compute reporting for destination groups

report.rb

monthly_reports = []
date = '10-10'
 Journal.only('_id').where(:account.in => accounts, :date => Regexp.new(date)).each do |j|
  j.reload
  entries = j.billing_entries.to_a
  existing_report_for_account = monthly_reports.find_index do |account|
      account[:journal] == j.account
  end
  if existing_report_for_account
    monthly_report = monthly_reports[existing_report_for_account]
  else
    monthly_report = {:journal => j.account}
  end

  destinations_groups = {
      :total => ['select', '.*'],
      :france => ['select', '(france_fixe|france_olo)'],
      :france_mobile => ['select', 'france_(gsm|mobile)'],
      :etranger => ['reject', 'france']
  }
  destinations_groups.each do |destination_group, pattern|
    unless monthly_report[destination_group]
      monthly_report[destination_group] = {}
    end

    %w(count duration total_cost).each do |indicator|

      block = Proc.new { |e| e.destination =~ Regexp.new(pattern[1]) }
      value = case indicator

                when 'count'
                  entries.__send__( pattern[0].to_sym,  &block ).count
                else
                  entries.__send__( pattern[0].to_sym, &block).sum(&indicator.to_sym)
              end
      if monthly_report[destination_group][indicator] != nil
        monthly_report[destination_group][indicator] += value
      else
        monthly_report[destination_group][indicator] = value
      end
    end

  end
  (existing_report_for_account != nil) && (monthly_reports[existing_report_for_account] = monthly_report) || monthly_reports << monthly_report

end