from machine import SoftI2C, Pin, ADC
from machine_i2c_lcd import I2cLcd
from time import sleep

#LCD setup
i2c = SoftI2C(scl=Pin(1), sda=Pin(0), freq=400000) 
lcd = I2cLcd(i2c, 0x27, 2, 16)

#Buttons
next_button = Pin(14, Pin.IN, Pin.PULL_DOWN)
select_button = Pin(15, Pin.IN, Pin.PULL_DOWN)
analog_pin = ADC(28) 

#Variables
Rc = 10000 # 10kΩ
t = 50000 # microseconds
Known_resistor = 1000 
Shunt_resistor = 1
menu_options = ["1.Ammeter", "2.Ohmmeter", "3.Voltmeter", "4.Capacitance"]
current_option = 0

def menu():
    lcd.clear()
    lcd.move_to(0, 0)
    lcd.putstr("* MAIN MENU: ")
    lcd.move_to(0, 1)
    lcd.putstr(menu_options[current_option])

def Ohmmeter():
    lcd.clear()
    while True:
        reading = analog_pin.read_u16()
        voltage = (reading / 65535.0) * 3.3
        print("RAW ADC:", reading, " Voltage:", voltage)
        
        # Calculate resistance
        if (3.3 - voltage) != 0:
            unknown_resistance = (voltage * Known_resistor) / (3.3 - voltage)
        else:
            unknown_resistance = 0
            
        lcd.move_to(0, 0)
        if voltage > 3.2: 
            lcd.putstr("R: Open Circuit ")
        elif reading < 500: 
            lcd.putstr("R: 0.00 Ohm     ")
        else:
            if unknown_resistance < 1000:
                lcd.putstr("R: {:.2f} ohms  ".format(unknown_resistance))
            else:
                lcd.putstr("R: {:.2f} kOhms ".format(unknown_resistance / 1000))
        
        # Exit to menu
        if select_button.value() == 1: 
            sleep(0.3)
            break
        sleep(0.5)

def Voltmeter():
    lcd.clear()
    while True:
        reading = analog_pin.read_u16()
        voltage = (reading / 65535.0) * 3.3
        print("RAW ADC:", reading, " Voltage:", voltage)

        lcd.move_to(0, 0)
        if reading < 100: 
            lcd.putstr("V: 0.00 v   ")
        else:
            lcd.putstr("V: {:.2f} v   ".format(voltage))
            
        if select_button.value() == 1: 
            sleep(0.3)
            break
        sleep(0.5)

def Ammeter():
    lcd.clear()
    while True:
        reading = analog_pin.read_u16()
        voltage = (reading / 65535.0) * 3.3
        print("RAW ADC:", reading, " Voltage:", voltage)

        current_amps = voltage / Shunt_resistor
        lcd.move_to(0, 0)
        
        if current_amps < 1.0:
            lcd.putstr("I: {:.2f} mA  ".format(current_amps * 1000))
        else:
            lcd.putstr("I: {:.2f} A   ".format(current_amps))
            
        if select_button.value() == 1: 
            sleep(0.3)
            
            break
        sleep(0.5)

def capacitancemeter():
    C = t / (Rc * 1000000)
    lcd.clear()
    print("\n" * 1)
    print("This is a simulated C and cannot be changed through the potentiometer")
    while True:
        lcd.move_to(0, 0)
        lcd.putstr("Simulated C:")
        lcd.move_to(0, 1)
        lcd.putstr("{:.6f}F".format(C))
        

        if select_button.value() == 1: 
            sleep(0.3)
            break
        sleep(0.5)
# --- Main Loop ---
menu() # Initial draw
#learn this
while True:
    # Check Next Button
    if next_button.value() == 1:
        current_option = (current_option + 1) % len(menu_options)
        menu()
        # Wait until button is released 
        while next_button.value() == 1:
            sleep(0.01)
    
    # Check Select Button
    if select_button.value() == 1:
        # Wait until button is released
        while select_button.value() == 1:
            sleep(0.01)
        
        if current_option == 0:
            Ammeter()
        elif current_option == 1:
            Ohmmeter()
        elif current_option == 2:
            Voltmeter()
        elif current_option == 3:
            capacitancemeter()
        
        # After exiting any function, redraw the menu
        menu()
    
    sleep(0.1) # Small power-saving delay