import datetime
import hashlib
import hmac
import json
import logging
import os

import flask
import flask_apscheduler
import flask_restful
import flask_restful.reqparse

from sender import Sender


subscriptions = {}

app = flask.Flask(__name__)
app.logger.setLevel(logging.INFO)
app.config.update(
    ERROR_404_HELP=False,
    SCHEDULER_TIMEZONE='UTC',
    SCHEDULER_JOBS=[
        dict(id='subscribe',
             func='twitch:Twitch.subscribe',
             args=(app, subscriptions, 86400),
             max_instances=1,
             trigger='interval',
             seconds=3600,
             next_run_time=datetime.datetime.utcnow() + datetime.timedelta(seconds=10))])

scheduler = flask_apscheduler.APScheduler()
scheduler.init_app(app)

api = flask_restful.Api(app)

sender = Sender(app)


verification_parser = flask_restful.reqparse.RequestParser()
verification_parser.add_argument('hub.challenge', type=str, required=True)
verification_parser.add_argument('hub.lease_seconds', type=int, required=True)
verification_parser.add_argument('hub.mode', type=str, required=True)
verification_parser.add_argument('hub.topic', type=str, required=True)


class WebhooksResource(flask_restful.Resource):
    def get(self):
        args = verification_parser.parse_args()
        verified = False
        for sub in subscriptions.values():
            h = '{0[hub.mode]}|{0[hub.topic]}|{0[hub.lease_seconds]}'.format(args)
            if hashlib.sha256(h.encode()).hexdigest() == sub['request_hash']:
                verified = True
                break
        if not verified:
            flask_restful.abort(400, message='Verification failed')
        r = app.make_response(args['hub.challenge'])
        r.mimetype = 'text/plain'
        r.status_code = 200
        return r

    def post(self):
        sha, signature = flask.request.headers.get('X-Hub-Signature').split('=')
        data = flask.request.data
        for topic, sub in subscriptions.items():
            mac = hmac.new(sub['secret'].encode(), data, getattr(hashlib, sha))
            if not hmac.compare_digest(mac.hexdigest(), signature):
                continue
            message = flask.request.get_json(force=True)
            message['topic'] = topic
            sender.send(json.dumps(message).encode())
        return None, 204


api.add_resource(WebhooksResource, '/webhooks')


if __name__ == '__main__':
    scheduler.start()
    app.run(host='0.0.0.0', threaded=True, debug=False)