from datetime import date, timedelta

from loguru import logger

from ..config import QUERY_PATHS, SESSION_PARAMS
from ..db import get_rdb
from ..db.queries import QueryLoader


def _get_dates(rdb, ql: QueryLoader) -> tuple[date | None, date | None]:
    data = rdb.query(ql.load(QUERY_PATHS.get_dates))
    last_processed = data["last_processed"][0]
    last_available = data["last_available"][0]
    if last_processed is None or last_available is None:
        return last_processed, last_available
    start_date = last_processed + timedelta(days=1)
    return start_date, last_available


def run_update() -> str | None:
    """Compute sessions and append skip rate data for new dates."""
    logger.info("Starting skiprate update")
    rdb = get_rdb()
    ql = QueryLoader()

    start_date, end_date = _get_dates(rdb, ql)

    if start_date is None or end_date is None:
        logger.warning("Could not determine date range (empty table or no source data)")
        return None

    if start_date > end_date:
        logger.info("No new data")
        return None

    date_list = [start_date + timedelta(days=x)
                 for x in range((end_date - start_date).days + 1)]
    logger.info(f"Updating {len(date_list)} day(s): {date_list[0]} to {date_list[-1]}")

    for d in date_list:
        ds = str(d)
        logger.info(f"Processing {d}")

        logger.debug(f"Computing sessions for {d}")
        status = rdb.execute(ql.load(
            QUERY_PATHS.make_session,
            date=ds,
            **SESSION_PARAMS,
        ))
        if not status:
            logger.error(f"Failed to compute sessions for {d}")
            return None

        logger.debug(f"Appending skiprate for {d}")
        status = rdb.execute(ql.load(
            QUERY_PATHS.append_skiprate,
            date=ds,
        ))
        if not status:
            logger.error(f"Failed to append skiprate for {d}")
            return None

    logger.success(f"Skiprate updated to {date_list[-1]}")
    return date_list[-1].strftime("%Y-%m-%d")