use std::error::Error;
use std::fmt::{self, Display};

use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};

pub struct NoopSymbol;

impl Symbol for NoopSymbol {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    Ok(true)
  }
  fn execute(&self) -> Result<(), Box<dyn Error>> {
    Ok(())
  }
  fn as_action<'a>(&'a self, runner: &'a dyn SymbolRunner) -> Box<dyn Action + 'a> {
    Box::new(SymbolAction::new(runner, self))
  }

  fn into_action<'a>(self: Box<Self>, runner: &'a dyn SymbolRunner) -> Box<dyn Action + 'a>
  where
    Self: 'a,
  {
    Box::new(OwnedSymbolAction::new(runner, *self))
  }
}

impl Display for NoopSymbol {
  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
    write!(f, "Noop")
  }
}