From a92db2c7e72f704233770989d09f5a71ed085dc7 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Tue, 22 Sep 2026 20:37:11 +0300 Subject: [PATCH 1/8] all_checks_passed --- src/part1/constants.py | 16 +++--- src/part1/snowflake.py | 114 ++++++++++------------------------------- 2 files changed, 35 insertions(+), 95 deletions(-) mode change 100644 => 100755 src/part1/snowflake.py diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..7a112a77 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,20 @@ # 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 old mode 100644 new mode 100755 index d3abf050..635568f6 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -1,85 +1,34 @@ -"""Twitter Snowflake identifier generator. +#!/usr/bin/env python3 -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). +import time -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_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 + return snowflake_id >> (NODE_ID_BITS + SEQUENCE_ID_BITS) + epoch_ms 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 + mask = (1 << NODE_ID_BITS) - 1 + return (snowflake_id >> SEQUENCE_ID_BITS) & mask 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 + mask = (1 << SEQUENCE_ID_BITS) - 1 + return snowflake_id & mask def generate_snowflake_id( @@ -87,28 +36,19 @@ 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 + if not (0 < node_id < NODE_ID_MAX): + print("node_id must be in [0, " + str(NODE_ID_MAX) + "], got " + str(node_id)) + elif not (0 < sequence_id < SEQUENCE_ID_MAX): + print( + "sequence_id must be in [0, " + + str(SEQUENCE_ID_MAX) + + "], got " + + str(sequence_id) + ) + elif read_current_millis(epoch_ms) > TIMESTAMP_MS_MAX: + print("overflows") + return ( + (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) + | (node_id << NODE_ID_BITS) + | (sequence_id) + ) From 54b7b5426de04f3c4fb15818bb2a47e428f7e4d2 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Tue, 22 Sep 2026 20:51:25 +0300 Subject: [PATCH 2/8] fix_last_func --- src/part1/snowflake.py | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 635568f6..3d8152c4 100755 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -47,8 +47,10 @@ def generate_snowflake_id( ) elif read_current_millis(epoch_ms) > TIMESTAMP_MS_MAX: print("overflows") - return ( - (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) - | (node_id << NODE_ID_BITS) - | (sequence_id) - ) + else: + return ( + (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) + | (node_id << NODE_ID_BITS) + | (sequence_id) + ) + return None From b4aa2826e6931dd6d1847a1e223244e0d5afbc21 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Tue, 22 Sep 2026 20:58:14 +0300 Subject: [PATCH 3/8] fix_last_func --- src/part1/snowflake.py | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 635568f6..3d8152c4 100755 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -47,8 +47,10 @@ def generate_snowflake_id( ) elif read_current_millis(epoch_ms) > TIMESTAMP_MS_MAX: print("overflows") - return ( - (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) - | (node_id << NODE_ID_BITS) - | (sequence_id) - ) + else: + return ( + (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) + | (node_id << NODE_ID_BITS) + | (sequence_id) + ) + return None From 20af08efd8b3faa0a5ebf3d826c393704ff3a492 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Tue, 22 Sep 2026 21:51:01 +0300 Subject: [PATCH 4/8] fix_logic_errors --- src/part1/constants.py | 4 ++++ src/part1/snowflake.py | 43 ++++++++++++++++++++++-------------------- 2 files changed, 27 insertions(+), 20 deletions(-) diff --git a/src/part1/constants.py b/src/part1/constants.py index 7a112a77..ddc08257 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -36,3 +36,7 @@ # Здесь можно добавить собственные вспомогательные константы # (например, сдвиги полей при сборке идентификатора). + +TIMESTAMP_SHIFT: Final[int] = SEQUENCE_ID_BITS + NODE_ID_BITS + +NODE_ID_SHIFT: Final[int] = SEQUENCE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 3d8152c4..5fa359d8 100755 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -7,23 +7,25 @@ NODE_ID_BITS, NODE_ID_DEFAULT, NODE_ID_MAX, + NODE_ID_SHIFT, SEQUENCE_ID_BITS, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) def read_current_millis(epoch_ms: int) -> int: - return int(time.time() * 1000 - epoch_ms) + return int(time.time() * 1000) - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: - return snowflake_id >> (NODE_ID_BITS + SEQUENCE_ID_BITS) + epoch_ms + return (snowflake_id >> (TIMESTAMP_SHIFT)) + epoch_ms def decode_node_id(snowflake_id: int) -> int: mask = (1 << NODE_ID_BITS) - 1 - return (snowflake_id >> SEQUENCE_ID_BITS) & mask + return (snowflake_id >> NODE_ID_SHIFT) & mask def decode_sequence_id(snowflake_id: int) -> int: @@ -36,21 +38,22 @@ def