commands-processing/CommandHandler/Navigation/States/NavigationStateBase.cs

using System.Text;
using CommandHandler.Commands;

namespace CommandHandler.Navigation.States;

internal abstract class NavigationStateBase : INavigationState, INavigationDrawer
{
    private INavigationContext? _context;

    protected readonly IDictionary<string, Func<ICommand>> Commands = new Dictionary<string, Func<ICommand>>();

    protected ICommand ChangeNavigationState(INavigationState  newState)
    {
        if (_context == null)
        {
            throw new InvalidOperationException();
        }

        var commands = new List<ICommand>
        {
            new ChangeNavigationStateCommand(_context, newState)
        };

        if (newState is INavigationDrawer drawer)
        {
            commands.Add(new DrawMenuCommand(drawer));
        }

        return new CombinedCommand([.. commands]);
    }

    public void SetContext(INavigationContext context)
    {
        _context = context;
    }

    public ICommand GetCommand(string message)
    {
        var parts = message.Split(' ', StringSplitOptions.RemoveEmptyEntries);
        if (parts.Length <= 0)
        {
            return new EmptyCommand();
        }

        if (Commands.TryGetValue(parts[0], out var commandFactory))
        {
            return commandFactory();
        }

        if (this is INavigationDrawer navigationDrawer)
        {
            return new DrawMenuCommand(navigationDrawer);
        }

        throw new NotImplementedException();
    }

    public string DrawNavigationMenu()
    {
        var builder = new StringBuilder();

        foreach (var command in Commands.Keys)
        {
            builder.AppendLine(command);
        }

        return builder.ToString();
    }
}