dbnonsense.py

"""Contains the User, Category, and Recipe classes"""


from types import SimpleNamespace
class DB(dict):
    def query(self, **query_params):
        results = []
        for key, obj in self.items():
            if all(getattr(obj, attr) == value for attr, value in query_params.items()):
                results.append(obj)
        return results


    def update(self, key, **update_values):
        obj = self[key]
        for attr, value in update_values.items():
            if not hasattr(obj, attr):
                raise AttributeError('{} object has no attribute {}'.format(type(obj), value))
            setattr(obj, attr, value)
        return obj

    def insert(self, key, obj):
        if key in self:
            raise ValueError('{} already exists'.format(key))
        self[key] = obj

        return obj

    def get(self, **attributes):
        """
        overrides builtin get
        """
        results = self.query(**attributes)
        if not results:
            raise ValueError('No results matching query parameters')
        if len(results) > 1:
            raise ValueError('Not a unique result')
        return results[0]

    def bulk_insert(self, *items):
        for item in items:
            self.insert(item)


class UserDatabase(DB):
    def insert(self, user):
        key = user.email
        return super().insert(key, user)


class CategoryDatabase(DB):
    def insert(self, category):
        key = category.name
        return super().insert(key, category)


class RecipeDatabase(DB):
    def insert(self, recipe):
        key = recipe.name
        super().insert(key, recipe)


class User(SimpleNamespace):
    def __init__(self, email, first_name, last_name):
        super().__init__(email=email, first_name=first_name, last_name=last_name)

    @property
    def recipes(self):
        results = recipes.query(user=self)
        return results


class Category(SimpleNamespace):
    def __init__(self, name, category_recipes=None):
        super().__init__(name=name)
        if category_recipes is None:
            category_recipes = []
        for recipe in category_recipes:
            if not isinstance(recipe, Recipe):
                raise ValueError('recipes must be instance of Recipe')
            recipe.category = self
            if recipe.name not in recipes:
                recipes.insert(recipe)

    @property
    def recipes(self):
        return recipes.query(category=self)



class Recipe(SimpleNamespace):
    def __init__(self, name, text='', category=None, user=None):
        self.name = name
        self.text = text
        if category is None:
            self._category = None
        elif isinstance(category, str):
            self._category = categories[category]
        elif isinstance(category, Category):
            self._category = category
        else:
            raise ValueError('category must be an instance of Category or a string of an existing category name')

        if user is None:
            self.user = None
        elif isinstance(user, User):
            self.user = user
        elif isinstance(user, str):
            self.user = users[user]
        else:
            raise ValueError('user must be an instance of User or a string of an existing user email')

    @property
    def category(self):
        return self._category

    @category.setter
    def category(self, value):
        if isinstance(value, str):
            value = categories[value]
        if not isinstance(value, Category):
            raise ValueError('Category must be an instance of Category or a string of an existing category name')
        self._category = value

users = UserDatabase()
categories = CategoryDatabase()
recipes = RecipeDatabase()


bob_ross = User('bob.ross@example.com', 'Bob', 'Ross')
bob_martin = User('bob.martin@example.com', 'Bob', 'Martin')
alice_cooper = User('alice@example.com', 'Alice', 'Cooper')
alice_walker = User('alice.walker@example.com', 'Alice', 'Walker')
john_smith = User('john.smith@example.com', 'John', 'Smith')
john_two = User('john@example.com', 'John', 'Smith')

users.bulk_insert(bob_ross, bob_martin, alice_cooper, alice_walker, john_smith, john_two)

italian = Category(name='Italian')
deserts = Category(name='Deserts')

categories.bulk_insert(italian, deserts)

pasta = Recipe(name='Pasta', text='1. Boil Water\n2.???\n3. enjoy', category=italian, user=bob_ross)
ice_cream = Recipe(name='Ice cream', text='1.Get Cream\n2. Add Ice', category=deserts,user=alice_cooper)
recipes.bulk_insert(pasta, ice_cream)