Convert Itaú CSV extrato to OFX

csv_to_ofx.rb

# Modified from https://github.com/fgrehm/itau_to_ofx
def write_transaction(txn)
  type = txn[:amount] > 0 ? 'CREDIT' : 'DEBIT'                                                                                                                                                              
  date = txn[:date].strftime('%Y%m%d100000[-03:EST]')
  id = txn[:date].strftime("%Y%m%d#{txn[:inc].to_s.rjust(3, '0')}")
  memo = txn[:description]

  amount = '%.2f' % txn[:amount]

  "<STMTTRN>
  <TRNTYPE>#{type}
  <DTPOSTED>#{date}
  <TRNAMT>#{amount}
  <FITID>#{id}
  <CHECKNUM>#{id}
  <MEMO>#{memo}
  </STMTTRN>"
end

require 'csv'

csv = CSV.read("./dump.csv")
keys = csv.shift
keys = keys.map(&:to_sym)

txns = csv.map {|arr| keys.zip(arr).to_h}
txns.each {|a| a[:amount] = a[:amount].to_f}
txns.each {|a| a[:date] =  Date.strptime(a[:date], "%d/%m") }

gs = txns.group_by{|x| x[:date]}
ordered_txns = gs.values.each {|group| inc = 1; group.each {|y| y[:inc] = inc; inc+=1} }.flatten

puts ordered_txns.map {|a| write_transaction(a) }.join("\n")