"""Fake timestamp implementation."""

import decimal
import time

from dfdatetime import definitions
from dfdatetime import interface
from dfdatetime import posix_time


class FakeTime(interface.DateTimeValues):
    """Fake timestamp.

    The fake timestamp is intended for testing purposes. On initialization
    it contains the current time in UTC in microsecond precision.

    Attributes:
      is_local_time (bool): True if the date and time value is in local time.
    """

    _EPOCH = posix_time.PosixTimeEpoch()

    def __init__(self, precision=None, time_zone_offset=None):
        """Initializes a fake timestamp.

        Args:
          precision (Optional[str]): precision of the date and time value, which
              should be one of the PRECISION_VALUES in definitions.
          time_zone_offset (Optional[int]): time zone offset in number of minutes
              from UTC or None if not set.
        """
        # Note that time.time() and divmod return floating point values.
        timestamp, fraction_of_second = divmod(time.time(), 1)

        super().__init__(
            precision=precision or definitions.PRECISION_1_MICROSECOND,
            time_zone_offset=time_zone_offset,
        )
        self._microseconds = int(
            fraction_of_second * definitions.MICROSECONDS_PER_SECOND
        )
        self._number_of_seconds = int(timestamp)

    def _GetNormalizedTimestamp(self):
        """Retrieves the normalized timestamp.

        Returns:
          decimal.Decimal: normalized timestamp, which contains the number of
              seconds since January 1, 1970 00:00:00 and a fraction of second used
              for increased precision, or None if the normalized timestamp cannot be
              determined.
        """
        if self._normalized_timestamp is None:
            if self._number_of_seconds is not None:
                self._normalized_timestamp = (
                    decimal.Decimal(self._microseconds)
                    / definitions.MICROSECONDS_PER_SECOND
                )
                self._normalized_timestamp += decimal.Decimal(self._number_of_seconds)

                if self._time_zone_offset:
                    self._normalized_timestamp -= self._time_zone_offset * 60

        return self._normalized_timestamp

    def CopyFromDateTimeString(self, time_string):
        """Copies a fake timestamp from a date and time string.

        Args:
          time_string (str): date and time value formatted as:
              YYYY-MM-DD hh:mm:ss.######[+-]##:##

              Where # are numeric digits ranging from 0 to 9 and the seconds
              fraction can be either 3, 6 or 9 digits. The time of day, seconds
              fraction and time zone offset are optional. The default time zone
              is UTC.
        """
        date_time_values = self._CopyDateTimeFromString(time_string)

        year = date_time_values.get("year", 0)
        month = date_time_values.get("month", 0)
        day_of_month = date_time_values.get("day_of_month", 0)
        hours = date_time_values.get("hours", 0)
        minutes = date_time_values.get("minutes", 0)
        seconds = date_time_values.get("seconds", 0)
        nanoseconds = date_time_values.get("nanoseconds")
        time_zone_offset = date_time_values.get("time_zone_offset")

        self._normalized_timestamp = None
        self._number_of_seconds = self._GetNumberOfSecondsFromElements(
            year, month, day_of_month, hours, minutes, seconds
        )
        if nanoseconds is None:
            self._microseconds = None
        else:
            self._microseconds, _ = divmod(nanoseconds, 1000)

        self._time_zone_offset = time_zone_offset

    def CopyToDateTimeString(self):
        """Copies the fake timestamp to a date and time string.

        Returns:
          str: date and time value formatted as: "YYYY-MM-DD hh:mm:ss" or
              "YYYY-MM-DD hh:mm:ss.######" or None if the number of seconds
              is missing.
        """
        if self._number_of_seconds is None:
            return None

        number_of_days, hours, minutes, seconds = self._GetTimeValues(
            self._number_of_seconds
        )
        year, month, day_of_month = self._GetDateValuesWithEpoch(
            number_of_days, self._EPOCH
        )
        date_time_string = (
            f"{year:04d}-{month:02d}-{day_of_month:02d} "
            f"{hours:02d}:{minutes:02d}:{seconds:02d}"
        )
        if self._microseconds is not None:
            date_time_string = ".".join([date_time_string, f"{self._microseconds:06d}"])

        return date_time_string

    def CopyToSerializableDict(self):
        """Copies the date time value to a serializable dictionary.

        Returns:
          dict[str, object]: serializable dictionary.
        """
        normalized_timestamp = self._GetNormalizedTimestamp()

        serializable_dict = self._CreateSerializableDict()

        serializable_dict["timestamp"] = int(
            normalized_timestamp * definitions.MICROSECONDS_PER_SECOND
        )
        return serializable_dict
