#!/usr/bin/env ruby

abort "No tempfile given" if ARGV.empty?

commit_file = ARGV[0]

commit_msg = File.read(commit_file)
abort "No commit given" if commit_msg.nil?

branch_match = commit_msg.match(%r{# On branch (?<ticket>[A-Z]{1,10}-\d+)})

if branch_match.nil? or branch_match["ticket"].nil?
  puts "Could not extract a ticket from the commit message"
  exit
end

ticket = branch_match["ticket"]
new_commit = "#{ticket}: \n" + commit_msg
File.write(commit_file, new_commit, mode: "w")