from __future__ import annotations

from datetime import date

from apps.farms.models import Cycle
from apps.operations.models import FeedSacks


def recompute_feed_sack_in_totals(cycle: Cycle) -> None:
    """Rebuild cumulative in_total from daily IoT feed-in only (excludes opening balance)."""
    running = 0
    for fs_row in FeedSacks.objects.filter(cycle=cycle).order_by("date", "pk"):
        running += fs_row.in_today
        if fs_row.in_total != running:
            fs_row.in_total = running
            fs_row.save(update_fields=["in_total", "updated_at"])


def remove_opening_balance_feed_row(
    cycle: Cycle,
    *,
    balance_date: date | None,
    balance_amount: int,
) -> None:
    """Drop a FeedSacks row that only existed to carry opening balance."""
    if balance_date is None or balance_amount <= 0:
        return
    FeedSacks.objects.filter(
        cycle=cycle,
        date=balance_date,
        in_today=balance_amount,
        out_today=0,
        feed_use_today=0,
        out_total=0,
        feed_use_total=0,
    ).delete()


def cleanup_opening_balance_feed_rows(
    cycle: Cycle,
    *,
    previous_date: date | None,
    previous_balance: int,
    balance_date: date,
    balance_amount: int,
) -> None:
    """Remove opening-balance snapshot rows for the previous and current save."""
    for row_date, amount in (
        (previous_date, previous_balance),
        (balance_date, balance_amount),
    ):
        remove_opening_balance_feed_row(
            cycle,
            balance_date=row_date,
            balance_amount=amount,
        )

    # Legacy cleanup: drop opening-only rows left from earlier saves on other dates.
    opening_amounts = {
        amount for amount in (previous_balance, balance_amount) if amount > 0
    }
    if not opening_amounts:
        return
    FeedSacks.objects.filter(
        cycle=cycle,
        in_today__in=opening_amounts,
        out_today=0,
        feed_use_today=0,
        out_total=0,
        feed_use_total=0,
    ).delete()