module WhitelistScope

# File lib/whitelist_scope.rb, line 18
def call_whitelisted_scope(*scope_names)
  existing_scope = nil

  scope_names.flatten.each do |scope_name|
    existing_scope = call_scope_by_name(existing_scope, scope_name)
  end
  existing_scope
end

# File lib/whitelist_scope.rb, line 6
def whitelist_scope(name, body)
  @whitelist ||= []
  name = name.to_sym

  if respond_to?(name)
    raise ArgumentError, "Could not create scope, There is an existing method with this name."
  end

  scope name, body
  @whitelist << name
end

# File lib/whitelist_scope.rb, line 29
def call_scope_by_name(existing_scope, scope_name)
  scope_name = scope_name.to_sym unless scope_name.nil?

  if @whitelist.include? scope_name
    if existing_scope
      existing_scope.send(scope_name)
    else
      send(scope_name)
    end
  else
    raise NoMethodError, "The scope you provided, '#{scope_name}', does not exist."
  end
end