diff --git a/README.md b/README.md index efd62134..c0786143 100644 --- a/README.md +++ b/README.md @@ -16,12 +16,12 @@ ## Дедлайны -| Задание | Дедлайн (включительно) | Статус | -|---|---|---| -| [Часть 1. Генератор идентификаторов Twitter Snowflake](src/part1/TASK.md) | 25.09.2026 | дедлайн истек | -| [Часть 2. CRUD и корзина для интернет-магазина](src/part2/TASK.md) | 02.10.2026 | дедлайн истек | -| [Часть 3. Нормализация имён и консоль администратора](src/part3/TASK.md) | 12.10.2026 | дедлайн истек | -| [Часть 4. Хранилище-словарь и UUID-идентификаторы](src/part4/TASK.md) | 01.11.2026 | активно | +| Задание | Дедлайн (включительно) | Статус | +| ------------------------------------------------------------------------- | ---------------------- | ------------- | +| [Часть 1. Генератор идентификаторов Twitter Snowflake](src/part1/TASK.md) | 25.09.2026 | дедлайн истек | +| [Часть 2. CRUD и корзина для интернет-магазина](src/part2/TASK.md) | 02.10.2026 | дедлайн истек | +| [Часть 3. Нормализация имён и консоль администратора](src/part3/TASK.md) | 12.10.2026 | дедлайн истек | +| [Часть 4. Хранилище-словарь и UUID-идентификаторы](src/part4/TASK.md) | 01.11.2026 | активно | ## Критерии оценивания diff --git a/docs/grading_criteria.md b/docs/grading_criteria.md index 4253fa2d..aa9b2051 100644 --- a/docs/grading_criteria.md +++ b/docs/grading_criteria.md @@ -13,14 +13,28 @@ ## Как считается балл за правильность +Тесты разбиты на функциональные блоки: каждый блок соответствует функции или классу из задания и имеет свой вес (более сложные блоки весят больше). Внутри блока тесты делятся на две группы: + +| Группа тестов | Доля веса блока | Что проверяет | +| ----------------------------------------------------------------------- | --------------- | --------------------------------- | +| Базовые (типичные входные данные) | 70% | Основная логика реализована верно | +| Граничные (пустой ввод, нулевые и предельные значения, повторы и т. п.) | 30% | Обработка особых случаев | + +Формулы: + +``` +балл_блока = 0.7 · доля_пройденных_базовых + 0.3 · доля_пройденных_граничных +балл_за_правильность = 10 · Σ(вес_блока · балл_блока) / Σ(вес_блока) Задание состоит из модулей, и у каждого модуля есть свой вес. Балл за правильность считается в два шага: 1. Для каждого модуля вычисляется доля пройденных тестов этого модуля от общего числа его тестов. Она умножается на 10 и округляется до двух знаков после запятой. 2. Балл за правильность — взвешенная сумма баллов за модули. ``` -балл_модуля = round(10 · пройденные_тесты_модуля / все_тесты_модуля, 2) -балл_за_правильность = Σ(вес_модуля · балл_модуля) / Σ(вес_модуля) + +балл*модуля = round(10 · пройденные*тесты*модуля / все*тесты*модуля, 2) +балл*за*правильность = Σ(вес*модуля · балл*модуля) / Σ(вес*модуля) + ``` Дополнительные правила: @@ -77,10 +91,12 @@ ## Итоговая оценка ``` + если есть подозрение в списывании: - итоговая_оценка = −5 +итоговая*оценка = −5 иначе: - итоговая_оценка = max(0, балл_за_правильность − штрафы_за_оформление) +итоговая*оценка = max(0, балл*за*правильность − штрафы*за*оформление) + ``` Итоговая оценка за домашнее задание округляется до ближайшего целого по правилам математики: дробная часть от 0.5 и выше округляется вверх, меньше 0.5 — вниз (например, 7.5 → 8, 7.4 → 7). @@ -88,3 +104,4 @@ ## Как оспорить оценку Если вы не согласны с оценкой, напишите преподавателю. Укажите, с каким блоком или с какой частью критериев вы не согласны, и приведите аргументы. Оценка пересматривается по тем же критериям, которые описаны выше. +``` diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..12e23773 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -1,38 +1,21 @@ -"""Bit layout and default epoch for the Twitter Snowflake ID generator. - -A Snowflake identifier is a 63-bit positive integer packed as follows, from -the most significant bit downwards: - - 1 bit unused sign bit, always zero - 41 bits milliseconds elapsed since a custom epoch - 10 bits node identifier - 12 bits per-millisecond sequence counter - -The shift and mask constants should be derived from the bit widths so that -changing a width keeps everything else consistent. -""" - from typing import Final -# TODO: замените заглушки (0) на корректные значения, см. TASK.md. -# Все константы, зависящие от ёмкостей *_BITS, должны вычисляться из них. - # Twitter's original Snowflake epoch: 2010-11-04 01:42:54.657 UTC. -EPOCH_MS_DEFAULT: Final[int] = 0 +EPOCH_MS_DEFAULT: Final[int] = 1288834974657 # Node identifier used when the caller does not supply one. -NODE_ID_DEFAULT: Final[int] = 0 +NODE_ID_DEFAULT: Final[int] = 1 # Width of each field, in bits. -TIMESTAMP_BITS: Final[int] = 0 -NODE_ID_BITS: Final[int] = 0 -SEQUENCE_ID_BITS: Final[int] = 0 +TIMESTAMP_BITS: Final[int] = 41 +NODE_ID_BITS: Final[int] = 10 +SEQUENCE_ID_BITS: Final[int] = 12 # Largest value each field can hold. -TIMESTAMP_MS_MAX: Final[int] = 0 -NODE_ID_MAX: Final[int] = 0 -SEQUENCE_ID_MAX: Final[int] = 0 +TIMESTAMP_MS_MAX: Final[int] = 2**TIMESTAMP_BITS - 1 +NODE_ID_MAX: Final[int] = 2**NODE_ID_BITS - 1 +SEQUENCE_ID_MAX: Final[int] = 2**SEQUENCE_ID_BITS - 1 # Здесь можно добавить собственные вспомогательные константы # (например, сдвиги полей при сборке идентификатора). diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..1f0e0673 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -1,85 +1,34 @@ -"""Twitter Snowflake identifier generator. +import time -Snowflake produces roughly time-ordered 64-bit integer identifiers without -coordination between nodes. Each identifier packs the milliseconds elapsed -since a custom epoch, a node identifier and a per-millisecond sequence counter -into a single 63-bit positive integer (see ``constants`` for the layout). - -The public entry point is :func:`generate_snowflake_id`. It is stateless: the -caller passes the sequence counter on