Transpose transformer

transpose_transformer.rb

module TransformationEngine
  ##
  # This class is for transpose the rows
  class TransposeTransformer < BaseTransformer
    attr_accessor :fixed_cols, :varying_cols

    def initialize(rule_hash)
      super(rule_hash)
      self.type = 'collection'
      self.fixed_cols = rule_hash[:fixed_cols].split(',').map(&:to_sym)
      self.varying_cols = rule_hash[:varying_cols]
    end

    def process(rows)
      rows.map { |row| process_row(row) }.flatten
    end

    def process_row(row)
      fixed_row = row.select { |key, value| fixed_cols.include?(key) }
      varying_cols.map do |cols|
        cols = cols.split(',').map(&:to_sym)
        result_row = fixed_row.clone
        cols.each do |col|
          result_row = row[col]
        end
        result_row
      end
    end
  end
end