diff --git a/.gitignore b/.gitignore index 8ca254de..f035f5c9 100644 --- a/.gitignore +++ b/.gitignore @@ -11,3 +11,6 @@ __pycache__/ # Claude .claude + +# local repo dumps +repo_dump*.txt diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..1eb7dbde 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,22 @@ # 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] = (1 << TIMESTAMP_BITS) - 1 +NODE_ID_MAX: Final[int] = (1 << NODE_ID_BITS) - 1 +SEQUENCE_ID_MAX: Final[int] = (1 << SEQUENCE_ID_BITS) - 1 # Здесь можно добавить собственные вспомогательные константы # (например, сдвиги полей при сборке идентификатора). +NODE_ID_SHIFT = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT = NODE_ID_SHIFT + NODE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..b3a1593f 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -4,23 +4,24 @@ 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 +caller passes the sequence counter on every call and is responsible 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 +import time -from .constants import ( # noqa: F401 +from .constants import ( EPOCH_MS_DEFAULT, NODE_ID_DEFAULT, NODE_ID_MAX, + NODE_ID_SHIFT, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) @@ -34,8 +35,8 @@ def read_current_millis(epoch_ms: int) -> int: 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 + current_ms = int(time.time() * 1000) + return current_ms - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -50,8 +51,8 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> The absolute Unix time in milliseconds at which the identifier was generated. """ - # TODO: реализуйте функцию - return 0 + timestamp = snowflake_id >> TIMESTAMP_SHIFT + return timestamp + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -64,8 +65,7 @@ def decode_node_id(snowflake_id: int) -> int: The node identifier packed into ``snowflake_id``, in the range ``[0, NODE_ID_MAX]``. """ - # TODO: реализуйте функцию - return 0 + return (snowflake_id >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: @@ -78,8 +78,7 @@ def decode_sequence_id(snowflake_id: int) -> int: 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( @@ -110,5 +109,16 @@ def generate_snowflake_id( 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(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_ms = read_current_millis(epoch_ms) + if current_ms > TIMESTAMP_MS_MAX: + print("timestamp overflows") + return None + return (current_ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..1c6355e4 100644 --- a/src/part2/cart.py +++ b/src/part2/cart.py @@ -11,8 +11,8 @@ 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 +22,15 @@ 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) -> int | None: + for cart_ in cart: + if cart_[LINE_PRODUCT_ID_INDEX] == product_id: + return cart.index(cart_) + return None def add_to_cart( @@ -53,8 +59,32 @@ def add_to_cart( 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_person = read_product(storage, product_id) + if not product_person: + return None + storage_quantity = product_person[QUANTITY_INDEX] + if storage_quantity < quantity: + print( + f"not enough stock for product {product_id} : {product_person[QUANTITY_INDEX]} available, {quantity} requested" + ) + return None + + fields_ = ( + product_person[NAME_INDEX], + product_person[PRICE_INDEX], + product_person[QUANTITY_INDEX] - quantity, + ) + update_product(storage, product_id, fields_) + + line_index = find_cart_line(cart, product_id) + if line_index is None: + cartLine = (product_id, quantity) + cart.append(cartLine) + return cartLine + old_quantity = cart[line_index][LINE_QUANTITY_INDEX] + cartLine = (product_id, old_quantity + quantity) + cart[line_index] = cartLine + return cartLine def remove_from_cart( @@ -85,5 +115,31 @@ def remove_from_cart( 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) + line_index = find_cart_line(cart, product_id) + if line_index is None: + print(f"product {product_id} is not in the cart") + return None + + cart_quantity = cart[line_index][LINE_QUANTITY_INDEX] + if cart_quantity < quantity: + print(f"cart holds only {cart_quantity} unit(s) of product") + print(f"{product_id}, cannot remove {quantity}") + return None + + product_person = read_product(storage, product_id) + if not product_person: + return None + + fields_ = ( + product_person[NAME_INDEX], + product_person[PRICE_INDEX], + product_person[QUANTITY_INDEX] + quantity, + ) + update_product(storage, product_id, fields_) + + new_cart_quantity = cart_quantity - quantity + if new_cart_quantity == 0: + del cart[line_index] + else: + cart[line_index] = (product_id, new_cart_quantity) + return (product_id, new_cart_quantity) diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..7ecf8f26 100644 --- a/src/part2/crud.py +++ b/src/part2/crud.py @@ -14,13 +14,13 @@ 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: @@ -34,8 +34,9 @@ def generate_product_id(storage: list[Product]) -> int: :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( @@ -56,8 +57,16 @@ def create_product( ``storage`` is left unchanged and a message naming the clashing name is printed. """ - # TODO: реализуйте функцию - return 0 + name, price, quantity = fields + for product in storage: + if product[NAME_INDEX] == name: + print(f"product name{name} is already taken.") + return None + product_id = generate_product_id(storage) + product_price = normalize_price(price) + new_product = (product_id, name, product_price, quantity) + storage.append(new_product) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -72,8 +81,12 @@ 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 - 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( @@ -99,8 +112,16 @@ def update_product( ``None`` when no product carries that identifier (``storage`` is left unchanged and a message is printed). """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + name, price, quantity = fields + + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + new_product = (product_id, name, normalize_price(price), quantity) + storage[storage.index(product)] = new_product + return new_product + + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -116,5 +137,10 @@ 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 - return 0 + for product_index in storage: + if product_index[PRODUCT_ID_INDEX] == product_id: + storage.remove(product_index) + 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..e4bceff1 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -24,11 +24,9 @@ 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..0c430bd0 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -6,13 +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: @@ -26,4 +26,5 @@ def normalize_price(price: Decimal) -> Decimal: with halves rounded up. """ # TODO: реализуйте функцию - return Decimal(0) + # + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) diff --git a/src/part3/crud.py b/src/part3/crud.py index 68811d7e..06103577 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -1,87 +1,47 @@ -"""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. -""" - 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, 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 + if not storage: + return 1 + 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. - ``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 + name, price, quantity = fields + normalize_name = " ".join(name.lower().split()) + if not normalize_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 product in storage: + if product[NAME_INDEX] == normalize_name: + print(f"product name '{normalize_name}' is already taken") + return None + product_id = generate_product_id(storage) + product_price = normalize_price(price) + new_product = (product_id, normalize_name, product_price, quantity) + storage.append(new_product) + return 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 (используйте своё решение части 2) - return (0, "", Decimal(0), 0) +def read_product(storage: list[Product], product_id: int) -> Product | None: + 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( @@ -89,43 +49,44 @@ 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) + name, price, quantity = fields + normalize_name = normalize_product_name(name) + + if not normalize_name: + print("product name must not be blank") + return None + + found_index: int | None = None + + for index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + found_index = index + break + + if found_index is None: + print(f"no product with id {product_id}") + return None + + for index, product in enumerate(storage): + if index != found_index and product[NAME_INDEX] == normalize_name: + print(f"product name '{normalize_name}' is already taken") + return None + + new_product = ( + product_id, + normalize_name, + normalize_price(price), + quantity, + ) + storage[found_index] = new_product + return new_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 + for product_index in storage: + if product_index[PRODUCT_ID_INDEX] == product_id: + storage.remove(product_index) + 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..ca2a0cde 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -1,107 +1,100 @@ -"""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 +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: -def show_help() -> None: - """Print the command reference to stdout. +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 - 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 +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 print_result(result: object) -> None: - """Print a CRUD result to stdout unless it is ``None``. +def show_help() -> None: + print(HELP_TEXT) + - 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 +def print_result(result: object) -> 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. + parts = line.split() + + if not parts: + print(f"{line!r} is not a command") + return True + command = parts[0] + result: object + + if command == "help" and len(parts) == 1: + show_help() + return True + + if command == "exit" and len(parts) == 1: + return False + + if command == "show" and len(parts) == 1: + print(get_storage_str_representation(storage)) + return True + + if command == "create" and len(parts) >= 4: + name = " ".join(parts[1:-2]) + price = Decimal(parts[-2]) + quantity = int(parts[-1]) + + result = create_product(storage, (name, price, quantity)) + print_result(result) + return True + + if command == "read" and len(parts) == 2: + product_id = int(parts[1]) + + result = read_product(storage, product_id) + print_result(result) + return True + + if command == "update" and len(parts) >= 5: + product_id = int(parts[1]) + name = " ".join(parts[2:-2]) + price = Decimal(parts[-2]) + quantity = int(parts[-1]) + + result = update_product(storage, product_id, (name, price, quantity)) + print_result(result) + return True - 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. + if command == "delete" and len(parts) == 2: + product_id = int(parts[1]) - 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``. + result = delete_product(storage, product_id) + print_result(result) + return 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 + print(f"{line!r} 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. - """ storage: list[Product] = [] running = True diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..81651a75 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -1,35 +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.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. -""" - from decimal import Decimal from typing import Final 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..f779dc43 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -1,95 +1,62 @@ -"""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 +from .storage import ( + NAME_INDEX, + PRICE_INDEX, + PRODUCT_ID_INDEX, + QUANTITY_INDEX, + 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) +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 -TABLE_HEADERS: Final[tuple[str, ...]] = () +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) + 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 + return " ".join(name.lower().split()) 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 "" + rows: list[tuple[str, ...]] = [ + ( + str(product[PRODUCT_ID_INDEX]), + product[NAME_INDEX], + str(product[PRICE_INDEX]), + str(product[QUANTITY_INDEX]), + ) + for product in storage + ] + + widths = [len(header) for header in TABLE_HEADERS] + for row in rows: + for index, cell in enumerate(row): + widths[index] = max(widths[index], len(cell)) + + def format_row(cells: tuple[str, ...]) -> str: + return ( + "| " + + " | ".join(cell.ljust(widths[index]) for index, cell in enumerate(cells)) + + " |" + ) + + header_line = format_row(TABLE_HEADERS) + separator_line = "|" + "|".join("-" * (width + 2) for width in widths) + "|" + + lines = [header_line, separator_line] + lines.extend(format_row(row) for row in rows) + return "\n".join(lines) diff --git a/src/part4/cart.py b/src/part4/cart.py index aed9bb72..c681a472 100644 --- a/src/part4/cart.py +++ b/src/part4/cart.py @@ -1,18 +1,4 @@ -"""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 QUANTITY_KEY, Product def add_to_cart( @@ -22,32 +8,20 @@ def add_to_cart( product_id: str, quantity: int, ) -> int | None: - """Move ``quantity`` units of ``product_id`` from the store into ``cart``. + if product_id not in storage: + print(f"no product with id {product_id}") + return None - The product is looked up in ``storage``. If it is missing, a message is - printed 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 - gains ``quantity`` units of ``product_id`` -- the product is added when - the cart had none of it. + product = storage[product_id] + if product[QUANTITY_KEY] < quantity: + print( + f"not enough stock for product {product_id}: {product[QUANTITY_KEY]} available, {quantity} requested" + ) + return None - Args: - storage: The product store to draw stock from; modified in place on - success. - product_names: The normalised names in ``storage``; a - quantity-only change never renames a product, so it is left - unchanged here. - 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 quantity of ``product_id`` in the cart after the addition, or - ``None`` when the product is unknown or the store cannot cover the - request. - """ - # TODO: реализуйте функцию - return 0 + product[QUANTITY_KEY] -= quantity + cart[product_id] = cart.get(product_id, 0) + quantity + return cart[product_id] def remove_from_cart( @@ -57,31 +31,24 @@ def remove_from_cart( product_id: str, quantity: int, ) -> int | None: - """Move ``quantity`` units of ``product_id`` from ``cart`` back to the store. - - If the cart holds no units of ``product_id``, a message is printed and - nothing changes. If it holds fewer units than requested, an explanatory - message is printed and nothing changes. If the product is missing from - ``storage``, a message is printed and nothing changes. Otherwise the cart loses - ``quantity`` units of the product -- the product is dropped from the - cart when its quantity reaches zero -- and the store record gains - ``quantity`` units back. - - Args: - storage: The product store to return stock to; modified in place on - success. - product_names: The normalised names in ``storage``; a - quantity-only change never renames a product, so it is left - unchanged here. - 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 quantity of ``product_id`` left in the cart after the removal - (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 + + if cart[product_id] < quantity: + print( + f"cart holds only {cart[product_id]} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + cart[product_id] -= quantity + storage[product_id][QUANTITY_KEY] += quantity + + if cart[product_id] == 0: + del cart[product_id] + return 0 + return cart[product_id] diff --git a/src/part4/crud.py b/src/part4/crud.py index 471eff00..f916af20 100644 --- a/src/part4/crud.py +++ b/src/part4/crud.py @@ -1,95 +1,49 @@ -"""Create/read/update/delete operations over the in-memory product store. - -Every operation takes the store -- a dictionary mapping product id to its -:data:`~src.part4.storage.Product` record -- as its first argument and -works on it in place. ``create_product``, ``update_product`` and -``delete_product`` additionally take ``product_names``, the ``set[str]`` -of normalised names currently in ``storage`` (see -:mod:`src.part4.storage`), and keep it in sync with ``storage`` on -every successful call. The failure path never raises: the operation -prints an explanatory message to stdout and returns ``None``. - -The identifier of a new product is a freshly generated UUID string -(:func:`generate_product_id`), independent of insertion order or of any -identifier already in ``storage``. - -Every product name that reaches the store is passed through -:func:`~src.part4.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 -- via an O(1) membership test against ``product_names`` rather -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: - """Generate an identifier for a new product. - - Returns: - A freshly generated UUID, stringified. - """ - # TODO: реализуйте функцию - return "" + return str(uuid.uuid4()) def create_product( - storage: dict[str, Product], + storage: dict[str, Product], # хранилище product_names: set[str], - fields: dict[str, Any], + fields: dict[str, Any], # поля ) -> str | None: - """Add a new product to ``storage`` and return its new identifier. - - Args: - storage: The product store to add to; modified in place on - success. - product_names: The normalised names already in ``storage``; the - new name is added to it in place on success. - fields: A dictionary with the ``name``, ``price`` and ``quantity`` - keys (see :data:`~src.part4.storage.NAME_KEY`, - :data:`~src.part4.storage.PRICE_KEY` and - :data:`~src.part4.storage.QUANTITY_KEY`) 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`` - and ``product_names`` are left unchanged and an explanatory - message is printed. - """ - # TODO: реализуйте функцию - return "" + name = normalize_product_name(fields[NAME_KEY]) + if len(name) == 0: + print("product name must not be blank") + return None + if name in product_names: + print(f"product name '{name}' is already taken") + return None -def read_product(storage: dict[str, Product], product_id: str) -> Product | None: - """Return the product stored under ``product_id``. + 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 - Args: - storage: The product store to search. - product_id: The identifier to look up. - Returns: - The matching product record, or ``None`` when no product carries - that identifier (a message is printed in that case). - """ - # TODO: реализуйте функцию - return {} +def read_product(storage: dict[str, Product], product_id: str) -> Product | None: + if product_id not in storage: + print(f"no product with id {product_id}") + return None + + return storage[product_id] def update_product( @@ -98,39 +52,32 @@ def update_product( product_id: str, fields: dict[str, Any], ) -> Product | None: - """Overwrite the fields of the product stored under ``product_id``. - - The identifier itself is preserved. ``fields`` may carry any subset of - ``name``, ``price`` and ``quantity``; a key that is missing keeps the - value the product already has, so a caller can update a single field - without repeating the other two. - - Args: - storage: The product store to modify; the matching record is - updated in place on success. - product_names: The normalised names already in ``storage``; on a - successful rename the old name is removed from it and the new - one added. - product_id: The identifier of the product to change. - fields: A dictionary with any of the ``name``, ``price`` and - ``quantity`` keys (see :data:`~src.part4.storage.NAME_KEY`, - :data:`~src.part4.storage.PRICE_KEY` and - :data:`~src.part4.storage.QUANTITY_KEY`) holding the new - values. ``price`` is a :class:`~decimal.Decimal` amount and is - rounded to the stored money precision before it is saved. - Mutated in place: a ``name`` or ``price`` value present in - ``fields`` is overwritten with its normalised form. - - Returns: - The updated product record, or ``None`` when ``name`` is present - and blank once normalised, no product carries that identifier, or - the normalised name is already taken by another product. In every - ``None`` case ``storage`` and ``product_names`` are left unchanged - 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 + + tmp = storage[product_id] + + if NAME_KEY in fields: + name = normalize_product_name(fields[NAME_KEY]) + if len(name) == 0: + print("product name must not be blank") + return None + + if name != tmp[NAME_KEY] and name in product_names: + print(f"product name '{name}' is already taken") + return None + fields[NAME_KEY] = name + + if PRICE_KEY in fields: + fields[PRICE_KEY] = normalize_price(fields[PRICE_KEY]) + + if NAME_KEY in fields and