Searchable Concern

searchable.rb

module Searchable
  extend ActiveSupport::Concern

  included do
    self.whitelist = {}
    self.joins_whitelist = []

    scope :search, -> (search_string){ joins(joins_actable_query).joins(joins_whitelist).where(make_search_query search_string) }
  end

  module ClassMethods
    attr_accessor :whitelist
    attr_accessor :joins_whitelist

    def search_whitelist *args
      act_as_attributes = []
      if name.constantize.methods.include? :acting_as_model
        act_as_attributes = name.constantize.acting_as_model.columns.map{|column| column.name if column.sql_type == "character varying" and column.name != "actable_type"}.compact
      end

      args.each do |arg|
        case arg.class.name.to_sym
        when :Array
          if whitelist[arg[0].to_s.camelcase.constantize.name]
              whitelist[arg[0].to_s.camelcase.constantize.name] << arg[1].to_s
          else
              whitelist[arg[0].to_s.camelcase.constantize.name] = [arg[1].to_s]
          end

          joins_whitelist << arg[0].to_sym if name.constantize.reflect_on_all_associations(:belongs_to).map(&:name).include?(arg[0].to_sym) and !joins_whitelist.include?(arg[0].to_s)

        when :Symbol, :String
         table_name = if act_as_attributes.include? arg.to_s
                        name.constantize.acting_as_model.to_s
                      else
                        name
                      end

         if whitelist[table_name]
            whitelist[table_name] << arg.to_s
         else
            whitelist[table_name] = [arg.to_s]
        end
        end
      end
    end

    private

    def make_search_query string
      query = ""
      whitelist.each do |key, value|
        sub_query = (key.constantize.columns.map{|column| column.name if column.sql_type == "character varying"}.compact & value)
                    .inject("") { |query, column|
                                        if query == ""
                                          "#{key.constantize.table_name}.#{column} ILIKE '%#{string}%'"
                                        else
                                          "#{query} OR #{key.constantize.table_name}.#{column} ILIKE '%#{string}%'"
                                        end
                                }

        query = if query == ""
                  sub_query
                else
                  "#{query} OR #{sub_query}"
                end
      end
      query
    end

    def joins_actable_query
        if name.constantize.methods.include? :acting_as_model
          "LEFT JOIN #{name.constantize.acting_as_model.table_name}
          ON #{name.constantize.acting_as_model.table_name}.actable_id = #{name.constantize.table_name}.id
          AND #{name.constantize.acting_as_model.table_name}.actable_type = '#{name}'"
        else
          ""
        end
    end
  end
end