#
# File:: RSNProfiler.rb
# Description:: A simpler profiler.
# Author:: Derek Ward <derek.ward@rockstarnorth.com>
# Date:: 14 April 2009
#

#----------------------------------------------------------------------------
# Uses
#----------------------------------------------------------------------------
# None

#----------------------------------------------------------------------------
# Implementation
#----------------------------------------------------------------------------
module Pipeline
	module Util
	
		# == Description
		# a simple timer/profiler class for profiling performance
		# eg. 
		#
		#	myTimer = RSNProfiler.new("mytimername")
		#		func()
		#	myTimer.end
		# 
		# OR ( with multiple samples counted )
		#
		#	myTimer = RSNProfiler.new("mytimername",false)
		#	10.times do
		#		myTimer.start
		#			func()
		#		myTimer.stop
		#	end
		#	myTimer.end
		
		class RSNProfiler
			@@verbose = true				# puts the results?
			@@display_detail = true			# detailed profile info?
			@@display_in_minutes = true		# allows you to disable the higher order display units, useful for comparitive display
			@@display_in_seconds = true		# allows you to disable the higher order display units, useful for comparitive display
			@@precision = "%0.4f"			# fractional precision formatting string
			
			# == Description
			# create the timer, and possibly start it running.
			def initialize( name = "RSNProfiler", startup = true )
				@name = name
				@elapsed = 0.0
				@samples = 0
				#Kernel.sleep(0.1) # 'supposedly' this might be required to address the update frequency of the Time class , but didn't work?
				start()	if startup		
			end
			
			# == Description
			# end the timer and optionally display it
			def end( display = true )
				stop( display )
			end
			
			# == Description
			# start the timer
			def start()
				@samples += 1
				@start = timestamp()
			end
			
			# == Description
			# stop/pause the timer and optionally display it
			def stop( display = false )
				@end = timestamp()			
				@elapsed += last_duration
				throw RuntimeError.new("End and Start times suspect : Start #{@start} End #{@end} Elapsed #{@elapsed}") if @elapsed < 0
				puts to_s if ( @@verbose and display )			
			end		
			
			def last_duration
				@end-@start
			end
			
			def to_s()
				@@display_detail ? to_s_detailed : to_s_simple
			end
						
			def to_s_detailed()
				"#{@name.to_s.ljust(25)} : (samples=#{@samples.to_s.rjust(8)}) : (mean=#{(@@precision % mean_milliseconds()).to_s.rjust(15)}ms) : (elapsed=#{elapsed_string.rjust(20)})"
			end		
			
			def to_s_simple()
				"#{@name.to_s.ljust(25)} : (elapsed=#{elapsed_string.rjust(20)})"		
			end
			
			def mean_milliseconds()
				elapsed_milliseconds/@samples
			end
			
			def elapsed_minutes()
				@elapsed / 60.0
			end
			
			def elapsed_seconds()
				@elapsed
			end
				
			def elapsed_milliseconds()
				@elapsed * 1000.0
			end
			
			private		
			def elapsed_string()
				return "#{(@@precision % elapsed_minutes).to_s.rjust(20)} mins" if elapsed_minutes > 1.0 and @@display_in_minutes
				return "#{(@@precision % elapsed_seconds).to_s.rjust(20)} secs" if elapsed_seconds > 1.0 and @@display_in_seconds
				return "#{(@@precision % elapsed_milliseconds).to_s.rjust(20)} ms"  				  
			end		
			
			# == Description
			# Return the time in micro seconds
			def timestamp()			
				#timestamp = Time.now.floor + (Time.now.usec/1000000.0) 
				#puts "timestamp : #{timestamp}"
				# DW - it looks suspect but sometimes the timestamp look very similar from call to call 
				#      however it seems to have worked in a test I've done.... to be tested a bit better when I get time.
				Time.now.to_f
			end			
		end # class RSNProfiler
	end # module util
end # module pipeline