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

#Pin Declaration
TRIG = Pin(5, Pin.OUT)
ECHO = Pin(18, Pin.IN)
GREEN_LED = Pin(19, Pin.OUT)
RED_LED = Pin(25, Pin.OUT)
BUTTON_SCAN = Pin(15, Pin.IN, Pin.PULL_UP)  #Single button for scanning
BUZZER = PWM(Pin(23), freq=2000, duty=0)

#OLED Setup
i2c = I2C(0, scl=Pin(22), sda=Pin(21))
oled = SSD1306_I2C(128, 64, i2c)

#Simulated Queue of QR Codes
scan_queue = ["12345", "67890", "12345", "00000", "54321", "67890"]

#Registered Users
registered_users = {
    "12345": "Ali",
    "67890": "Siti",
    "54321": "Raju",
    "11111": "Aminah"
}

#Track who already claimed
claimed_today = set()

#Buzzer Functions
def buzzer_on():
    BUZZER.freq(2000)
    BUZZER.duty(512)

def buzzer_off():
    BUZZER.duty(0)

#OLED Display Functions
def display_message(title, line2):
    oled.fill(0)
    oled.text(title, 0, 0)
    oled.text(line2, 0, 20)
    oled.show()

#Measure food level (Ultrasonic)
def measure_distance():
    TRIG.value(0)
    time.sleep_us(2)
    TRIG.value(1)
    time.sleep_us(10)
    TRIG.value(0)
    duration = time_pulse_us(ECHO, 1)
    distance_cm = (duration * 0.0343) / 2
    return distance_cm

#Food Level Checking
def check_food_level():
    distance = measure_distance()
    print("Current Food Level: {:.2f} cm".format(distance))
    if distance > 100:
        display_message("FOOD LOW", "")
        RED_LED.on()
        GREEN_LED.off()
        buzzer_on()
        time.sleep(2)
        buzzer_off()
        RED_LED.off()
    else:
        display_message("FOOD OK", "")
        GREEN_LED.on()
        RED_LED.off()
    return distance

#Feedback when scan QR
def give_feedback(success):
    if success:
        GREEN_LED.on()
        RED_LED.off()
        buzzer_off()
    else:
        GREEN_LED.off()
        RED_LED.on()
        buzzer_on()
    time.sleep(2)
    GREEN_LED.off()
    RED_LED.off()
    buzzer_off()

#Main Program
print("System Initialized. Ready for QR Scan Simulation...\n")

while True:
    # Always check food level
    food_level = check_food_level()

    if BUTTON_SCAN.value() == 0 and scan_queue:
        scanned_qr = scan_queue.pop(0)
        print("QR Scanned:", scanned_qr)
        time.sleep(0.5)  # Debounce

        if scanned_qr in registered_users:
            name = registered_users[scanned_qr]
            if scanned_qr in claimed_today:
                display_message("ALREADY CLAIMED", name)
                print(f"{name} already claimed today!")
                give_feedback(False)
            else:
                if food_level <= 100:
                    claimed_today.add(scanned_qr)
                    display_message("CLAIM APPROVED", name)
                    print(f"{name} successfully claimed.")
                    give_feedback(True)
                else:
                    display_message("NO STOCK", name)
                    print(f"Cannot claim. Food stock low!")
                    give_feedback(False)
        else:
            display_message("NOT REGISTERED", "Unknown")
            print("QR not recognized.")
            give_feedback(False)

        time.sleep(1.5)

    time.sleep(0.1)