generate_snowflake_id( node_id: int = NODE_ID_DEFAULT, epoch_ms: int = EPOCH_MS_DEFAULT, ) -> int | None: - if not (0 < node_id < NODE_ID_MAX): - print("node_id must be in [0, " + str(NODE_ID_MAX) + "], got " + str(node_id)) - elif not (0 < sequence_id < SEQUENCE_ID_MAX): - print( - "sequence_id must be in [0, " - + str(SEQUENCE_ID_MAX) - + "], got " - + str(sequence_id) - ) - elif read_current_millis(epoch_ms) > TIMESTAMP_MS_MAX: + + if not (0 <= node_id <= NODE_ID_MAX): + print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}") + return None + + if not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + + current_millis = read_current_millis(epoch_ms) + + if not (0 <= current_millis <= TIMESTAMP_MS_MAX): print("overflows") - else: - return ( - (read_current_millis(epoch_ms) << (NODE_ID_BITS + SEQUENCE_ID_BITS)) - | (node_id << NODE_ID_BITS) - | (sequence_id) - ) - return None + return None + return ( + (current_millis << (TIMESTAMP_SHIFT)) + | (node_id << NODE_ID_SHIFT) + | (sequence_id) + ) From 49966846f6220be8aab2b0657543204addea1514 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Fri, 2 Oct 2026 19:33:42 +0300 Subject: [PATCH 5/8] complete task --- src/part2/cart.py | 134 ++++++++++++++++++++++++------------------- src/part2/crud.py | 131 +++++++++++++++--------------------------- src/part2/storage.py | 28 ++------- src/part2/utils.py | 28 ++------- 4 files changed, 131 insertions(+), 190 deletions(-) diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..83acd049 100644 --- a/src/part2/cart.py +++ b/src/part2/cart.py @@ -1,18 +1,10 @@ -"""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``. -""" +# Shopping-cart operations layered on top of the product store. +import sys 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, @@ -24,7 +16,17 @@ # 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 +) -> tuple[int, CartLine] | None: + # Вспомогательная функция для поиска строки в корзине и её индекса. + for i, line in enumerate(cart): + if line[LINE_PRODUCT_ID_INDEX] == product_id: + return i, line + return None def add_to_cart( @@ -33,28 +35,33 @@ 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) + # Move ``quantity`` units of ``product_id`` from the store into ``cart``. + # 1. Поиск товара на складе + product = read_product(storage, product_id) + if product is None: + return None + # 2. Проверка доступного количества + available = product[QUANTITY_INDEX] + if available < quantity: + print( + f"not enough stock for product {product_id}: " + f"{available} available, {quantity} requested", + file=sys.stdout, + ) + return None + # 3. Обновление склада + new_fields = (product[NAME_INDEX], product[PRICE_INDEX], available - quantity) + update_product(storage, product_id, new_fields) + # 4. Обновление корзины + cart_search = find_cart_line(cart, product_id) + if cart_search: + idx, old_line = cart_search + new_line: CartLine = (product_id, old_line[LINE_QUANTITY_INDEX] + quantity) + cart[idx] = new_line + else: + new_line = (product_id, quantity) + cart.append(new_line) + return new_line def remove_from_cart( @@ -63,27 +70,36 @@ 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) + # Move ``quantity`` units of ``product_id`` from ``cart`` back to the store. + # 1. Поиск строки в корзине + cart_search = find_cart_line(cart, product_id) + if not cart_search: + print(f"product {product_id} is not in the cart", file=sys.stdout) + return None + + idx, line = cart_search + in_cart = line[LINE_QUANTITY_INDEX] + # 2. Проверка количества в корзине + if in_cart < quantity: + print( + f"cart holds only {in_cart} unit(s) of product {product_id}, " + f"cannot remove {quantity}", + file=sys.stdout, + ) + return None + # 3. Проверка существования товара на складе + product = read_product(storage, product_id) + if product is None: + return None + # 4. Обновление склада и корзины + available = product[QUANTITY_INDEX] + new_fields = (product[NAME_INDEX], product[PRICE_INDEX], available + quantity) + update_product(storage, product_id, new_fields) + remaining_quantity = in_cart - quantity + if remaining_quantity == 0: + cart.pop(idx) + return (product_id, 0) + else: + new_line: CartLine = (product_id, remaining_quantity) + cart[idx] = new_line + return new_line diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..ac43d730 100644 --- a/src/part2/crud.py +++ b/src/part2/crud.py @@ -1,79 +1,52 @@ -"""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. -""" +# Create/read/update/delete operations over the in-memory product store. +import sys 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 + # Choose the identifier for the next product added to ``storage``. + if not storage: + return PRODUCT_ID_MIN + return max(p[PRODUCT_ID_INDEX] for p 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. + # Append a new