#!/usr/bin/env ruby
# morea-watch.rb dport@hawaii.edu 
# Adapted from watch.rb by Brett Terpstra, 2011 <http://brettterpstra.com>
# with credit to Carlo Zottmann <https://github.com/carlo/haml-sass-file-watcher>
# 
# This file must be in the same directory as morea-run-local.sh
#
# *Warning* If you watch a folder (or subfolder) that jekyll generates files in when run in it may unpleasantly 
# stop and re-start for each generated file since we don't check when output is completed 
# after forking morea-run-local (probably should do this though...)
#

if RUBY_PLATFORM =~ /mswin32/ then
 puts "Sorry, morea-watch does not work on Windows"
 exit
end

def fork_MOREA()
# stdout, stderr pipes
	rout, wout = IO.pipe
	rerr, werr = IO.pipe

	pid = Process.spawn("./morea-run-local.sh", :out => wout, :err => werr)
	Process.detach(pid)
	
# Wait until we see the MOREA server is running 
	until (line=rout.gets) =~ /Server running/ 
    	puts(line) 
  	end
	wout.close
	werr.close
	
	return pid 
end

trap("SIGINT") { exit }

if ARGV.length > 1
  puts "Usage: #{$0} watch_folder"
  puts "Example: #{$0} ./master/src/morea"
  exit
elseif ARGV.length == 1
  watch_folder = watch_folder = ARGV[0]
else 
  watch_folder = "./master/src/morea"
end

filetypes = ['css','html','htm', 'js', 'md']


morea_pid = fork_MOREA

puts "Watching #{watch_folder} and subfolders for changes in project files..."

while true do
  files = []
  filetypes.each {|type|
    files += Dir.glob( File.join( watch_folder, "**", "*.#{type}" ) )
  }
  new_hash = files.collect {|f| [ f, File.stat(f).mtime.to_i ] }
  hash ||= new_hash
  diff_hash = new_hash - hash

  unless diff_hash.empty?
    hash = new_hash
    
    diff_hash.each do |df|
      puts "Detected change in #{df[0]}"
    end
    
    unless `pgrep -f .*morea-run-local.*` == ""
    
      base=Process.pid
      descendants = Hash.new{|ht,k| ht[k]=[k]}
      Hash[*`ps -eo pid,ppid`.scan(/\d+/).map{|x|x.to_i}].each{|pid,ppid|
        descendants[ppid] << descendants[pid]
      }
      descendants[base].flatten - [base]
      kills = descendants[base].flatten - [base]
      kills.each do |cpid|
        begin
          puts "killing pid #{cpid}"
          Process.kill("SIGTERM", cpid)
        rescue
          next
        end
      end
      Process.waitall
      puts "goodby pid #{morea_pid}, restarting MOREA"
    end
    morea_pid = fork_MOREA
# If using Chrome, tell it to reload the page so changes can be seen
    `osascript -e 'tell application "Google Chrome" to tell the active tab of its first window to reload'`
  end
  sleep 1
end