from typing import Any

from sqlalchemy.orm import Session

from app.shopping.service import ShoppingService

MAX_LISTS_IN_CONTEXT = 8
MAX_ITEMS_PER_LIST = 12


def get_shopping_snapshot(db: Session) -> dict[str, Any]:
    return ShoppingService(db).snapshot()


def format_shopping_context(snapshot: dict[str, Any]) -> str:
    lines = ["[Списки покупок]"]
    lists = snapshot.get("lists") or []

    if not lists:
        lines.append("Списков пока нет. create_shopping_list или add_shopping_items.")
        return "\n".join(lines)

    lines.append(
        f"Всего списков: {snapshot.get('list_count', len(lists))}, "
        f"неотмеченных позиций: {snapshot.get('unchecked_items', 0)}."
    )
    lines.append("Для изменений вызывай tools: list_shopping_lists, add_shopping_items, check_shopping_item.")

    for lst in lists[:MAX_LISTS_IN_CONTEXT]:
        items = lst.get("items") or []
        unchecked = [i for i in items if not i.get("checked")]
        preview = unchecked[:MAX_ITEMS_PER_LIST]
        parts = []
        for item in preview:
            qty = item.get("quantity")
            unit = (item.get("unit") or "").strip()
            label = item["text"]
            if qty is not None:
                label = f"{label} ({qty}{' ' + unit if unit else ''})"
            parts.append(f"#{item['id']} {label}")
        tail = f" +{len(unchecked) - len(preview)} ещё" if len(unchecked) > len(preview) else ""
        if parts:
            lines.append(f"- «{lst['name']}» (#{lst['id']}): {', '.join(parts)}{tail}")
        else:
            lines.append(f"- «{lst['name']}» (#{lst['id']}): всё отмечено или пусто")

    return "\n".join(lines)