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


def fill_date(ret=None, tz=None):
    date_list = [k for k in ret]
    min_date = min(date_list)
    max_date = datetime.now(tz).date()
    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)]
    return ret


def get_daily_statistic(enable_container=False):
    device_container = {}
    daily_ret = {}
    queryset = DeviceCount.objects.raw('select id, date(data_time) as date from device_count group by date')
    if queryset:
        tz = pytz.timezone("UTC")
        device_list = {item.device_id for item in DeviceCount.objects.distinct()}
        for item in device_list:
            device_container[item] = set()
        for q in queryset:
            # 按照 device_id 分组查询最新时间 max_time，然后通过id + max_time 获取实例，用来得到count
            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]
                if enable_container:
                    for device_id in device_list:
                        device_container[device_id] = device_container[device_id] | \
                                                      {(entry.count, entry.data_time)
                                                       for entry in daily_queryset if entry.device_id == device_id}
                calc_result = sum(map(lambda x: int(x.count), daily_queryset))
                date = q.date
                daily_ret[date] = calc_result
    return daily_ret, device_container


def update_daily_statistic():
    full_ret = None
    # 计算每天聚合值
    daily_ret, device_container = get_daily_statistic(enable_container=True)
    for k in device_container: print(k, device_container[k])

    # 计算没有记录的日期，值
    if daily_ret:
        full_ret = fill_date(daily_ret, tz=pytz.timezone("UTC"))

    # 写入数据库
    if full_ret:
        _date_list = [k for k in full_ret]
        _date_list.sort()
        is_first = True
        for d in _date_list:
            try:
                obj = MosqPostStatistic.objects.get(date=d)
            except MosqPostStatistic.DoesNotExist:
                obj = None
            if is_first:
                if obj:
                    obj.total, obj.increment = full_ret[d], full_ret[d]
                    obj.save()
                else:
                    MosqPostStatistic.objects.create(date=d, total=full_ret[d], increment=full_ret[d])
            else:
                increment = full_ret[d] - full_ret[d - timedelta(days=1)]
                if obj:
                    obj.total, obj.increment = full_ret[d], increment
                    obj.save()
                else:
                    MosqPostStatistic.objects.create(date=d, total=full_ret[d], increment=increment)
            is_first = False
        return _date_list


@task()
def update_latest_statistic():
    pass