product to ``storage`` and return its new identifier. + name, price, quantity = fields - 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. + # Проверка уникальности имени + for product in storage: + if product[NAME_INDEX] == name: + print(f"product name '{name}' is already taken", file=sys.stdout) + 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) + norm_price = normalize_price(price) + new_product: Product = (product_id, name, norm_price, quantity) + storage.append(new_product) + 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. +def read_product(storage: list[Product], product_id: int) -> Product | None: + # Return the product stored under ``product_id``. + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + return product - 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) + print(f"no product with id {product_id}", file=sys.stdout) + return None def update_product( @@ -81,40 +54,26 @@ 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. + # Overwrite the fields of the product stored under ``product_id``. + name, price, quantity = fields - 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. + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + norm_price = normalize_price(price) + updated_product: Product = (product_id, name, norm_price, quantity) + storage[i] = updated_product + return updated_product - 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) + print(f"no product with id {product_id}", file=sys.stdout) + 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 + # Remove the product stored under ``product_id`` from ``storage``. + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + storage.pop(i) + return product_id + + print(f"no product with id {product_id}", file=sys.stdout) + return None diff --git a/src/part2/storage.py b/src/part2/storage.py index b63d5fc7..c69abc65 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -1,22 +1,4 @@ -"""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. -""" +# In-memory product store for the shop CRUD exercise. from decimal import Decimal from typing import Final @@ -26,9 +8,9 @@ # 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 ec0348d3..d575120c 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -1,29 +1,13 @@ -"""Standalone helpers shared by the hw4 storage and CRUD modules. +# Standalone helpers shared by the hw4 storage and CRUD modules. -For now this is limited to money handling: :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. -""" - -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) + # Round a price to the precision every stored record uses. + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) From d8ab34fcfeef65ee52736379df1b996456b2c5a0 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Fri, 9 Oct 2026 20:07:09 +0300 Subject: [PATCH 6/8] finish task --- src/part3/crud.py | 167 ++++++++++++++---------------------- src/part3/run_admin.py | 190 ++++++++++++++++++++++------------------- src/part3/storage.py | 33 ++----- src/part3/utils.py | 122 +++++++++----------------- 4 files changed, 219 insertions(+), 293 deletions(-) diff --git a/src/part3/crud.py b/src/part3/crud.py index 68811d7e..3fd3313b 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -1,87 +1,55 @@ -"""Create/read/update/delete operations over the in-memory product store. - -Every operation takes the store -- a list of -:data:`~src.part3.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.part3.storage.PRODUCT_ID_MIN` when the store is empty. - -Every product name that reaches the store is passed through -:func:`~src.part3.utils.normalize_product_name` first. A name that -normalises to an empty string is rejected -- the operation prints a -message and changes nothing. Names are also kept unique -- -:func:`create_product` refuses a normalised name that is already taken, -and :func:`update_product` refuses one that is already taken by another -product. -""" +"""Create/read/update/delete operations over the in-memory product store.""" from decimal import Decimal -from .storage import ( # noqa: F401 +from .storage import ( NAME_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, Product, + PRICE_INDEX, + QUANTITY_INDEX, ) -from .utils import normalize_price, normalize_product_name # noqa: F401 +from .utils import normalize_price, normalize_product_name 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.part3.storage.PRODUCT_ID_MIN` when ``storage`` is - empty. - """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + """Choose the identifier for the next product added to ``storage``.""" + if not storage: + return PRODUCT_ID_MIN + return max(p[PRODUCT_ID_INDEX] for p 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. - ``name`` is normalised (surrounding whitespace stripped, - lower-cased) before it is stored or