from django.http import HttpResponse, Http404
from django.db.models import Count
from django.shortcuts import get_object_or_404, redirect, render
from django.utils import timezone

from edt.models import Timetable, LastUpdate, Group, Subscription, Course
from edt.utils import get_week

import datetime

def index(request):
    timetables = Timetable.objects.all()
    groups = Group.objects.filter(tp__isnull=False).order_by("name")

    for group in groups:
        courses = Course.objects.get_courses_for_group(group).values("begin").annotate(count=Count("begin"))
        weeks = []
        for course in courses:
            year, week, _ = course["begin"].isocalendar()
            date, _ = get_week(year, week)
            if date not in weeks:
                weeks.append(date)
        group.weeks = weeks

    return render(request, "index.html", {"timetables": timetables, "groups": groups})

def timetable(request, timetable_slug, year, week, group_slug):
    start, end = get_week(int(year), int(week))

    timetable = get_object_or_404(Timetable, slug=timetable_slug)
    group = get_object_or_404(Group, slug=group_slug, timetable=timetable)

    courses = Course.objects.get_courses_for_group(group, begin__gte=start, begin__lt=end)
    last_update = LastUpdate.objects.get(timetable=timetable, week=week, year=year)

    grouped_courses = []
    for i, course in enumerate(courses):
        if i == 0 or courses[i - 1].begin.day != course.begin.day:
            grouped_courses.append([course])
        else:
            grouped_courses[-1].append(course)

    return render(request, "timetable.html", {"timetable": timetable, "group": group, "courses": grouped_courses, "last_update": last_update.date, "year": year, "week": week})

def subscribe(request, timetable_slug, year, week, group_slug):
    group = get_object_or_404(Group, slug=group_slug)

    if request.method == "POST":
        subscription = Subscription(email=request.POST["email"], group=group)
        subscription.save()

        return redirect("timetable", timetable_slug=timetable_slug, year=year, week=week, group_slug=group_slug)
    else:
        timetable = get_object_or_404(Timetable, slug=timetable_slug)
        return render(request, "subscribe.html", {"timetable": timetable, "year": year, "week": week, "group": group})

def confirm_subscription(request, token):
    subscription = get_object_or_404(Subscription, token=token)
    if subscription.active:
        raise Http404()

    subscription.active = True
    subscription.save()

    year, week, day = timezone.now().isocalendar()
    if day >= 6:
        year, week, _ = (timezone.now() + datetime.timedelta(weeks=1)).isocalendar()

    return redirect("timetable", timetable_slug=subscription.group.timetable.slug, year=year, week=week, group_slug=subscription.group.slug)

def cancel_subscription(request, token):
    subscription = get_object_or_404(Subscription, token=token)
    subscription.delete()

    return redirect("index")