concord-consortium/rigse

# adds object#changeable? method which retruns true
# if user has admin or manager roles or
# if user is the author of object or
# if the object is the User object for this user
# otherwise return false
module Changeable

  def changeable?(user)
    # the Anonymous user can't change anything, always return false
    if(user.anonymous?)
      return false

    # admin and manager users can change everything the system delivers to them
    elsif user.has_role?("admin", "manager")
      true

    # Some things (eg: portal_clazes) might havemultiple owners (users)
    # So provide alternate "is_user?" pattern for those cases.
    # is_user? should take precedence, because "user" is more ambiguous
    # in the case of models with multiple owners
    elsif self.respond_to?(:is_user?)
      if self.is_user?(user)
        true
      else
        false
      end

    # is this object a User object?
    # if so a normal User can only change their own User object
    elsif self.respond_to?(:user)
      if self.user == user
        true
      else
        false
      end

    # if this object is owned and the user is the owner return true
    elsif owned?
      self.user == user

    # else return false
    else
      false
    end
  end

  def owned?
    if self.respond_to? :user
      if self.user.nil?
        return false
      end
      if self.user.anonymous?
        return false
      end
      true
    else
      false
    end
  end

  def un_owned?
    return (! self.owned?)
  end
end