from __future__ import annotations

import datetime
import logging
import os
from typing import TYPE_CHECKING
from zoneinfo import ZoneInfo

import dateparser
from apscheduler.triggers.cron import CronTrigger
from apscheduler.triggers.date import DateTrigger
from apscheduler.triggers.interval import IntervalTrigger

if TYPE_CHECKING:
    from apscheduler.job import Job

logger: logging.Logger = logging.getLogger("discord_reminder_bot")


def parse_time(date_to_parse: str | None, timezone: str | None = os.getenv("TIMEZONE")) -> datetime.datetime | None:
    """Parse a date string into a datetime object.

    Args:
        date_to_parse(str): The date string to parse.
        timezone(str, optional): The timezone to use. Defaults to the TIMEZONE environment variable.

    Returns:
        datetime.datetime: The parsed datetime object.
    """
    if not date_to_parse:
        logger.error("No date provided to parse.")
        return None

    if not timezone:
        logger.error("No timezone provided to parse date.")
        return None

    logger.info("Parsing date: '%s' with timezone: '%s'", date_to_parse, timezone)

    try:
        parsed_date: datetime.datetime | None = dateparser.parse(
            date_string=date_to_parse,
            settings={
                "PREFER_DATES_FROM": "future",
                "TIMEZONE": f"{timezone}",
                "RETURN_AS_TIMEZONE_AWARE": True,
                "RELATIVE_BASE": datetime.datetime.now(tz=ZoneInfo(str(timezone))),
            },
        )
    except (ValueError, TypeError):
        logger.exception("Failed to parse date: '%s'", date_to_parse)
        return None

    logger.debug("Parsed date: %s with timezone: %s", parsed_date, timezone)

    return parsed_date


def calculate(job: Job) -> str:
    """Calculate the time left for a job.

    Args:
        job: The job to calculate the time for.

    Returns:
        str: The time left for the job or "Paused" if the job is paused or has no next run time.
    """
    trigger_time = None
    if isinstance(job.trigger, DateTrigger | IntervalTrigger):
        if not hasattr(job, "next_run_time"):
            logger.debug("No next run time found for '%s'", job.id)
            logger.debug("%s", job.__getstate__())
            return "Paused"
        trigger_time = job.next_run_time or None

    elif isinstance(job.trigger, CronTrigger):
        if not job.next_run_time:
            logger.debug("No next run time found for '%s', probably paused?", job.id)
            logger.debug("%s", job.__getstate__())
            return "Paused"

        trigger_time = job.trigger.get_next_fire_time(None, datetime.datetime.now(tz=job._scheduler.timezone))  # noqa: SLF001

    logger.debug("Trigger type: %s, Trigger time: %s", type(job.trigger), trigger_time)

    if not trigger_time:
        logger.debug("No trigger time found")
        return "Paused"

    return f"<t:{int(trigger_time.timestamp())}:R>"


def get_human_readable_time(job: Job) -> str:
    """Get the human-readable time for a job.

    Args:
        job: The job to get the time for.

    Returns:
        str: The human-readable time.
    """
    trigger_time = None
    if isinstance(job.trigger, DateTrigger | IntervalTrigger):
        trigger_time = job.next_run_time or None

    elif isinstance(job.trigger, CronTrigger):
        if not job.next_run_time:
            logger.debug("No next run time found for '%s', probably paused?", job.id)
            logger.debug("%s", job.__getstate__())
            return "Paused"

        trigger_time = job.trigger.get_next_fire_time(None, datetime.datetime.now(tz=job._scheduler.timezone))  # noqa: SLF001

    if not trigger_time:
        logger.debug("No trigger time found")
        return "Paused"

    return trigger_time.strftime("%Y-%m-%d %H:%M:%S")