module AceOfBase
  # Aggregates records together.
  class AggregatedRecord
    def initialize(records, aggregations)
      @records = records
      @aggregations = aggregations
    end

    AceOfBase::Record::ATTRIBUTES.each do |field|
      define_method field do
        aggregate_field(field)
      end
    end

    private

    attr_reader :records, :aggregations

    def aggregate_field(field)
      return records.first.public_send(field) unless aggregations.keys.include?(field)

      send("aggregate_field_with_#{aggregations[field]}", field)
    end

    def aggregate_field_with_min(field)
      records
        .map { |record| record.public_send(field) }
        .min
    end

    def aggregate_field_with_max(field)
      records
        .map { |record| record.public_send(field) }
        .min
    end

    def aggregate_field_with_sum(field)
      records
        .map { |record| record.public_send(field) }
        .reduce(:+)
    end

    def aggregate_field_with_count(field)
      records
        .map { |record| record.public_send(field) }
        .uniq
        .size
    end

    def aggregate_field_with_collect(field)
      records
        .map { |record| record.public_send(field) }
        .uniq
    end
  end
end