compared. ``price`` is a - :class:`~decimal.Decimal` amount and is rounded to the stored - money precision before it is saved. - - Returns: - The identifier generated for the new product, or ``None`` when - ``name`` is blank once normalised or a product with the same - normalised name already exists. In the ``None`` case ``storage`` - is left unchanged and an explanatory message is printed. - """ - # TODO: реализуйте функцию - return 0 + """Append a new product to ``storage`` and return its new identifier.""" + name, price, quantity = fields + norm_name = normalize_product_name(name) + if not norm_name: + print("product name must not be blank") + return None -def read_product(storage: list[Product], product_id: int) -> Product | None: - """Return the product stored under ``product_id``. + for p in storage: + if p[NAME_INDEX] == norm_name: + print(f"product name '{norm_name}' is already taken") + return None - Args: - storage: The product store to search. - product_id: The identifier to look up. + product_id = generate_product_id(storage) + norm_price = normalize_price(price) + + storage.append((product_id, norm_name, norm_price, quantity)) + return product_id - 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 (используйте своё решение части 2) - return (0, "", Decimal(0), 0) + +def read_product(storage: list[Product], product_id: int) -> Product | None: + """Return the product stored under ``product_id``.""" + for p in storage: + if p[PRODUCT_ID_INDEX] == product_id: + return p + print(f"no product with id {product_id}") + return None def update_product( @@ -89,43 +57,40 @@ 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 ``name`` is blank once normalised, no product - carries that identifier, or the normalised name is already taken - by another product. In every ``None`` case ``storage`` is left - 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) + """Overwrite the fields of the product stored under ``product_id``.""" + name, price, quantity = fields + norm_name = normalize_product_name(name) + + if not norm_name: + print("product name must not be blank") + return None + + target_idx = -1 + for i, p in enumerate(storage): + if p[PRODUCT_ID_INDEX] == product_id: + target_idx = i + break + + if target_idx == -1: + print(f"no product with id {product_id}") + return None + + for i, p in enumerate(storage): + if i != target_idx and p[NAME_INDEX] == norm_name: + print(f"product name '{norm_name}' is already taken") + return None + + norm_price = normalize_price(price) + updated_product = (product_id, norm_name, norm_price, quantity) + storage[target_idx] = updated_product + return updated_product 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 (используйте своё решение части 2) - return 0 + """Remove the product stored under ``product_id`` from ``storage``.""" + for i, p in enumerate(storage): + if p[PRODUCT_ID_INDEX] == product_id: + storage.pop(i) + 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..c85f8551 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -1,116 +1,134 @@ -"""Interactive admin console for the part3 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 -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.part3.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 id, 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 +"""Interactive admin console for the part3 in-memory product store.""" + +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 - - -# TODO: задайте приглашение и текст справки -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +from .utils import get_storage_str_representation + +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = ( + "Available commands:\n" + " help show this message\n" + " exit leave the console\n" + " show print the whole store as a table\n" + " create add a product, print its new id\n" + " read print the product with that id\n" + " update overwrite that product's fields\n" + " delete remove the product with that id\n\n" + "For create and update the price and quantity are the last two words of the\n" + "line; everything before them is the product name, so it may contain spaces\n" + "(for example \"Gibson SG Junior\") and needs no quoting." +) def show_help() -> None: - """Print the command reference to stdout. - - The text is the module-level :data:`HELP_TEXT` constant, printed as - 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 the command reference to stdout.""" + print(HELP_TEXT) def print_result(result: object) -> None: - """Print a CRUD result to stdout unless it is ``None``. - - Args: - result: The value returned by a CRUD operation. ``None`` means the - operation already reported its own failure, so nothing is - printed in that case. - """ - # TODO: реализуйте функцию + """Print a CRUD result to stdout unless it is ``None``.""" + if result is not None: + print(result) def run_command(storage: list[Product], line: str) -> bool: - """Parse one console line and carry out the command it names. - - Args: - storage: The product store shared across the session; mutated in - place by the ``create``, ``update`` and ``delete`` commands. - line: One line of console input, already stripped of surrounding - whitespace. - - Returns: - ``True`` to keep the read-eval-print loop running, or ``False`` - once the ``exit`` command has been seen. A line that is not a - known command prints a notice and still returns ``True``. - - Raises: - ValueError: If an id or quantity argument of a CRUD command does - not parse as a base-10 integer. - decimal.InvalidOperation: If the price argument of ``create`` or - ``update`` does not parse as a decimal number. - """ - # TODO: реализуйте функцию - return False + """Parse one console line and carry out the command it names.""" + words = line.split() + if not words: + print(f"'{line}' is not a command") + return True + + command = words[0] + + if command == "exit": + if len(words) != 1: + print(f"'{line}' is not a command") + return True + return False + + elif command == "help": + if len(words) != 1: + print(f"'{line}' is not a command") + return True + show_help() + return True + + elif command == "show": + if len(words) != 1: + print(f"'{line}' is not a command") + return True + print(get_storage_str_representation(storage)) + return True + + elif command == "read": + if len(words) != 2: + print(f"'{line}' is not a command") + return True + product_id = int(words[1]) + res = read_product(storage, product_id) + print_result(res) + return True + + elif command == "delete": + if len(words) != 2: + print(f"'{line}' is not a command") + return True + product_id = int(words[1]) + res = delete_product(storage, product_id) + print_result(res) + return True + + elif command == "create": + # Минимум: 'create', одно слово имени, цена, количество (итого 4 слова) + if len(words) < 4: + print(f"'{line}' is not a command") + return True + quantity = int(words[-1]) + price = Decimal(words[-2]) + name = " ".join(words[1:-2]) + res = create_product(storage, (name, price, quantity)) + print_result(res) + return True + + elif command == "update": + # Минимум: 'update', id, одно слово имени, цена, количество (итого 5 слов) + if len(words) < 5: + print(f"'{line}' is not a command") + return True + product_id = int(words[1]) + quantity = int(words[-1]) + price = Decimal(words[-2]) + name = " ".join(words[2:-2]) + res = update_product(storage, product_id, (name, price, quantity)) + print_result(res) + return True + + else: + print(f"'{line}' is not a command") + return True def main() -> None: - """Run the admin console until the ``exit`` command is entered. - - A single product store is created empty and kept in memory for the - whole session. Each iteration reads one line from stdin, strips its - surrounding whitespace and hands it to :func:`run_command`. A line - that names a command but whose id, price or quantity argument does - not parse is caught here and reported without stopping the loop; only - ``exit`` ends it. - """ + """Run the admin console until the ``exit`` command is entered.""" storage: list[Product] = [] running = True while running: - line = input(PROMPT).strip() + try: + line = input(PROMPT).strip() + except EOFError: + break try: running = run_command(storage, line) - except (ValueError, InvalidOperation): print(f"{line!r} names a command but its arguments are invalid") diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..b8acf919 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -1,22 +1,4 @@ -"""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.part3.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.part3.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. -""" +"""In-memory product store for the shop CRUD exercise.""" from decimal import Decimal from typing import Final @@ -24,12 +6,11 @@ type Product = tuple[int, str, Decimal, int] -# TODO: задайте позиции полей внутри кортежа Product (используйте своё решение -# части 2) +# 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 +# Идентификатор первого товара в пустом хранилище +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part3/utils.py b/src/part3/utils.py index 318ded0b..5d0f65c9 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -1,95 +1,57 @@ -"""Standalone helpers shared by the part3 storage and CRUD modules. +"""Standalone helpers shared by the part3 storage and CRUD modules.""" -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 decimal import ROUND_HALF_UP, Decimal from typing import Final from .storage import Product +# Округление цен +PRICE_PRECISION: Final[int] = 2 +PRICE_STEP: Final = Decimal("0.01") -# 