diff --git a/.gitignore b/.gitignore index 8ca254de..9cf60825 100644 --- a/.gitignore +++ b/.gitignore @@ -11,3 +11,6 @@ __pycache__/ # Claude .claude + +# Macos system stuff +.DS_Store \ No newline at end of file diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..83c446ec 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,23 @@ # 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). + +NODE_ID_SHIFT: Final[int] = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT: Final[int] = SEQUENCE_ID_BITS + NODE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..739896ec 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,73 +13,37 @@ :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, ) 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 >> TIMESTAMP_SHIFT) + 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 + return (snowflake_id >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: - """Read the sequence counter field out of a Snowflake identifier. - - Args: - snowflake_id: An identifier produced by :func:`generate_snowflake_id`. - Returns: - The per-millisecond sequence counter packed into ``snowflake_id``, in - the range ``[0, SEQUENCE_ID_MAX]``. - """ - # TODO: реализуйте функцию - return 0 + return snowflake_id & SEQUENCE_ID_MAX def generate_snowflake_id( @@ -87,28 +51,14 @@ 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(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 + ms = read_current_millis(epoch_ms) + if ms > TIMESTAMP_MS_MAX: + print(f"timestamp overflows: {ms} > {TIMESTAMP_MS_MAX}") + return None + return (ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..cf3ad751 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) -> CartLine | None: + """Return the cart line for ``product_id``, if present.""" + return next( + (line for line in cart if line[LINE_PRODUCT_ID_INDEX] == product_id), None + ) def add_to_cart( @@ -53,8 +59,30 @@ 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 = read_product(storage, product_id) + if product is None: + return None + available = product[QUANTITY_INDEX] + if available < quantity: + print( + f"not enough stock for product {product_id}: {available} available, " + f"{quantity} requested" + ) + return None + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], available - quantity), + ) + line = find_cart_line(cart, product_id) + if line is None: + line = (product_id, quantity) + cart.append(line) + return line + index = cart.index(line) + updated = (product_id, line[LINE_QUANTITY_INDEX] + quantity) + cart[index] = updated + return updated def remove_from_cart( @@ -85,5 +113,28 @@ 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 = find_cart_line(cart, product_id) + if line is None: + print(f"product {product_id} is not in the cart") + return None + held = line[LINE_QUANTITY_INDEX] + if held < quantity: + print( + f"cart holds only {held} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + product = read_product(storage, product_id) + if product is None: + return None + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] + quantity), + ) + remaining = held - quantity + index = cart.index(line) + if remaining == 0: + del cart[index] + else: + cart[index] = (product_id, remaining) + return (product_id, remaining) diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..4e219a8e 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 +34,11 @@ def generate_product_id(storage: list[Product]) -> int: :data:`~src.part2.storage.PRODUCT_ID_MIN` when ``storage`` is empty. """ - # TODO: реализуйте функцию - return 0 + return ( + max(product[PRODUCT_ID_INDEX] for product in storage) + 1 + if storage + else PRODUCT_ID_MIN + ) def create_product( @@ -56,8 +59,13 @@ 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 + if any(product[NAME_INDEX] == name for product in storage): + print(f"product name {name!r} is already taken") + return None + product_id = generate_product_id(storage) + storage.append((product_id, name, normalize_price(price), quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -72,8 +80,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию - 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 +110,14 @@ 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 index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + updated = (product_id, name, normalize_price(price), quantity) + storage[index] = updated + return updated + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -116,5 +133,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None: product carried that identifier (``storage`` is left unchanged and a message is printed). """ - # TODO: реализуйте функцию - return 0 + for index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + del storage[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..6fbf19f7 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -6,13 +6,12 @@ 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: @@ -25,5 +24,4 @@ def normalize_price(price: Decimal) -> Decimal: ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, 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..e67db3f5 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -20,13 +20,13 @@ 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, normalize_product_name # noqa: F401 +from .utils import normalize_price, normalize_product_name def generate_product_id(storage: list[Product]) -> int: @@ -40,8 +40,11 @@ def generate_product_id(storage: list[Product]) -> int: :data:`~src.part3.storage.PRODUCT_ID_MIN` when ``storage`` is empty. """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + return ( + max(product[PRODUCT_ID_INDEX] for product in storage) + 1 + if storage + else PRODUCT_ID_MIN + ) def create_product( @@ -64,8 +67,17 @@ def create_product( normalised name already exists. In the ``None`` case ``storage`` is left unchanged and an explanatory message is printed. """ - # TODO: реализуйте функцию - return 0 + name, price, quantity = fields + name = normalize_product_name(name) + if