Display worked hours statistics based on git log

git_worked_hours.rb

#!/usr/bin/ruby

require 'date'

author="[email protected]"
period=(ARGV[0].to_i) || 30 # days
after = (DateTime.now - period).strftime('%Y-%m-%d')


log = %x{git log --all --author=#{author} --after=#{after} --date=iso-strict --pretty='%H|%cd'}

daily = {}

log.split(/\n/).each do |line|
  commit, date = line.split(/\|/)
  parsed_date = DateTime.parse(date)
  dk = parsed_date.strftime("%Y-%m-%d")

  if daily.has_key?(dk)
    daily[dk][:first_commit] = commit
    daily[dk][:start_date] = parsed_date
  else
    daily.store(dk, {
      first_commit: commit,
      last_commit: commit,
      start_date: parsed_date,
      end_date: parsed_date
    })
  end
end

def df(d)
  d.strftime('%H:%M')
end

puts "DATE        START   END   HOURS   VOLUME  DENSITY"

daily.each do |dk,daily|
  fc = daily[:first_commit]
  lc = daily[:last_commit]
  lc = "#{lc}~1" if fc == lc

  ed = daily[:end_date]
  sd = daily[:start_date]

  total_time = ((ed - sd) * 24).to_f.round(1)
  volume = %x{git diff #{fc} #{lc}}.size
  density = total_time > 0 ? (volume / total_time).round(0) : 0

  puts "#{dk}  #{df(sd)} ~ #{df(ed)} #{total_time.to_s.rjust(5)} #{volume.to_s.rjust(8)} #{density.to_s.rjust(8)}"
end