XML to CSV for Less Accounting

XMLtoCSV.rb

require 'nokogiri'
require 'csv'

@xml = Nokogiri::XML(open("Old-Accounting-System.xml"))
@csv = CSV.open("output.csv", "w")

def populate(opts = Hash.new(0))
  fields = []
  payload = []
  opts.each do |k,v|
    fields << k
    payload << v
  end
  @csv << CSV::Row.new(fields, payload)
end

def get_business_id_for(proposal_id)
  @xml.xpath('//invoice').each do |line|
    if line.text.include? proposal_id 
      return line.xpath('contact-id').text
    end
  end
end


fields = %w(account_number business_name)
@csv << CSV::Row.new(fields, fields)
@xml.xpath('//contact').each do |contact|
  id = contact.xpath('id').text
  business_name = contact.xpath('company-name').text
  name = contact.xpath('name').text
  if business_name.empty?
    business_name = name
  end
  if name.empty?
    name = "N/A"
  end
  populate(
    account_number: id,
    business_name: "#{business_name} (#{name})"
  )
end

fields = []
@csv << CSV::Row.new(fields, fields)
fields = %w(business_id proposal_id created_at type_of_work description quantity unit_price total)
@csv << CSV::Row.new(fields, fields)

@xml.xpath('//line-item').each do |line|
  business_id = get_business_id_for(line.xpath('proposal-id').text)
  if business_id.is_a? String
    populate(
      business_id:    business_id, 
      proposal_id:    line.xpath('proposal-id').text,
      created_at:     line.xpath('created-at').text,
      type_of_work:   line.xpath('line').text,
      description:    line.xpath('additional-description').text,
      quantity:       line.xpath('quantity').text,
      unit_price:     line.xpath('unit-price').text,
      total:          line.xpath('total').text
    )
  end
end

`open output.csv`