from pyb import millis
from math import pi, isnan
class PID:
	_kp = _ki = _kd = _integrator = _imax = 0
	_last_error = _last_derivative = _last_t = 0
	_RC = 1/(2 * pi * 20)
	def __init__(self, p=0, i=0, d=0, imax=0):
		self._kp = float(p)
		self._ki = float(i)
		self._kd = float(d)
		self._imax = abs(imax)
		self._last_derivative = float('nan')
	def get_pid(self, error, scaler):
		tnow = millis()
		dt = tnow - self._last_t
		output = 0
		if self._last_t == 0 or dt > 1000:
			dt = 0
			self.reset_I()
		self._last_t = tnow
		delta_time = float(dt) / float(1000)
		output += error * self._kp
		if abs(self._kd) > 0 and dt > 0:
			if isnan(self._last_derivative):
				derivative = 0
				self._last_derivative = 0
			else:
				derivative = (error - self._last_error) / delta_time
			derivative = self._last_derivative + \
									 ((delta_time / (self._RC + delta_time)) * \
										(derivative - self._last_derivative))
			self._last_error = error
			self._last_derivative = derivative
			output += self._kd * derivative
		output *= scaler
		if abs(self._ki) > 0 and dt > 0:
			self._integrator += (error * self._ki) * scaler * delta_time
			if self._integrator < -self._imax: self._integrator = -self._imax
			elif self._integrator > self._imax: self._integrator = self._imax
			output += self._integrator
		return output
	def reset_I(self):
		self._integrator = 0
		self._last_derivative = float('nan')

from pyb import Pin, Timer
inverse_left=False
inverse_right=False
ain1 =  Pin('P0', Pin.OUT_PP)
ain2 =  Pin('P1', Pin.OUT_PP)
bin1 =  Pin('P2', Pin.OUT_PP)
bin2 =  Pin('P3', Pin.OUT_PP)
ain1.low()
ain2.low()
bin1.low()
bin2.low()
pwma = Pin('P7')
pwmb = Pin('P8')
tim = Timer(4, freq=1000)
ch1 = tim.channel(1, Timer.PWM, pin=pwma)
ch2 = tim.channel(2, Timer.PWM, pin=pwmb)
ch1.pulse_width_percent(0)
ch2.pulse_width_percent(0)
def run(left_speed, right_speed):
	if inverse_left==True:
		left_speed=(-left_speed)
	if inverse_right==True:
		right_speed=(-right_speed)
	if left_speed < 0:
		ain1.low()
		ain2.high()
	else:
		ain1.high()
		ain2.low()
	ch1.pulse_width_percent(abs(left_speed))
	if right_speed < 0:
		bin1.low()
		bin2.high()
	else:
		bin1.high()
		bin2.low()
	ch2.pulse_width_percent(abs(right_speed))

import sensor, image, time
import car
from pid import PID
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QQVGA)
sensor.skip_frames(10)
sensor.set_auto_whitebal(False)
clock = time.clock()
green_threshold   = (76, 96, -110, -30, 8, 66)
size_threshold = 2000
x_pid = PID(p=0.5, i=1, imax=100)
h_pid = PID(p=0.05, i=0.1, imax=50)
def find_max(blobs):
	max_size=0
	for blob in blobs:
		if blob[2]*blob[3] > max_size:
			max_blob=blob
			max_size = blob[2]*blob[3]
	return max_blob
while(True):
	clock.tick()
	img = sensor.snapshot()
	blobs = img.find_blobs([green_threshold])
	if blobs:
		max_blob = find_max(blobs)
		x_error = max_blob[5]-img.width()/2
		h_error = max_blob[2]*max_blob[3]-size_threshold
		print("x error: ", x_error)
		img.draw_rectangle(max_blob[0:4])
		img.draw_cross(max_blob[5], max_blob[6])
		x_output=x_pid.get_pid(x_error,1)
		h_output=h_pid.get_pid(h_error,1)
		print("h_output",h_output)
		car.run(-h_output-x_output,-h_output+x_output)
	else:
		car.run(18,-18)