#!/usr/bin/env ruby

## git-rank-contributors: a simple script to trace through the logs and
## rank contributors by the total size of the diffs they're responsible for.
## A change counts twice as much as a plain addition or deletion.
##
## Output may or may not be suitable for inclusion in a CREDITS file.
## Probably not without some editing, because people often commit from more
## than one address.
##
## git-rank-contributors Copyright 2008 William Morgan <wmorgan-git-wt-add@masanjin.net>.
## This program is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or (at
## your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You can find the GNU General Public License at:
##   http://www.gnu.org/licenses/

class String
  def obfuscate; gsub(/@/, " at the ").gsub(/\.(\w+)(>|$)/, ' dot \1s\2') end
end

lines = {}
verbose = ARGV.delete("-v")
obfuscate = ARGV.delete("-o")

author = nil
state = :pre_author
`git log -p --no-color`.lines.each do |l|
  case
  when (state == :pre_author || state == :post_author) && l =~ /Author: (.*)$/
    author = $1
    state = :post_author
    lines[author] ||= 0
  when state == :post_author && l =~ /^\+\+\+/
    state = :in_diff
  when state == :in_diff && l =~ /^[\+\-]/
    lines[author] += 1
  when state == :in_diff && l =~ /^commit /
    state = :pre_author
  end
end

lines.sort_by { |a, c| -c }.each do |a, c|
  a = a.obfuscate if obfuscate
  if verbose
    puts "#{a}: #{c} lines of diff"
  else
    puts a
  end
end
