class UserBlock < ActiveRecord::Base
  validate :moderator_permissions

  belongs_to :user, :class_name => "User", :foreign_key => :user_id
  belongs_to :moderator, :class_name => "User", :foreign_key => :moderator_id
  belongs_to :revoker, :class_name => "User", :foreign_key => :revoker_id
  
  PERIODS = [0, 1, 3, 6, 12, 24, 48, 96]

  ##
  # returns true if the block is currently active (i.e: the user can't
  # use the API).
  def active?
    needs_view or end_at > Time.now.getutc
  end

  ##
  # revokes the block, allowing the user to use the API again. the argument
  # is the user object who is revoking the ban.
  def revoke!(revoker)
    attrs = { :end_at => Time.now.getutc(),
              :revoker_id => @user.id,
              :needs_view => false }
    revoker.moderator? and update_attributes(attrs)
  end

  private
  ##
  # validate that only moderators are allowed to change the
  # block. this should be caught and dealt with in the controller,
  # but i've also included it here just in case.
  def moderator_permissions
    errors.add_to_base("Must be a moderator to create or update a block.") if moderator_id_changed? and !moderator.moderator?
    errors.add_to_base("Must be a moderator to revoke a block.") unless revoker_id.nil? or revoker.moderator?
  end
end