import network, time, ujson, machine, dht
from umqtt.simple import MQTTClient
from machine import Pin

SSID = "Wokwi-GUEST"
BROKER = "broker.hivemq.com"
GROUP = "ia-z41"
DEVICE = "node-09"
CLIENT_ID = "ia-edge09-" + machine.unique_id().hex()
T_ALERT = "ia/{}/{}/alerts".format(GROUP, DEVICE).encode()
T_BEAT = "ia/{}/{}/heartbeat".format(GROUP, DEVICE).encode()

ALPHA = 0.10
K = 3.0
WARMUP = 30
MIN_STD = 0.5

state = {
    "temp": {"mean": None, "var": 0.0, "n": 0},
    "hum":  {"mean": None, "var": 0.0, "n": 0}
}
sensor = dht.DHT22(Pin(15))

def connect_mqtt():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        wlan.connect(SSID, "")
        while not wlan.isconnected():
            time.sleep(0.5)
    
    client = MQTTClient(CLIENT_ID, BROKER, port=1883, keepalive=60)
    client.connect()
    return client

def process_metric(metric_name, value):
    s = state[metric_name]
    if s["mean"] is None:
        s["mean"] = value
        s["n"] += 1
        return False, 0.0
        
    std = s["var"] ** 0.5
    if std < MIN_STD: std = MIN_STD
    z = (value - s["mean"]) / std
    
    s["n"] += 1
    is_anom = (s["n"] > WARMUP) and (abs(z) > K)
    
    diff = value - s["mean"]
    s["mean"] = s["mean"] + ALPHA * diff
    s["var"] = (1 - ALPHA) * (s["var"] + ALPHA * diff * diff)
    return is_anom, z

client = connect_mqtt()
print("Мережа OK. Очікування розігріву (60 сек)...")
last_beat = time.time()

while True:
    try:
        sensor.measure()
        t = sensor.temperature()
        h = sensor.humidity()
    except OSError:
        time.sleep(2)
        continue
        
    t_alarm, t_z = process_metric("temp", t)
    h_alarm, h_z = process_metric("hum", h)
    now = time.time()
    
    if t_alarm or h_alarm:
        broken = []
        if t_alarm: broken.append("temperature")
        if h_alarm: broken.append("humidity")
        msg = {
            "ts": now, "broken_signal": broken,
            "temperature": t, "t_z": round(t_z, 2),
            "humidity": h, "h_z": round(h_z, 2),
            "type": "anomaly"
        }
        try:
            client.publish(T_ALERT, ujson.dumps(msg))
            print("ALERT ->", msg)
        except Exception:
            try:
                client = connect_mqtt() 
                client.publish(T_ALERT, ujson.dumps(msg))
                print("ALERT (відправлено після відновлення зв'язку) ->", msg)
            except: pass

    if now - last_beat >= 60:
        beat_msg = {
            "ts": now,
            "t_mean": round(state["temp"]["mean"] or 0, 2),
            "h_mean": round(state["hum"]["mean"] or 0, 2)
        }
        try:
            client.publish(T_BEAT, ujson.dumps(beat_msg))
            print("HEARTBEAT ->", beat_msg)
            last_beat = now
        except Exception:
            try:
                client = connect_mqtt()
                client.publish(T_BEAT, ujson.dumps(beat_msg))
                print("HEARTBEAT (після відновлення) ->", beat_msg)
                last_beat = now
            except: pass

    time.sleep(2)