import RPi.GPIO as GPIO
import time
import requests

# Pin Definitions
TRIG_PIN = 12          # Ultrasonic Trigger pin (BCM GPIO)
ECHO_PIN = 18          # Ultrasonic Echo pin (BCM GPIO)
GREEN_LED_PIN = 16     # Green LED pin (BCM GPIO)
YELLOW_LED_PIN = 20    # Yellow LED pin (BCM GPIO)
RED_LED_PIN = 21       # Red LED pin (BCM GPIO)

# ESP32-CAM Web Server URL
ESP32_CAM_URL = "http://192.168.x.x/stream"  # Replace with ESP32-CAM IP address

# Setup GPIO mode and pins
GPIO.setmode(GPIO.BCM)
GPIO.setup(TRIG_PIN, GPIO.OUT)
GPIO.setup(ECHO_PIN, GPIO.IN)
GPIO.setup(GREEN_LED_PIN, GPIO.OUT)
GPIO.setup(YELLOW_LED_PIN, GPIO.OUT)
GPIO.setup(RED_LED_PIN, GPIO.OUT)

def measure_distance():
    """Measure distance using HC-SR04 ultrasonic sensor."""
    # Send trigger pulse
    GPIO.output(TRIG_PIN, True)
    time.sleep(0.00001)  # Trigger pulse duration: ~10µs
    GPIO.output(TRIG_PIN, False)

    # Wait for echo response and calculate duration
    while GPIO.input(ECHO_PIN) == False:
        pulse_start_time = time.time()
    
    while GPIO.input(ECHO_PIN) == True:
        pulse_end_time = time.time()

    pulse_duration = pulse_end_time - pulse_start_time

    # Calculate distance in cm: speed of sound ~343m/s or ~34300cm/s
    distance_cm = round(pulse_duration * (34300 / 2), 2)
    
    return distance_cm

def update_leds(distance):
    """Update LEDs based on distance."""
    GPIO.output(GREEN_LED_PIN, False)
    GPIO.output(YELLOW_LED_PIN, False)
    GPIO.output(RED_LED_PIN, False)

    if distance < 100:  # Short distance → Green LED
        GPIO.output(GREEN_LED_PIN, True)
    elif distance < 200:  # Medium distance → Yellow LED
        GPIO.output(YELLOW_LED_PIN, True)
    else:  # Long distance → Red LED
        GPIO.output(RED_LED_PIN, True)

def fetch_traffic_data():
    """Fetch traffic data from ESP32-CAM."""
    try:
        response = requests.get(ESP32_CAM_URL)  # Fetch video stream or image data
        if response.status_code == 200:
            print("Traffic data received from ESP32-CAM.")
            return "Heavy Traffic" if len(response.content) > 30000 else "Light Traffic"
        else:
            print("Failed to fetch traffic data.")
            return "Unknown"
    except Exception as e:
        print(f"Error fetching traffic data: {e}")
        return "Unknown"

def main():
    """Main loop."""
    try:
        while True:
            # Measure distance using ultrasonic sensor
            distance = measure_distance()
            print(f"Distance: {distance} cm")

            # Update LEDs based on measured distance
            update_leds(distance)

            # Fetch traffic data from ESP32-CAM
            traffic_status = fetch_traffic_data()
            print(f"Traffic Status: {traffic_status}")

            time.sleep(2)  # Delay between measurements
    except KeyboardInterrupt:
        print("Measurement stopped by user.")
        GPIO.cleanup()

if __name__ == "__main__":
    main()