import numpy as np
import json
from aplant import APlant
from math import sqrt

class Mass(APlant):
	def __init__(self, params):
		print(json.dumps({'Mass': params}, indent=4, sort_keys=True))
		self.dt = params['dt']
		self.alpha = 1.0

		self.e = 0
		self.x = 0
		self.gain = 0.95

		self.C = params['C']
		self.M = params['M']
		self.L = params['L']
		self.Td = params['Td']
		self.kn = params['kn']
		self.theta_amb = params['theta_amb']

		self.theta = 0
		self.P = 0

		if self.Td > 0:
			self.alpha = self.dt/self.Td

	def process(self):
		self.e = self.e*(1 - ((self.L*self.theta)*self.dt)/(self.M*self.C))
		self.x = (1-self.alpha)*self.x + self.gain*self.alpha*self.P
		self.e += self.x
		self.theta = self.e/(self.M*self.C)

	def setPower(self, power_w):
		self.P = power_w

	def getPower(self):
		return self.P
	
	def getTemperature(self):
		return self.theta + self.theta_amb + self.kn*np.random.normal(0,1)/sqrt(12.0)