#!/usr/bin/env python
  
  import argparse, time, os
  import matplotlib.pyplot as plt
  
  #==============================================================================
  
  # Path
  PATH = os.getcwd()
  # File footer
  OFILENAME = '130'
  
  #==============================================================================
  
  def parse():

  	"""
  	Specific parsing procedure for transfering data from Thorlabs PM100D.
  	:returns: populated namespace (parser)
  	"""
  	parser = argparse.ArgumentParser(description = 'Acquire data from Thorlabs PM100D',
  									 epilog = 'Example: \'./pm100d.py -st 10 -o toto\' logs PM100D every 10 seconds to output file YYYYMMDD-HHMMSS-toto.dat')
  
  	parser.add_argument('-p',
  						action='store',
  						dest='path',
  						default=PATH,
  						help='Absolute path (default '+PATH+')')
  
  	parser.add_argument('-o',
  						action='store',
  						dest='ofile',
  						default=OFILENAME,
  						help='Output data filename (default '+OFILENAME+')')
  
  	args = parser.parse_args()
  	return args

  
  #==============================================================================
  
  class usbtmc:

  	def __init__(self, device):
  		self.device = device
  		self.FILE = os.open(device, os.O_RDWR)

  	def write(self, command):
  		os.write(self.FILE, command);

  	def read(self, length = 4000):
  		return os.read(self.FILE, length)

  	def getName(self):
  		self.write("*IDN?")
  		return self.read(300)

  	def sendReset(self):
  		self.write("*RST")

  
  #==============================================================================
  
  class instrument:

  	"""Class to control a SCPI compatible instrument"""
  	def __init__(self, device):
  		print 'Connecting to device %s...' %device
  		self.meas = usbtmc(device)
  		self.name = self.meas.getName()
  		print self.name
  		print '  --> Ok'
  
  	def write(self, command):
  		"""Send an arbitrary command directly to the scope"""
  		self.meas.write(command)
  
  	def read(self, command):
  		"""Read an arbitrary amount of data directly from the scope"""
  		return self.meas.read(command)
  
  	def reset(self):
  		"""Reset the instrument"""
  		self.meas.sendReset()
  
  	def value(self):
  		self.write('MEAS?')
  		return self.read(300)

  
  #==============================================================================
  
  def acqu_PM100D(instrument, path, ofile):

  	t0 = time.time()
  	filename = time.strftime("%Y%m%d-%H%M%S", time.gmtime(t0)) + '-' + ofile + '.dat'
  	print('Opening %s' %filename)
  	data_file = open(filename, 'wr', 0)
  	dx = 0.
  
  	xmes = []
  	Pmes = []
  	plt.ion()
  	fig = plt.figure()
  	ax1 = fig.add_subplot(111)
  	line1, = ax1.plot(xmes, Pmes, 'o')
  
  	# Infinite loop
  	while True:
  		try:
  			keypressed = raw_input("Press Enter to continue...
  ")

  			if keypressed.isdigit():

  				print('Closing %s' %filename)
  				data_file.close()
  				t0 = time.time()
  				filename = time.strftime("%Y%m%d-%H%M%S", time.gmtime(t0)) + '-' + keypressed + '.dat'
  				print('Opening %s' %filename)
  				data_file = open(filename, 'wr', 0)
  				dx = 0.
  
  				xmes = []
  				Pmes = []
  				line1, = ax1.plot(xmes, Pmes, 'o')
  
  			else:

  				# Power values
  				sensors_values = instrument.value()
  				sensors_values = sensors_values.replace('E', 'e')
  				string = "%f\t%s" % (dx , sensors_values)
  				data_file.write(string) # Write in a file
  				print(string)

  				xmes.append(dx)
  				Pmes.append(float(sensors_values))

  				dx = dx + 0.05

  
  			line1.set_data(xmes, Pmes)
  			ax1.relim()
  			ax1.autoscale_view()
  			fig.canvas.draw()
  
  		except Exception as ex:
  			print 'Exception during controler data reading: ' + str(ex)
  
  		except KeyboardInterrupt:
  			print '
    --> Disconnected'
  			data_file.close()
  
  			# To stop the loop in a clean way
  			break

  
  #==============================================================================
  
  def main():

  	"""
  	Main script
  	"""
  	# Parse command line
  	args = parse()
  	# path
  	path = args.path
  	# Data output filename
  	ofile = args.ofile
  
  	try:
  		pm100 = instrument("/dev/usbtmc0")
  
  		# acquisition with 2 sec. timeout
  		acqu_PM100D(pm100, path, ofile)
  
  	except Exception as ex:
  			print 'Oups '+str(ex)
  	print 'Program ending
  '

  
  #==============================================================================
  
  if __name__ == "__main__":

  	main()