#This is a class that is used to time program run times

import time

class Stopwatch:
	#Initialize the class and all the variables you will need
	def __init__(self):
		self.timeStarted = 0.0		#This variable holds the time that the start function was called
		self.timeStopped = 0.0		#This variable holds the time that the stop function was called
		self.started = False		#This variable holds true after the start function has been called
		self.finished = False	#This variable holds true after the start and stop functions have been called

	#Save the time at this point. Simulates starting a stopwatch
	def start(self):
		self.started = True
		self.finished = False
		self.timeStarted = time.perf_counter_ns()

	#Save the time at this point. Simulates stopping a stopwatch
	def stop(self):
		#If the stopwatch has been started then you record the stopping time
		if(self.started):
			self.timeStopped = time.perf_counter_ns()
			self.finished = True
		#Otherwise just ignore the function call

	#Returns the difference between two times, usually start and stop times, but can be start time and now
	#Simulates looking at the stopwatch; it can still be running when you look at it
	def getTime(self):
		#If the start and stop function have been called then calculate the time between the calls
		if(self.finished):
			return (self.timeStopped - self.timeStarted)
		#If start was called but not stop calculate the time between start and now. Simulates looking at the watch while still running
		elif(self.started):
			return (time.perf_counter_ns() - self.timeStarted)
		#If start was never called return a negative number. In this context time can never be negative
		else:
			return -1

	#Return a specific resolution of time. This is done as a floating point number
	#Returns the result of getTime() in terms of seconds
	def getSeconds(self):
		second = self.getTime()
		if(second < 0):
			return second
		else:
			return (second / 1000000000)

	#Returns the result of getTime() in terms of milliseconds
	def getMilliseconds(self):
		milli = self.getTime()
		if(milli < 0):
			return milli
		else:
			return (milli / 1000000)

	#Returns the result of getTime() in terms of microseconds
	def getMicroseconds(self):
		micro = self.getTime()
		if(micro < 0):
			return micro
		else:
			return (micro / 1000)

	#Returns the result of getTime() in terms of nanoseconds
	def getNanoseconds(self):
		return self.getTime()