"""Generic project-wide utilities."""
import datetime

import strict_rfc3339


class DotDict(dict):
    """Simple wrapper around dict to access its items using dot notation."""

    def __getattr__(self, item):
        """Get item from dictionary by it's key, using dot-notation.

        Args:
            item (str): a dictionary key.

        Returns:
            value, or None if there is no item with such key.
        """
        return self.get(item)

    def __setattr__(self, key, value):
        """Set value in dictionary, using dot-notation.

        Args:
            key (str): item key
            value: item value
        """
        self[key] = value


def to_datetime(date):
    """Convert RFC 3339 date string to UTC datetime instance.

    Args:
        date (string): RFC 3339 date string with offset.

    Returns:
        datetime.datetime: UTC datetime object.
    """
    timestamp = strict_rfc3339.rfc3339_to_timestamp(date)
    return datetime.datetime.utcfromtimestamp(timestamp)