refactoring_met.rb

# Example of refactoring long method. 

def self.get_troubled_reasons(where_cond, session_country)
  reasons = (1..18).map { |e| "TR#{e.to_s.rjust(3, '0')}" }
  query = reasons.map do |reason|
    "SUM(CASE WHEN reason_code LIKE '%#{reason}%' THEN 1 ELSE 0 END) AS #{reason}"
  end.join(',')

  TroubledOrder.joins(:order).select(query).where(orders: { country_code: session_country }).where(where_cond).first
end

# def self.get_troubled_reasons(where_cond, session_country)
#     troubled_reason = TroubledOrder.joins(:order).select(
#       "SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR001,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR002,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR003,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR004,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR005,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR006,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR007,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR008,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR009,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR010,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR011,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR012,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR013,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR014,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR015,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR016,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR017,
#       SUM(CASE WHEN reason_code LIKE '%TR001%' THEN 1 ELSE 0 END) AS TR018"
#     ).where("orders.country_code = '#{session_country}'").where(where_cond).first

#     troubled_reason
#   end