# PyVisa simulator

import numpy as np

def get_instruments_list():
	return ["USB0::0x0699::0x0346::C031285", "USB0::0x0699::0x0366::C040717", "COM1", "COM3", "LPT1"]

class instrument :
	
	def __init__(self, visa_id) :
		# If visa_id = "USB0::0x0699::0x0346::C031285", then this instrument is a Tek AFG3021B awg.
		# If visa_id = "USB0::0x0699::0x0366::C040717", then this instrument is a Tek TDS102B scope.
		self.visa_id = visa_id
		self.identity = 'Pseudo instrument ' + visa_id
		self.status = {}
		self.out_buffer = ''
		self.output_form = 'short'		# 'long' is the other choice.
		if visa_id == "USB0::0x0699::0x0366::C040717" :
			self.function = 'scope'
			self.idn = 'Fake TDS1012B'
			# Set some typical operational values
			self.status['wfmpre:xunit'] = 's'
			self.status['wfmpre:xincr'] = '1.0e-6'
			self.status['wfmpre:yunit'] = 'V'
			self.status['wfmpre:ymult'] = '1.0e-3'
			self.status['wfmpre:yoff'] = '0'
			self.status['wfmpre:yzero'] = '0'
			k = 2.0 * np.pi/1250.0
			self.ascii_data = ''
			for i in range(2500) :
				self.ascii_data += str(int(127.50 * (np.sin(k * i) + 1))) + ','
			self.ascii_data = self.ascii_data.rstrip(',')
			#print self.curve

		elif visa_id == "USB0::0x0699::0x0346::C031285" :
			self.function = 'wg'
			self.idn = 'Fake AFG3021B'
		else :
			self.function = '?'
		"""
		if self.function == 'scope' :
			self.status['ch1:coupling'] = 'ac'
			self.status['ch1:bandwidth'] = 'off'
		if self.function == 'wg' :
			self.status['function'] = 'sin'
			self.status['function:frequency'] = '1.0e3'
			self.status['voltage:amplitude'] = '1.000'
		"""
	
	def write(self, stuff) :
		# Is this a query or an action?
		stuff.strip()
		query = stuff.find('?')
		if query > -1 :
			# Strip leading ':' or '::'.
			com = stuff[0:query].strip(':').strip()
			# Only one query is assumed.
			if com.lower() == '*idn' :
				response = self.idn
			if com.lower() == 'curve' :
				if self.status['data:encdg'] == 'ascii' :
					response = self.ascii_data
			else :
				try: 
					response = self.status[com]		# This is the short form response.  Long would be com + ' ' + status[com].
				except :
					response = 'Error, ' + com + ' not specified.'
				if self.output_form == 'long' :
					response = com + ' ' + response
			self.output_buffer = response
		else :
			# Strip leading ':' or '::'.
			stuff.strip(':')
			# Then split by the continuation character ';'
			coms = stuff.split(';')
			lc = len(coms)
			# If length of coms is 1, then the single command and argument are simple to add to the dictionary.
			# If coms has more than one entry, then subsequent entries must be analyzed to determine if they 
			#   are continuations of the first entry.
			if lc == 1 :
				# Split on space to get the argument
				splits = coms[0].split(' ')		# Warning: there might be more than one consecutive space in the command.
				command = splits[0].strip()
				argument = splits[-1].strip()	# Use the last element to handle the possibility of consecutive spaces.
				self.status[command] = argument
			else :
				# For the first command, split on space to get the argument
				splits = coms[0].split(' ')		# Warning: there might be more than one consecutive space in the command.
				command = splits[0].strip()
				argument = splits[-1].strip()	# Use the last element to handle the possibility of consecutive spaces.
				self.status[command] = argument
				base_command = command.split(':')[0].strip() + ':'
				for c in coms[1:] :		# From com[1] to the last element.
					splits = c.split(' ')		# Warning: there might be more than one consecutive space in the command.
					command = splits[0].strip()
					argument = splits[-1].strip()	# Use the last element to handle the possibility of consecutive spaces.
					self.status[base_command + command] = argument
				
	def read(self) :
		return self.output_buffer

def Test() :
	inst = get_instruments_list()
	print inst
	scope = instrument(inst[1])
	scope.write('*IDN?')
	print scope.read()
	print scope.status
	scope.write('ch1:probe 1;scale 0.5;position -2.0')
	print scope.status
	scope.write('ch1:probe ?')
	print scope.read()
	wg = instrument(inst[0])
	print wg.status
	wg.write('voltage:offset 0')
	wg.write('voltage:phase:adjust 0')
	print wg.status
	
#--------------------------------------------------------------------------------

if __name__ == '__main__' :
	Test()