Calculate installments

gistfile1.rb

MDR_1X = '3'
MDR_3X = '3.35'
MDR_6X = '3.35'
MDR_12X = '4.8'
ANTECIPATION_FEE = '0'
FREE_INSTALLMENTS = 3
PASS_MDR = :full

def calculate_installments(amount, installments)
  if installments ==  1
	fee = MDR_1X
  elsif installments > 1 && installments <= 3
	fee = MDR_3X
  elsif installments > 3 && installments <= 6
	fee = MDR_6X
  elsif installments > 6 && installments <= 12
	fee = MDR_12X
  end

  if PASS_MDR == :full
	liquid_value = amount / (1 - fee.to_f/100)
  elsif PASS_MDR == :partial
	liquid_value = amount / (1 - (fee.to_f - MDR_1X.to_f)/100)
  else
	liquid_value = amount * (1 - mdr_1x.to_f/100)
  end

  if installments > FREE_INSTALLMENTS
	total_value = liquid_value / (1 - (ANTECIPATION_FEE.to_f/100) * (installments + 1)/2)
  else
	total_value = amount
  end
end

amount = ARGV[0].to_f

puts "Repassando MDR total? #{(PASS_MDR == :full) ? 'SIM' : 'NÃO'}"
puts "Repassando MDR parcial? #{(PASS_MDR == :partial) ? 'SIM' : 'NÃO'}"
puts "Quantas parcelas sem juros? #{FREE_INSTALLMENTS}"

12.times do |i|
  total_value = calculate_installments(amount, i+1).round(2)
  each_installment = (total_value / (i+1)).round(2)
  puts "#{i+1} Parcela(s) - Valor total: #{total_value}, Valor por parcela: #{each_installment}"
end