from machine import Pin, ADC, I2C
from ssd1306 import SSD1306_I2C
import utime

BTN_PIN  = 7
LED_PIN  = 0
POT_PIN  = 28
SDA_PIN  = 16
SCL_PIN  = 13
OLED_W   = 128
OLED_H   = 64
OLED_ADR = 0x3C
RESET_THRESHOLD = 65535

button = Pin(BTN_PIN, Pin.IN, Pin.PULL_UP)
led    = Pin(LED_PIN, Pin.OUT)
pot    = ADC(Pin(POT_PIN))

i2c  = I2C(0, sda=Pin(SDA_PIN), scl=Pin(SCL_PIN), freq=400_000)
oled = SSD1306_I2C(OLED_W, OLED_H, i2c, addr=OLED_ADR)

running        = False
start_ms       = 0
elapsed_ms     = 0
last_btn       = button.value()
pot_reset_done = False

def ms_to_hms(ms):
    total_s, ms_part = divmod(ms, 1000)
    minutes, seconds = divmod(total_s, 60)
    return minutes, seconds, ms_part // 10

def update_oled(mins, secs, cs, state_str, reset_msg=False):
    oled.fill(0)
    oled.text("CHRONOMETRE", 14, 0, 1)
    oled.text("{:02d}:{:02d}.{:02d}".format(mins, secs, cs), 24, 22, 1)
    oled.text("Etat: " + state_str, 0, 42, 1)
    if reset_msg:
        oled.text("RESET !", 36, 54, 1)
    oled.show()

update_oled(0, 0, 0, "Arrete")

while True:

    btn_val = button.value()

    if last_btn == 1 and btn_val == 0:
        if running:
            elapsed_ms += utime.ticks_diff(utime.ticks_ms(), start_ms)
            running = False
            led.off()
        else:
            start_ms = utime.ticks_ms()
            running = True
            led.on()

    last_btn = btn_val

    pot_val = pot.read_u16()

    if pot_val >= RESET_THRESHOLD:
        if not pot_reset_done:
            elapsed_ms = 0
            running = False
            led.off()
            update_oled(0, 0, 0, "Arrete", reset_msg=True)
            utime.sleep_ms(1000)
            pot_reset_done = True
    else:
        pot_reset_done = False

    if running:
        current_ms = elapsed_ms + utime.ticks_diff(utime.ticks_ms(), start_ms)
    else:
        current_ms = elapsed_ms

    mins, secs, cs = ms_to_hms(current_ms)
    update_oled(mins, secs, cs, "En cours" if running else "Arrete")

    utime.sleep_ms(50)