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, ...]] = () +# Заголовки столбцов таблицы +TABLE_HEADERS: Final[tuple[str, ...]] = ("ID", "name", "price", "quantity") 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 (используйте своё решение части 2) - return Decimal(0) + """Round a price to the precision every stored record uses.""" + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) def normalize_product_name(name: str) -> str: - """Reduce a product name to the canonical form the store keeps. - - Args: - name: The raw product name. - - Returns: - ``name`` with every leading and trailing whitespace character - removed, every internal run of whitespace (spaces, tabs and the - like) collapsed to a single space, and the rest lower-cased. For - example ``"abc def\tghi\tjkl"`` becomes ``"abc def ghi jkl"``. - The result is an empty string when ``name`` holds nothing but - whitespace. - """ - # TODO: реализуйте функцию - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + """Reduce a product name to the canonical form the store keeps.""" + words = name.split() + if not words: + return "" + return " ".join(words).lower() def get_storage_str_representation(storage: list[Product]) -> str: - """Render the product store as a text table with data-sized columns. - - The table has the columns named by :data:`TABLE_HEADERS` -- id, name, - price and quantity. Each column is made exactly as wide as the longest - value it carries in this call (its header counted), so the columns - line up when the string is printed to a terminal and no value is ever - truncated. - - Args: - storage: The product store to render. - - Returns: - A multi-line string: a header row, a dashed separator row, then - one row per product in ``storage`` in list order. When ``storage`` - is empty only the header and separator rows are returned, sized to - the header labels. - """ - # TODO: реализуйте функцию - return "" + """Render the product store as a text table with data-sized columns.""" + # Собираем все строки таблицы (сначала заголовки) + rows_data = [TABLE_HEADERS] + for p in storage: + rows_data.append((str(p[0]), p[1], str(p[2]), str(p[3]))) + + # Вычисляем максимальную ширину для каждого столбца + col_widths = [] + for col_idx in range(len(TABLE_HEADERS)): + max_w = max(len(row[col_idx]) for row in rows_data) + col_widths.append(max_w) + + # Строим строку заголовков + header_parts = [f" {TABLE_HEADERS[i].ljust(col_widths[i])} " for i in range(len(TABLE_HEADERS))] + header_row = f"|{'|'.join(header_parts)}|" + + # Строим разделительную строку + sep_parts = ["-" * (w + 2) for w in col_widths] + sep_row = f"|{'|'.join(sep_parts)}|" + + result_lines = [header_row, sep_row] + + # Строим строки с данными товаров + for row in rows_data[1:]: + row_parts = [f" {row[i].ljust(col_widths[i])} " for i in range(len(TABLE_HEADERS))] + result_lines.append(f"|{'|'.join(row_parts)}|") + + return "\n".join(result_lines) From 4e12d440ec85460e71acaf71875b530c7de18cc8 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Fri, 9 Oct 2026 20:13:52 +0300 Subject: [PATCH 7/8] fix checks --- src/part3/crud.py | 2 -- src/part3/run_admin.py | 2 +- 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/src/part3/crud.py b/src/part3/crud.py index 3fd3313b..b181e525 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -7,8 +7,6 @@ PRODUCT_ID_INDEX, PRODUCT_ID_MIN, Product, - PRICE_INDEX, - QUANTITY_INDEX, ) from .utils import normalize_price, normalize_product_name diff --git a/src/part3/run_admin.py b/src/part3/run_admin.py index c85f8551..15f96bc2 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -24,7 +24,7 @@ " delete remove the product with that id\n\n" "For create and update the price and quantity are the last two words of the\n" "line; everything before them is the product name, so it may contain spaces\n" - "(for example \"Gibson SG Junior\") and needs no quoting." + '(for example "Gibson SG Junior") and needs no quoting.' ) From 9a3212a1b5a641e935dc9011ec9835288f2e0794 Mon Sep 17 00:00:00 2001 From: rdontsov01 Date: Fri, 30 Oct 2026 20:56:33 +0300 Subject: [PATCH 8/8] Task 4 --- src/part2/utils.py | 13 ----- src/part3/run_admin.py | 1 + src/part3/utils.py | 1 + src/part4/cart.py | 47 +++++++++++++--- src/part4/crud.py | 79 +++++++++++++++++++++----- src/part4/run_admin.py | 123 ++++++++++++++++++++++++++++++++++++----- src/part4/storage.py | 7 +-- src/part4/utils.py | 53 ++++++++++++------ 8 files changed, 255 insertions(+), 69 deletions(-) diff --git a/src/part2/utils.py b/src/part2/utils.py index c47b5e2b..e69de29b 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -1,13 +0,0 @@ -"""Standalone helpers shared by the hw4 storage and CRUD modules. - -from decimal import ROUND_HALF_UP, Decimal -from typing import Final - - -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. - return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) diff --git a/src/part3/run_admin.py b/src/part3/run_admin.py index 15f96bc2..7a4d3b90 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -12,6 +12,7 @@ from .storage import Product from .utils import get_storage_str_representation + PROMPT: Final[str] = "admin> " HELP_TEXT: Final[str] = ( "Available commands:\n" diff --git a/src/part3/utils.py b/src/part3/utils.py index 5d0f65c9..23e13f87 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -5,6 +5,7 @@ from .storage import Product + # Округление цен PRICE_PRECISION: Final[int] = 2 PRICE_STEP: Final = Decimal("0.01") diff --git a/src/part4/cart.py b/src/part4/cart.py index aed9bb72..ed57c700 100644 --- a/src/part4/cart.py +++ b/src/part4/cart.py @@ -9,10 +9,7 @@ an explanatory message to stdout and returns ``None``. """ -from .storage import Product - - -# TODO: при необходимости добавьте свои вспомогательные функции +from .storage import QUANTITY_KEY, Product def add_to_cart( @@ -46,8 +43,21 @@ def add_to_cart( ``None`` when the product is unknown or the store cannot cover the request. """ - # TODO: реализуйте функцию - return 0 + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + available = storage[product_id][QUANTITY_KEY] + if available < quantity: + print( + f"not enough stock for product {product_id}: " + f"{available} available, {quantity} requested" + ) + return None + + storage[product_id][QUANTITY_KEY] = available - quantity + cart[product_id] = cart.get(product_id, 0) + quantity + return cart[product_id] def remove_from_cart( @@ -83,5 +93,26 @@ 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 product_id not in cart: + print(f"product {product_id} is not in the cart") + return None + + in_cart = cart[product_id] + if in_cart < quantity: + print( + f"cart holds only {in_cart} unit(s) of product {product_id}, " + f"cannot remove {quantity}" + ) + return None + + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + storage[product_id][QUANTITY_KEY] += quantity + remaining = in_cart - quantity + if remaining == 0: + del cart[product_id] + else: + cart[product_id] = remaining + return remaining diff --git a/src/part4/crud.py b/src/part4/crud.py index 471eff00..590f6a03 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 +72,22 @@ def create_product( and ``product_names`` are left unchanged and an explanatory message is printed. """ - # TODO: реализуйте функцию - return "" + name = normalize_product_name(fields[NAME_KEY]) + if not name: + print("product name must not be blank") + return None + if name in product_names: + print(f"product name '{name}' is already taken") + return None + + product_id = generate_product_id() + storage[product_id] = { + NAME_KEY: name, + PRICE_KEY: normalize_price(fields[PRICE_KEY]), + QUANTITY_KEY: fields[QUANTITY_KEY], + } + product_names.add(name) + return product_id def read_product(storage: dict[str, Product], product_id: str) -> Product | None: @@ -88,8 +101,10 @@ 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 product_id not in storage: + print(f"no product with id {product_id}") + return None + return storage[product_id] def update_product( @@ -129,8 +144,41 @@ def update_product( and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию - return {} + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + product = storage[product_id] + old_name = product[NAME_KEY] + + if NAME_KEY in fields: + new_name = normalize_product_name(fields[NAME_KEY]) + fields[NAME_KEY] = new_name + if not new_name: + print("product name must not be blank") + return None + if new_name != old_name and new_name in product_names: + print(f"product name '{new_name}' is already taken") + return None + + if PRICE_KEY in fields: + fields[PRICE_KEY] = normalize_price(fields[PRICE_KEY]) + + # Apply updates + if NAME_KEY in fields: + new_name = fields[NAME_KEY] + if new_name != old_name: + product_names.discard(old_name) + product_names.add(new_name) + product[NAME_KEY] = new_name + + if PRICE_KEY in fields: + product[PRICE_KEY] = fields[PRICE_KEY] + + if QUANTITY_KEY in fields: + product[QUANTITY_KEY] = fields[QUANTITY_KEY] + + return product def delete_product( @@ -153,5 +201,10 @@ def delete_product( product carried that identifier (``storage`` and ``product_names`` are left unchanged and a message is printed). """ - # TODO: реализуйте функцию - return "" + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + product = storage.pop(product_id) + product_names.discard(product[NAME_KEY]) + return product_id diff --git a/src/part4/run_admin.py b/src/part4/run_admin.py index 2247b29b..92a44502 100644 --- a/src/part4/run_admin.py +++ b/src/part4/run_admin.py @@ -28,22 +28,34 @@ 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 - - -# TODO: задайте приглашение и