#!/usr/bin/env ruby
# encoding: UTF-8
require 'csv'
require 'iconv'

@converter = Iconv.new("ISO8859-15", "utf-8")

date = /\d\d [A-Z][a-z][a-z] \d\d\d\d/
string = /.*/
nothing = /^$/
amount = /£\d+\.\d\d/
money_in = [date, string, nothing, amount, amount]
money_out = [date, string, amount, nothing, amount]

def normalise(t)
  t.map { |s| s.to_s.gsub("\xA3".force_encoding(Encoding.aliases["ISO8859-15"]), "£").force_encoding(Encoding.default_external) }
end

def transaction_type(array, pattern)
  !array.empty? && array.zip(pattern).inject(true) {|m, (string, pattern)| m && string =~ pattern}
end

def date(transaction)
  Date.parse(transaction[0]).strftime("%d/%m/%Y")
end

def description(transaction)
  transaction[1].strip[0..31]
end

def outgoing(transaction)
  transaction[2].gsub("£", "-")
end

def incoming(transaction)
  transaction[3].gsub("£", "")
end

CSV.open(ARGV[1], "wb") do |o|
  CSV.foreach(ARGV[0], :encoding => Encoding.aliases["ISO8859-15"]) do |t|
    t = normalise(t)
    if transaction_type(t, money_in)
      o << [date(t), incoming(t), description(t)]
    elsif transaction_type(t, money_out)
      o << [date(t), outgoing(t), description(t)]
    end    
  end
end