#!/usr/bin/env ruby
#
# git watchlist - report changes in certain files only
#
# To use this, create a file `.git/watchlist' which is simply a list of files
# that you want to monitor, one file per line. Populate it with `fd' or `find'
# or `git ls-files | grep'. Then, `git watchlist <range>' can be used to get a
# changelog for only those files you care about.
#
# This is very useful in a post-checkout script, so you can quickly see what
# changed in the files you care about every time you pull from upstream.

require 'optparse'

gitdir = `git rev-parse --git-common-dir`.chomp
watchlist = File.readlines(gitdir+"/watchlist").map(&:chomp).join(' ')
opts = {}

OptionParser.new do |opt|
  opt.banner = "usage: git watchlist [--short|--stat] <range>"
  opt.on('--short') do
    opts[:short] = true
  end
  opt.on('--stat') do
    opts[:stat] = true
  end
end.parse!

if opts[:short]
    puts `git shortlog --no-merges #{ARGV[0]} -- #{watchlist}`
elsif opts[:stat]
    puts `git log --stat --color=always --no-merges #{ARGV[0]} -- #{watchlist}`
else
    puts `git log --color=always --no-merges #{ARGV[0]} -- #{watchlist}`
end