#!/usr/local/bin/ruby

# ABC metric
#
# Assignments, Branches, and Calls
#
# A simple way to measure the complexity of a function or method.

begin
  require 'rubygems'
  require_gem 'ParseTree'
rescue LoadError
  require 'parse_tree'
end

  require 'sexp_processor'

old_classes = []
ObjectSpace.each_object(Module) do |klass|
  old_classes << klass
end

ARGV.each do |name|
  require name
end

new_classes = []
ObjectSpace.each_object(Module) do |klass|
  new_classes << klass
end

score = {}

new_classes -= old_classes

klasses = Sexp.from_array(ParseTree.new.parse_tree(*new_classes))
klasses.each do |klass|
  klass.shift # :class
  klassname = klass.shift
  klass.shift # superclass
  methods = klass

  methods.each do |defn|
    a=b=c=0
    defn.shift
    methodname = defn.shift
    tokens = defn.structure.flatten
    tokens.each do |token|
      case token
      when :attrasgn, :attrset, :dasgn_curr, :iasgn, :lasgn, :masgn then
        a += 1
      when :and, :case, :else, :if, :iter, :or, :rescue, :until, :when, :while  then
        b += 1
      when :call, :fcall, :super, :vcall, :yield then
        c += 1
      when :args, :argscat, :array, :begin, :block, :block_arg, :block_pass, :bool, :cfunc, :colon2, :const, :cvar, :defined, :defn, :dregx, :dstr, :dvar, :dxstr, :ensure, :false, :fbody, :gvar, :hash, :ivar, :lit, :long, :lvar, :match2, :match3, :nil, :not, :nth_ref, :return, :scope, :self, :splat, :str, :to_ary, :true, :unknown, :value, :void, :zarray, :zarray, :zclass, :zsuper then
        # ignore
      else
        puts "unhandled token #{token.inspect}" if $VERBOSE
      end
    end
    key = ["#{klassname}.#{methodname}", a, b, c]
    val = a+b+c
    score[key] = val
  end
end

puts "Method = assignments + branches + calls = total"
puts
count = 1
ta = tb = tc = tval = 0
score.sort_by { |k,v| v }.reverse.each do |key,val|
  name, a, b, c = *key
  ta += a
  tb += b
  tc += c
  tval += val
  printf "%3d) %-50s = %2d + %2d + %2d = %3d\n", count, name, a, b, c, val
  count += 1
end
printf "%3d) %-50s = %2d + %2d + %2d = %3d\n", count, "Total", ta, tb, tc, tval