import time
from machine import Pin,I2C
from lcd_api import LcdApi 
from i2c_lcd import I2cLcd
i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)
I2C_ADDR = 0x27
lcd= I2cLcd(i2c, I2C_ADDR, 2, 16)
ROW = [13, 12, 11, 10]
COL = [9, 8, 7, 6]
KEYS = [
    ["1", "2", "3", "+"],
    ["4", "5", "6", "-"],
    ["7", "8", "9", "*"],
    ["C", "0", "=", "/"]
]
rows = [Pin(pin, Pin.OUT) for pin in ROW]
cols = [Pin(pin, Pin.IN, Pin.PULL_DOWN) for pin in COL]
def check_keypad():
    for i, row in enumerate(rows):
        for r in rows:
            r.value(0)
        row.value(1)

        for j, col in enumerate(cols):
            if col.value() == 1:
                return KEYS[i][j]
    return None
num1 = ""
num2 = ""
operator = ""
last_key = None
lcd.clear()
while True:
    key = check_keypad()
    if key != last_key:
        if key is not None:
            print("Key:", key)
            if key == "C":
                num1 = ""
                num2 = ""
                operator = ""
                print("Cleared")
                lcd.clear()
            elif key in ["+", "-", "*", "/"]:
                operator = key
                print("Operator:", operator)
                lcd.putstr(str(operator))
            elif key == "=":
                if num1 != "" and num2 != "" and operator != "":
                    a = int(num1)
                    b = int(num2)
                    if operator == "+":
                        result = a + b
                    elif operator == "-":
                        result = a - b
                    elif operator == "*":
                        result = a * b
                    elif operator == "/":
                        result = a / b
                    print("Result:", result)
                    lcd.putstr("=")
                    lcd.move_to(0,1)
                    lcd.putstr(str(result))
                    num1 = ""
                    num2 = ""
                    operator = ""
            else:
                if operator == "":
                    num1 += key
                    print("Num1:", num1)
                    lcd.putstr(str(key))
                else:
                    num2 += key
                    print("Num2:", num2)
                    lcd.putstr(str(key))
        last_key = key
    time.sleep(0.2)