import pytz
from functools import reduce
# from collections import OrderedDict
from datetime import datetime, time, timedelta
from django.db.models import Max
from celery import task
from counter.models import DeviceCount
from mosquito.models import MosqPostStatistic


def max_count(x, y):
    if x.count > y.count:
        return x
    return y


def shortest_date(date, date_list):
    distance_list = [(date - _date).days for _date in date_list]
    shortest_distance = min(filter(lambda x: x > 0, distance_list))
    return shortest_distance


@task()
def update_daily_statistic():
    # calc_ret = {}
    # queryset = DeviceCount.objects.raw(
    #     'select id, device_id, max(data_time) as max_date '
    #     'from device_count group by device_id, date(data_time) order by max_date')
    #
    # if queryset:
    #     ret = []
    #     for q in queryset:
    #         entry = DeviceCount.objects.filter(device_id=q.device_id, data_time=q.max_date)
    #         entry = reduce(max_count, entry) if len(entry) > 1 else entry[0]
    #         ret.append((entry.data_time.date(), int(entry.count)))
    #     if ret:
    #         for item in ret:
    #             key, value = item[0], item[1]
    #             try:
    #                 calc_ret[key] += value
    #             except KeyError:
    #                 calc_ret[key] = value
    queryset = DeviceCount.objects.raw('select id, date(data_time) as date from device_count group by date')
    if queryset:
        tz = pytz.timezone("UTC")
        ret = {}
        for q in queryset:
            midnight = tz.localize(datetime.combine(q.date, time(23, 59)), is_dst=None)
            daily_queryset = [DeviceCount.objects.filter(device_id=x['device_id'], data_time=x['max_time'])
                              for x in DeviceCount.objects.filter(data_time__lte=midnight).values(
                              'device_id').annotate(max_time=Max('data_time'))]
            if daily_queryset:
                daily_queryset = [reduce(max_count, entry) if len(entry) > 1 else entry[0] for entry in daily_queryset]
                calc_result = sum(map(lambda x: int(x.count), daily_queryset))
                date = q.date
                ret[date] = calc_result
        date_list = [k for k in ret]
        min_date = min(date_list)
        max_date = max(date_list)
        days = (max_date - min_date).days
        for d in range(1, days+1):
            date_ahead = min_date + timedelta(days=d)
            if date_ahead not in ret:
                distance = shortest_date(date_ahead, date_list)
                ret[date_ahead] = ret[date_ahead - timedelta(days=distance)]

        # Update statistic to MosqPostStatistic
        _date_list = [k for k in ret]
        _date_list.sort()
        is_first = True
        for d in _date_list:
            obj = MosqPostStatistic.objects.get(date=d)
            if is_first:
                if obj:
                    obj.total, obj.increment = ret[d], ret[d]
                    obj.save()
                else:
                    MosqPostStatistic.objects.create(date=d, total=ret[d], increment=ret[d])
            else:
                increment = ret[d] - ret[d-timedelta(days=1)]
                if obj:
                    obj.total, obj.increment = ret[d], increment
                    obj.save()
                else:
                    MosqPostStatistic.objects.create(date=d, total=ret[d], increment=increment)
            is_first = False
        return _date_list


@task()
def update_latest_statistic():
    pass