payment_request.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'activesupport'
require 'chronic'
require 'optparse'

DAY_VALUE = 0       # regular value per day
WDAY_REGULAR = 1..5   # range for regular days 1..5 means from monday to friday
EXTRAS_VALUES = {
  :h => 0,          # value for an extra day with half time
  :f => 0           # value for an full extra day
}

options = {:billing_date => Date.current}

optparse = OptionParser.new do |opts|
  # to generate charge for extra days you can use the -e option, examples:
  #
  # ./payment_request -e 10f,11h
  #
  # example above will charge day 10 for full day extra and day 11 as half day,
  # note these days should be in the range of current charge time, otherwise
  # they will be ignored
  opts.on('-e', '--extra EXTRA') do |extra|
    options[:extra] = extra
  end

  opts.on('-b', '--billing BILLING_DATE') do |billing|
    billing_date = Chronic.parse(billing)
    options[:billing_date] = Chronic.parse(billing) if billing_date
  end
end

optparse.parse!

extras = []

if options[:extra]
  options[:extra].split(",").each do |extra|
    if extra =~ /(\d+)(f|h)/
      extras << [$1.to_i, $2]
    end
  end
end

def compute_start_finish(start, finish)
  start_print = start.strftime("%b %d")
  end_print = finish.strftime(start.month == finish.month ? "%d" : "%b %d")

  [start_print, end_print]
end

def compute_segment(segment)
  start = segment.first[0]
  finish = segment.last[0]
  ammount = segment.sum { |s| s[1] }

  sl, fl = compute_start_finish(start, finish)

  ["#{sl} ~ #{fl} - regular time: R$#{ammount}", ammount]
end

start_date = Chronic.parse("1 week before last monday", :now => options[:billing_date])
end_date = start_date + 2.weeks - 1.days

start_date = start_date.to_date
end_date = end_date.to_date

last_received = nil
segments = []
current_segment = []

(start_date..end_date).each do |date|
  if WDAY_REGULAR.include?(date.wday)
    current_segment << [date, DAY_VALUE]
  elsif extras.map {|e| e[0]}.include? date.day
    segments << compute_segment(current_segment) if current_segment.length > 0
    current_segment = []

    extra = extras.find { |e| date.day == e[0] }
    value = EXTRAS_VALUES[extra[1].to_sym]
    segments << [date.strftime("%b %d") + " - extra time: R$#{value}", value]
  else
    segments << compute_segment(current_segment) if current_segment.length > 0
    current_segment = []
  end
end

segments << compute_segment(current_segment) if current_segment.length > 0
total_ammount = segments.sum { |s| s[1] }

start_date_print, end_date_print = compute_start_finish(start_date, end_date)

output = <<EOS
Hi Laura

Im requesting the payment for the period of #{start_date_print} to #{end_date_print}.

#{segments.map {|s| s[0]}.join("\n")}

total: R$#{total_ammount}
EOS

puts output