views.py

# Create your views here.
import base64
from datetime import datetime, timedelta, timezone
from hashlib import sha512
from json import loads
from time import time

from django.core import serializers
from django.http import HttpResponse, JsonResponse
from django.shortcuts import render

from .models import Computer, User

n = 24758167959654528007156374531915464081839760935532218683689708649238085888673119
e = 1792365660034190580552551249494619970913188709474773556763388672115404129751573

DAILY_QUOTA = 3600 * 2

twitchUsers = {
    "jaze": "alxjaze",
    "jonathanjtan": "dragaanwawa",
    "nlingarkar": "sirnellington",
}


def index(request):
    computers = Computer.objects.all()
    users = User.objects.all()
    for computer in computers:
        if (
            computer.user is not None
            and computer.local_timestamp
            and (datetime.now(timezone.utc) - computer.local_timestamp).seconds > 5 * 60
        ):
            computer.user = None
            computer.save()

    return render(request, "computers.html", {"computers": computers, "users": users})


def json(request):
    computers = Computer.objects.all()
    users = User.objects.all()
    for computer in computers:
        if (
            computer.user is not None
            and computer.local_timestamp
            and (datetime.now(timezone.utc) - computer.local_timestamp).seconds > 5 * 60
        ):
            computer.user = None
            computer.save()

    return JsonResponse(
        {
            # "computers": list(computers.values("hostname", "user_id")),
            # "users": list(users.values("username")),
            "computers": list(computers.values()),
            "users": list(users.values()),
        }
    )


def _verify_signature(code_text, signature):
    return (
        signature.isdigit()
        and pow(int(signature), e, n)
        == int(sha512(code_text.encode("utf-8")).hexdigest(), 16) % n
    )


def ping(request, code_text=None, signature=None):
    if not _verify_signature(code_text, signature):
        print("Bad ping request.")
        return HttpResponse("Bad Request.", status=403)

    code_text = base64.b64decode(code_text).decode("utf-8")
    data = loads(code_text)
    delta = data["delta"]
    username = data["username"]
    hostname = data["host"].lower()

    # data["timestamp"] is in milliseconds since the epoch
    timestamp = datetime.fromtimestamp(int(data["timestamp"] / 1000), tz=timezone.utc)

    user, _ = User.objects.get_or_create(username=username)
    computer, _ = Computer.objects.get_or_create(hostname=hostname)

    now = datetime.now(tz=timezone.utc)
    # invatiant: pings from a user should come at least once every two time
    # DELTAs, but not more than once every half a DELTA. (default DELTA is 5).
    if user.last_ping and (0.5 * delta) < (now - user.last_ping).seconds < (
        1.5 * delta
    ):
        user.time_spent += (now - user.last_ping).seconds
    user.last_ping = now
    user.save()

    computer.local_timestamp = datetime.now(tz=timezone.utc)
    if computer.user is not user:
        computer.user = user
    computer.save()

    return HttpResponse(str(user.time_spent))