every call and is responsible for -advancing it within a millisecond and resetting it when the clock ticks over. - -Each packed field can be read back on its own with :func:`decode_timestamp_ms`, -:func:`decode_node_id` and :func:`decode_sequence_id`. -""" - -import time # noqa: F401 - -from .constants import ( # noqa: F401 +from .constants import ( EPOCH_MS_DEFAULT, + NODE_ID_BITS, NODE_ID_DEFAULT, NODE_ID_MAX, + SEQUENCE_ID_BITS, SEQUENCE_ID_MAX, + TIMESTAMP_BITS, TIMESTAMP_MS_MAX, ) def read_current_millis(epoch_ms: int) -> int: - """Read the number of milliseconds elapsed since the custom epoch. - - Args: - epoch_ms: The custom epoch expressed as Unix milliseconds. - - Returns: - The count of whole milliseconds between ``epoch_ms`` and now. May be - negative if ``epoch_ms`` lies in the future. - """ - # TODO: реализуйте функцию - return 0 + return int(time.time() * 1000) - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: - """Read the timestamp field out of a Snowflake identifier. - - Args: - snowflake_id: An identifier produced against the same epoch. - epoch_ms: The epoch the identifier was generated against. Defaults to - the original Twitter epoch (2010-11-04 01:42:54.657 UTC). - - Returns: - The absolute Unix time in milliseconds at which the identifier was - generated. - """ - # TODO: реализуйте функцию - return 0 + relative_time = ( + snowflake_id >> SEQUENCE_ID_BITS >> NODE_ID_BITS + ) & TIMESTAMP_MS_MAX + return epoch_ms + relative_time def decode_node_id(snowflake_id: int) -> int: - """Read the node identifier field out of a Snowflake identifier. - - Args: - snowflake_id: An identifier produced by :func:`generate_snowflake_id`. - - Returns: - The node identifier packed into ``snowflake_id``, in the range - ``[0, NODE_ID_MAX]``. - """ - # TODO: реализуйте функцию - return 0 + return (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: - """Read the sequence counter field out of a Snowflake identifier. - - Args: - snowflake_id: An identifier produced by :func:`generate_snowflake_id`. - - Returns: - The per-millisecond sequence counter packed into ``snowflake_id``, in - the range ``[0, SEQUENCE_ID_MAX]``. - """ - # TODO: реализуйте функцию - return 0 + return snowflake_id & SEQUENCE_ID_MAX def generate_snowflake_id( @@ -87,28 +36,27 @@ def generate_snowflake_id( node_id: int = NODE_ID_DEFAULT, epoch_ms: int = EPOCH_MS_DEFAULT, ) -> int | None: - """Build and return a Snowflake identifier for the current millisecond. - - The function is stateless: the caller passes the per-millisecond sequence - counter explicitly. It is the caller's responsibility to increment - ``sequence_id`` for identifiers minted within the same millisecond and to - reset it once the clock advances. - - Args: - sequence_id: The per-millisecond sequence counter, in the range - ``[0, SEQUENCE_ID_MAX]``. - node_id: The identifier of this node, in the range ``[0, NODE_ID_MAX]``. - Optional; defaults to ``NODE_ID_DEFAULT``. - epoch_ms: The start of the epoch as Unix milliseconds. Optional; - defaults to the original Twitter epoch (2010-11-04 01:42:54.657 - UTC). - - Returns: - The Snowflake identifier as a positive 63-bit integer, or ``None`` if - ``node_id`` is outside ``[0, NODE_ID_MAX]``, ``sequence_id`` is outside - ``[0, SEQUENCE_ID_MAX]``, or the elapsed time no longer fits in the - timestamp field (roughly 69 years after ``epoch_ms``). In each of those - cases an explanatory message is printed to stdout first. - """ - # TODO: реализуйте функцию - return 0 + current_millis = read_current_millis(epoch_ms) + + if node_id not in range(NODE_ID_MAX + 1): + print(f"node_id is {node_id}, but must be in [0, {NODE_ID_MAX}]") + return None + elif sequence_id not in range(SEQUENCE_ID_MAX + 1): + print(f"sequence_id is {sequence_id}, but must be in [0, {SEQUENCE_ID_MAX}]") + return None + else: + if current_millis > TIMESTAMP_MS_MAX: + print("overflows") + return None + + snowflake_id = int( + "0" + + bin(current_millis)[2:].zfill(TIMESTAMP_BITS) + + bin(node_id)[2:].zfill(NODE_ID_BITS) + + bin(sequence_id)[2:].zfill(SEQUENCE_ID_BITS), + base=2, + ) + # print(decode_node_id(snowflake_id) == node_id, + # decode_sequence_id(snowflake_id) == sequence_id, + # decode_timestamp_ms(snowflake_id, epoch_ms) == current_millis + epoch_ms) + return snowflake_id diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..668f7360 100644 --- a/src/part2/cart.py +++ b/src/part2/cart.py @@ -1,18 +1,7 @@ -"""Shopping-cart operations layered on top of the product store. - -The cart is a plain list of tuples, one :data:`CartLine` -- -``(product_id, quantity)`` -- per distinct product. Moving units between the -store and the cart keeps the two sides in balance: :func:`add_to_cart` takes -units out of stock, :func:`remove_from_cart` puts them back. - -Like the CRUD layer, the failure path never raises -- the operation prints -an explanatory message to stdout and returns ``None``. -""" - from typing import Final -from .crud import read_product, update_product # noqa: F401 -from .storage import ( # noqa: F401 +from .crud import read_product, update_product +from .storage import ( NAME_INDEX, PRICE_INDEX, QUANTITY_INDEX, @@ -22,9 +11,15 @@ type CartLine = tuple[int, int] -# TODO: задайте позиции полей внутри кортежа CartLine LINE_PRODUCT_ID_INDEX: Final = 0 -LINE_QUANTITY_INDEX: Final = 0 +LINE_QUANTITY_INDEX: Final = 1 + + +def find_cart_line(cart: list[CartLine], product_id: int) -> CartLine | None: + for cartline in cart: + if cartline[LINE_PRODUCT_ID_INDEX] == product_id: + return cartline + return None def add_to_cart( @@ -33,28 +28,33 @@ def add_to_cart( product_id: int, quantity: int, ) -> CartLine | None: - """Move ``quantity`` units of ``product_id`` from the store into ``cart``. - - The product is looked up in ``storage``. If it is missing, a message is - printed (by :func:`~src.part2.crud.read_product`) and nothing - changes. If the store holds fewer units than requested, an explanatory - message is printed and nothing changes. Otherwise the store record is - decremented by ``quantity`` and the cart line for ``product_id`` gains - ``quantity`` units -- a new line is created when the cart had none. - - Args: - storage: The product store to draw stock from; modified in place on - success. - cart: The cart to add the units to; modified in place on success. - product_id: The identifier of the product to add. - quantity: Number of units to move into the cart. - - Returns: - The cart line for ``product_id`` after the addition, or ``None`` - when the product is unknown or the store cannot cover the request. - """ - # TODO: реализуйте функцию - return (0, 0) + product = read_product(storage, product_id) + if not product: + return None + + if product[QUANTITY_INDEX] < quantity: + print( + f"not enough stock for product {product_id}: " + f"{product[QUANTITY_INDEX]} available, {quantity} requested" + ) + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] - quantity), + ) + + existing_line = find_cart_line(cart, product_id) + if existing_line: + cart.remove(existing_line) + updated_line = (product_id, existing_line[LINE_QUANTITY_INDEX] + quantity) + cart.append(updated_line) + return updated_line + else: + new_line = (product_id, quantity) + cart.append(new_line) + return new_line def remove_from_cart( @@ -63,27 +63,33 @@ def remove_from_cart( product_id: int, quantity: int, ) -> CartLine | None: - """Move ``quantity`` units of ``product_id`` from ``cart`` back to the store. - - The cart line for ``product_id`` is looked up. If there is none, a - message is printed and nothing changes. If the line holds fewer units - than requested, an explanatory message is printed and nothing changes. - Otherwise the cart line loses ``quantity`` units -- the line is dropped - when it reaches zero -- and the store record gains ``quantity`` units - back. - - Args: - storage: The product store to return stock to; modified in place on - success. - cart: The cart to take the units from; modified in place on - success. - product_id: The identifier of the product to remove. - quantity: Number of units to move back into the store. - - Returns: - The cart line for ``product_id`` after the removal (a quantity of - zero means the line was dropped), or ``None`` when the cart has no - line for the product or holds too few units. - """ - # TODO: реализуйте функцию - return (0, 0) + cartline = find_cart_line(cart, product_id) + if not cartline: + print(f"product {product_id} is not in the cart") + return None + + if cartline[LINE_QUANTITY_INDEX] < quantity: + print( + f"cart holds only {cartline[LINE_QUANTITY_INDEX]} " + f"unit(s) of product {product_id}, " + f"cannot remove {quantity}" + ) + return None + + product = read_product(storage, product_id) + if not product: + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] + quantity), + ) + + new_quantity = cartline[LINE_QUANTITY_INDEX] - quantity + cart.remove(cartline) + if new_quantity == 0: + return (product_id, 0) + updated_line = (product_id, new_quantity) + cart.append(updated_line) + return updated_line diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..b42bfa51 100644 --- a/src/part2/crud.py +++ b/src/part2/crud.py @@ -1,79 +1,42 @@ -"""Create/read/update/delete operations over the in-memory product store. - -Every operation takes the store -- a list of -:data:`~src.part2.storage.Product` tuples -- as its first argument and -works on it in place. The failure path never raises: the operation prints -an explanatory message to stdout and returns ``None``. - -The identifier of a new product is derived from the store itself -(:func:`generate_product_id`): one past the greatest identifier in use, or -:data:`~src.part2.storage.PRODUCT_ID_MIN` when the store is empty. -Product names are kept unique -- :func:`create_product` refuses a name that -is already taken. -""" - from decimal import Decimal -from .storage import ( # noqa: F401 +from .storage import ( NAME_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, Product, ) -from .utils import normalize_price # noqa: F401 +from .utils import normalize_price def generate_product_id(storage: list[Product]) -> int: - """Choose the identifier for the next product added to ``storage``. - - Args: - storage: The product store to inspect. - - Returns: - One past the greatest identifier currently held in ``storage``, or - :data:`~src.part2.storage.PRODUCT_ID_MIN` when ``storage`` is - empty. - """ - # TODO: реализуйте функцию - return 0 + if not storage: + return PRODUCT_ID_MIN + return max([product[PRODUCT_ID_INDEX] for product in storage]) + 1 def create_product( storage: list[Product], fields: tuple[str, Decimal, int] ) -> int | None: - """Append a new product to ``storage`` and return its new identifier. - - Args: - storage: The product store to append to; modified in place on - success. - fields: A ``(name, price, quantity)`` tuple describing the product. - ``price`` is a :class:`~decimal.Decimal` amount and is rounded - to the stored money precision before it is saved. + product_name = fields[0] + storage_product_names = [product[NAME_INDEX] for product in storage] + if product_name in storage_product_names: + print(f"product name '{product_name}' is already taken") + return None - Returns: - The identifier generated for the new product, or ``None`` when a - product with the same name already exists. In the ``None`` case - ``storage`` is left unchanged and a message naming the clashing - name is printed. - """ - # TODO: реализуйте функцию - return 0 + product_id = generate_product_id(storage) + product_price = normalize_price(fields[1]) + product_quantity = fields[2] + storage.append((product_id, product_name, product_price, product_quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: - """Return the product stored under ``product_id``. - - Args: - storage: The product store to search. - product_id: The identifier to look up. - - Returns: - The matching ``(product_id, name, price, quantity)`` record, or - ``None`` when no product carries that identifier (a message is - printed in that case). - """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + return product + print(f"no product with id {product_id}") + return None def update_product( @@ -81,40 +44,24 @@ def update_product( product_id: int, fields: tuple[str, Decimal, int], ) -> Product | None: - """Overwrite the fields of the product stored under ``product_id``. - - The identifier itself is preserved; only ``name``, ``price`` and - ``quantity`` are replaced. - - Args: - storage: The product store to modify; the matching record is - replaced in place on success. - product_id: The identifier of the product to change. - fields: A ``(name, price, quantity)`` tuple with the new values. - ``price`` is a :class:`~decimal.Decimal` amount and is rounded - to the stored money precision before it is saved. - - Returns: - The updated ``(product_id, name, price, quantity)`` record, or - ``None`` when no product carries that identifier (``storage`` is - left unchanged and a message is printed). - """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + updated_product = ( + product_id, + fields[0], + normalize_price(fields[1]), + fields[2], + ) + storage[i] = updated_product + return updated_product + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: - """Remove the product stored under ``product_id`` from ``storage``. - - Args: - storage: The product store to remove from; modified in place on - success. - product_id: The identifier of the product to remove. - - Returns: - ``product_id`` when a product was removed, or ``None`` when no - product carried that identifier (``storage`` is left unchanged and - a message is printed). - """ - # TODO: реализуйте функцию - return 0 + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + storage.remove(product) + return product_id + print(f"no product with id {product_id}") + return None diff --git a/src/part2/storage.py b/src/part2/storage.py index b63d5fc7..81651a75 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -1,34 +1,12 @@ -"""In-memory product store for the shop CRUD exercise. - -The store is deliberately primitive: a plain list of tuples, with no -persistence, no indexing and no schema enforcement. Each element is a -:data:`Product` record -- a ``(product_id, name, price, quantity)`` tuple -where: - -* ``product_id`` -- unique positive integer key, assigned by the create - operation in :mod:`src.part2.crud`; -* ``name`` -- human-readable product name, unique across the store; -* ``price`` -- price of a single unit, held as a :class:`~decimal.Decimal` - amount rounded to a fixed number of decimal places (see - :func:`src.part2.utils.normalize_price`) so that money is never - subject to binary floating-point error; -* ``quantity`` -- number of units currently in stock. - -Field positions are exposed as ``*_INDEX`` constants so callers never -hard-code tuple offsets. -""" - from decimal import Decimal from typing import Final type Product = tuple[int, str, Decimal, int] -# TODO: задайте позиции полей внутри кортежа Product PRODUCT_ID_INDEX: Final = 0 -NAME_INDEX: Final = 0 -PRICE_INDEX: Final = 0 -QUANTITY_INDEX: Final = 0 +NAME_INDEX: Final = 1 +PRICE_INDEX: Final = 2 +QUANTITY_INDEX: Final = 3 -# TODO: задайте идентификатор первого товара в пустом хранилище -PRODUCT_ID_MIN: Final[int] = 0 +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part2/utils.py b/src/part2/utils.py index 11bd7a76..413f9564 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -6,24 +6,13 @@ currency values free of binary floating-point error. """ -from decimal import ROUND_HALF_UP, Decimal # noqa: F401 +from decimal import ROUND_HALF_UP, Decimal from typing import Final -# TODO: задайте число знаков после запятой и шаг квантования -PRICE_PRECISION: Final[int] = 0 -PRICE_STEP: Final = Decimal(0) +PRICE_PRECISION: Final[int] = 2 +PRICE_STEP: Final = Decimal(1).scaleb(-PRICE_PRECISION) def normalize_price(price: Decimal) -> Decimal: - """Round a price to the precision every stored record uses. - - Args: - price: The raw price amount. - - Returns: - ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, - with halves rounded up. - """ - # TODO: реализуйте функцию - return Decimal(0) + return price.quantize(PRICE_STEP, ROUND_HALF_UP) diff --git a/src/part3/crud.py b/src/part3/crud.py index 68811d7e..d1287f93 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -20,13 +20,8 @@ from decimal import Decimal -from .storage import ( # noqa: F401 - NAME_INDEX, - PRODUCT_ID_INDEX, - PRODUCT_ID_MIN, - Product, -) -from .utils import normalize_price, normalize_product_name # noqa: F401 +from .storage import NAME_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, Product +from .utils import normalize_price, normalize_product_name def generate_product_id(storage: list[Product]) -> int: @@ -40,8 +35,9 @@ def generate_product_id(storage: list[Product]) -> int: :data:`~src.part3.storage.PRODUCT_ID_MIN` when ``storage`` is empty. """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + if not storage: + return PRODUCT_ID_MIN + return max([product[PRODUCT_ID_INDEX] for product in storage]) + 1 def create_product( @@ -64,8 +60,20 @@ def create_product( normalised name already exists. In the ``None`` case ``storage`` is left unchanged and an explanatory message is printed. """ - # TODO: реализуйте функцию - return 0 + product_name = normalize_product_name(fields[0]) + if not product_name: + print("product name must not be blank") + return None + storage_product_names = [product[NAME_INDEX] for product in storage] + if product_name