from machine import ADC, Pin, Timer
import math
from time import sleep

# Pin and constant definitions
SEVEN_SEGMENT_START_PIN = 0
DISPLAY_COUNT = 4
DECIMAL_PRECISION = 3

interrupt_pin = Pin(16, Pin.IN, Pin.PULL_UP)
Adc_pin = ADC(Pin(26))

digit_list_hex = [
    0x40,  # 0
    0x79,  # 1
    0x24,  # 2
    0x30,  # 3
    0x19,  # 4
    0x12,  # 5
    0x02,  # 6
    0x78,  # 7
    0x00,  # 8
    0x10,  # 9
    0x08,  # A
    0x03,  # B
    0x46,  # C
    0x21,  # D
    0x06,  # E
    0x0E,  # F
    0x7F   # Empty
]

# Global variables
display_value = 0
segment_pins = []
display_select_pins = []
current_display_index = DISPLAY_COUNT - 1
display_timer = None
btn_pressed = False

# Interrupt handler function
def read_analogue_voltage(pin):
    global btn_pressed
    btn_pressed = True

interrupt_pin.irq(trigger=Pin.IRQ_FALLING, handler=read_analogue_voltage)

# Timer control functions
def disable_display_timer():
    global display_timer
    if display_timer:
        display_timer.deinit()

def enable_display_timer():
    global display_timer
    if not display_timer:
        display_timer = Timer()
    display_timer.init(period=30, mode=Timer.PERIODIC, callback=scan_display)

# Display functions
def scan_display(timer_int):
    global current_display_index, display_value

    digit = int((display_value // math.pow(10, current_display_index))) % 10

    display_digit(digit, current_display_index,
                  current_display_index == DECIMAL_PRECISION and DECIMAL_PRECISION != 0)

    current_display_index = (current_display_index - 1) % DISPLAY_COUNT

def display_digit(digit_value, digit_index, dp_enable=False):
    if digit_value < 0 or digit_value >= len(digit_list_hex):
        return

    for pin in display_select_pins:
        pin.value(0)

    mask = digit_list_hex[digit_value]
    for i in range(7):
        segment_pins[i].value((mask >> i) & 1)

    segment_pins[7].value(1 if not dp_enable else 0)

    if digit_index == -1:
        for pin in display_select_pins:
            pin.value(1)
    elif 0 <= digit_index < DISPLAY_COUNT:
        display_select_pins[digit_index].value(1)

def display_value_test():
    global display_value

    disable_display_timer()
    current_display_index = 0

    for i in range(len(digit_list_hex)):
        display_digit(i, -1, i % 2 != 0)
        sleep(0.5)

    for i in range(len(digit_list_hex)):
        display_digit(i, DISPLAY_COUNT - 1 - (i % DISPLAY_COUNT), True)
        sleep(0.5)

    display_digit(16, -1, False)
    enable_display_timer()

# Setup function
def setup():
    global segment_pins, display_select_pins
    global display_timer

    for i in range(SEVEN_SEGMENT_START_PIN + 8, SEVEN_SEGMENT_START_PIN + 8 + DISPLAY_COUNT):
        pin = Pin(i, Pin.OUT)
        pin.value(0)
        display_select_pins.append(pin)

    for i in range(SEVEN_SEGMENT_START_PIN, SEVEN_SEGMENT_START_PIN + 8):
        pin = Pin(i, Pin.OUT)
        pin.value(1)
        segment_pins.append(pin)

    enable_display_timer()

    while True:
        global btn_pressed, display_value
        if btn_pressed:
            btn_pressed = False
            digital_value = Adc_pin.read_u16()
            voltage = float((digital_value / (2**16 - 1)) * 3.3)
            print("voltage: " + str(voltage) + " V")
            display_value = int(voltage * 1000)
        sleep(0.2)

# Main execution
if __name__ == '__main__':
    setup()
    display_value_test()