mchail/mongoid_flaggable

module Mongoid
    module Flaggable
        module ClassMethods
            def flag_frequency
                aggregation = collection.aggregate([
                    {
                        '$match' => {
                            'flag_array' => {
                                '$ne' => nil
                            }
                        }
                    },
                    {
                        '$project' => {
                            'flag_array' => 1
                        }
                    },
                    {
                        '$unwind' => '$flag_array'
                    },
                    {
                        '$group' => {
                            '_id' => '$flag_array',
                            'count' => {
                                '$sum' => 1
                            }
                        }
                    }
                ])
                aggregation.map!(&:values)
                aggregation.sort_by! do |value|
                    value.last * -1
                end
                Hash[aggregation]
            end

            def by_all_flags(*flags)
                flags.flatten!
                where(:flag_array.all => flags)
            end
            alias_method :by_flag, :by_all_flags
            alias_method :by_flags, :by_all_flags

            def by_any_flags(*flags)
                flags.flatten!
                where(:flag_array.in => flags)
            end

            def flag_count(*flags)
                flags.flatten!
                if flags.size == 1
                    where(:flag_array => flags.first).count
                else
                    by_all_flags(flags).count
                end
            end

            def bulk_add_flag!(flag, conditions = {})
                where(conditions).add_to_set(:flag_array, flag.to_s)
            end

            def bulk_remove_flag!(flag, conditions = {})
                where(conditions).pull(:flag_array, flag.to_s)
            end

            def distinct_flags
                distinct :flag_array
            end
        end
    end
end