# imports
import machine
import math
import time

#######################################
# Pin and constant definitions
#######################################
ANALOG_PIN = machine.Pin(26, machine.Pin.IN)
SEGMENT_PINS = [machine.Pin(0, machine.Pin.OUT), machine.Pin(1, machine.Pin.OUT), machine.Pin(2, machine.Pin.OUT), machine.Pin(3, machine.Pin.OUT), machine.Pin(4, machine.Pin.OUT), machine.Pin(5, machine.Pin.OUT), machine.Pin(6, machine.Pin.OUT)] 
DECIMAL_POINT_PIN = machine.Pin(7, machine.Pin.OUT)  
SELECT_PINS = [machine.Pin(11, machine.Pin.OUT), machine.Pin(10, machine.Pin.OUT), machine.Pin(9, machine.Pin.OUT), machine.Pin(8, machine.Pin.OUT)]  
BUTTON_PIN = machine.Pin(16, machine.Pin.IN, machine.Pin.PULL_UP) 
#######################################
# Global variables
VOLTAGE_RANGE = 3.3

#######################################
display_value = 0

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

# Function to read the ADC pin and
# to convert the digital value to a voltage level in the 0-3.3V range
# This function updates the value of the display_value global variable
def read_analogue_voltage(pin):      # We can use the pin parameter if needed
    adc = machine.ADC(26)
    value = adc.read()
    voltage = (value / 1023) * VOLTAGE_RANGE
    display_value = voltage
    pass
    
# Function to disable timer that triggers scanning 7 segment displays
def disable_display_timer():
    timer.deinit()
    pass
    
# Function to enable timer that triggers scanning 7 segment displays
def enable_display_timer():
    timer.init(period=500, mode=machine.Timer.PERIODIC, callback=scan_display)
    pass

# Function to handle scanning 7 segment displays
# Display the value stored in the display_value global variable
# on available 7-segment displays
def scan_display(timer_int):
    digits = []
    for i in range(4):
        digit_value = int(display_value * 10 ** i) % 10
        digits.append(digit_value)
    for i, digit in enumerate(digits):
        display_digit(digit, i)
    pass
    
# Function display the given value on the display with the specified index
# dp_enable specifies if the decimal pooint should be on or off
def display_digit(digit_value, digit_index, dp_enable=False):
    for pin in SEGMENT_PINS:
        pin.off()
    DECIMAL_POINT_PIN.off()
    SELECT_PINS[digit_index].on()
    if dp_enable:
        DECIMAL_POINT_PIN.on()
    for i in range(7):
        if (digit_value >> i) & 1:
            SEGMENT_PINS[i].on()
    pass    

# Function to test avaiable 7-segment displays
def display_value_test():
    for i, pin in enumerate(SEGMENT_PINS):
        pin.on()
        time.sleep(0.5)
        pin.off()
    pass

# Function to setup GPIO/ADC pins, timers and interrupts
def setup():
    for pin in SEGMENT_PINS:
        pin.init(machine.Pin.OUT)
    DECIMAL_POINT_PIN.init(machine.Pin.OUT)
    for pin in SELECT_PINS:
        pin.init(machine.Pin.OUT)
    ANALOG_PIN.init(machine.Pin.IN)
    
    timer = machine.Timer(0)
    timer.init(period=500, mode=machine.Timer.PERIODIC, callback=scan_display)
    
    BUTTON_PIN.irq(trigger=machine.Pin.IRQ_FALLING, handler=read_analogue_voltage, debounce=200)
    pass
    
if __name__ == '__main__':
    setup()
    display_value_test()
    while True:
        # Read the analog input from the slide potentiometer or other sensors
        analog_value = read_analog_voltage(ANALOG_PIN)
        
        # Update the display value
        display_value = analog_value
        
        # Delay to control the update rate
        time.sleep(0.1)
        pass