# This is an example script for a JMRI "Siglet" in Python
#
# It listens for changes to two sensors and a turnout,
# and then recalculates a signal aspect based on the values
#
# Author: Bob Jacobsen, copyright 2004
# Part of the JMRI distribution
#
# The next line is maintained by CVS, please don't change it
# $Revision: 1.5 $

import jarray
import jmri

class SigletExample(jmri.jmrit.automat.Siglet) :
	# defineIO() is called exactly once at the beginning, and is
	# required to load the "inputs" array with the turnouts, sensors
	# and signal heads that are used. Any changes in these will result
	# in setOutput being called to recalculate the result. 
	# 
	# Modify this to define all of your turnouts, sensors and 
	# signal heads.
	def defineIO(self):
		
		self.to12 = turnouts.provideTurnout("12")
		
		self.bo21 = sensors.provideSensor("21")
		self.bo22 = sensors.provideSensor("22")
		
		# The signalhead should have been previously defined. Since this
		# is an example, we detect whether it was already defined, and
		# if not we create a particular signal head.
		self.si35 = signals.getSignalHead("35")
		if (self.si35 == None) :
			self.si35 = jmri.TripleTurnoutSignalHead("si35", "", 
					turnouts.provideTurnout("101"),
					turnouts.provideTurnout("102"),
					turnouts.provideTurnout("103"))
			signals.register(self.si35)
 		
 		# Register the inputs so setOutput will be called when needed.
 		# Note that the output si35 should _not_ in included as an input.
		self.setInputs(jarray.array([self.to12, self.bo21, self.bo22], jmri.NamedBean))

		return

	# setOutput is called when one of the inputs changes, and is
	# responsible for setting the correct output
	#
	# Modify this to do your calculation.
	def setOutput(self):
		newvalue = RED
		
		if self.to12.commandedState==THROWN:
			if self.bo21.knownState==INACTIVE:
				newvalue = GREEN
		else:
			if self.bo22.knownState==INACTIVE:
				newvalue = GREEN
		
		# set the signal aspect to the new value
		self.si35.appearance = newvalue;
	
		# print the value for diagnostic purposes
		print "output set to ", newvalue
		
		return
	
# end of class definition

# start one of these up
SigletExample().start()