"""Local USB-REPL maintenance-mode selection for the T-Dongle-S3."""

import time
from machine import Pin

# The T-Dongle-S3 BOOT switch connects GPIO0 to ground.
_BUTTON_PIN = 0
_WINDOW_MS = 1500

active = False
_button = None


def button_pressed():
    """Return whether the BOOT button is currently pressed."""
    global _button
    if _button is None:
        _button = Pin(_BUTTON_PIN, Pin.IN, Pin.PULL_UP)
    return not _button.value()


def check_button():
    """Return true when BOOT is pressed shortly after a normal reset.

    Do not hold BOOT while resetting: GPIO0 is also an ESP ROM boot strap and
    that combination intentionally enters the download bootloader instead.
    """
    global active
    deadline = time.ticks_add(time.ticks_ms(), _WINDOW_MS)
    while time.ticks_diff(deadline, time.ticks_ms()) > 0:
        if button_pressed():
            # Debounce the switch and leave the user enough time to release it.
            time.sleep_ms(40)
            if button_pressed():
                active = True
                return True
        time.sleep_ms(20)
    active = False
    return False