# Use service object when:
# 1- The action is complex.
# 2- The action reaches across multiple models.
# 3- The action interacts with an external service (e.g. posting to social networks)
# 4- The action is not a core concern of the underlying model (e.g. sweeping up outdated data after a certain time period).
# 5- There are multiple ways of performing the action (e.g. authenticating with an access token or password). 

class Authentication
  def initialize(params, omniauth = nil)
    @params = params
    @omniauth = omniauth
  end

  def user
    @user = @omniauth ? user_from_omniauth : user_with_password
  end

  def authenticated?
    user.present?
  end

private

  def user_from_omniauth
    # Authenticate with omniauth
  end

  def user_with_password
    # Authenticate with password
  end
end