import datetime
from functools import wraps

from django.contrib.auth.mixins import LoginRequiredMixin
from django.conf import settings
from django.core import serializers
from django.core.exceptions import PermissionDenied
from django.http import HttpResponse, HttpResponseRedirect
from django.urls import reverse
from django.views.decorators.csrf import csrf_exempt
from django.views.generic import TemplateView
from django.views.generic.list import ListView

from logtracker.journal.models import Entry
from logtracker.journal.journalstream import get_journal_entries


class APIEntriesList(LoginRequiredMixin, ListView):
    def get_queryset(self):
        lines = self.request.GET.get('lines', 100)
        host = self.request.GET.get('host', '')
        return Entry.objects.dump(host=host, lines=lines)

    def get(self, request, *args, **kwargs):
        queryset = self.get_queryset()
        response = serializers.serialize("json", queryset)
        return HttpResponse(response, content_type='application/json')


class EntriesList(LoginRequiredMixin, ListView):
    template_name = 'journal/entry_list.html'

    def get_queryset(self):
        lines = self.request.GET.get('lines', 100)
        host = self.request.GET.get('host')
        options = {k: v for k, v in self.request.GET.items() if k not in ('lines', 'host', 'timestamp')}
        return Entry.objects.dump(host=host, lines=lines, **options)

    def get_context_data(self, **kwargs):
        data = super().get_context_data(**kwargs)
        data['hosts'] = Entry.objects.hosts
        data['units'] = Entry.objects.units
        return data


class HomeView(LoginRequiredMixin, TemplateView):
    template_name = 'home.html'

    def post(self, request, *args, **kwargs):
        url = '%s?%s' % (reverse('mail-api'), '%s=%s' % (request.POST['field'], request.POST['address']))
        return HttpResponseRedirect(url)


def get_chunks(gen, n):
    chunk = []
    ended = False
    while True:
        for i in range(n):
            try:
                chunk.append(next(gen))
            except StopIteration:
                ended = True
        yield chunk
        chunk = []
        if ended:
            break


def ssl_client_verify(view):
    @wraps(view)
    def wrapper(request, *args, **kwargs):
        headers = request.META
        if headers.get('HTTP_X_SSL') == "1" and (
            headers.get('HTTP_X_SSL_CLIENT_VERIFY') == "0"
            or headers.get('HTTP_X_SSL_CLIENT_VERIFY') == "SUCCESS"
        ):
            cn = headers.get('HTTP_X_SSL_CLIENT_CN')
            dn = headers.get('HTTP_X_SSL_CLIENT_DN')
            if cn:
                request.host_verified = cn
            else:
                request.host_verified = dn.split(',')[0].split('=')[1]
            if settings.CA_ISSUER:
                ca_issuer = headers.get('HTTP_X_SSL_ISSUER')
                if ca_issuer != settings.CA_ISSUER:
                    raise PermissionDenied
        else:
            if settings.DEBUG:
                request.host_verified = 'test_host'
            else:
                raise PermissionDenied
        return view(request, *args, **kwargs)
    return wrapper


@ssl_client_verify
@csrf_exempt
def UploadView(request, debug=False):
    if request.method == "POST":
        count = 0
        data = {}
        new_entries = []
        now = datetime.datetime.now()
        timestamp = now
        journal_stream = request.META.get('wsgi.input')
        for chunk in get_chunks(get_journal_entries(journal_stream), 20):
            for el in chunk:
                data = {k: v for k, v in el}
                try:
                    timestamp = datetime.datetime.fromtimestamp(int(data['__REALTIME_TIMESTAMP']) / 1000000)
                except (KeyError, TypeError, ValueError):
                    continue
                if (now - timestamp).days > settings.JOURNAL_HISTORY:
                    continue
                entry = Entry(timestamp=timestamp, host=request.host_verified, data=data)
                new_entries.append(entry)
                count += 1
                if debug and count % 1000 == 0:
                    print(count, timestamp)
            Entry.objects.bulk_create(new_entries)
            new_entries = []
        if debug:
            elapsed = datetime.datetime.now() - now
            print('elapsed: %s' % elapsed)
            print('count: %s' % count)
        return HttpResponse('added %s' % count)
    raise PermissionDenied