people = []
purposes = {}

payment = {}
total = 0.0

(File.read("muenchen-2005.rech") + "\n\n---\n").each { |line|
  line.chomp!
  next  if line =~ /^ *(#|$)/       # emacs: /

  if line == "---"
    puts
    puts payment.map { |don, v|
      v.map { |rec, n|
        if n == 0
          nil
        elsif n > 0
          "%s -> %s: %.2f" % [rec, don, n]
        else
          "%s -> %s: %.2f" % [don, rec, -n]
        end
      }
    }.flatten.compact.sort

    payment.each { |name, v|
      v.each { |other, w|
        v[other] = 0.0
      }
    }
    next
  end

  if line =~ /^-(\w+)/
    people.delete $1
    next
  end

  name, money, reason = line.split "\t"
  money = money.to_f
  total += money
  people = (people << name).uniq
  (purposes[name] ||= []) << reason  if reason =~ /\w/

  na = name
  (people-[na]).each { |ot|
    next  if money == 0
    pay = money/people.size
    
    if na > ot
      other, name = na, ot
      pay = -pay
    else
      name, other = na, ot
    end
    
    payment[name] ||= {}
    payment[name][other] ||= 0
    payment[name][other] += pay
  }

}

avg = total / people.size

puts
puts "%d Leute, %.2f pro Person (Cashflow: %.2f)" % [people.size, avg, total]
purposes.each { |name, purp|
  unless purp.empty?
    puts "#{name}: #{purp.join ', '}"
  end
}