git_core_stats

#!/usr/bin/env ruby 
#
#
# Quick and dirty script to extract some statistics about
# Rails core contributers.
#
# Usage: git_core_stats <path to rails git project>
# Example: git_core_stats ~/code/rails
#
# OR
#
# Example: cd ~/code/rails; /usr/local/bin/git_core_stats

class GitStats
  def initialize(directory=nil)
    @author = @committer = 0
    @contributers = []
    @directory = directory
    @core_members = [
      "David Heinemeier Hansson",
      "Jeremy Kemper",
      "Michael Koziarski",
      "Pratik Naik",
      "Joshua Peek",
      "Yehuda Katz",
      "José Valim",
      "Carl Lerche"
    ]
  end

  def reset!
    @author = @committer = 0
    @contributers = []
  end

  def run
    @core_members.each {|c| reset!; stats(c) }
  end

  def stats(name)
    @directory ||= "."
    command = "cd #{@directory}; git --no-pager log --format='%cn:%an' --committer='#{name}'"
    results = `#{command}`
    print_results(name, split_entries(results))
  end

  def split_entries(results)
    results.split("\n").each do |line|
      entry = line.split(":")
      if same?(entry)
        @author += 1
      else
        @committer += 1
      end
      @contributers << entry.last unless has_contributer?(entry.last)
    end
    {
      :total => @author + @committer, 
      :author => @author, 
      :author_percentage => (@author/(@author+@committer).to_f*100),
      :committer => @committer,
      :committer_percentage => (@committer/(@author+@committer).to_f*100)
    }
  end

  def has_contributer?(contributer)
    @contributers.include?(contributer)
  end

  def same?(entry)
    entry.first == entry.last
  end

  def print_results(name, results)
    puts "---------"
    puts "Git status for: #{name}\n"
    puts "Total commits: #{results[:total]}"
    puts "Commits by author: #{results[:author]} (#{results[:author_percentage]}%)\n"
    puts "Commits by someone else: #{results[:committer]} (#{results[:committer_percentage]}%)"
    puts "Total contributers: #{@contributers.count}"
  end
end

GitStats.new(ARGV.first).run