from contextlib import asynccontextmanager
import random
import time
import json
from fastapi import FastAPI, BackgroundTasks
import paho.mqtt.client as mqtt
emulator_rnd = f"emulator_{random.randint(1, 50)}"

@asynccontextmanager
async def lifespan(app: FastAPI):
    try:
        global mqtt_client
        mqtt_client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, protocol=mqtt.MQTTv5, client_id='enertec_client')
        mqtt_client.username_pw_set('enertec', 'pwd@mqtt!enertec')
        mqtt_client.connect(MQTT_BROKER, MQTT_PORT, 60)
        mqtt_client.loop_start()
    except Exception as e:
        print(f"Errore durante la connessione al broker MQTT: {e}")
    yield
    try:
        mqtt_client.loop_stop()
        mqtt_client.disconnect()
    except Exception as e:
        print(f"Errore durante la disconnessione dal broker MQTT: {e}")

# Configurazione FastAPI
app = FastAPI(lifespan=lifespan)

# Configurazione MQTT
MQTT_BROKER = "mqtt"
MQTT_PORT = 1883
MQTT_TOPIC_STATUS = f"iot/ipnode/{emulator_rnd}/update/event/change-device-status"
MQTT_TOPIC_SENSOR = f"iot/ipnode/{emulator_rnd}/update/event/measure-sensor"

mqtt_client = None

# Simulazione sensori
def generate_sensor_data():
    sensors = [
        {"channel": "1", "type": "temperature", "min": 20.0, "max": 30.0},
        {"channel": "2", "type": "humidity", "min": 40.0, "max": 60.0},
    ]
    data = []
    for sensor in sensors:
        value = random.uniform(sensor["min"], sensor["max"])
        data.append({
            "channel": sensor["channel"],
            "measurements": {sensor["type"]: round(value, 2)},
            "measureTime": int(time.time() * 1000),
        })
    return data

def generate_status():
    return {
        "battery": random.randint(50, 100),
        "signal_strength": random.randint(-70, -50),
        "timestamp": int(time.time() * 1000),
    }

def publish_status(client):
    payload = {
        "deviceEui": emulator_rnd,
        "events": [
            {
                "name": "change-device-status",
                "value": generate_status(),
                "timestamp": int(time.time() * 1000),
            }
        ],
    }
    client.publish(MQTT_TOPIC_STATUS, json.dumps(payload), qos=1,retain=True)
    print(f"Published status: {payload}")

def publish_sensor_data(client):
    payload = {
        "deviceEui": emulator_rnd,
        "events": [
            {
                "name": "measure-sensor",
                "value": generate_sensor_data(),
                "timestamp": int(time.time() * 1000),
            }
        ],
    }
    client.publish(MQTT_TOPIC_SENSOR, json.dumps(payload), qos=1)
    print(f"Published sensor data: {payload}")

# Servizio di simulazione
def run_emulation(client):
    while True:
        publish_status(client)
        publish_sensor_data(client)
        time.sleep(0.1)  # Invio ogni 10 secondi

@app.post("/start_emulation")
def start_emulation(background_tasks: BackgroundTasks):
    background_tasks.add_task(run_emulation, mqtt_client)
    return {"message": "Emulazione avviata"}

@app.post("/stop_emulation")
def stop_emulation():
    return {"message": "Non implementato, fermare manualmente il processo"}