using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using TermApp.Commands;



namespace TermApp.Core
{

    public class CommandInterpreter
    {
        public readonly Dictionary<string, ICommand> _commands = new();

        public CommandInterpreter()
        {

            RegisterCommand(new GreetCommand());
            RegisterCommand(new HelpCommand(this));
            RegisterCommand(new AddCommand());
            RegisterCommand(new EchoCommand());
            RegisterCommand(new ClearCommand());

        }
        public void RegisterCommand(ICommand command)
        {

            _commands[command.Name.ToLower()] = command;

        }

        public void Execute(string input)
        {

            string[] pipedCommands = input.Split("|", StringSplitOptions.RemoveEmptyEntries);
            string pipedOutput = null;

            foreach (var cmdInput in pipedCommands)
            {

                string trimmed = cmdInput.Trim();

                string[] parts = input.Split(" ", StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length == 0) continue;
                string commandName = parts[0].ToLower();
                string[] args = parts.Length > 1 ? parts[1..] : new string[0];



                if (_commands.TryGetValue(commandName, out var command))
                {

                    command.Execute(args);

                }
                else
                {
                    Console.WriteLine($"Err - uknown Command : '{commandName}'. Type help For a list of commands");
                    return;
                }


            }


            if (!string.IsNullOrWhiteSpace(pipedOutput))
            {

                Console.WriteLine(pipedOutput);

            }

        }







        public IEnumerable<ICommand> GetAllCommands()
        {

            return _commands.Values;

        }


    }
}