import utime
import machine

# ---------------------------------------------------------
# 1. HARDWARE SETUP
# ---------------------------------------------------------

# Onboard LED (GP25 on Pico / Pico W)
led = machine.Pin("LED", machine.Pin.OUT)

# Push button on GP5, connected to 3.3V
# We enable an internal pull-down resistor:
# Button not pressed -> 0
# Button pressed     -> 1
button = machine.Pin(5, machine.Pin.IN, machine.Pin.PULL_DOWN)

# ---------------------------------------------------------
# 2. VARIABLES FOR BUTTON STATE & DEBOUNCE
# ---------------------------------------------------------

previous_state = 0        # last stable reading of the button (0 or 1)
press_count = 0           # how many times the button has been pressed

last_change_time = utime.ticks_ms()   # timestamp of last state change
DEBOUNCE_MS = 2                      # minimum time for stable signal

# ---------------------------------------------------------
# 3. FUNCTION: CHECK BUTTON WITH DEBOUNCE
# ---------------------------------------------------------

def update_button():
    """
    Reads the button, applies a debounce filter,
    and increases press_count on every complete
    press-and-release cycle.
    """
    global previous_state, press_count, last_change_time

    # Read the raw button value (0 or 1)
    current_state = button.value()
    now = utime.ticks_ms()

    # Did the button reading change?
    if current_state != previous_state:

        # Has the state been stable for long enough?
        if utime.ticks_diff(now, last_change_time) > DEBOUNCE_MS:

            # Count only a RELEASE (1 -> 0)
            if previous_state == 1 and current_state == 0:
                press_count += 1
                print("Button press detected! Total =", press_count)

            # Update stored values
            previous_state = current_state
            last_change_time = now


# ---------------------------------------------------------
# 4. MAIN PROGRAM LOOP
# ---------------------------------------------------------

print("Program started. Press the button 3 times.")
led.value(1)   # LED on while waiting

while press_count < 3:    # stop after three presses
    update_button()

led.value(0)   # LED turns OFF to show program finished
print("Finished! Final count:", press_count)