текст справки (используйте своё решение части 3) -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product +from .utils import get_storage_str_representation + + +PROMPT: Final[str] = "> " +HELP_TEXT: Final[str] = """\ +Available commands: + help - show this help + exit - leave the console + show - print the whole product store + create - add a new product + read - print one product by id + update - overwrite a product + delete - remove a product + +For create and update the last two tokens are price and quantity; +everything between the command (and id for update) and those two tokens +is the product name (multi-word names need no quoting). +""" def show_help() -> None: @@ -53,7 +65,7 @@ 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, end="") def print_result(result: object) -> None: @@ -64,7 +76,8 @@ 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 is not None: + print(result) def run_command( @@ -91,8 +104,92 @@ 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 + if not line: + return True + + parts = line.split() + verb = parts[0] + + match verb: + case "help": + if len(parts) != 1: + print(f"{line!r} is not a command") + return True + show_help() + return True + + case "exit": + if len(parts) != 1: + print(f"{line!r} is not a command") + return True + return False + + case "show": + if len(parts) != 1: + print(f"{line!r} is not a command") + return True + print(get_storage_str_representation(storage)) + return True + + case "create": + if len(parts) < 4: + print(f"{line!r} is not a command") + return True + name = " ".join(parts[1:-2]) + price = Decimal(parts[-2]) + quantity = int(parts[-1]) + result = create_product( + storage, + product_names, + { + NAME_KEY: name, + PRICE_KEY: price, + QUANTITY_KEY: quantity, + }, + ) + print_result(result) + return True + + case "read": + if len(parts) != 2: + print(f"{line!r} is not a command") + return True + result = read_product(storage, parts[1]) + print_result(result) + return True + + case "update": + if len(parts) < 5: + print(f"{line!r} is not a command") + return True + product_id = parts[1] + name = " ".join(parts[2:-2]) + price = Decimal(parts[-2]) + quantity = int(parts[-1]) + result = update_product( + storage, + product_names, + product_id, + { + NAME_KEY: name, + PRICE_KEY: price, + QUANTITY_KEY: quantity, + }, + ) + print_result(result) + return True + + case "delete": + if len(parts) != 2: + print(f"{line!r} is not a command") + return True + result = delete_product(storage, product_names, parts[1]) + print_result(result) + return True + + case _: + print(f"{line!r} is not a command") + return True def main() -> None: diff --git a/src/part4/storage.py b/src/part4/storage.py index 9acedf07..f0034782 100644 --- a/src/part4/storage.py +++ b/src/part4/storage.py @@ -39,7 +39,6 @@ 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..3a9b3ec0 100644 --- a/src/part4/utils.py +++ b/src/part4/utils.py @@ -18,10 +18,10 @@ 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 ( # noqa: F401 +from .storage import ( NAME_KEY, PRICE_KEY, QUANTITY_KEY, @@ -31,16 +31,13 @@ # 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("0.01") # 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", "price", "quantity") def normalize_price(price: Decimal) -> Decimal: @@ -53,8 +50,7 @@ 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, rounding=ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -67,15 +63,11 @@ def normalize_product_name(name: str) -> str: ``name`` with every leading and trailing whitespace character removed, every internal run of whitespace (spaces, tabs and the like) collapsed to a single space, and the rest lower-cased. For - example ``"abc def\tghi\tjkl"`` becomes ``"abc def ghi jkl"``. + example ``"abc def\\tghi\\tjkl"`` becomes ``"abc def ghi jkl"``. The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + return " ".join(name.split()).lower() def get_storage_str_representation(storage: dict[str, Product]) -> str: @@ -96,5 +88,30 @@ 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 "" + headers = TABLE_HEADERS + rows: list[tuple[str, str, str, str]] = [] + + for product_id, product in storage.items(): + rows.append( + ( + product_id, + str(product[NAME_KEY]), + str(product[PRICE_KEY]), + str(product[QUANTITY_KEY]), + ) + ) + + # Compute column widths from headers and all row values + widths = [len(h) for h in headers] + for row in rows: + for i, cell in enumerate(row): + widths[i] = max(widths[i], len(cell)) + + def format_row(cells: tuple[str, ...]) -> str: + return " | ".join(cell.ljust(widths[i]) for i, cell in enumerate(cells)) + + header_line = format_row(headers) + separator = "-+-".join("-" * w for w in widths) + body_lines = [format_row(row) for row in rows] + + return "\n".join([header_line, separator, *body_lines])