#!/usr/bin/env python

import sys
import pytz
from datetime import datetime, timedelta


def main():
    tz = pytz.timezone('Europe/Sofia')
    dt = pytz.utc.localize(datetime(year=2019, month=3, day=31, hour=14, minute=45))
    print(f'We start with the datetime in UTC: {dt}')
    dt = dt.astimezone(tz)
    print(f'Then convert it to Europe/Sofia timezone: {dt}')

    result = dt.replace(hour=0, minute=0, second=0, microsecond=0)
    print(f'Then make it the start of the day midnight: {result}')
    result = result.astimezone(pytz.utc)
    print(f'Then convert it back to UTC (the final result we want): {result}')
    print(f'But notice the time is wrong now when converted back to Europe/Sofia: {result.astimezone(tz)}')

    result = dt - timedelta(hours=dt.hour, minutes=dt.minute, seconds=dt.second, microseconds=dt.microsecond)
    print(f'Using a timedelta instead of replace has the same result: {result}')
    print(f'The time is still wrong when converted back to Europe/Sofia: {result.astimezone(pytz.utc).astimezone(tz)}')

    return 0


if __name__ == '__main__':
    sys.exit(main())