text: '''This Module is the main screen file.'''
  
  #Imports
  import os
  from datetime import date
  
  #Function to convert folder name into human readable format date
  def conv_readdate(dt):
  	dt_year = 2000+int(dt/1000)
  	dt_doy = dt%1000
  	t = date.fromordinal(date(dt_year, 1, 1).toordinal() + dt_doy - 1)
  	return t
  
  #Check latest date of the data available
  os.chdir('/home/deathstroke/projects/IITI_GNSSR/data/')
  sub = [x for x in os.listdir('.') if os.path.isdir(x)]
  dt = max(sub)
  date_upto = conv_readdate(int(dt))
  os.chdir('/home/deathstroke/projects/IITI_GNSSR/iiti_gnssr/')
  
  
  print ('''
  	Select any one of the following options
  ----------------------------------------------------------
  1. Plot cummulative graph of TEC vs time for all satellites of a given constellation for given dates
  2. Plot cummulative graph of VTEC vs time for all satellites of a given constellation for given dates
  3. Plot cummulative graph of Iono delay(in meters) Vs time for all satellites of a given constellation for given dates
  4. Quit
  '''
  	)
  print ("\nData available upto %s\n" %date_upto)
  
  cnt = 0
  while(cnt!=1):
  	select = input("Enter your choice>> ")
  
  	if select==1:
  		cnt = 1
  		import tecvtime
  		tecvtime.main()
  	elif select==2:
  		cnt = 1
  		import vtecvtime
  		altvtecvtime.main()
  	elif select==3:
  		cnt = 1
  		import ionodelayvtime
  		ionodelayvtime.main()
  	elif select==4:
  		cnt = 1
  		quit()
  	else:
  		print ("Please enter a valid choice!!!")
  
  