create ledger entries for repeating transactions

ledger-envelope-generator.rb

#!/bin/env ruby
# (C) 2015 Thomas R. Koll, <info@ananasblau.com>
# licensed under WTFPL
#
# This script generates entries for the ledger format.
# Think of it as an envelope generator

require 'highline'
require 'date'
require 'active_support/core_ext/date/calculations'
require 'active_support/core_ext/numeric/time'

def add_repeat(date, r)
  case(r)
    when 'daily'
      return date.next_day
    when 'weekly'
      return date + 7
    when 'monthly'
      return date.next_month
    when 'yearly'
      return date.next_year
  end
  interval = r.match(/^([.\d]+)/)
  if interval.nil?
    puts "Bad interval"
    return false
  end
  interval = interval[1].to_f
  if r.match /days/
    return date + interval
  elsif r.match /months/
    interval.to_i.times {|i| date = date.next_month }
    return date
  else
    puts "Bad interval"
    return
  end
end

cli = HighLine.new

date_format = "%Y/%m/%d" 
last_date = Date.today
transaction = {}
transaction[:start_date] = cli.ask("Date [%s]: " % last_date.strftime(date_format), Date) {|q| q.default = last_date }
transaction[:description] = cli.ask("Description (use # for the counter): ")
transaction[:account1] = cli.ask("Account 1: ")
transaction[:amount1] = cli.ask("Amount 1: ")
transaction[:account2] = cli.ask("Account 2: ")
negative_amount = "-" + transaction[:amount1] 
transaction[:amount2] = cli.ask("Amount 2 [%s]: " % negative_amount) {|q| q.default = negative_amount}
transaction[:repeat] = cli.ask("Repeat (yearly, monthly, weekly, daily, N days, N months): ", lambda {|s| s.strip } ) do |q|
  q.validate = /([\d.]+ (days|months)|yearly|monthly|weekly|daily)/
end
transaction[:times] = cli.ask("How often: ", Integer)

date = transaction[:start_date]
transaction[:times].times.each do |i|
  puts "%s %s" % [date.strftime(date_format), transaction[:description].gsub("#", (i + 1).to_s)]
  puts "\t%s    %s" % [transaction[:account1], transaction[:amount1]]
  puts "\t%s    %s" % [transaction[:account2], transaction[:amount2]]
  puts ""
  date = add_repeat(date, transaction[:repeat])
end