Thor autocomplete

thor_autocomplete.rb

#!/usr/bin/env ruby

# Complete thor tasks script for bash
# Save it somewhere and then add
# complete -C path/to/script -o default thor
# to your ~/.bashrc

require 'fileutils'

THORFILES = ['thorfile', 'Thorfile', 'thorfile.rb', 'Thorfile.rb', '*.thor']
thor_files = THORFILES.flat_map { |rf| Dir[File.join(Dir.pwd, rf)] }
exit 0 unless thor_files.any?
exit 0 unless /^thor\b/ =~ ENV["COMP_LINE"]

after_match = $'
task_match = (after_match.empty? || after_match =~ /\s$/) ? nil : after_match.split.last

cache_dir = File.join( ENV['HOME'], '.thor_tc_cache' )
FileUtils.mkdir_p cache_dir

cache_file = File.join(cache_dir, Dir.pwd.gsub( %r{/}, '_' ))

last_task_update = thor_files.map { |file| File.mtime(file) }.max

if File.exist?(cache_file) && File.mtime(cache_file) >=  last_task_update
  task_lines = File.read(cache_file)
else
  task_lines = `thor list`
  File.write(cache_file, task_lines)
end

tasks = task_lines.split("\n")[1..-1].collect {|line| line.split[1]}
tasks = tasks.select {|t| /^#{Regexp.escape task_match}/ =~ t} if task_match

# handle namespaces
if task_match =~ /^([-\w:]+:)/
  upto_last_colon = $1
  after_match = $'
  tasks = tasks.collect { |t| (t =~ /^#{Regexp.escape upto_last_colon}([-\w:]+)$/) ? "#{$1}" : t }
end

puts tasks
exit 0