pub type Distance = isize;

pub struct Position {
  pub x: Distance,
  pub y: Distance,
}

pub struct Direction {
  pub x: Distance,
  pub y: Distance,
}

pub type AgentId = usize;

pub struct WorldView {
  pub self_tagged: bool,
  pub bounds_distance: (Distance, Distance, Distance, Distance),
  pub other_agents: Vec<(Direction, AgentId)>,
}

pub enum Move {
  Noop, // Why not an Option?
  TryTag(AgentId),
  TryMove(Direction),
}

pub trait Agent {
  fn next_move(&self, view: WorldView) -> Move;
  fn get_tagged(&mut self, by: AgentId);
}