def login
    # Check that the use is not already logged in
    unless session[:rbac_user].nil?
      redirect_with_notice_or_render 'You are already logged in.',
        'active_rbac/login/already_logged_in'
      return
    end

    # Set the location to redirect to in the session if it was passed in through
    # a parameter and none is stored in the session.
    if session[:return_to].nil? and !params[:return_to].nil?
      session[:return_to] = params[:return_to]
    end

    # Simply render the login form on everything but POST.
    logger.info "Log: " + request.method.to_s
    return unless request.method == :post

    # Handle the login request otherwise.
    @errors = Array.new

    # If login or password is missing, we can stop processing right away.
    raise ActiveRecord::RecordNotFound if params[:login].to_s.empty? or params[:password].to_s.empty?

    # Try to log the user in.
    user = User.find_with_credentials(params[:login], params[:password])

    # Check whether a user with these credentials could be found.
    raise ActiveRecord::RecordNotFound unless not user.nil?

    # Check that the user has the correct state
    raise ActiveRecord::RecordNotFound unless User.state_allows_login?(user.state)

    # Write the user into the session object.
    write_user_to_session(user)

    session[:return_to] = '/articles'

    redirect_with_notice_or_render 'You have logged in successfully.',
      'active_rbac/login/login_success'
  rescue ActiveRecord::RecordNotFound
    # Add an error and let the action render normally.
    @errors << 'Invalid user name or password!'
  end

def redirect_with_notice_or_render(notice, template)
 if session[:return_to].nil?
   render :template => template
 else
   flash[:notice] = notice
   redirect_to session[:return_to]
   session[:return_to] = nil
 end
end