from typing import Any, AsyncIterator, Dict, 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

import meals, recipes, ingredients

async def to_lookups(conn, items: List[ShoppingListItem], meals_lookup: Dict[int, Any] = None, recipes_lookup: Dict[int, Any] = None, ingredients_lookup: Dict[int, Any] = None) -> Tuple[Dict[int, Any], Dict[int, Any], Dict[int, Any]]:
    meals_lookup = meals_lookup or {}
    recipes_lookup = recipes_lookup or {}
    ingredients_lookup = ingredients_lookup or {}

    lookups = (meals_lookup, recipes_lookup, ingredients_lookup)
    _move_refs_to_lookups(items, *lookups)
    await _ensure_lookups_populated(conn, items, *lookups)
    return lookups


def _move_refs_to_lookups(items: List[ShoppingListItem], meals_lookup: Dict[int, Any], recipes_lookup: Dict[int, Any], ingredients_lookup: Dict[int, Any]):
    for item in items:
        if item.meal and not item.meal.id in meals_lookup:
            meals_lookup[item.meal.id] = item.meal
        item.meal = None

        if item.ingredient and not item.ingredient.id in ingredients_lookup:
            ingredients_lookup[item.ingredient.id] = item.ingredient
        item.ingredient = None

        if item.recipe and not item.recipe.id in recipes_lookup:
            recipes_lookup[item.recipe.id] = item.recipe
        item.recipe = None

async def _ensure_lookups_populated(conn, items: List[ShoppingListItem], meals_lookup, recipes_lookup, ingredients_lookup):
    for item in items:
        # If the any item is not in the lookup, we need to add it
        if item.meal_id and item.meal_id not in meals_lookup:
            meals_lookup[item.meal_id] = await meals.find_meal_by_id(conn, item.meal_id)
        if item.recipe_id and item.recipe_id not in recipes_lookup:
            recipes_lookup[item.recipe_id] = await recipes.find_recipe_by_id(conn, item.recipe_id)
        if item.ingredient_id and item.ingredient_id not in ingredients_lookup:
            ingredients_lookup[item.ingredient_id] = await ingredients.find_ingredient_by_id(conn, item.ingredient_id)

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 mealRecipe in item.meal.recipes:
                for ingredient in mealRecipe.recipe.ingredients:
                    yield ShoppingListItem(ingredient=ingredient, meal=item.meal, recipe=mealRecipe.recipe, person_id=item.person_id, created_date=item.created_date)

            for ingredient in 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], List[ShoppingListItem]]:
    current_requests = [r async for r in _find_items_by_list_id(conn, None)]
    meal_requests = [r for r in current_requests if r.meal_id is not None and r.meal_id > 0 and r.meal is not None]
    meals = {r.meal_id: r.meal for r in meal_requests}
    purchased_ingredients = {(r.ingredient_id, r.meal_id, r.recipe_id): r async for r in _get_purchased_ingredients(conn, list(meals.keys()))}

    outstanding_items = []
    purchased_items = []
    flattened = flatten_items(current_requests)
    for r in flattened:
        # Meal ingredients may have already been purchased
        if r.meal_id is not None and r.meal_id > 0:
            purchased_item = purchased_ingredients.get((r.ingredient_id, r.meal_id, r.recipe_id))
            if purchased_item:
                purchased_items.append(purchased_item)
                continue

        outstanding_items.append(r)

    return outstanding_items, purchased_items, meal_requests