fields[NAME_KEY] != tmp[NAME_KEY]: + product_names.remove(tmp[NAME_KEY]) + product_names.add(fields[NAME_KEY]) + + tmp.update(fields) + return tmp def delete_product( @@ -138,20 +85,10 @@ def delete_product( product_names: set[str], product_id: str, ) -> str | None: - """Remove the product stored under ``product_id`` from ``storage``. - - Args: - storage: The product store to remove from; modified in place on - success. - product_names: The normalised names already in ``storage``; the - departing product's name is removed from it 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`` 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_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..252bac3e 100644 --- a/src/part4/run_admin.py +++ b/src/part4/run_admin.py @@ -1,110 +1,114 @@ -"""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 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: -def show_help() -> None: - """Print the command reference to stdout. +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 - 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 (используйте своё решение части 3) +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 print_result(result: object) -> None: - """Print a CRUD result to stdout unless it is ``None``. +def show_help() -> None: + print(HELP_TEXT) - 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 (используйте своё решение части 3) + +def print_result(result: object) -> None: + if result is not None: + print(result) def run_command( storage: dict[str, Product], product_names: set[str], 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. - product_names: The normalised names already in ``storage``; kept - in sync 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 the 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 + parts = line.split() + if not parts: + print(f"{line!r} is not a command") + return True + + command = parts[0] + result: object + + if command == "help" and len(parts) == 1: + show_help() + return True + + if command == "exit" and len(parts) == 1: + return False + + if command == "show" and len(parts) == 1: + print(get_storage_str_representation(storage)) + return True + + if command == "create" and len(parts) >= 4: + 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 + if command == "read" and len(parts) == 2: + product_id = parts[1] + result = read_product(storage, product_id) + print_result(result) + return True + + if command == "update" and len(parts) >= 5: + 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 + + if command == "delete" and len(parts) == 2: + product_id = parts[1] + result = delete_product(storage, product_names, product_id) + print_result(result) + return True + + print(f"{line!r} is not a command") + return True def main() -> None: - """Run the admin console until the ``exit`` command is entered. - - A single product store, and the set of normalised names it holds, are - 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 price - or quantity argument does not parse is caught here and reported - without stopping the loop; only ``exit`` ends it. - """ storage: dict[str, Product] = {} product_names: set[str] = set() running = True @@ -115,7 +119,7 @@ def main() -> None: try: running = run_command(storage, product_names, line) - except (ValueError, InvalidOperation): + except Exception: # noqa: BLE001 print(f"{line!r} names a command but its arguments are invalid") diff --git a/src/part4/storage.py b/src/part4/storage.py index 9acedf07..048ce1b6 100644 --- a/src/part4/storage.py +++ b/src/part4/storage.py @@ -1,45 +1,8 @@ -"""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[str] = "name" +PRICE_KEY: Final[str] = "price" +QUANTITY_KEY: Final[str] = "quantity" diff --git a/src/part4/utils.py b/src/part4/utils.py index d2a940ea..2ea4dbca 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. - -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 ( # noqa: F401 +from .storage import ( NAME_KEY, PRICE_KEY, QUANTITY_KEY, @@ -29,72 +9,51 @@ ) -# 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", + "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 3) - return Decimal(0) + 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 (используйте своё решение части 3) - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + return " ".join(name.lower().split()) def get_storage_str_representation(storage: dict[str, 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 insertion order. When - ``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: list[tuple[str, ...]] = [ + ( + product_id, + product[NAME_KEY], + str(product[PRICE_KEY]), + str(product[QUANTITY_KEY]), + ) + for product_id, product in storage.items() + ] + + widths = [len(header) for header in TABLE_HEADERS] + for row in rows: + for index, cell in enumerate(row): + widths[index] = max(widths[index], len(cell)) + + def format_row(cells: tuple[str, ...]) -> str: + return ( + "| " + + " | ".join(cell.ljust(widths[index]) for index, cell in enumerate(cells)) + + " |" + ) + + header_line = format_row(TABLE_HEADERS) + separator_line = "|" + "|".join("-" * (width + 2) for width in widths) + "|" + + lines = [header_line, separator_line] + lines.extend(format_row(row) for row in rows) + return "\n".join(lines)