import argparse
import configparser
import json
import os
import threading

import paho.mqtt.subscribe as mqtt

database_filename = "clients.json"
database_lock = threading.Lock()


# noinspection PyUnusedLocal
def update_client_record(client, userdata, message):
    database_lock.acquire()

    if not os.path.exists(database_filename):
        with open(database_filename, 'w') as database_blank:
            json.dump({}, database_blank)

    with open(database_filename, 'r') as infile:
        database = json.load(infile)

    payload = message.payload.decode('utf-8')
    response = json.loads(payload)

    database[response['clientId']] = response

    with open(database_filename, 'w') as outfile:
        json.dump(database, outfile)

    database_lock.release()


def subscribe(broker_hostname, broker_port, topic="torch", tls=None):
    mqtt.callback(update_client_record,
                  topic,
                  hostname=broker_hostname,
                  port=broker_port,
                  tls=tls)


class Config:
    def __init__(self):
        self.broker_hostname = None
        self.broker_port = None
        self.topic = None
        self.tls = None
        parser = self.do_cli_argument_parsing()
        config_path = self.get_config_path(parser.parse_args())
        print("Using torch configuration path: " + config_path)
        self.read_configuration_file(config_path)

    @staticmethod
    def do_cli_argument_parsing():
        parser = argparse.ArgumentParser(description='Simple Torch Flat-file Database Subscriber')
        parser.add_argument('--config-dir', nargs='?', dest='configPath', default='/etc/torch',
                            help='configuration directory (default: /etc/torch)')
        return parser

    @staticmethod
    def get_config_path(args):
        config_path = args.configPath
        if "TORCH_CONFIG_DIR" in os.environ:
            config_path = os.environ.get("TORCH_CONFIG_DIR")
        if not config_path.endswith("/"):
            config_path = config_path + "/"
        return config_path

    def read_configuration_file(self, config_path):
        config = configparser.ConfigParser()
        config.read(config_path + "torch-sub.conf")
        mqtt_config = config['mqtt']
        self.broker_hostname = mqtt_config.get('BrokerHost', fallback="localhost")
        self.broker_port = mqtt_config.getint('BrokerPort', fallback=1883)
        self.topic = mqtt_config.get('Topic', fallback="torch/+/onion_url")
        require_certificate = mqtt_config.getboolean('RequireCertificate', fallback=False)
        ca_file = config_path + mqtt_config.get('CaFile')
        cert_file = config_path + mqtt_config.get('CertFile')
        key_file = config_path + mqtt_config.get('KeyFile')
        self.tls = None
        if require_certificate:
            self.tls = {
                'ca_certs': ca_file,
                'certfile': cert_file,
                'keyfile': key_file
            }


def main():
    config = Config()
    subscribe(config.broker_hostname,
              config.broker_port,
              config.topic,
              config.tls)