#! /usr/local/bin/ruby

# load the fam bindings
require 'fam'

class TraverseDirWatcher
  def initialize(_path)
    @path = _path
    @childwatchers = Array.new

    # open a connection to FAM
    @fam = Fam::Connection.new $0

    # create watcher for child directory
    if FileTest.directory?(@path)
      puts "watch directory : #{@path}"
      
      dir = Dir.open(@path)
      while name = dir.read
        next if name == "."
        next if name == ".."

        # watch child directory
        childpath = @path + "/" + name
        if FileTest.directory?(childpath)
          childwatcher = TraverseDirWatcher.new(childpath)
          @childwatchers.push(childwatcher)
        end
      end
    end
  end

  def start_mon(_sleep)
    puts "start mon : #{@path}"

    @fam.monitor_dir(@path)

    @thread_mon = Thread.start {
      puts "thread start : #{@path}"
      start_time = Time.now
      loop {
        # if there are fam events pending, then process them
        if @fam.pending?
          ev = @fam.next_event
          targetfile = @path + "/" + ev.file

          case ev.code
          when Fam::Event::CHANGED
            # ignore child directory's change
            next if FileTest.directory?(targetfile)

            puts "File Changed(#{@path}) :" << targetfile
          when Fam::Event::DELETED
            # remove watcher of deleted dir
            @childwatchers.delete_if { |watcher|
              watcher.path == targetfile
            }

            puts "File Deleted(#{@path}) :" << targetfile
          when Fam::Event::CREATED
            # add watcher for created dir
            if FileTest.directory?(targetfile)
              newwatcher = TraverseDirWatcher.new(targetfile)
              newwatcher.start_mon(_sleep)

              @childwatchers.push(newwatcher)
            end

            puts "File Created(#{@path}) :" << targetfile
          end
        end
      
        sleep _sleep
      }
    }

    @childwatchers.each { |watcher|
      watcher.start_mon(_sleep)
    }
  end

  def stop_mon()
    @thread_mon.kill

    @childwatchers.each{ |watcher|
      watcher.stop_mon()
    }
  end

  attr_accessor :path
end

path = ARGV[0]
mon = TraverseDirWatcher.new(path)
mon.start_mon(1)
loop{ sleep 10; }