module RememberParams

# File lib/remember_params.rb, line 7
def self.remember_params(*params, on: :index, duration: 1.hour)
  on = on.to_s

  raise '[remember_params] must specify one or more params to remember' if
    params.empty?
  raise '[remember_params] param name remembered_at is reserved' if
    params.include? :remembered_at
  raise '[remember_params] \'for\' must be ActiveSupport::Duration' unless
    duration.is_a?(ActiveSupport::Duration)
  raise '[remember_params] \'for\' must be gte 1 second' unless
    duration >= 1.second

  cattr_accessor :remember_params_config
  self.remember_params_config ||= {}
  self.remember_params_config[on] = {}
  self.remember_params_config[on][:params] = params
  self.remember_params_config[on][:duration] = duration

  self.before_action :restore_or_save_params
end

# File lib/remember_params.rb, line 29
def restore_or_save_params
  return unless request.get?
  return unless respond_to? :remember_params_config
  return unless config = self.remember_params_config[action_name]

  session[:remembered_params] ||= {}
  key = params.slice(:controller, :action).values.join('/').parameterize
  params_to_remember = params.permit(*config[:params]).to_h

  # Restore params
  if params_to_remember.empty? &&
    session[:remembered_params][key]&.except('remembered_at')&.select{|_,v| v.present?}&.any? &&
    DateTime.parse(session[:remembered_params][key]['remembered_at']) >
      (DateTime.now - config[:duration])
  then
    redirect_to params: session[:remembered_params][key].except('remembered_at')
  end

  # Save params (also refreshes remembered_at after restore)
  if params_to_remember.any?
    params_to_remember['remembered_at'] = DateTime.now
    session[:remembered_params][key] = params_to_remember
  end
end