"""
This is the webhook server that interfaces with Google's WebSub (formerly
pubsubhubbub) server. This can be run either as a module on the main frontend,
or as its own server, so it can live on a different host than the frontend.
"""

import time
import sqlite3
from flask import Flask, Blueprint, request
from urllib.parse import parse_qs, urlparse

from ..common.common import *

frontend = Blueprint('webhooks', __name__)

def app():
    app = Flask(__name__)
    app.register_blueprint(frontend)
    return app

@frontend.route('/websub/v1/<int:timestamp>/<nonce>/<subject>/<sig>', methods=["GET"])
def websub(timestamp, nonce, subject, sig):
    hmackey = cf['websub']['hmac_key']
    mode = request.args.get('hub.mode', '')
    topic = request.args.get('hub.topic', '')
    challenge = request.args.get('hub.challenge', '')
    until = int(request.args.get('hub.lease_seconds', '0'))

    if sig != websub_url_hmac(hmackey, subject, timestamp, nonce):
        return '', 400

    if time.time() - timestamp > int(cf['websub']['lease']):
        return '', 400

    if mode != "subscribe":
        return '', 200
        # Note: channels are not purged from the websub dbtable.

    with sqlite3.connect(cf['global']['database']) as conn:
        c = conn.cursor()
        c.execute("""
		INSERT OR REPLACE INTO websub (channel_id, subscribed_until)
                           VALUES (?, datetime(?, 'unixepoch'))
        """, (subject, time.time()+until))
    return challenge, 200

@frontend.route('/websub/v1/<int:timestamp>/<nonce>/<subject>/<sig>', methods=["POST"])
def websub_post(timestamp, nonce, subject, sig):
    lease = cf['websub']['lease']
    hmackey = cf['websub']['hmac_key']
    hub_signature = request.headers.get('X-Hub-Signature').replace("sha1=", "")

    if sig != websub_url_hmac(hmackey, subject, timestamp, nonce):
        return '', 400
    if hub_signature != websub_body_hmac(hmackey, request.data):
        return '', 400

    with sqlite3.connect(cf['global']['database']) as conn:
        c = conn.cursor()
        try:
            update_channel(conn, request.data, from_webhook=True)
        except Exception as e:
            app.logger.error(e)
            with open('/tmp/websub-subscriptions.err', 'ab') as f:
                f.write(f"<!-- {time.ctime()} ({int(time.time())}) -->\n".encode('ascii'))
                f.write(request.data + b"\n")
    return '', 200

if __name__ == '__main__':
    app().run(debug=True)