import json
import time

import paho.mqtt.client as mqtt
from prometheus_client import Gauge, start_http_server

CONFIG = json.load(open("/etc/mqtt2prometheus.json", mode="r", encoding="utf-8"))

people_now_present = Gauge(
    "people_now_present", "People currently present in the space"
)

space_state = Gauge("space_state", "The current space state")
space_lastchange = Gauge(
    "space_lastchange", "The lastchange timestamp of the current space state"
)

member_count = Gauge(
    "member_count", "The current count of members", labelnames=["name"]
)

availability = Gauge(
    "availability",
    "The availability status of different MQTT clients",
    labelnames=["clientname"],
)

temperature = Gauge(
    "temperature_celsius", "The current temperature", labelnames=["location"]
)

humidity = Gauge("humidity_percent", "The current humidity", labelnames=["location"])

barometer = Gauge(
    "barometer_hectopascal", "The current air pressure", labelnames=["location"]
)

power_consumption = Gauge(
    "power_consumption_watt", "The current power used", labelnames=["location"]
)

co2_emission = Gauge(
    "co2_emission_kilogramm", "The CO2 emission in kilogramm", labelnames=["location"]
)

energy_consumption = Gauge(
    "energy_consumption_kilowatthour",
    "The energy consumption in kilowatthour",
    labelnames=["location"],
)


class Mqtt2Prometheus(mqtt.Client):
    def on_connect(self, client, userdata, flags, rc):
        self.publish("availability/mqtt2prometheus", "online", 2, True)

        topics_handler = {
            "availability/#": self.handle_availability,
            "space/status": self.handle_space_status,
            "space/member_count": self.handle_member_count,
            "sensors/people_now_present": self.handle_people_now_present,
            "sensors/#": self.handle_sensor,
        }

        for topic, handler in topics_handler.items():
            self.message_callback_add(topic, handler)
            self.subscribe(topic)

    def handle_people_now_present(self, client, userdata, msg):
        people_now_present.set(json.loads(msg.payload))

    def handle_space_status(self, client, userdata, msg):
        state = json.loads(msg.payload)
        space_state.set(int(state["open"]))
        space_lastchange.set(state["lastchange"])

    def handle_member_count(self, client, userdata, msg):
        count = json.loads(msg.payload)
        member_count.labels(count["name"]).set(count["value"])

    def handle_availability(self, client, userdata, msg):
        t = msg.topic.split("/")
        if len(t) == 2:
            c = t[-1]
        else:
            c = "_".join(t[1:])
        v = 1 if msg.payload == b"online" else 0
        availability.labels(c).set(v)

    def handle_sensor(self, client, userdata, msg):
        t = msg.topic.split("/")

        if t[1] == "people_now_present":
            return

        metric = globals().get(t[1], None)
        if metric is not None:
            try:
                location = "-".join(t[2:])
                metric.labels(location).set(float(msg.payload))
            except:
                pass


def main():

    client = Mqtt2Prometheus("mqtt2prometheus")
    client.username_pw_set(CONFIG["mqtt"]["username"], CONFIG["mqtt"]["password"])
    client.will_set("availability/mqtt2prometheus", "offline", 2, True)

    client.connect(CONFIG["mqtt"]["host"])
    client.loop_start()
    start_http_server(CONFIG["prometheus"]["port"])
    while True:
        time.sleep(1)


if __name__ == "__main__":
    main()