from typing import AsyncIterator, Iterator, List, Tuple
from shopping.db import ShoppingList, ShoppingListItem, load_shopping_list, purchase, remove_request, request

from shopping.db import find_items_by_list_id as _find_items_by_list_id, get_purchased_ingredients as _get_purchased_ingredients

async def get_persons_requests(conn, person_id: int) -> AsyncIterator[ShoppingListItem]:
    async for item in _find_items_by_list_id(conn, None):
        if item.person_id == person_id and item.ingredient_id is not None:
            yield item

def flatten_items(items: Iterator[ShoppingListItem]) -> Iterator[ShoppingListItem]:
    for item in items:
        if item.meal:
            for ingredient in item.meal.ingredients + item.meal.extra_ingredients:
                yield ShoppingListItem(ingredient=ingredient, meal=item.meal, person_id=item.person_id, created_date=item.created_date)
        else:
            yield item

async def get_outstanding_requests(conn) -> Tuple[List[ShoppingListItem], List[ShoppingListItem]]:
    current_requests = [r async for r in _find_items_by_list_id(conn, None)]

    meal_ids = {item.meal_id for item in current_requests if item.meal_id is not None and item.meal_id > 0}
    purchased_ingredients = {r.ingredient_id async for r in _get_purchased_ingredients(conn, meal_ids)}

    flattened = flatten_items(current_requests)
    outstanding_items = [r for r in flattened if r.ingredient_id not in purchased_ingredients]
    purchased_items = [r for r in flattened if r.ingredient_id in purchased_ingredients]

    return outstanding_items, purchased_items