=begin

The purpose of this code was to write a little practice program that would enable me to generate a thread safe way of writing strings to a logfile.  I would also like to use the Queue with my threads.  I read that it was thread safe in my handbook.  The reason why this is helpful is because it is more efficient to buffer a fixed number of reports before writing it to a file rather than continuously writing to a file every time a single string is received.  As you can see, I haven't even gotten to a point where I could write to a file.  For some reason, I never seem to get the first thread inside of the synchronize method inside of thread_queuetest().  I am open to any suggestions.  Sorry if this is pretty complicated.

=end


require 'thread'
require 'monitor'

class ReportManagement

   def Initialize()

      @queuemax = 256
      @queue = queue.new
      @queue.extend(MonitorMixin)
      @maxed_reports_cond = @queue.new_cond
      @shutdown_ok = false
   end

   def ts_reportlogs(outfile)

      if(outfile.class != File)

         print "invalid arguments passed into ReportManagement::ts_reportlogs()\n"
         exit
      end

      report_thread = Thread.new(outfile) {
          loop do
            @queue.synchronize do
                @maxed_reports_cond.wait_while {@queue.empty?}
                res = @queue.pop
                print "[!] Report #{Thread.current} dequeued #{res} from report buffer.\n"
             end
          end
      }
   end

   def self.open_logfile(filename=nil)
      filename ||= get_filename_from_time
      outfile = File.new(filename, File::WRONLY|File::CREAT|File::APPEND)
      return outfile
   end
   def thread_queuetest()

      threads = []

      1000.times do |x|
         threads << Thread.new(x) {

            @queue.synchronize do
               if(@shutdown_ok && queue.empty?)
                  break
               elsif(@queue.length >= @queuemax)
                  @maxed_reports_cond.signal
                  @queue.wait_while {@queue.length >= @queuemax}
               end
               @queue.enq("\"#{x} hello from #{Thread.current}\"")
            end
         }
      end
      threads.join
   end

   protected
   def self.get_filename_from_time
      t = Time.now()
      filename = t.strftime("%Y.%m.%d.%H.%M.%S.log")
   end
end

# instantiate the object that will manage a thread safe logging system
myobject = ReportManagement.new

# generate an output file for logging
outfile  = ReportManagement.open_logfile()

# populate a queue with simulated results from  multithreaded tasks
myqueue  = myobject.thread_queuetest()

# This is where we do the real work - write results to a file...
# in a threadsafe manner using mixins (signals/cond variables)
myobject.ts_reportlogs(outfile)
@shutdown_ok = true