1and1/yap

require 'active_support/concern'
require 'yap/exceptions'
require 'yap/column_mapper'
require 'yap/filter'

##
# ActiveRecords can be filtered by their attributes if either Yap or Filterable is included into the model. Filters can
# be applied through the filter or paginate scope. Multiple filters for the same attribute can be separated by comma,
# negative filters have a leading exclamation mark (!) and 'null' will be translated to the NULL value.
#
#   User.filtered('gender' => 'f')      # => All female users.
#   User.filtered(
#       'team_id' => '1,2',
#       'gender' => 'm'
#   )                                   # => All males of teams 1 and 2.
#   User.filtered('team_id' => '!null') # => All users with any team.
#   User.paginate(params)               # => Passing parameters in controller (http://localhost/users?filter[gender]=f)
#   User.paginate(
#       page:   1,
#       filter: { 'team' => 'null' }
#   )                                   # => Combining filter and pagination.
#
module Yap
  module Filterable
    extend ActiveSupport::Concern

    included do
      extend ColumnMapper

      ##
      # Filter scope can be invoked explicitly or implicitly by passing :filter to paginate.
      #
      # @param [Hash] Attribute/value pairs to filter ( { 'gender' => 'f' } )
      #
      scope :filtered, lambda { |params = nil|
        if params.blank?
          all
        else
          filter = extract_filter_params(params)
          where(filter.where).where.not(filter.not)
        end
      }

      def self.extract_filter_params(params)
        filter = Filter.new
        filter.parse!(self, params)

        filter
      end
    end
  end
end