#!/usr/bin/env python

import argparse
import yaml

import paho.mqtt.client
import sqlite3
import datetime

MAX_VALUE_CACHE_SIZE = 1024

def init_db(path, topics):
    db = sqlite3.connect(path)
    return db


def main():
    options = argparse.ArgumentParser()
    options.add_argument('--broker', '-b', default='localhost')
    options.add_argument('--port', '-p', default='1883', type=int)
    options.add_argument('topicfile')
    options.add_argument('db')
    args = options.parse_args()

    with open(args.topicfile, 'r') as f:
        config_dict = yaml.load(f, Loader=yaml.Loader)

    print(config_dict['topics'])
    db = init_db(args.db, config_dict['topics'])
    client = paho.mqtt.client.Client()

    def on_disconnect(client, userdata, rc):
        client.reconnect()

    current_values = {}

    def on_message(client, userdata, msg):
        try:
            c = db.cursor()
            table = msg.topic.replace("/", "_")
            ts = datetime.datetime.now()
            textual = {
                b"on": 1.,
                b"off": 0.,
                b"yes": 1.,
                b"no": 0.
            }

            if msg.payload.lower() in textual:
                value = textual[msg.payload.lower()]
            else:
                value = float(msg.payload)
            print(f"{table}: {value} ")

            if current_values.get(table, None) != value:
                current_values[table] = value
                if len(current_values) > MAX_VALUE_CACHE_SIZE:
                    first_entry = current_values.keys().next()
                    del current_values[first_entry]

                c.execute(f'CREATE TABLE IF NOT EXISTS "{table}" '
                          '(timestamp timestamp, value real)')
                c.execute(f'INSERT INTO "{table}" VALUES (?, ?)', (ts, value))
                db.commit()

        except Exception as e:
            print(f'Error writing to database: {e}')

    client.on_disconnect = on_disconnect
    client.on_message = on_message

    client.connect(args.broker, args.port)
    client.subscribe([(topic, 2) for topic in config_dict['topics']])
    try:
        client.loop_forever()
    except Exception:
        db.commit()
        db.close()


if __name__ == '__main__':
    main()