Bugspots

# File lib/bugspots/scanner.rb, line 8
def self.scan(repo, branch = "master", depth = 500, regex = nil)
  repo = Grit::Repo.new(repo)
  unless repo.branches.find { |e| e.name == branch }
    raise ArgumentError, "no such branch in the repo: #{branch}"
  end
  fixes = []

  regex ||= /fix(es|ed)?|close(s|d)?/

  tree = repo.tree(branch)

  commit_list = repo.git.rev_list({:max_count => false, :no_merges => true, :pretty => "raw", :timeout => false}, branch)
  Grit::Commit.list_from_string(repo, commit_list).each do |commit|
    if commit.message =~ regex
      files = commit.stats.files.map {|s| s.first}.select{ |s| tree/s }    
      fixes << Fix.new(commit.short_message, commit.date, files)
    end
  end

  hotspots = Hash.new(0)
  fixes.each do |fix|
    fix.files.each do |file|
      t = 1 - ((Time.now - fix.date).to_f / (Time.now - fixes.last.date))
      hotspots[file] += 1/(1+Math.exp((-12*t)+12))
    end
  end

  spots = hotspots.sort_by {|k,v| v}.reverse.collect do |spot|
    Spot.new(spot.first, sprintf('%.4f', spot.last))
  end

  return fixes, spots
end