import datetime
import json

import dateutil.parser
import dateutil.rrule
from django.db.models import Count, DateTimeField, Max, OuterRef, Subquery
from django.utils import timezone
from django.views.generic import TemplateView

from pretix.base.models import (
    Item, Order, OrderPayment, OrderPosition, SubEvent,
)
from pretix.control.permissions import EventPermissionRequiredMixin
from pretix.control.views import ChartContainingView
from pretix.plugins.statistics.signals import clear_cache


class IndexView(EventPermissionRequiredMixin, ChartContainingView, TemplateView):
    template_name = 'pretixplugins/statistics/index.html'
    permission = 'can_view_orders'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        tz = timezone.get_current_timezone()

        if 'latest' in self.request.GET:
            clear_cache(self.request.event)

        subevent = None
        if self.request.GET.get("subevent", "") != "" and self.request.event.has_subevents:
            i = self.request.GET.get("subevent", "")
            try:
                subevent = self.request.event.subevents.get(pk=i)
            except SubEvent.DoesNotExist:
                pass

        cache = self.request.event.cache
        ckey = str(subevent.pk) if subevent else 'all'

        p_date = OrderPayment.objects.filter(
            order=OuterRef('pk'),
            state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED),
            payment_date__isnull=False
        ).values('order').annotate(
            m=Max('payment_date')
        ).values(
            'm'
        ).order_by()
        op_date = OrderPayment.objects.filter(
            order=OuterRef('order'),
            state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED),
            payment_date__isnull=False
        ).values('order').annotate(
            m=Max('payment_date')
        ).values(
            'm'
        ).order_by()

        # Orders by day
        ctx['obd_data'] = cache.get('statistics_obd_data' + ckey)
        if not ctx['obd_data']:
            oqs = Order.objects.annotate(payment_date=Subquery(p_date, output_field=DateTimeField()))
            if subevent:
                oqs = oqs.filter(all_positions__subevent_id=subevent, all_positions__canceled=False).distinct()

            ordered_by_day = {}
            for o in oqs.filter(event=self.request.event).values('datetime'):
                day = o['datetime'].astimezone(tz).date()
                ordered_by_day[day] = ordered_by_day.get(day, 0) + 1
            paid_by_day = {}
            for o in oqs.filter(event=self.request.event, payment_date__isnull=False).values('payment_date'):
                day = o['payment_date'].astimezone(tz).date()
                paid_by_day[day] = paid_by_day.get(day, 0) + 1

            data = []
            for d in dateutil.rrule.rrule(
                    dateutil.rrule.DAILY,
                    dtstart=min(ordered_by_day.keys()) if ordered_by_day else datetime.date.today(),
                    until=max(
                        max(ordered_by_day.keys() if paid_by_day else [datetime.date.today()]),
                        max(paid_by_day.keys() if paid_by_day else [datetime.date(1970, 1, 1)])
                    )):
                d = d.date()
                data.append({
                    'date': d.strftime('%Y-%m-%d'),
                    'ordered': ordered_by_day.get(d, 0),
                    'paid': paid_by_day.get(d, 0)
                })

            ctx['obd_data'] = json.dumps(data)
            cache.set('statistics_obd_data' + ckey, ctx['obd_data'])

        # Orders by product
        ctx['obp_data'] = cache.get('statistics_obp_data' + ckey)
        if not ctx['obp_data']:
            opqs = OrderPosition.objects
            if subevent:
                opqs = opqs.filter(subevent=subevent)
            num_ordered = {
                p['item']: p['cnt']
                for p in (opqs
                          .filter(order__event=self.request.event)
                          .values('item')
                          .annotate(cnt=Count('id')).order_by())
            }
            num_paid = {
                p['item']: p['cnt']
                for p in (opqs
                          .filter(order__event=self.request.event, order__status=Order.STATUS_PAID)
                          .values('item')
                          .annotate(cnt=Count('id')).order_by())
            }
            item_names = {
                i.id: str(i)
                for i in Item.objects.filter(event=self.request.event)
            }
            ctx['obp_data'] = json.dumps([
                {
                    'item': item_names[item],
                    'item_short': item_names[item] if len(item_names[item]) < 15 else (item_names[item][:15] + "…"),
                    'ordered': cnt,
                    'paid': num_paid.get(item, 0)
                } for item, cnt in num_ordered.items()
            ])
            cache.set('statistics_obp_data' + ckey, ctx['obp_data'])

        ctx['rev_data'] = cache.get('statistics_rev_data' + ckey)
        if not ctx['rev_data']:
            rev_by_day = {}
            if subevent:
                for o in OrderPosition.objects.annotate(
                        payment_date=Subquery(op_date, output_field=DateTimeField())
                ).filter(order__event=self.request.event,
                         subevent=subevent,
                         order__status=Order.STATUS_PAID,
                         payment_date__isnull=False).values('payment_date', 'price'):
                    day = o['payment_date'].astimezone(tz).date()
                    rev_by_day[day] = rev_by_day.get(day, 0) + o['price']
            else:
                for o in Order.objects.annotate(
                        payment_date=Subquery(p_date, output_field=DateTimeField())
                ).filter(event=self.request.event,
                         status=Order.STATUS_PAID,
                         payment_date__isnull=False).values('payment_date', 'total'):
                    day = o['payment_date'].astimezone(tz).date()
                    rev_by_day[day] = rev_by_day.get(day, 0) + o['total']

            data = []
            total = 0
            for d in dateutil.rrule.rrule(
                    dateutil.rrule.DAILY,
                    dtstart=min(rev_by_day.keys() if rev_by_day else [datetime.date.today()]),
                    until=max(rev_by_day.keys() if rev_by_day else [datetime.date.today()])):
                d = d.date()
                total += float(rev_by_day.get(d, 0))
                data.append({
                    'date': d.strftime('%Y-%m-%d'),
                    'revenue': round(total, 2),
                })
            ctx['rev_data'] = json.dumps(data)
            cache.set('statistics_rev_data' + ckey, ctx['rev_data'])

        ctx['has_orders'] = self.request.event.orders.exists()

        return ctx