'''
Mission 11 - Remix 1B - Mild
This remix adds an intro and ending to the program. In this 
solution, the intro is a function, but it doesn't have to be.
This solution also includes the functions from Remix 1A --
The remix challenge is to create a function from existing code.
This solution shows two functions (set_screen and calc_degrees).
'''

from codex import *
from time import sleep
import math
# center of display (240 x 240)
CENTER = 120

# draw two lines on the screen
# leave space in the middle for the circle 
def set_screen():
    display.fill(WHITE)
    display.draw_line(CENTER, 0, CENTER, 105, BLACK)
    display.draw_line(CENTER, 135, CENTER, 239, BLACK)

def calc_degrees():
    global degrees
    # read from the accelerometer and get x value
    val = accel.read()
    tilt_x = val[]
    # change accelerometer reading to degrees
    scaled = (tilt_x / 16384)
    scaled = min(max(scaled, -1), 1)
    degrees = math.asin(scaled) * 180 / math.pi
    degrees = int(degrees)

def intro():
    display.print("Spirit Level")
    display.print("")
    display.print("A to start")
    display.print("B to quit")
    while True:
        if buttons.was_pressed(BTN_A):
            break

# define a variable to use for the circle's position
x = CENTER

intro()
set_screen()
# start an infinite loop
while True:
    calc_degrees()
    # erase current circle, recalculate, and draw new circle
    display.draw_circle(x, CENTER, 15, WHITE)
    x = CENTER + degrees
    display.draw_circle(x, CENTER, 15, ORANGE)
    sleep(0.5)

    if buttons.was_pressed(BTN_B):
        break

# ending message
display.clear()
display.print("DONE", scale=6)