    class EchoCommand : Command
    {
        public EchoCommand()
            : base("echo", docstring:
                """
                A simple echo command that repeats back whatever the user sends.

                If the first argument is a number, it will be treated as the number of times
                to repeat the following sequence of characters, joined by a space.

                Usage
                -----
                >>> echo hello world
                hello world

                >>> echo 3 hi
                hi hi hi
                """
            )
        {
        }

        public override void Callback()
        {
            string echoString = ReturnedArguments[0];
            string[] echoStringParts = echoString.Split(' ');

            if (echoStringParts.Length == 1)
            {
                Console.WriteLine(echoString);
                return;
            }
            
            string firstEchoWord  = echoStringParts[0];
            string restOfEchoWord = string.Join(" ", echoStringParts[1 .. echoStringParts.Length]);

            if (int.TryParse(firstEchoWord, out int count))
            {
                Console.WriteLine(string.Join(" ", Enumerable.Range(0, count + 1).Select(_ => restOfEchoWord)));
            }
            else
            {
                Console.WriteLine(echoString);
            }
        }
    }

    // Close command
    class CloseCommand : Command
    {
        public CloseCommand()
            : base("close", docstring:
                """
                A simple close command that stops the process entirely and closes the window.

                Usage
                -----
                >>> close
                """)
        {
        }

        public override void Callback()
        {
            Environment.Exit(0);
        }
    }

    // Help command
    class HelpCommand : Command
    {
        public HelpCommand()
            : base("help")
        {
        }

        public override void Callback()
        {
            // Get what the user queried with the help command
            string query = ReturnedArguments[0];

            // Get all the commands subclassing command
            List<Command> search = CreatedCommands.Where(cmd => cmd.Name == query).ToList();

            if (search.Count == 0)
            {
                Console.WriteLine($"The search for command '{query}' yielded no results.");
                return;
            }

            Command command = search[0];

            string title = $"Help on command '{command}':";

            Console.WriteLine($"{title}\n{new string('-', title.Length)}\n{command.Docstring}\n{new string('-', title.Length)}");
        }
    }
}