"""
DDNS Service - Dynamic DNS update service.

A daemon that accepts HTTP(S) requests to dynamically update DNS entries.
Includes CLI administration tools for user and hostname management.
"""

import datetime

__version__ = "1.0.1"
__author__ = "Thomas Oettli <spacefreak@noop.ch>"

__all__ = [
    "app",
    "cleanup",
    "cli",
    "config",
    "datetime_aware_utc",
    "datetime_naive_utc",
    "datetime_str",
    "dns",
    "email",
    "logging",
    "main",
    "models",
    "now_utc",
    "ratelimit",
    "server",
    "STATUS_GOOD",
    "STATUS_NOCHG",
    "STATUS_BADAUTH",
    "STATUS_NOHOST",
    "STATUS_DNSERR",
    "STATUS_ABUSE",
    "STATUS_BADIP",
]

# DynDNS-compatible response statuses
STATUS_GOOD = "good"
STATUS_NOCHG = "nochg"
STATUS_BADAUTH = "badauth"
STATUS_NOHOST = "nohost"
STATUS_DNSERR = "dnserr"
STATUS_ABUSE = "abuse"
STATUS_BADIP = "badip"

DATETIME_FORMAT = "%Y-%m-%d %H:%M:%S %Z"

# Datetime convention:
# All datetime objects in this codebase are timezone-aware.
# - now_utc(): returns timezone-aware UTC datetime
# - datetime_str(): converts naive UTC (adds tzinfo for formatting)
#   or timezone-aware datetime to display string
# - Database stores/returns naive datetimes (always UTC by convention)
# - Database models automatically convert between naive/timezone-aware datetimes


def now_utc():
    """
    Get current date and time in UTC.

    Returns:
        Timezone-aware datetime object in UTC.
    """
    return datetime.datetime.now(datetime.UTC)


def datetime_naive_utc(dt):
    """
    Convert datetime to naive UTC datetime.

    Args:
        dt: Datetime object (naive UTC or timezone-aware or None).

    Returns:
        Naive datetime object in UTC or None if dt is not a datetime.
    """
    if not isinstance(dt, datetime.datetime):
        return None

    if not dt.tzinfo:
        return dt

    return dt.astimezone(datetime.UTC).replace(tzinfo=None)


def datetime_aware_utc(dt):
    """
    Convert datetime to UTC datetime.

    Args:
        dt: Datetime object (naive UTC or timezone-aware or None).

    Returns:
        Timzone-aware datetime object in UTC or None if dt is not a datetime.
    """
    if not isinstance(dt, datetime.datetime):
        return None

    if not dt.tzinfo:
        return dt.replace(tzinfo=datetime.UTC)

    if dt.tzinfo == datetime.UTC:
        return dt

    return dt.astimezone(datetime.UTC)


def datetime_str(dt, utc=False):
    """
    Convert datetime to display string.

    Assumes naive datetimes are UTC per codebase convention.

    Args:
        dt: Datetime object (naive UTC or timezone-aware).
        utc: If True, display in UTC; otherwise convert to local timezone.

    Returns:
        Formatted datetime string, or "Never" if dt is not a datetime.
    """
    if not isinstance(dt, datetime.datetime):
        return "Never"

    aware_dt = dt.replace(tzinfo=datetime.UTC) if not dt.tzinfo else dt

    if utc:
        return aware_dt.strftime(DATETIME_FORMAT)
    else:
        return aware_dt.astimezone().strftime(DATETIME_FORMAT)