defmodule HighScore do
  @default_score 0

  def new(),
    do: %{}

  def add_player(scores, name, score \\ @default_score),
    do: Map.put(scores, name, score)

  def remove_player(scores, name),
    do: Map.delete(scores, name)

  def reset_score(scores, name),
    do: Map.put(scores, name, @default_score)

  def update_score(scores, name, score),
    do: Map.update(scores, name, score, &(&1 + score))

  def get_players(scores),
    do: Map.keys(scores)
end