from machine import Pin, I2C
import time
import random
import ssd1306
import gc

# OLED
i2c = I2C(0, sda=Pin(0), scl=Pin(1))
display = ssd1306.SSD1306_I2C(128, 64, i2c)

# Hardware
led = Pin(15, Pin.OUT)
button = Pin(16, Pin.IN, Pin.PULL_UP)

# Predefined text (avoid GC)
TXT_READY = "READY..."
TXT_WAIT  = "Wait for LED"
TXT_EARLY = "TOO EARLY!"
TXT_CHEAT = "Cheating!"
TXT_TIME  = "TIME:"
TXT_START = "REACTION GAME"
TXT_PRESS = "Press to start"

def update_screen(l1, l2=""):
    display.fill(0)
    display.text(l1, 0, 10)
    display.text(l2, 0, 30)
    display.show()

def wait_release():
    while button.value() == 0:
        time.sleep_ms(10)

def game_loop():
    gc.collect()  # prevent lag spikes

    update_screen(TXT_READY, TXT_WAIT)
    led.off()

    # Fast integer random delay (2000–5000 ms)
    delay_ms = random.getrandbits(12) % 3000 + 2000
    start = time.ticks_ms()

    # Early press detection
    while time.ticks_diff(time.ticks_ms(), start) < delay_ms:
        if button.value() == 0:
            update_screen(TXT_EARLY, TXT_CHEAT)
            time.sleep_ms(1500)
            wait_release()
            return
        time.sleep_ms(5)

    # LED ON
    led.on()
    start_time = time.ticks_ms()

    while button.value() == 1:
        time.sleep_ms(1)

    reaction = time.ticks_diff(time.ticks_ms(), start_time)
    led.off()

    update_screen(TXT_TIME, str(reaction) + " ms")
    print("Reaction:", reaction, "ms")

    wait_release()
    time.sleep_ms(1500)

# -------- MAIN --------
update_screen(TXT_START, TXT_PRESS)

while True:
    if button.value() == 0:
        wait_release()
        game_loop()