#!/usr/bin/env python
from CBD.src.CBD import *

class CostFunctionBlock(BaseBlock):
	def __init__(self, block_name):
		BaseBlock.__init__(self, block_name, ["InVi","InVTrain","InDelta","InXPerson"], ["OutCost"])
		self.viChanged = False
		self.timeInWhichViChanged = 0.0
		self.cummulativeCost = 0.0

	def compute(self, curIteration):
		displacement_person = self.getInputSignal(curIteration, "InXPerson").value
		velocity_train = self.getInputSignal(curIteration, "InVTrain").value

		if abs(displacement_person) > 0.4 or velocity_train<0.0:
			raise StopSimulationException()

		currentVi = self.getInputSignal(curIteration, "InVi").value
		currentTime = self.getClock().getTime()
		lastVi = self.getInputSignal(curIteration-1, "InVi").value
		if lastVi != currentVi:
			self.viChanged = True
			self.timeInWhichViChanged = currentTime
			self.attainedVelocity = False
		else:
			self.viChanged = False

		lastVTrain = self.getInputSignal(curIteration-1, "InVTrain").value
		currentVTrain = self.getInputSignal(curIteration, "InVTrain").value
		if ((lastVTrain-currentVi)*(currentVTrain-currentVi) <= 0):
			self.attainedVelocity = True;

		if (not self.attainedVelocity):
			instantCostTime = currentTime - self.timeInWhichViChanged
			assert instantCostTime >= 0
			delta_t = self.getInputSignal(curIteration, "InDelta").value
			self.cummulativeCost = self.cummulativeCost + instantCostTime*delta_t

		self.appendToSignal(self.cummulativeCost, name_output="OutCost")



class AboveThresholdBlock(BaseBlock):
	def __init__(self, block_name, threshold):
		BaseBlock.__init__(self, block_name, ["IN1"], ["OUT1"])
		self.threshold = threshold

	def compute(self, curIteration):
		self.appendToSignal(1.0 if self.getInputSignal(curIteration).value > self.threshold else -1.0)



class StopSimulationBlock(BaseBlock):
	def __init__(self, block_name):
		BaseBlock.__init__(self, block_name, ["IN1"], [])

	def compute(self, curIteration):
		inSignalValue = self.getInputSignal(curIteration).value
		if inSignalValue > 0.0:
			raise StopSimulationException()


class StopSimulationException(Exception):
	pass