from machine import Pin, PWM, I2C
from ssd1306 import SSD1306_I2C

# Define OLED display
i2c = I2C(scl=Pin(22), sda=Pin(21))
oled = SSD1306_I2C(128, 64, i2c)

# Define LED, buzzer, and servo motor pins
led = Pin(23, Pin.OUT)
buzzer = PWM(Pin(18), 1000)
servo = PWM(Pin(5), 50)

# Define product data
products = {
    1: {"name": "Coke"},
    2: {"name": "Chips"},
    3: {"name": "Candy"},
}

# Define global variables
current_product = None
inserted_amount = 0.0

def clear_screen():
    oled.fill(0)
    oled.show()

def display_welcome():
    clear_screen()
    oled.text("Welcome to the Vending Machine!", 0, 0)
    oled.text("Please select a product:", 0, 16)
    for i, product in enumerate(products):
        oled.text(f"{i+1}. {products[product]['name']}", 0, 32 + (i * 8))
    oled.show()

def select_product(product_id):
    global current_product
    current_product = product_id
    clear_screen()
    oled.text(f"You selected {products[current_product]['name']}.", 0, 0)
    oled.text("Please insert coins.", 0, 16)
    oled.show()

def insert_coin(coin_value):
    global inserted_amount
    inserted_amount += coin_value
    clear_screen()
    oled.text(f"Inserted amount: ${inserted_amount:.2f}", 0, 0)
    # Check if inserted amount is sufficient
    if inserted_amount >= get_price(current_product):
        oled.text("Sufficient amount inserted.", 0, 16)
    else:
        oled.text(f"Remaining amount: ${get_price(current_product) - inserted_amount:.2f}", 0, 16)
    oled.show()

def get_price(product_id):
    # Implement your logic to retrieve product price from external source (e.g., database, file)
    # This example assumes a static price list
    return {
        1: 1.5,
        2: 1.0,
        3: 0.5,
    }[product_id]

def dispense_product():
    global inserted_amount
    # Turn on servo motor to dispense product
    servo.duty(50)
    time.sleep(1)
    servo.duty(0)
    # Play sound
    buzzer.duty(1023)
    time.sleep(0.2)
    buzzer.duty(0)
    # Turn on LED
    led.on()
    time.sleep(0.5)
    led.off()
    # Return change
    change = inserted_amount - get_price(current_product)
    if change > 0:
        # TODO: Implement coin dispenser to return change
        print(f"Returning change: ${change:.2f}")
    inserted_amount = 0.0
    current_product = None
    display_welcome()

def main():
    display_welcome()
    while True:
        # Read input from user
        # TODO: Implement user input using buttons or other interface
        user_input = int(input("Enter your selection: "))
        if 1 <= user_input <= len(products):
            select_product(user_input)
        elif user_input == 5:
            insert_coin(0.25)
        elif user_input == 10:
            insert_coin(0.10)
        elif user_input == 12:
            dispenser_product()
        else:
            print("Invalid selection.")

if _name_ == "_main_":
main()