"""报销模块日期范围工具（从 bx-backend 迁移）。"""
from __future__ import annotations

from datetime import datetime, timedelta


def current_month_bounds(now: datetime | None = None) -> tuple[datetime, datetime]:
    """当前自然月 [month_start, next_month_start)。"""
    if now is None:
        now = datetime.now()
    month_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
    if now.month == 12:
        month_end = datetime(now.year + 1, 1, 1)
    else:
        month_end = datetime(now.year, now.month + 1, 1)
    return month_start, month_end


def parse_create_time_day_bounds(apply_date: str | None) -> tuple[datetime, datetime] | None:
    if not apply_date or not str(apply_date).strip():
        return None
    try:
        day_start = datetime.strptime(str(apply_date).strip(), "%Y-%m-%d")
        return day_start, day_start + timedelta(days=1)
    except ValueError:
        return None


def _parse_day_start(date_str: str | None) -> datetime | None:
    if not date_str or not str(date_str).strip():
        return None
    try:
        return datetime.strptime(str(date_str).strip(), "%Y-%m-%d")
    except ValueError:
        return None


def resolve_create_time_bounds(
    apply_date: str | None = None,
    apply_date_from: str | None = None,
    apply_date_to: str | None = None,
) -> tuple[datetime | None, datetime | None]:
    """解析申请时间筛选边界，返回 (含起, 不含止)。"""
    if apply_date_from or apply_date_to:
        start = _parse_day_start(apply_date_from)
        end = None
        day_end = _parse_day_start(apply_date_to)
        if day_end is not None:
            end = day_end + timedelta(days=1)
        return start, end
    bounds = parse_create_time_day_bounds(apply_date)
    if bounds:
        return bounds[0], bounds[1]
    return None, None


def append_create_time_filters(
    filters: list,
    model,
    *,
    apply_date: str | None = None,
    apply_date_from: str | None = None,
    apply_date_to: str | None = None,
) -> None:
    start, end = resolve_create_time_bounds(
        apply_date=apply_date,
        apply_date_from=apply_date_from,
        apply_date_to=apply_date_to,
    )
    if start is not None:
        filters.append(model.create_time >= start)
    if end is not None:
        filters.append(model.create_time < end)