# (A) INIT
# (A1) LOAD MODULES
from flask import Flask, render_template, request, make_response, send_from_directory
from pywebpush import webpush, WebPushException
import json
import time
import threading

# (A2) FLASK SETTINGS + INIT - CHANGE TO YOUR OWN!
HOST_NAME = "localhost"
HOST_NAME = "0.0.0.0"
HOST_PORT = 80
VAPID_SUBJECT = "mailto:your@email.com"
VAPID_PRIVATE = "YOUR-PRIVATE-KEY"
app = Flask(__name__,
    static_folder='../static',
    template_folder='.',
)
app.debug = True
#app.config['EXPLAIN_TEMPLATE_LOADING'] = True

# (B) VIEWS
# (B1) "LANDING PAGE"
@app.route("/")
def index():
  return render_template("S2_perm_sw.html")

# (B2) SERVICE WORKER
@app.route("/S3_sw.js")
def sw():
  import sys
  print(repr(app.static_folder), file=sys.stderr)
  response = make_response(send_from_directory(app.static_folder, "S3_sw.js"))
  return response

threadlist = []

def donotify(sub, sleep=10):
  global threadlist
  for t in threadlist:
    t.join(0)
  threadlist = [ t for t in threadlist if t.is_alive() ]

  if sleep:
    time.sleep(sleep)

  print('sending notification...')
  try:
    # Mozilla appears to not require the vapid key.
    # Chrome requires the vapid key.
    if True:
      kwargs = dict(vapid_private_key=None,
      #vapid_claims=None,
      )
    else:
      kwargs = dict(vapid_private_key=VAPID_PRIVATE,
      vapid_claims={ "sub": VAPID_SUBJECT },
      )

    webpush(
      subscription_info = sub,
      data = json.dumps({
        "title" : "Welcome!",
        "body" : "Yes, it works!",
        "icon" : "static/i-ico.png",
        "image" : "static/i-banner.png"
      }), **kwargs
    )
    print('done')
  except WebPushException as ex:
    print(ex)

  t = threading.Thread(target=donotify, args=(sub,))
  t.run()
  threadlist.append(t)


# (B3) PUSH DEMO
@app.route("/push", methods=["POST"])
def push():
  # (B3-1) GET SUBSCRIBER
  sub = json.loads(request.form["sub"])
  import sys
  print('sub:', repr(json.dumps(sub)), file=sys.stderr)

  # (B3-2) TEST PUSH NOTIFICATION
  result = "OK"
  donotify(sub, 1)
  return result

# (C) START
if __name__ == "__main__":
  app.run(HOST_NAME, HOST_PORT)