from functools import partial

from django.conf import settings
from django.db import models
from django.db.models.signals import post_save
from django.dispatch import receiver
from django.urls import reverse
from django.utils.crypto import get_random_string


make_stream_key = partial(get_random_string, 20)


class Stream(models.Model):

    user = models.OneToOneField(
        settings.AUTH_USER_MODEL, related_name="stream", on_delete=models.CASCADE)
    key = models.CharField(max_length=20, default=make_stream_key, unique=True)
    started_at = models.DateTimeField(null=True, blank=True)

    def __str__(self):
        return self.user.username

    @property
    def is_live(self):
        return self.started_at is not None

    @property
    def hls_url(self):
        return reverse("hls-url", args=(self.user.username,))


@receiver(post_save, sender=settings.AUTH_USER_MODEL, dispatch_uid="create_stream_for_user")
def create_stream_for_user(sender, instance=None, created=False, **kwargs):
    """ Create a stream for new users.
    """
    if created:
        Stream.objects.create(user=instance)

from django.contrib import admin

from .models import Stream


@admin.register(Stream)
class StreamAdmin(admin.ModelAdmin):
    list_display = ("__str__", "started_at", "is_live")
    readonly_fields = ("hls_url",)

from django.http import HttpResponse, HttpResponseForbidden
from django.shortcuts import redirect, get_object_or_404
from django.utils import timezone
from django.views.decorators.http import require_POST
from django.views.decorators.csrf import csrf_exempt

from .models import Stream


@require_POST
@csrf_exempt
def start_stream(request):
    """ This view is called when a stream starts.
    """
    stream = get_object_or_404(Stream, key=request.POST["name"])

    # Ban streamers by setting them inactive
    if not stream.user.is_active:
        return HttpResponseForbidden("Inactive user")

    # Don't allow the same stream to be published multiple times
    if stream.started_at:
        return HttpResponseForbidden("Already streaming")

    stream.started_at = timezone.now()
    stream.save()

    # Redirect to the streamer's public username
    return redirect(stream.user.username)


@require_POST
@csrf_exempt
def stop_stream(request):
    """ This view is called when a stream stops.
    """
    Stream.objects.filter(key=request.POST["name"]).update(started_at=None)
    return HttpResponse("OK")

from django.contrib import admin
from django.urls import path

from .views import start_stream, stop_stream


def fake_view(*args, **kwargs):
    """ This view should never be called because the URL paths
        that map here will be served by nginx directly.
    """
    raise Exception("This should never be called!")


urlpatterns = [
    path("admin/", admin.site.urls),
    path("start_stream", start_stream, name="start-stream"),
    path("stop_stream", stop_stream, name="stop-stream"),
    path("live/<username>/index.m3u8", fake_view, name="hls-url")
]

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    "boltstream"
]