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

from edt.models import Timetable, Group, Course

import datetime

def get_week(year, week):
    start = timezone.make_aware(datetime.datetime.strptime("{0}-W{1:02d}-1".format(year, week), "%Y-W%W-%w"))
    end = start + datetime.timedelta(weeks=1)

    return start, end

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_to_response("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)

    return render_to_response("timetable.html", {"timetable": timetable, "group": group, "courses": courses})