import pytz
from datetime import timedelta
from dateutil.parser import parse as dt_parse

from isc_video_record.db import influxdb

tz = pytz.timezone('Asia/Shanghai')


class PreEvent(object):

    def __init__(self, start_time, end_time):
        influxdb.reconnect()
        self.start_time = start_time
        self.end_time = end_time
        self.tz_start_time = dt_parse(self.start_time.replace(' ', 'T') + '.001000Z').astimezone(tz)
        self.tz_end_time = dt_parse(self.end_time.replace(' ', 'T') + '.001000Z').astimezone(tz)

    def get_alarm_list(self, camera_index):
        sql = '''
            select *
            from "one_week"."event_vss"
            where
                time >= $start_time
                and time < $end_time
                and camera_index = $camera_index
        '''
        res = influxdb.query(sql, bind_params={
            'start_time': self.start_time,
            'end_time': self.end_time,
            'camera_index': camera_index
        })
        points = []
        if res and len(res) > 0:
            points = res['event_vss']

        return points

    def merge_alarm_to_event(self, alarm_list):

        pre_events = []
        pre_status = -1
        # 告警消息转换成事件
        for alarm_point in alarm_list:
            # 报警时间转换成上海时区
            alarm_time = dt_parse(alarm_point['time']).astimezone(tz)

            if alarm_point['status'] == 1:
                if pre_status == 1:
                    pre_events[-1]['end_time'] = alarm_time
                else:
                    # 预录5s
                    pre_events.append({'start_time': alarm_time - timedelta(seconds=5)})
            else:
                if pre_status == 1:
                    pre_events[-1]['end_time'] = alarm_time + timedelta(seconds=10)
                elif pre_status == -1:
                    pre_events.append({
                        'start_time': self.tz_start_time,
                        'end_time': alarm_time + timedelta(seconds=10)
                    })
                else:
                    pre_events.append({
                        'start_time': alarm_time - timedelta(seconds=30),
                        'end_time': alarm_time + timedelta(seconds=10)
                    })

            pre_status = alarm_point['status']

        if pre_status == 1:
            pre_events[-1]['end_time'] = self.tz_end_time

        # 合并时间间隔较短的事件或切分时间过长的事件
        events = []
        for pre_event in pre_events:
            if len(events) > 0 \
               and pre_event['start_time'] - events[-1]['end_time'] <= timedelta(seconds=30) \
               and events[-1]['end_time'] - events[-1]['start_time'] <= timedelta(hours=0.5):
                events[-1]['end_time'] = pre_event['end_time']
            else:
                events.append({
                    'start_time': pre_event['start_time'],
                    'end_time': pre_event['end_time'],
                })

        return events


if __name__ == '__main__':

    from isc_video_record.recorder import recorder

    pre_event = PreEvent('2021-04-26 00:00:00', '2021-04-26 16:00:00')
    alarm_points = pre_event.get_alarm_list('f8a3c4d9b8ae42118b4db9fcf7895031')
    for event in pre_event.merge_alarm_to_event(alarm_points):
        recorder('f8a3c4d9b8ae42118b4db9fcf7895031', event['start_time'], event['end_time'])