# the below is an example of how to subscribe to a WIS2 topic
# and download the data from the URL provided in the WIS2 data notifcations

import json
import paho.mqtt.client as mqtt_client

import requests
import uuid
import os
import sys

BROKER_HOST = 'wis2box-training.wis2dev.io'
WEBSOCKETS_PATH = '/mqtt'

topics_to_subscribe = [
    'origin/a/wis2/maaike-test/data/recommended/weather/experimental/wis2box-training'
]

# function to download data from a given URL and save it to a local directory
def download_data(url):
    # create a directory to save the downloaded data if it doesn't exist
    download_dir = 'downloaded_data'
    if not os.path.exists(download_dir):
        os.makedirs(download_dir)
    print(f"Downloading data from {url}")
    # make a GET request to the URL to download the data
    response = requests.get(url)
    if response.status_code == 200:
        filename = url.split('/')[-1]
        with open(download_dir+'/'+filename, 'wb') as f:
            f.write(response.content)
        print(f"Data downloaded and saved as {filename}")
    else:
        print(f"Failed to download data from {url}. Status code: {response.status_code}")

# function to be called whenever a message is received on a subscribed topic
def on_message(client, userdata, message):
    j = json.loads(message.payload.decode('utf-8'))
    for link in j['links']:
        if link['rel'] == 'canonical' or link['rel'] == 'update':
            download_data(link['href'])

# function to be called when connection is made
def on_connect(client, userdata, flags, reason_code, properties=None):
    if reason_code != 0:
        print(f"Connection failed. reason_code={reason_code}")

# function to be called when connection to the MQTT broker is stopped
def on_disconnect(client, userdata, reason_code, properties=None):
    print(f"Disconnected. reason_code={reason_code}")
    if reason_code != 0:
        print("Unexpected disconnect. Check TLS/WebSocket path/credentials/network.")
        sys.exit(1)

# generate a unique client ID for the MQTT client
client_id = f"python-mqtt-{str(uuid.uuid4().int)[-5:]}"
client = mqtt_client.Client(client_id, transport='websockets')

# In WIS2 the default READONLY broker-credentials are "everyone" for both username and password
client.username_pw_set("everyone", "everyone")
# set TLS encrypted (secure connection, e.g. HTTPS instead of HTTP))
client.tls_set()
client.ws_set_options(path=WEBSOCKETS_PATH)
# add the on_message callback to the MQTT client, this will be called whenever a message is received on a subscribed topic
client.on_message = on_message
# add the on_connect and on_disconnect callbacks to the MQTT client
client.on_connect = on_connect
client.on_disconnect = on_disconnect
# use port 443, which is the default port for HTTPS
print(f"Connecting client_id={client_id} to MQTT broker at {BROKER_HOST} on port 443 with TLS encryption")
client.connect(BROKER_HOST, port=443, keepalive=60)
# subscribe to the topics defined in the "topics_to_subscribe" list
print(f"Subscribing to topics: {topics_to_subscribe}")
for topic in topics_to_subscribe:
    client.subscribe(topic)
# "loop_forever" starts the MQTT client loop to listen for messages
# this will get the python script running while waiting for messages to arrive
# if you stop the script, it will stop listening for messages and you won't get any data downloaded
# you can stop the script by pressing Ctrl+C in the terminal
print("MQTT client loop started, waiting for messages... (press Ctrl+C to stop)")
client.loop_forever()