from machine import Pin, ADC, PWM
import time

# -------------------------------
# Hardware Configuration
# -------------------------------

# Ultrasonic Sensor (HC-SR04)
trigger = Pin(16, Pin.OUT)
echo = Pin(17, Pin.IN)

# LDR (ADC)
ldr = ADC(26)  # GP26 = ADC0

# LEDs
red_led = Pin(14, Pin.OUT)
green_led = Pin(15, Pin.OUT)

# Buzzer (PWM for sound)
buzzer = PWM(Pin(13))
buzzer.freq(1000)  # 1kHz audible tone

# -------------------------------
# Thresholds
# -------------------------------
INTRUDER_DISTANCE = 50      # cm
DARK_THRESHOLD = 30000      # LDR ADC value (tune if needed)

# -------------------------------
# Ultrasonic Distance Function
# -------------------------------
def measure_distance():
    trigger.low()
    time.sleep_us(2)
    trigger.high()
    time.sleep_us(10)
    trigger.low()

    while echo.value() == 0:
        start = time.ticks_us()

    while echo.value() == 1:
        end = time.ticks_us()

    duration = time.ticks_diff(end, start)
    distance = (duration * 0.0343) / 2
    return distance

print("Security System Initialized")
print("---------------------------")

# -------------------------------
# Main Loop
# -------------------------------
while True:
    distance = measure_distance()
    light_value = ldr.read_u16()

    print(f"Distance: {distance:.1f} cm | LDR: {light_value}")

    # 🚨 PRIORITY 1: INTRUDER ALERT
    if distance < INTRUDER_DISTANCE:
        print("🚨 INTRUDER DETECTED!")

        red_led.value(1)
        green_led.value(0)

        buzzer.duty_u16(30000)  # Turn buzzer ON

    # 🌗 PRIORITY 2: ENVIRONMENT STATUS
    else:
        red_led.value(0)
        buzzer.duty_u16(0)      # Turn buzzer OFF

        if light_value > DARK_THRESHOLD:
            print("🌙 Night Watch Mode")
            green_led.toggle()
            time.sleep(0.5)
        else:
            print("☀️ Day Safe Mode")
            green_led.value(1)
            time.sleep(0.5)