import machine
import time
from hcsr04 import HCSR04  # Assuming you saved the HC-SR04 driver code as `hcsr04.py`
from ssd1306 import SSD1306_I2C  # Assuming you added SSD1306 driver
from umqtt.simple import MQTTClient

# Hardware setup (based on updated Wokwi diagram)
trigger_pin = 4   # Ultrasonic Trigger (D4)
echo_pin = 15     # Ultrasonic Echo (D15)
oled_scl = 22     # OLED SCL (D22)
oled_sda = 21     # OLED SDA (D21)
button_pin = 13   # Push button (D13)
led_pin = 2       # LED (D2)

# Initialize components
sensor = HCSR04(trigger_pin=trigger_pin, echo_pin=echo_pin)
i2c = machine.I2C(0, scl=machine.Pin(oled_scl), sda=machine.Pin(oled_sda))
oled = SSD1306_I2C(128, 64, i2c)
button = machine.Pin(button_pin, machine.Pin.IN, machine.Pin.PULL_UP)
led = machine.Pin(led_pin, machine.Pin.OUT)

# MQTT setup (NETPIE 2020 credentials)
CLIENT_ID = "your-client-id"
TOKEN = "your-token"
HOST = "broker.netpie.io"
TOPIC_SHADOW = "@shadow/data/update"
TOPIC_STRING = "esp32/data"

mqtt_client = MQTTClient(CLIENT_ID, HOST, user=TOKEN, password="")

# Variables
mindist = 20  # Default minimum distance in cm
actual_distance = 0
last_sent_time = 0  # Time tracking for MQTT updates
NAME = "Your Name"
STUDENT_ID = "Your Student ID"

# Connect to NETPIE
def connect_mqtt():
    try:
        mqtt_client.connect()
        print("Connected to MQTT broker")
    except Exception as e:
        print("MQTT connection failed:", e)

# Send shadow update to NETPIE
def send_shadow():
    global actual_distance, mindist
    alert_status = "Too Close" if actual_distance < mindist else "OK"
    payload = {
        "data": {
            "mindist": mindist,
            "actual_distance": actual_distance,
            "alert": alert_status,
        }
    }
    try:
        mqtt_client.publish(TOPIC_SHADOW, str(payload))
        print("Shadow updated:", payload)
    except Exception as e:
        print("Failed to send shadow:", e)

# Send string to NETPIE and Node-RED
def send_string():
    timestamp = time.ticks_ms()
    message = f"{timestamp} : {NAME} {STUDENT_ID}"
    try:
        mqtt_client.publish(TOPIC_STRING, message)
        print("String sent:", message)
    except Exception as e:
        print("Failed to send string:", e)

# Button press handler
def button_handler(pin):
    send_string()

# Display information on OLED
def update_display():
    global actual_distance, mindist
    oled.fill(0)
    oled.text(f"Dist: {actual_distance} cm", 0, 0)
    oled.text(f"MinDist: {mindist} cm", 0, 10)
    if actual_distance < mindist:
        oled.text("Alert: Too Close!", 0, 20)
        led.on()
    else:
        oled.text("Alert: OK", 0, 20)
        led.off()
    oled.show()

# Initialize button interrupt
button.irq(trigger=machine.Pin.IRQ_FALLING, handler=button_handler)

# Main loop
def main():
    global actual_distance, last_sent_time, mindist
    connect_mqtt()

    while True:
        try:
            # Measure distance
            actual_distance = sensor.distance_cm()
            update_display()

            # Send shadow every 2 seconds
            if time.ticks_ms() - last_sent_time > 2000:
                send_shadow()
                last_sent_time = time.ticks_ms()

            time.sleep(0.3)  # Measure every 300 ms
        except OSError as e:
            print("Sensor error:", e)
        except Exception as e:
            print("Error:", e)

if __name__ == "__main__":
    main()