in storage_product_names: + print(f"product name '{product_name}' is already taken") + return None + + product_id = generate_product_id(storage) + product_price = normalize_price(fields[1]) + product_quantity = fields[2] + storage.append((product_id, product_name, product_price, product_quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -80,8 +88,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return (0, "", Decimal(0), 0) + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + return product + print(f"no product with id {product_id}") + return None def update_product( @@ -110,8 +121,35 @@ def update_product( unchanged and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + product_name = normalize_product_name(fields[0]) + if not product_name: + print("product name must not be blank") + return None + + product_index = -1 + is_name_taken = False + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + product_index = i + elif product[NAME_INDEX] == product_name: + is_name_taken = True + + if product_index < 0: + print(f"no product with id {product_id}") + return None + + if is_name_taken: + print(f"product name '{product_name}' is already taken") + return None + + updated_product = ( + product_id, + product_name, + normalize_price(fields[1]), + fields[2], + ) + storage[product_index] = updated_product + return updated_product def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -127,5 +165,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None: product carried that identifier (``storage`` is left unchanged and a message is printed). """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + storage.remove(product) + return product_id + print(f"no product with id {product_id}") + return None diff --git a/src/part3/run_admin.py b/src/part3/run_admin.py index c5feeb0b..6d469f6a 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -29,22 +29,34 @@ it. """ -from decimal import Decimal, InvalidOperation # noqa: F401 +from decimal import Decimal, InvalidOperation from typing import Final -from .crud import ( # noqa: F401 +from .crud import ( create_product, delete_product, read_product, update_product, ) from .storage import Product -from .utils import get_storage_str_representation # noqa: F401 +from .utils import get_storage_str_representation -# TODO: задайте приглашение и текст справки -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = """ + Available commands: + help show this message + exit leave the console + show print the whole store as a table + create add a product, print its new id + read print the product with that id + update overwrite that product's fields + delete remove the product with that id + + For create and update the price and quantity are the last two words of the + line; everything before them is the product name, so it may contain spaces + (for example "Gibson SG Junior") and needs no quoting. + """ def show_help() -> None: @@ -54,7 +66,7 @@ def show_help() -> None: is: a heading, one line per command with a short description, and a note on how multi-word names are parsed. """ - # TODO: реализуйте функцию + print(HELP_TEXT) def print_result(result: object) -> None: @@ -65,7 +77,8 @@ def print_result(result: object) -> None: operation already reported its own failure, so nothing is printed in that case. """ - # TODO: реализуйте функцию + if result: + print(result) def run_command(storage: list[Product], line: str) -> bool: @@ -88,8 +101,26 @@ def run_command(storage: list[Product], line: str) -> bool: decimal.InvalidOperation: If the price argument of ``create`` or ``update`` does not parse as a decimal number. """ - # TODO: реализуйте функцию - return False + match line.split(): + case ["help"]: + show_help() + case ["exit"]: + return False + case ["show"]: + print(get_storage_str_representation(storage)) + case ["create", *name, price, quantity]: + fields = (" ".join(name), Decimal(price), int(quantity)) + print_result(create_product(storage, fields)) + case ["read", product_id]: + print_result(read_product(storage, int(product_id))) + case ["update", product_id, *name, price, quantity]: + fields = (" ".join(name), Decimal(price), int(quantity)) + print_result(update_product(storage, int(product_id), fields)) + case ["delete", product_id]: + print_result(delete_product(storage, int(product_id))) + case _: + print(f"'{line}' is not a command") + return True def main() -> None: diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..c516645b 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -24,12 +24,9 @@ type Product = tuple[int, str, Decimal, int] -# TODO: задайте позиции полей внутри кортежа Product (используйте своё решение -# части 2) PRODUCT_ID_INDEX: Final = 0 -NAME_INDEX: Final = 0 -PRICE_INDEX: Final = 0 -QUANTITY_INDEX: Final = 0 +NAME_INDEX: Final = 1 +PRICE_INDEX: Final = 2 +QUANTITY_INDEX: Final = 3 -# TODO: задайте идентификатор первого товара в пустом хранилище -PRODUCT_ID_MIN: Final[int] = 0 +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part3/utils.py b/src/part3/utils.py index 318ded0b..572e13a1 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -18,24 +18,15 @@ the longest value it holds in that particular call. """ -from decimal import ROUND_HALF_UP, Decimal # noqa: F401 +from decimal import ROUND_HALF_UP, Decimal from typing import Final from .storage import Product -# Number of fractional digits every stored price is rounded to. -# Quantisation step derived from PRICE_PRECISION, e.g. Decimal("0.01"). -# TODO: задайте число знаков после запятой и шаг квантования (используйте своё -# решение части 2) -PRICE_PRECISION: Final[int] = 0 -PRICE_STEP: Final = Decimal(0) - -# Column headers of the table produced by get_storage_str_representation, -# left to right. The width of each column is not fixed here -- it is -# measured per call from the data (see the function). -# TODO: