import sensor, image, time, math
import uart
from consts import *

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.HVGA)
sensor.skip_frames(time = 2000)
clock = time.clock()

WIDTH = 480
HEIGHT = 320
MAX_AREA = WIDTH * HEIGHT / 10
MIN_AREA = 40

HORIZON = 150
STRETCH = 40
SQUEEZE = 400

STEERING_ENTHOUSIASM = 3.0
ROAD_MIN_BRIGHTNESS = 0xa0

points = [(STRETCH, HORIZON),
          (WIDTH-1-STRETCH, HORIZON),
          (WIDTH-1+SQUEEZE, HEIGHT-1),
          (-SQUEEZE, HEIGHT-1)]

def main():
  img = sensor.snapshot()
  img.to_grayscale()
  img.replace(vflip=True, hmirror=True)
  img.rotation_corr(corners=points)
  img.gaussian(3)

  offset_sum = 0.0
  offset_count = 0.0

  for blob in img.find_blobs([(ROAD_MIN_BRIGHTNESS, 0xff)], pixels_threshold=100):
    img.draw_rectangle(blob.rect())
    area_weight = MIN_AREA + min(MAX_AREA, blob.w() * blob.h()) # limit max area_weight so small blobs still have impact
    horizontal_pos = (blob.x() + blob.w()/2) / WIDTH
    offset_sum += horizontal_pos * area_weight
    offset_count += area_weight

  # dit tegen niemand zeggen
  if offset_count < 0.01: return
  avg = offset_sum / offset_count
  avg = avg * 2 - 1
  avg *= STEERING_ENTHOUSIASM
  avg = max(-1, min(1, avg))

  print(avg)
  steerByte = int((avg + 1.0) * (DUI_CMD_STEER_END - DUI_CMD_STEER_START) / 2 + DUI_CMD_STEER_START)
  uart.uart_buffer(steerByte)

while(True):
  main()
  uart.uart_buffer(DUI_CMD_SPEED_END)
  clock.tick()