Source code for financialdatapy.date

"""This module parses and converts objects to date format objects"""
from datetime import datetime
from typing import Union
import pandas as pd
from financialdatapy.exception import IntegerDateInputError


def _convert_none_to_date(start: bool) -> pd.Timestamp:
    """Returns either current date or date 30 days ago.

    If argument passed in start is True, date 30 days ago will be returned.
    Otherwise, date of today will be returned.

    :param start: Whether argument passed is a starting date or an ending date.
    :type start: bool
    :return: Current date.
    :rtype: pandas.Timestamp
    """
    today = pd.Timestamp.today().normalize()

    if start:
        one_month = pd.Timedelta(days=30)
        one_month_ago = today - one_month
        return one_month_ago
    return today


def validate_date(period: str, start: bool = False) -> pd.Timestamp:
    """Validate the format of date passed as a string.

    :param period: Date in string. If None, date of today is assigned.
    :type period: str
    :param start: Whether argument passed is a starting date or an ending date,
        defaults to False.
    :type start: bool, optional
    :raises IntegerDateInputError: If integer type object is passed.
    :return: Date with format YYYY-MM-DD or YY-MM-DD.
    :rtype: pandas.Timestamp
    """
    if isinstance(period, int):
        raise IntegerDateInputError('Input type of period should be in string.')

    if period is None:
        date = _convert_none_to_date(start)
    else:
        try:
            date_format = '%y-%m-%d'
            period = datetime.strptime(period, date_format)
        except ValueError:
            date_format = '%Y-%m-%d'
        finally:
            date = string_to_date(period, date_format)
    return date


def string_to_date(period: Union[str, datetime], date_format: str) -> pd.Timestamp:
    """Convert date in string format or datetime object to pandas.Timestamp.

    :param period: Date object either string or datetime.datetime.
    :type period: Union[str, datetime]
    :param date_format: Date format to convert to.
    :type date_format: str
    :return: Date in :class:`Pandas.Timestamp`.
    :rtype: pd.Timestamp
    """
    date = pd.to_datetime(period, yearfirst=True, format=date_format)
    return date


def date_to_timestamp(period: pd.Timestamp) -> int:
    """Parse date passed in into a timestamp.

    :param period: Date object.
    :type period: pandas.Timestamp
    :return: The timestamp value equivalent to the date passed.
    :rtype: int
    """

    date = period.tz_localize(tz='Etc/GMT+4')
    timestamp = int(date.timestamp())
    return timestamp


def convert_date_format(period: pd.Timestamp, format: str) -> str:
    """Convert date object to desired date format.

    :param period: Date object.
    :type period: pandas.Timestamp
    :param format: Desired date format to convert to.
    :type format: str
    :return: Converted date in string.
    :rtype: str
    """
    new_date = period.strftime(format)
    return new_date