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)