задайте заголовки столбцов таблицы -TABLE_HEADERS: Final[tuple[str, ...]] = () +PRICE_PRECISION: Final[int] = 2 +PRICE_STEP: Final = Decimal(1).scaleb(-PRICE_PRECISION) +TABLE_HEADERS: Final = ("ID", "name", "price", "quantity") def normalize_price(price: Decimal) -> Decimal: @@ -48,8 +39,7 @@ def normalize_price(price: Decimal) -> Decimal: ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, with halves rounded up. """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return Decimal(0) + return price.quantize(PRICE_STEP, ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -66,11 +56,7 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + return " ".join(name.split()).lower() def get_storage_str_representation(storage: list[Product]) -> str: @@ -91,5 +77,24 @@ def get_storage_str_representation(storage: list[Product]) -> str: is empty only the header and separator rows are returned, sized to the header labels. """ - # TODO: реализуйте функцию - return "" + col_width = [ + max( + max( + [len(str(product[i])) for product in storage] + [0] + ), # + [0] во избежание + len(TABLE_HEADERS[i]), # пустоты списка + ) + for i in range(len(TABLE_HEADERS)) + ] + rows_data = [TABLE_HEADERS] + storage + rows = [] + for row_data in rows_data: + row = "|" + for i, cell_data in enumerate(row_data): + cell = str(cell_data).ljust(col_width[i]) + row = row + " " + cell + " |" + rows.append(row) + dividing_row_data = ["-" * (width + 2) for width in col_width] + dividing_row = "|" + "|".join(dividing_row_data) + "|" + rows.insert(1, dividing_row) + return "\n".join(rows) diff --git a/src/part4.zip b/src/part4.zip new file mode 100644 index 00000000..0f906586 Binary files /dev/null and b/src/part4.zip differ diff --git a/src/part4/cart.py b/src/part4/cart.py index aed9bb72..f2cda1e7 100644 --- a/src/part4/cart.py +++ b/src/part4/cart.py @@ -1,18 +1,9 @@ -"""Shopping-cart operations layered on top of the product store. - -The cart is a plain dictionary mapping each product identifier to the -number of units of that product in the cart. Moving units between the -store and the cart keeps the two sides in balance: :func:`add_to_cart` takes -units out of stock, :func:`remove_from_cart` puts them back. - -Like the CRUD layer, the failure path never raises -- the operation prints -an explanatory message to stdout and returns ``None``. -""" - -from .storage import Product - - -# TODO: при необходимости добавьте свои вспомогательные функции +from .storage import ( # noqa: F401 + NAME_KEY, + PRICE_KEY, + QUANTITY_KEY, + Product, +) def add_to_cart( @@ -46,8 +37,19 @@ def add_to_cart( ``None`` when the product is unknown or the store cannot cover the request. """ - # TODO: реализуйте функцию - return 0 + if not product_id in storage: + print(f"no product with id {product_id}") + return None + if (storage_quantity := storage[product_id][QUANTITY_KEY]) < quantity: + print( + f"not enough stock for product {product_id}: " + f"{storage_quantity} available, " + f"{quantity} requested" + ) + return None + storage[product_id][QUANTITY_KEY] -= quantity + cart[product_id] = cart.get(product_id, 0) + quantity + return cart[product_id] def remove_from_cart( @@ -83,5 +85,21 @@ def remove_from_cart( (zero means the product was dropped from the cart), or ``None`` when the cart does not hold the product or holds too few units. """ - # TODO: реализуйте функцию - return 0 + if not product_id in cart: + print(f"product {product_id} is not in the cart") + return None + if cart[product_id] < quantity: + print( + f"cart holds only {cart[product_id]} " + f"unit(s) of product {product_id}, " + f"cannot remove {quantity}" + ) + return None + if not product_id in storage: + print(f"no product with id {product_id}") + return None + storage[product_id][QUANTITY_KEY] += quantity + cart[product_id] -= quantity + if cart[product_id] == 0: + return cart.pop(product_id) + return cart[product_id] diff --git a/src/part4/crud.py b/src/part4/crud.py index 471eff00..b5dcb9c8 100644 --- a/src/part4/crud.py +++ b/src/part4/crud.py @@ -23,16 +23,16 @@ than a scan over ``storage.values()``. """ -import uuid # noqa: F401 +import uuid from typing import Any -from .storage import ( # noqa: F401 +from .storage import ( NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product, ) -from .utils import normalize_price, normalize_product_name # noqa: F401 +from .utils import normalize_price, normalize_product_name def generate_product_id() -> str: @@ -41,8 +41,7 @@ def generate_product_id() -> str: Returns: A freshly generated UUID, stringified. """ - # TODO: реализуйте функцию - return "" + return str(uuid.uuid4()) def create_product( @@ -73,8 +72,21 @@ def create_product( and ``product_names`` are left unchanged and an explanatory message is printed. """ - # TODO: реализуйте функцию - return "" + normalized_name = normalize_product_name(fields[NAME_KEY]) + if not normalized_name: + print("product name must not be blank") + return None + if normalized_name in product_names: + print(f"product name '{normalized_name}' is already taken") + return None + product_id = generate_product_id() + storage[product_id] = { + NAME_KEY: normalized_name, + PRICE_KEY: normalize_price(fields[PRICE_KEY]), + QUANTITY_KEY: fields[QUANTITY_KEY], + } + product_names.add(normalized_name) + return product_id def read_product(storage: dict[str, Product], product_id: str) -> Product | None: @@ -88,8 +100,10 @@ def read_product(storage: dict[str, Product], product_id: str) -> Product | None The matching product record, or ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию - return {} + if not product_id in storage: + print(f"no product with id {product_id}") + return None + return storage[product_id] def update_product( @@ -129,8 +143,29 @@ def update_product( and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию - return {} + if not