# Mission 5 Fence Patrol - final
from botcore import *
from time import sleep

threshold = 2000
line_count = 0

def detect_line(n):
    is_detected = ls.read(n) > threshold
    leds.ls_num(n, is_detected)
    return is_detected

def scan_lines():
    got_line = False
    n = 0
    while n < 5:
        if detect_line(n):
            got_line = True
        n = n + 1
    return got_line

def go_forward():
    motors.run(LEFT, 45)
    motors.run(RIGHT, 45)

def back_turn():
    # Go backward
    motors.run(LEFT, -30)
    motors.run(RIGHT, -30)
    sleep(0.65)
    # Turn
    motors.run(LEFT, 30)
    motors.run(RIGHT, -30)
    sleep(0.65)

# Safety feature
while True:
    if buttons.was_pressed(0):
        break

motors.enable(True)

# == Main Program ==
while True:
    hit = scan_lines()

    if hit:
        back_turn()
        line_count = line_count + 1
        if line_count == 256:
            line_count = 0
        leds.user(line_count)
    else:
        go_forward()