import machine, utime
utime.sleep(0.1) # Wait for USB to become ready

# LED related
led_onboard = machine.Pin(25, machine.Pin.OUT)
LEDS = tuple(machine.Pin(i, machine.Pin.OUT) for i in range(0, 8))

LED_mask = 0
top_to_down = True
move_LEDS = False

# button related
big_blue_button = machine.Pin(8, machine.Pin.IN, machine.Pin.PULL_UP)
big_red_button = machine.Pin(9, machine.Pin.IN, machine.Pin.PULL_UP)

button_state = 0 # 0 --> switch_not_pressed; 1 --> switch_pressed
button_pressed_released = False
last_time = 0 # the last time the button is pressed
debounce_time = 30 #ms

# FSM related
FSM_state = 0
do_sense = False
do_compute = False
do_actuate = False

# ISR callbacks
def sense_ISR(time):
    global do_sense
    do_sense = True

def compute_ISR(time):
    global do_compute
    do_compute = True

def actuate_ISR(time):
    global do_actuate
    do_actuate = True

# define the timers
timer_sense = machine.Timer()
timer_compute = machine.Timer()
timer_actuate = machine.Timer()

# freq in Hz, period in ms, mode= PERIODIC, ONE_SHOT, callback --> tic(timer)
timer_sense.init(period = 50, mode = machine.Timer.PERIODIC, callback = sense_ISR)
timer_compute.init(period = 100, mode = machine.Timer.PERIODIC, callback = compute_ISR)
timer_actuate.init(period = 300, mode = machine.Timer.PERIODIC, callback = actuate_ISR)

# function definitions
def check_button():
    global button_state, button_pressed_released, last_time
    now = utime.ticks_ms()

    if button_state == 0:
        if big_blue_button.value() == 0 and utime.ticks_diff(now, last_time) > debounce_time:
            last_time = now
            button_state = 1

    elif button_state == 1:
        if big_blue_button.value() == 1 and utime.ticks_diff(now, last_time) > debounce_time:
            last_time = now
            button_state = 0
            button_pressed_released = True

def initialize_game():
  global LED_mask, top_to_down
  LED_mask = 0
  top_to_down = True

def FSM():
  global FSM_state, move_LEDS, button_pressed_released
  if FSM_state == 0:
    FSM_state = 1
    initialize_game()
  elif FSM_state == 1:
    if button_pressed_released:
      FSM_state = 2
      move_LEDS = True
      button_pressed_released = False
  elif FSM_state == 2:
    if button_pressed_released:
      FSM_state = 3
      move_LEDS = False
      button_pressed_released = False
  else: # FSM_state = 3
    if button_pressed_released:
      FSM_state = 0
      button_pressed_released = False

def led_move_one_step():
    global LED_mask, top_to_down, move_LEDS
    if not move_LEDS:
        return
    if top_to_down:
        if LED_mask == 0:
            LED_mask = 0b10000000
            return
        if LED_mask != 0b00000001:
            LED_mask >>= 1
        else:
            LED_mask <<= 1
            top_to_down = False
    else:
        if LED_mask != 0b10000000:
            LED_mask <<= 1
        else:
            LED_mask >>= 1
            top_to_down = True

def move_lights():
    # output LED_mask onto LEDs
    # converts an 8-bit software variable into 
    # 8 physical LED outputs by extracting each bit 
    # and writing it to a GPIO pin.
    for i, led in enumerate(LEDS):
        bit = 7 - i
        led.value((LED_mask >> bit) & 1)

def clear_leds():
    global LED_mask
    LED_mask = 0
    move_lights()

# ---- main loop: STOP when red button pressed ----
print("Game started!")
while big_red_button.value() == 1:
    if do_sense:
        do_sense = False
        check_button()

    if do_compute:
        do_compute = False
        FSM()

    if do_actuate:
        do_actuate = False
        led_move_one_step()
        move_lights()

print("Finished the game!")
clear_leds()
timer_sense.deinit()
timer_compute.deinit()
timer_actuate.deinit()