read_product(storage, product_id): + return None + if NAME_KEY in fields: + if not (normalized_name := normalize_product_name(fields[NAME_KEY])): + print("product name must not be blank") + return None + if normalized_name != (old_name := storage[product_id][NAME_KEY]): + if normalized_name in product_names: + print(f"product name '{normalized_name}' is already taken") + return None + product_names.remove(old_name) + product_names.add(normalized_name) + fields[NAME_KEY] = normalized_name + + if PRICE_KEY in fields: + fields[PRICE_KEY] = normalize_price(fields[PRICE_KEY]) + + storage[product_id] = { + NAME_KEY: fields.get(NAME_KEY, storage[product_id][NAME_KEY]), + PRICE_KEY: fields.get(PRICE_KEY, storage[product_id][PRICE_KEY]), + QUANTITY_KEY: fields.get(QUANTITY_KEY, storage[product_id][QUANTITY_KEY]), + } + return storage[product_id] def delete_product( @@ -153,5 +188,8 @@ def delete_product( product carried that identifier (``storage`` and ``product_names`` are left unchanged and a message is printed). """ - # TODO: реализуйте функцию - return "" + if not read_product(storage, product_id): + return None + product_names.remove(storage[product_id][NAME_KEY]) + del storage[product_id] + return product_id diff --git a/src/part4/run_admin.py b/src/part4/run_admin.py index 2247b29b..80b3a78e 100644 --- a/src/part4/run_admin.py +++ b/src/part4/run_admin.py @@ -1,49 +1,32 @@ -"""Interactive admin console for the part4 in-memory product store. - -Running this module starts a read-eval-print loop over a single product -store that lives in memory for the lifetime of the process. Every line -typed at the prompt is stripped of surrounding whitespace and matched, -with a ``match`` statement, against the set of known commands: - -* ``help`` -- print the list of commands and what each one does; -* ``exit`` -- leave the loop and end the program; -* ``show`` -- print the whole store as a text table; -* ``create `` -- add a product; -* ``read `` -- print one product; -* ``update `` -- overwrite a product; -* ``delete `` -- remove a product. - -For ``create`` and ``update`` the price and quantity are always the last -two words of the line; everything between the verb (and, for ``update``, -the id) and those two words is joined with single spaces into the -product name, so a multi-word name such as ``Gibson SG Junior`` needs no -quoting. - -The four CRUD commands forward to :mod:`src.part4.crud`; whatever -that call returns is printed unless it is ``None``. A line whose first -word is not a known verb, or that carries the wrong number of arguments -for its verb, prints an "is not a command" notice. A line that names a -command correctly but whose price or quantity argument will not parse -prints a distinct "arguments are invalid" notice. Either way the store -is left untouched and the loop keeps running; only ``exit`` stops it. -""" - -from decimal import Decimal, InvalidOperation # noqa: F401 +from decimal import Decimal, InvalidOperation from typing import Final -from .crud import ( # noqa: F401 +from .crud import ( create_product, delete_product, read_product, update_product, ) -from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product # noqa: F401 -from .utils import get_storage_str_representation # noqa: F401 +from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product +from .utils import get_storage_str_representation # TODO: задайте приглашение и текст справки (используйте своё решение части 3) -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = """ + Available commands: + help show this message + exit leave the console + show print the whole store as a table + create add a product, print its new id + read print the product with that id + update overwrite that product's fields + delete remove the product with that id + + For create and update the price and quantity are the last two words of the + line; everything before them is the product name, so it may contain spaces + (for example "Gibson SG Junior") and needs no quoting. + """ def show_help() -> None: @@ -53,7 +36,7 @@ def show_help() -> None: is: a heading, one line per command with a short description, and a note on how multi-word names are parsed. """ - # TODO: реализуйте функцию (используйте своё решение части 3) + print(HELP_TEXT) def print_result(result: object) -> None: @@ -64,7 +47,16 @@ def print_result(result: object) -> None: operation already reported its own failure, so nothing is printed in that case. """ - # TODO: реализуйте функцию (используйте своё решение части 3) + if result: + print(result) + + +def get_fields(name: list[str], price: str, quantity: str) -> Product: + return { + NAME_KEY: " ".join(name), + PRICE_KEY: Decimal(price), + QUANTITY_KEY: int(quantity), + } def run_command( @@ -91,8 +83,26 @@ def run_command( decimal.InvalidOperation: If the price argument of ``create`` or ``update`` does not parse as a decimal number. """ - # TODO: реализуйте функцию - return False + match line.split(): + case ["help"]: + show_help() + case ["exit"]: + return False + case ["show"]: + print(get_storage_str_representation(storage)) + case ["create", *name, price, quantity]: + fields = get_fields(name, price, quantity) + print_result(create_product(storage, product_names, fields)) + case ["read", product_id]: + print_result(read_product(storage, product_id)) + case ["update", product_id, *name, price, quantity]: + fields = get_fields(name, price, quantity) + print_result(update_product(storage, product_names, product_id, fields)) + case ["delete", product_id]: + print_result(delete_product(storage, product_names, product_id)) + case _: + print(f"'{line}' is not a command") + return True def main() -> None: diff --git a/src/part4/storage.py b/src/part4/storage.py index 9acedf07..564aa4ac 100644 --- a/src/part4/storage.py +++ b/src/part4/storage.py @@ -1,45 +1,9 @@ -"""In-memory