'''
LineSense
Modified to use lists and for loops
'''
from botcore import *
from time import sleep
import random

threshold = 2000
line_count = 0

beeps = [400, 500, 600, 700, 800, 900, 1000, 1100, 1200]
patterns = [0b10101010, 0b01010101, 0b00111100, 
           0b00100100, 0b01000010, 0b10000001]

# - Traverse patterns list and get random beeps
def light_show(seconds, delay):
    num_lights = round(seconds/delay)
    for index in range(num_lights):
        freq = random.choice(beeps)
        lights = patterns[index % len(patterns)]
        leds.user(lights)
        spkr.pitch(freq)
        sleep(delay)
        spkr.off()
    # Turn off LEDs when finished
    leds.user(0)
 
def detect_line(n):
    val = ls.read(n)
    is_detected = val < threshold
    leds.ls_num(n, is_detected)
    return is_detected

# Modified to use a for loop
def scan_lines():
    got_line = False
    for n in range(5):
        if detect_line(n):
            got_line = True
    return got_line

def go_forward():
    motors.run(LEFT, 40)
    motors.run(RIGHT, 40)

def back_turn():
    motors.run(LEFT, -20)
    motors.run(RIGHT, -20)
    light_show(1.5, 0.3)
    motors.run(LEFT, 20)
    motors.run(RIGHT, -20)
    light_show(1.3, 0.1)
    
# -- Main Program --
while True:
    if buttons.was_pressed(0):
        break

motors.enable(True)
while True:
    hit = scan_lines()

    if hit:
        back_turn()
        line_count = line_count + 1
        if line_count > 255:
            line_count = 0
        leds.user(line_count)
    else:
        go_forward()