from machine import Pin, I2C
import time
import lcd

# Initialize the LCD
i2c = I2C(0, scl=Pin(21), sda=Pin(20), freq=400000)  # I2C on GPIO 21 (SCL) and GPIO 20 (SDA)
lcd_display = lcd.LCD1602(i2c)

# ATM Class to simulate basic ATM operations
class ATM:
    def __init__(self):
        self.balance = 1000  # Initial balance
        self.pin = "1234"    # Default PIN
    
    def check_pin(self, entered_pin):
        return entered_pin == self.pin
    
    def check_balance(self):
        return self.balance
    
    def deposit(self, amount):
        self.balance += amount
    
    def withdraw(self, amount):
        if amount <= self.balance:
            self.balance -= amount
            return True
        else:
            return False

    def print_balance(self):
        return self.balance

# Keypad Class (Updated)
class Keypad:
    def __init__(self, row_pins, col_pins, keymap):
        self.rows = [Pin(pin, Pin.OUT) for pin in row_pins]  # Set rows as outputs
        self.cols = [Pin(pin, Pin.IN, Pin.PULL_UP) for pin in col_pins]  # Set columns as inputs with pull-up resistors
        self.keymap = keymap  # Keymap for the 4x4 Keypad

    def scan(self):
        for row_num, row in enumerate(self.rows):
            row.value(0)  # Set the row low to scan
            for col_num, col in enumerate(self.cols):
                if col.value() == 0:  # If the key is pressed (low signal)
                    key = self.keymap[row_num][col_num]
                    time.sleep(0.2)  # Debounce delay
                    while col.value() == 0:  # Wait until the key is released
                        pass
                    row.value(1)  # Set the row back to high after scanning
                    return key
            row.value(1)  # Reset the row to high if no key is pressed
        return None  # Return None if no key is pressed

# Set up Keypad pins
keypad_pins = {
    "rows": [0, 1, 2, 3],  # GPIOs for Rows 1, 2, 3, 4
    "cols": [4, 5, 6, 7]   # GPIOs for Columns 1, 2, 3, 4
}

# Initialize the keypad
keypad_obj = Keypad(keypad_pins["rows"], keypad_pins["cols"], [
    ['1', '2', '3', 'A'],
    ['4', '5', '6', 'B'],
    ['7', '8', '9', 'C'],
    ['*', '0', '#', 'D']
])

# Create the ATM instance
atm = ATM()

# Set up LEDs
green_led = Pin(18, Pin.OUT)
red_led = Pin(19, Pin.OUT)

# Function to read a keypress from the keypad
def get_key():
    return keypad_obj.scan()

# Function to enter the PIN
def enter_pin():
    entered_pin = ""
    while len(entered_pin) < 4:
        key = get_key()
        if key:
            entered_pin += key
            time.sleep(0.3)  # Debounce delay
    return entered_pin

# Function to display balance on LCD
def show_balance():
    balance = atm.print_balance()
    lcd_display.clear()
    lcd_display.putstr(f"Balance: ${balance}")
    time.sleep(2)  # Display for 2 seconds

# Main ATM Menu
def atm_menu():
    while True:
        # Show menu options
        lcd_display.clear()
        lcd_display.putstr("ATM Menu:\n1. Balance\n2. Deposit\n3. Withdraw\n4. Exit")
        key = get_key()
        if key == '1':
            # Check balance
            show_balance()
            green_led.value(1)  # Green LED for success
            time.sleep(1)
            green_led.value(0)
        elif key == '2':
            # Deposit
            lcd_display.clear()
            lcd_display.putstr("Deposit Amt:")
            amount = int(input())  # Simulating user input
            atm.deposit(amount)
            show_balance()
            green_led.value(1)  # Green LED for success
            time.sleep(1)
            green_led.value(0)
        elif key == '3':
            # Withdraw
            lcd_display.clear()
            lcd_display.putstr("Withdraw Amt:")
            amount = int(input())  # Simulating user input
            if atm.withdraw(amount):
                show_balance()
                green_led.value(1)  # Green LED for success
                time.sleep(1)
                green_led.value(0)
            else:
                lcd_display.clear()
                lcd_display.putstr("Insufficient funds.")
                red_led.value(1)  # Red LED for error
                time.sleep(1)
                red_led.value(0)
        elif key == '4':
            lcd_display.clear()
            lcd_display.putstr("Thank you!")
            time.sleep(2)
            break

# Main Program Flow
def main():
    lcd_display.clear()
    lcd_display.putstr("Welcome to ATM!")
    while True:
        lcd_display.clear()
        lcd_display.putstr("Enter PIN:")
        pin = enter_pin()
        if atm.check_pin(pin):
            lcd_display.clear()
            lcd_display.putstr("PIN Accepted.")
            time.sleep(1)
            atm_menu()
        else:
            lcd_display.clear()
            lcd_display.putstr("Invalid PIN.")
            red_led.value(1)  # Red LED for error
            time.sleep(1)
            red_led.value(0)

# Start the ATM system
main()