"""
Mental Chronometry - Experiment #1
Code from completed "Mission 10-Reaction Time" program
"""
from codex import *
import time
import random

def wait_button():
    # Wait for button A.
    while True:
        if buttons.was_pressed(BTN_A):
            break

while True:
    display.print("Press Button A")
    wait_button()

    # Clear screen.
    display.clear()

    # All pixels off.
    pixels.set([BLACK, BLACK, BLACK, BLACK])

    display.print(3, scale=6)
    time.sleep(1)
    display.print(2, scale=6)
    time.sleep(1)
    display.print(1, scale=6)
    time.sleep(1)
    display.clear()

    # Get 1000 to 5000 millisecond delay.
    delay_time = random.randrange(1000, 5000) / 1000
    time.sleep(delay_time)

    # Reset button state to prevent cheating
    buttons.was_pressed(BTN_A)

    pixels.set([GREEN, GREEN, GREEN, GREEN])

    start_time = time.ticks_ms()

    wait_button()

    end_time = time.ticks_ms()

    reaction_time = time.ticks_diff(end_time, start_time)

    display.print("Reaction time:")
    display.print(reaction_time)
    display.print("milliseconds")