#!/usr/bin/env ruby
# Command of the day
# Picks a random executable from your path until it finds one with a manpage.
# Use this to learn about some of the really obscure yet really useful scripts that are already on your system.
DEBUG=ARGV.include?('--debug')

require 'timeout'

def debug(*args)
  puts args if DEBUG
  end

  def has_man_page?(cotd_basename)
    debug "  Looking for man-page for: #{cotd_basename}"
      man_path = Timeout::timeout(2) {`man -w #{cotd_basename} 2>&1`}
        if man_path.split("[\n\r]")[0].include?('No manual entry for')
            debug "  No man-page found.",""
                return false
                  end
                    debug "  man-page found at: #{man_path}",""
                      return true
                      rescue Timeout::Error
                        debug "    Timeout while looking for man-page for #{cotd_basename}"
                          false
                          end


                           files = ENV["PATH"].split(":").uniq.compact.map { |path|
                             Dir.glob(File.join(path,'*')).select {|file| File.file?(file) && File.executable?(file)}
                             }.flatten.compact.uniq
                             debug("#{files.size} commands found")

                              begin
                                cotd = files.sample rescue files[rand(files.size)]
                                  cotd_basename = File.basename(cotd)
                                    debug("Random command picked: #{cotd_basename} (#{cotd})")
                                    end until has_man_page?(cotd_basename)

                                    puts "Command of the day is: #{cotd}"
                                    if ARGV.include?('--man')
                                      exec "man #{cotd_basename}"
                                      else
                                        puts "Read more about it: `man #{cotd_basename}`"
                                          puts "Pass --man to automatically show the man-page."
                                          end