class Bullet::Detector::UnusedEagerLoading

def add_eager_loadings(objects, associations)
  return unless Bullet.start?
  return unless Bullet.unused_eager_loading_enable?
  return if objects.map(&:id).compact.empty?
  Bullet.debug("Detector::UnusedEagerLoading#add_eager_loadings", "objects: #{objects.map(&:bullet_ar_key).join(', ')}, associations: #{associations}")
  bullet_ar_keys = objects.map(&:bullet_ar_key)
  to_add = nil
  to_merge, to_delete = [], []
  eager_loadings.each do |k, v|
    key_objects_overlap = k & bullet_ar_keys
    next if key_objects_overlap.empty?
    if key_objects_overlap == k
      to_add = [k, associations]
      break
    else
      to_merge << [key_objects_overlap, ( eager_loadings[k].dup  << associations )]
      keys_without_objects = k - bullet_ar_keys
      to_merge << [keys_without_objects, eager_loadings[k]]
      to_delete << k
      bullet_ar_keys = bullet_ar_keys - k
    end
  end
  eager_loadings.add *to_add if to_add
  to_merge.each { |k,val| eager_loadings.merge k, val }
  to_delete.each { |k| eager_loadings.delete k }
  eager_loadings.add bullet_ar_keys, associations unless bullet_ar_keys.empty?
end

def call_associations(bullet_ar_key, associations)
  all = Set.new
  eager_loadings.similarly_associated(bullet_ar_key, associations).each do |related_bullet_ar_key|
    coa = call_object_associations[related_bullet_ar_key]
    next if coa.nil?
    all.merge coa
  end
  all.to_a
end

def check_unused_preload_associations
  return unless Bullet.start?
  return unless Bullet.unused_eager_loading_enable?
  object_associations.each do |bullet_ar_key, associations|
    object_association_diff = diff_object_associations bullet_ar_key, associations
    next if object_association_diff.empty?
    Bullet.debug("detect unused preload", "object: #{bullet_ar_key}, associations: #{object_association_diff}")
    create_notification bullet_ar_key.bullet_class_name, object_association_diff
  end
end

def create_notification(klazz, associations)
  notify_associations = Array(associations) - Bullet.get_whitelist_associations(:unused_eager_loading, klazz)
  if notify_associations.present?
    notice = Bullet::Notification::UnusedEagerLoading.new(klazz, notify_associations)
    Bullet.notification_collector.add(notice)
  end
end

def diff_object_associations(bullet_ar_key, associations)
  potential_associations = associations - call_associations(bullet_ar_key, associations)
  potential_associations.reject { |a| a.is_a?(Hash) }
end