import machine
import math
import time

# Pin and constant definitions
# Segment pins (a, b, c, d, e, f, g, dp)
segment_pins = [machine.Pin(pin, machine.Pin.OUT) for pin in [10,11,12,13,14,15,16,17]]

# Digit control pins for 4 digits (Common cathode)
digit_pins = [machine.Pin(pin, machine.Pin.OUT) for pin in [2,3,4,5]]

# ADC pin (e.g., Potentiometer on ADC0 / pin 26)
adc = machine.ADC(26)

# Button pin
button_pin = machine.Pin(18, machine.Pin.IN, machine.Pin.PULL_UP)

# Timer for display multiplexing
display_timer = machine.Timer()

#######################################
# Global variables
#######################################
display_value = 0.00
current_digit = 0

# Digit to segment mapping (without dp)
digit_map = {
    0: [1,1,1,1,1,1,0],
    1: [0,1,1,0,0,0,0],
    2: [1,1,0,1,1,0,1],
    3: [1,1,1,1,0,0,1],
    4: [0,1,1,0,0,1,1],
    5: [1,0,1,1,0,1,1],
    6: [1,0,1,1,1,1,1],
    7: [1,1,1,0,0,0,0],
    8: [1,1,1,1,1,1,1],
    9: [1,1,1,1,0,1,1]
}

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

# Function to read the ADC and convert to voltage
def read_analogue_voltage(pin):
    global display_value
    raw = adc.read_u16()
    voltage = (raw / 65535.0) * 3.3
    display_value = round(voltage, 2)
    print("Voltage:", display_value)

# Disable display timer
def disable_display_timer():
    display_timer.deinit()

# Enable display timer
def enable_display_timer():
    display_timer.init(freq=500, mode=machine.Timer.PERIODIC, callback=scan_display)

# Display scan interrupt (multiplex 4 digits)
def scan_display(timer_int):
    global current_digit, display_value

    # Turn off all digits before updating
    for dp in digit_pins:
        dp.value(0)

    # Format value to string (e.g., 3.30 -> "330" or "3.3")
    val_str = f"{display_value:.2f}"  # "3.30"
    val_str = val_str.replace('.', '')  # Remove dot: "330"
    val_str = val_str[:4].rjust(4, '0')  # Ensure 4 digits: "0330"

    try:
        digit_char = val_str[current_digit]
        digit_val = int(digit_char)
        dp_enable = (current_digit == 1)  # Enable decimal point after 1st digit (e.g. 3.30)
        display_digit(digit_val, current_digit, dp_enable)
    except:
        pass

    # Move to next digit
    current_digit = (current_digit + 1) % 4

# Display a single digit on the given digit index
def display_digit(digit_value, digit_index, dp_enable=False):
    segments = digit_map.get(digit_value, [0]*7)

    for i in range(7):
        segment_pins[i].value(segments[i])

    # Decimal point control
    segment_pins[7].value(1 if dp_enable else 0)

    # Enable only the current digit
    for i in range(4):
        digit_pins[i].value(1 if i == digit_index else 0)

# Button interrupt handler
def button_irq(pin):
    time.sleep_ms(200)  # debounce
    read_analogue_voltage(pin)

# Function to test all digits
def display_value_test():
    for i in range(10):
        for d in range(4):
            display_digit(i, d, dp_enable=(d==1))
            time.sleep(0.2)

# Setup all hardware
def setup():
    for dp in digit_pins:
        dp.init(mode=machine.Pin.OUT)
        dp.value(0)

    for sp in segment_pins:
        sp.init(mode=machine.Pin.OUT)
        sp.value(0)

    button_pin.irq(trigger=machine.Pin.IRQ_FALLING, handler=button_irq)

    enable_display_timer()

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