product store for the shop CRUD exercise. - -The store is deliberately primitive: a plain dictionary, with no -persistence and no schema enforcement. It maps a product's ``id`` -- a -UUID string assigned by the create operation in :mod:`src.part4.crud` --- to its :data:`Product` record -- a dictionary with the keys ``name``, -``price`` and ``quantity`` -- where: - -* the ``storage`` key itself -- unique string identifier, assigned by the - create operation in :mod:`src.part4.crud`; it is not duplicated - inside the record; -* ``name`` -- human-readable product name, unique across the store, held - in normalised form (see - :func:`src.part4.utils.normalize_product_name`); -* ``price`` -- price of a single unit, held as a :class:`~decimal.Decimal` - amount rounded to a fixed number of decimal places (see - :func:`src.part4.utils.normalize_price`) so that money is never - subject to binary floating-point error; -* ``quantity`` -- number of units currently in stock. - -Field names are exposed as ``*_KEY`` constants so callers never hard-code -the dictionary keys. - -Every caller that mutates the store also threads along a second -structure, a ``set[str]`` of the normalised names currently in use -- -see, for example, the ``product_names`` parameter of -:func:`src.part4.crud.create_product`. Keeping that name index as a -plain set passed next to ``storage``, rather than bundling the two into -an object, lets a name-uniqueness check become an O(1) membership test -against the set instead of a linear scan over ``storage.values()``. The -set must always mirror the normalised names present in ``storage``; the -functions in :mod:`src.part4.crud` keep the two in sync on every -successful create, update and delete. -""" - from typing import Any, Final type Product = dict[str, Any] # Name of each field inside a Product record. -# TODO: задайте имена полей записи -NAME_KEY: Final = "" -PRICE_KEY: Final = "" -QUANTITY_KEY: Final = "" +NAME_KEY: Final = "name" +PRICE_KEY: Final = "price" +QUANTITY_KEY: Final = "quantity" diff --git a/src/part4/utils.py b/src/part4/utils.py index d2a940ea..087098b0 100644 --- a/src/part4/utils.py +++ b/src/part4/utils.py @@ -1,27 +1,7 @@ -"""Standalone helpers shared by the part4 storage and CRUD modules. +from decimal import ROUND_HALF_UP, Decimal +from typing import Any, Final -Normalisation: - -* :func:`normalize_price` rounds a raw :class:`~decimal.Decimal` amount to - the fixed number of fractional digits (:data:`PRICE_PRECISION`) that - every stored price uses, keeping currency values free of binary - floating-point error. -* :func:`normalize_product_name` strips surrounding whitespace from a - product name, collapses every internal run of whitespace to a single - space and lower-cases it, giving every stored name a single canonical - form. - -Presentation: - -* :func:`get_storage_str_representation` renders the whole store as a - text table meant to be printed to a terminal; each column is sized to - the longest value it holds in that particular call. -""" - -from decimal import ROUND_HALF_UP, Decimal # noqa: F401 -from typing import Final - -from .storage import ( # noqa: F401 +from .storage import ( NAME_KEY, PRICE_KEY, QUANTITY_KEY, @@ -31,16 +11,13 @@ # Number of fractional digits every stored price is rounded to. # Quantisation step derived from PRICE_PRECISION, e.g. Decimal("0.01"). -# TODO: задайте число знаков после запятой и шаг квантования (используйте своё -# решение части 3) -PRICE_PRECISION: Final[int] = 0 -PRICE_STEP: Final = Decimal(0) +PRICE_PRECISION: Final[int] = 2 +PRICE_STEP: Final = Decimal(1).scaleb(-PRICE_PRECISION) # Column headers of the table produced by get_storage_str_representation, # left to right. The width of each column is not fixed here -- it is # measured per call from the data (see the function). -# TODO: задайте заголовки столбцов таблицы (используйте своё решение части 3) -TABLE_HEADERS: Final[tuple[str, ...]] = () +TABLE_HEADERS: Final[tuple[str, ...]] = ("ID", NAME_KEY, PRICE_KEY, QUANTITY_KEY) def normalize_price(price: Decimal) -> Decimal: @@ -53,8 +30,7 @@ def normalize_price(price: Decimal) -> Decimal: ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, with halves rounded up. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return Decimal(0) + return price.quantize(PRICE_STEP, ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -71,11 +47,26 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return "" + return " ".join(name.split()).lower() + + +def get_columns_width(rows_data: list[tuple[str, ...]]) -> list[int]: + return [ + max( + max([len(str(row_data[i])) for row_data in rows_data] + [0]), + len(TABLE_HEADERS[i]), + ) + for i in range(len(TABLE_HEADERS)) + ] + + +def merge_in_row_data(product_id: str, fields: dict[str, Any]) -> tuple[str, ...]: + return (product_id, *map(str, fields.values())) -# TODO: при необходимости добавьте свои вспомогательные функции +def get_dividing_row(cols_width: list[int]) -> str: + dividing_row_data = ["-" * (width + 2) for width in cols_width] + return "|" + "|".join(dividing_row_data) + "|" def get_storage_str_representation(storage: dict[str, Product]) -> str: @@ -96,5 +87,17 @@ def get_storage_str_representation(storage: dict[str, Product]) -> str: ``storage`` is empty only the header and separator rows are returned, sized to the header labels. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return "" + rows_data = [TABLE_HEADERS] + list( + map(merge_in_row_data, storage.keys(), storage.values()) + ) + cols_width = get_columns_width(rows_data) + rows = [] + for row_data in rows_data: + row = "|" + for i, cell_data in enumerate(row_data): + cell = cell_data.ljust(cols_width[i]) + row += " " + cell + " |" + rows.append(row) + dividing_row = get_dividing_row(cols_width) + rows.insert(1, dividing_row) + return "\n".join(rows)