# imports
import machine
import math
import time
from machine import ADC, Pin, Timer

#######################################
# 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, 
    0x79, 
    0x24, 
    0x30, 
    0x19, 
    0x12, 
    0x02, 
    0x78,
    0x00, 
    0x10, 
    0x08, 
    0x03, 
    0x46, 
    0x21, 
    0x06, 
    0x0E, 
    0x7F
]

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

#######################################
# Function definitions
#######################################

def debounce_callback(timer):
    global btn_pressed
    btn_pressed = True

def read_analogue_voltage(pin):
    global debounce_timer
    if debounce_timer is None:
        debounce_timer = Timer()
        debounce_timer.init(mode=Timer.ONE_SHOT, period=200, callback=debounce_callback)

def disable_display_timer():
    global display_timer
    if display_timer:
        display_timer.deinit()
        display_timer = None

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)

def scan_display(timer_int):
    global current_display_index, display_digits
    digit_index = DISPLAY_COUNT - 1 - current_display_index  
    digit = display_digits[digit_index]
    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)
        time.sleep(0.5)

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

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

def setup():
    global segment_pins, display_select_pins, btn_pressed, debounce_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)

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

    print("MicroPython v1.22.0 on 2023-12-27; Raspberry Pi Pico with RP2040")
    print("Type ""help()"" for more information.")

    while True:
        if btn_pressed:
            btn_pressed = False
            if debounce_timer:
                debounce_timer.deinit()
                debounce_timer = None
            digital_value = Adc_pin.read_u16()
            voltage = float((digital_value / (2**16 - 1)) * 3.3)
            print("Voltage: {:.3f} V".format(voltage))
            scaled_value = int(voltage * 1000)  
            display_digits[0] = (scaled_value // 1000) % 10
            display_digits[1] = (scaled_value // 100) % 10
            display_digits[2] = (scaled_value // 10) % 10
            display_digits[3] = scaled_value % 10

        time.sleep(0.2)
if __name__ == '__main__':
    setup()              
    display_value_test()