class ExecutionEnvironment < ActiveRecord::Base
  include Creation

  VALIDATION_COMMAND = 'whoami'

  has_many :exercises
  has_many :hints

  scope :with_exercises, -> { where('id IN (SELECT execution_environment_id FROM exercises)') }

  validate :valid_test_setup?
  validate :working_docker_image?, if: :validate_docker_image?
  validates :docker_image, presence: true
  validates :name, presence: true
  validates :permitted_execution_time, numericality: {only_integer: true}, presence: true
  validates :run_command, presence: true

  def to_s
    name
  end

  def valid_test_setup?
    if test_command? ^ testing_framework?
      errors.add(:test_command, I18n.t('activerecord.errors.messages.together', attribute: I18n.t('activerecord.attributes.execution_environment.testing_framework')))
    end
  end
  private :valid_test_setup?

  def validate_docker_image?
    docker_image.present? && Rails.env != 'test'
  end
  private :validate_docker_image?

  def working_docker_image?
    DockerClient.pull(docker_image) unless DockerClient.image_tags.include?(docker_image)
    output = DockerClient.new(execution_environment: self).execute_command(VALIDATION_COMMAND)
    errors.add(:docker_image, "error: #{output[:stderr]}") if output[:stderr].present?
  rescue DockerClient::Error => error
    errors.add(:docker_image, "error: #{error}")
  end
  private :working_docker_image?
end