module Spaceship
  module Tunes
    class << self
      # This client stores the default client when using the lazy syntax
      # Spaceship.app instead of using the spaceship launcher
      attr_accessor :client

      # Authenticates with Apple's web services. This method has to be called once
      # to generate a valid session. The session will automatically be used from then
      # on.
      # 
      # This method will automatically use the username from the Appfile (if available)
      # and fetch the password from the Keychain (if available)
      # 
      # @param user (String) (optional): The username (usually the email address)
      # @param password (String) (optional): The password
      # 
      # @raise InvalidUserCredentialsError: raised if authentication failed
      # 
      # @return (Spaceship::Client) The client the login method was called for
      def login(user = nil, password = nil)
        @client = TunesClient.login(user, password)
      end
    end
  end
end