import machine
import math
import time
from machine import ADC

SEVEN_SEGMENT_START_PIN = 0
DISPLAY_COUNT = 4
VOLTAGE_PRECISION = 3
ADC_RESOLUTION = 65535
thermo = ADC(26)
button_pin = machine.Pin(16, machine.Pin.IN, machine.Pin.PULL_UP)

digit_list_hex = [
    0x40, 
    0x79, 
    0x24, 
    0x30,
    0x19, 
    0x12, 
    0x02, 
    0x78,
    0x00, 
    0x10, 
    0x08, 
    0x03,
    0x46, 
    0x21, 
    0x06, 
    0x0E,
    0x7F  
]

display_value = 0
last_voltage = 0
segment_pins = []
display_select_pins = []
current_display_index = DISPLAY_COUNT - 1
display_timer = None

def read_voltage(adc):
    global display_value, last_voltage
    value = adc.read_u16()
    voltage = (value / ADC_RESOLUTION) * 3.3
    display_value = int(round(voltage, VOLTAGE_PRECISION) * (10 ** VOLTAGE_PRECISION))
    last_voltage = voltage
    print(f"The Voltage is : {voltage:.{VOLTAGE_PRECISION}f} V") 
 
def scan_display(timer_int):
    global current_display_index, display_value
    digit = int((display_value // (10 ** current_display_index)) % 10)
    display_digit(digit, current_display_index, current_display_index == VOLTAGE_PRECISION)
    current_display_index -= 1
    if current_display_index < 0:
        current_display_index = DISPLAY_COUNT - 1

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(0 if dp_enable else 1)
    if 0 <= digit_index < DISPLAY_COUNT:
        display_select_pins[digit_index].value(1)

def setup():
    global segment_pins, display_select_pins, display_timer
    for i in range(SEVEN_SEGMENT_START_PIN, SEVEN_SEGMENT_START_PIN + 8):
        pin = machine.Pin(i, machine.Pin.OUT)
        pin.value(1)
        segment_pins.append(pin)
    for i in range(SEVEN_SEGMENT_START_PIN + 8, SEVEN_SEGMENT_START_PIN + 8 + DISPLAY_COUNT):
        pin = machine.Pin(i, machine.Pin.OUT)
        pin.value(0)
        display_select_pins.append(pin)
    display_timer = machine.Timer()
    display_timer.init(period=30, mode=machine.Timer.PERIODIC, callback=scan_display)


if __name__ == '__main__':
    setup()
    last_button_state = 1  
    while True:
        current_state = button_pin.value()
        if last_button_state == 1 and current_state == 0:
            read_voltage(thermo)
        last_button_state = current_state
        time.sleep(0.05)