from typing import AsyncIterator, List, ClassVar, Optional
from pydantic import BaseModel
from ingredients import Ingredient, insert_ingredient, find_ingredients_by_meal_id, delete_ingredients_by_meal_id

from recipes import Recipe, row_to_recipe, load_recipe_ingredients

import persons
from persons import Person

import datetime

class Meal(BaseModel):
    KEYS: ClassVar[List[str]] = ['id', 'suggested_date']
    id: int = -1
    suggested_date: datetime.datetime
    purchase_date: Optional[datetime.datetime] = None

    chefs: List[Person] = []
    cleanup: List[Person] = []
    consumers: List[Person] = []
    recipes: List[Recipe] = []
    extra_ingredients: List[Ingredient] = []

async def create(conn):
    await conn.execute('''
        CREATE TABLE IF NOT EXISTS Meal (
            id INTEGER PRIMARY KEY,
            suggested_date TEXT
        );''')
    
    await conn.execute('''
        CREATE TABLE IF NOT EXISTS MealParticipant (
            meal_id INTEGER,
            person_id INTEGER,
            role TEXT,
            FOREIGN KEY(meal_id) REFERENCES Meal(id),
            FOREIGN KEY(person_id) REFERENCES Person(id)
        );''')
    
    await conn.execute('''
        CREATE TABLE IF NOT EXISTS MealRecipe (
            meal_id INTEGER,
            recipe_id INTEGER,
            FOREIGN KEY(meal_id) REFERENCES Meal(id),
            FOREIGN KEY(recipe_id) REFERENCES Recipe(id)
        );''')
    
async def insert_meal_participant(conn, meal_id: int, person_id: int, role: str):
    await conn.execute('''
        INSERT INTO MealParticipant (meal_id, person_id, role)
        VALUES (?, ?, ?)
    ''', (meal_id, person_id, role))

async def sync_meal_participants(conn, meal_id: int, participants: List[Person], role: str):
    await conn.execute('''
        DELETE FROM MealParticipant
        WHERE meal_id = ? AND role = ?
    ''', (meal_id, role))

    for person in participants:
        await insert_meal_participant(conn, meal_id, person.id, role)

async def insert_meal_recipe(conn, meal_id: int, recipe_id: int):
    if recipe_id < 0:
        raise ValueError('Recipe must be inserted before meal')
    
    await conn.execute('''
        INSERT INTO MealRecipe (meal_id, recipe_id)
        VALUES (?, ?)
    ''', (meal_id, recipe_id))

async def insert_meal(conn, meal: Meal):
    async with conn.execute('''
        INSERT INTO Meal (suggested_date)
        VALUES (?)
    ''', (meal.suggested_date,)) as cursor:
        meal.id = cursor.lastrowid

    await sync_meal_participants(conn, meal.id, meal.chefs, 'chef')
    await sync_meal_participants(conn, meal.id, meal.cleanup, 'cleanup')
    await sync_meal_participants(conn, meal.id, meal.consumers, 'consumer')

    for recipe in meal.recipes:
        await insert_meal_recipe(conn, meal.id, recipe.id)

    await sync_extra_ingredients(conn, meal.id, meal.extra_ingredients)

async def find_meal_by_id(conn, meal_id: int) -> Meal:
    async with conn.execute(f'''
        SELECT {','.join(Meal.KEYS)} FROM Meal
        WHERE id = ?
        LIMIT 1
    ''', (meal_id,)) as cursor:
        async for row in cursor:
            meal = await with_purchase_date(conn, Meal(**{k:v for k,v in zip(Meal.KEYS, row)}))

            await load_participants(conn, meal)
            await load_recipes(conn, meal)
            await load_extra_ingredients(conn, meal)
            return meal

async def find_meals_by_date_range(conn, start: datetime, end: datetime) -> AsyncIterator[Meal]:
    async with conn.execute(f'''
        SELECT {','.join(Meal.KEYS)} FROM Meal
        WHERE suggested_date >= ? AND suggested_date <= ?
    ''', (start, end)) as cursor:
        async for row in cursor:
            yield await with_purchase_date(conn, Meal(**{k:v for k,v in zip(Meal.KEYS, row)}))
    
async def load_participants(conn, meal: Meal) -> None:
    async with conn.execute(f'''
        SELECT person_id, role FROM MealParticipant
        WHERE meal_id = ?
    ''', (meal.id,)) as cursor:
        async for row in cursor:
            person = await persons.get_by_id(conn, row[0])
            if row[1] == 'chef':
                meal.chefs.append(person)
            elif row[1] == 'cleanup':
                meal.cleanup.append(person)
            elif row[1] == 'consumer':
                meal.consumers.append(person)
            else:
                raise Exception(f'Unknown role: {row[1]}')
            
async def load_recipes(conn, meal: Meal) -> None:
    async with conn.execute(f'''
        SELECT {','.join(Recipe.KEYS)} FROM Recipe
        JOIN MealRecipe ON MealRecipe.recipe_id = Recipe.id
        WHERE MealRecipe.meal_id = ?
    ''', (meal.id,)) as cursor:
        async for row in cursor:
            recipe = row_to_recipe(zip(Recipe.KEYS, row))
            await load_recipe_ingredients(conn, recipe)

            meal.recipes.append(recipe)

async def load_extra_ingredients(conn, meal: Meal) -> None:
    async for ingredient in find_ingredients_by_meal_id(conn, meal.id):
        meal.extra_ingredients.append(ingredient)

async def delete_meal(conn, meal_id: int) -> None:
    await conn.execute('''
        DELETE FROM MealParticipant
        WHERE meal_id = ?
    ''', (meal_id,))

    await conn.execute('''
        DELETE FROM MealRecipe
        WHERE meal_id = ?
    ''', (meal_id,))

    await conn.execute('''
        DELETE FROM Ingredient
        WHERE meal_id = ?
    ''', (meal_id,))

    await conn.execute('''
        DELETE FROM Meal
        WHERE id = ?
    ''', (meal_id,))

async def sync_extra_ingredients(conn, meal_id: int, ingredients: List[Ingredient]) -> None:
    await delete_ingredients_by_meal_id(conn, meal_id)

    for ingredient in ingredients:
        ingredient.meal_id = meal_id
        ingredient.recipe_id = None

        await insert_ingredient(conn, ingredient)

async def sync_recipes(conn, meal_id: int, recipes: List[Recipe]) -> None:
    await conn.execute('''
        DELETE FROM MealRecipe
        WHERE meal_id = ?
    ''', (meal_id,))

    for recipe in recipes:
        await insert_meal_recipe(conn, meal_id, recipe.id)

async def update_meal(conn, meal: Meal) -> None:
    await conn.execute('''
        UPDATE Meal
        SET suggested_date = ?
        WHERE id = ?
    ''', (meal.suggested_date, meal.id))

    await sync_meal_participants(conn, meal.id, meal.chefs, 'chef')
    await sync_meal_participants(conn, meal.id, meal.cleanup, 'cleanup')
    await sync_meal_participants(conn, meal.id, meal.consumers, 'consumer')

    await sync_extra_ingredients(conn, meal.id, meal.extra_ingredients)
    await sync_recipes(conn, meal.id, meal.recipes)

async def with_purchase_date(conn, meal: Meal) -> Meal:
    async with conn.execute('''
        SELECT purchased_date FROM ShoppingList
        WHERE id = (
            SELECT list_id FROM ShoppingListRequest
            WHERE meal_id = ?
            LIMIT 1
        )
    ''', (meal.id,)) as cursor:
        async for row in cursor:
            meal.purchase_date = row[0]
        
    return meal