not name: + print("product name must not be blank") + return None + if any(product[NAME_INDEX] == name for product in storage): + print(f"product name {name!r} is already taken") + return None + product_id = generate_product_id(storage) + storage.append((product_id, name, normalize_price(price), quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -80,8 +92,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return (0, "", Decimal(0), 0) + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + return product + print(f"no product with id {product_id}") + return None def update_product( @@ -110,8 +125,25 @@ def update_product( unchanged and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + name, price, quantity = fields + name = normalize_product_name(name) + if not name: + print("product name must not be blank") + return None + for index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] != product_id: + continue + if any( + other[PRODUCT_ID_INDEX] != product_id and other[NAME_INDEX] == name + for other in storage + ): + print(f"product name {name!r} is already taken") + return None + updated = (product_id, name, normalize_price(price), quantity) + storage[index] = updated + return updated + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -127,5 +159,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None: product carried that identifier (``storage`` is left unchanged and a message is printed). """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + for index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + del storage[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..e959bba7 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -2,8 +2,8 @@ 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: +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; @@ -29,22 +29,32 @@ it. """ -from decimal import Decimal, InvalidOperation # noqa: F401 +from decimal import Decimal, InvalidOperation from typing import Final -from .crud import ( # noqa: F401 +from .crud import ( create_product, delete_product, read_product, update_product, ) from .storage import Product -from .utils import get_storage_str_representation # noqa: F401 +from .utils import get_storage_str_representation -# TODO: задайте приглашение и текст справки -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = """Available commands: + help show this message + exit leave the console + show print the whole store as a table + create add a product, print its new id + read print the product with that id + update overwrite that product's fields + delete remove the product with that id + +For create and update the price and quantity are the last two words of the +line; everything before them is the product name, so it may contain spaces +(for example "Gibson SG Junior") and needs no quoting.""" def show_help() -> None: @@ -54,7 +64,7 @@ def show_help() -> None: is: a heading, one line per command with a short description, and a note on how multi-word names are parsed. """ - # TODO: реализуйте функцию + print(HELP_TEXT) def print_result(result: object) -> None: @@ -65,7 +75,8 @@ def print_result(result: object) -> None: operation already reported its own failure, so nothing is printed in that case. """ - # TODO: реализуйте функцию + if result is not None: + print(result) def run_command(storage: list[Product], line: str) -> bool: @@ -88,8 +99,35 @@ def run_command(storage: list[Product], line: str) -> bool: decimal.InvalidOperation: If the price argument of ``create`` or ``update`` does not parse as a decimal number. """ - # TODO: реализуйте функцию - return False + words = line.split() + match words: + case ["help"]: + show_help() + case ["exit"]: + return False + case ["show"]: + print(get_storage_str_representation(storage)) + case ["create", *name, price, quantity] if name: + fields = ( + " ".join(name), + Decimal(price), + int(quantity), + ) + print_result(create_product(storage, fields)) + case ["read", product_id]: + print_result(read_product(storage, int(product_id))) + case ["update", product_id, *name, price, quantity] if name: + fields = ( + " ".join(name), + Decimal(price), + int(quantity), + ) + print_result(update_product(storage, int(product_id), fields)) + case ["delete", product_id]: + print_result(delete_product(storage, int(product_id))) + case _: + print(f"{line!r} is not a command") + return True def main() -> None: diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..c516645b 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -24,12 +24,9 @@ type Product = tuple[int, str, Decimal, int] -# TODO: задайте позиции полей внутри кортежа Product (используйте своё решение -# части 2) PRODUCT_ID_INDEX: Final = 0 -NAME_INDEX: Final = 0 -PRICE_INDEX: Final = 0 -QUANTITY_INDEX: Final = 0 +NAME_INDEX: Final = 1 +PRICE_INDEX: Final = 2 +QUANTITY_INDEX: Final = 3 -# TODO: задайте идентификатор первого товара в пустом хранилище -PRODUCT_ID_MIN: Final[int] = 0 +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part3/utils.py b/src/part3/utils.py index 318ded0b..09f61211 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -18,7 +18,7 @@ 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 @@ -26,16 +26,13 @@ # 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 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: @@ -48,8 +45,7 @@ def normalize_price(price: Decimal) -> Decimal: ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, with halves rounded up. """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return Decimal(0) + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -66,11 +62,7 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + return " ".join(name.split()).lower() def get_storage_str_representation(storage: list[Product]) -> str: @@ -91,5 +83,21 @@ def get_storage_str_representation(storage: list[Product]) -> str: is empty only the header and separator rows are returned, sized to the header labels. """ - # TODO: реализуйте функцию - return "" + rows = [TABLE_HEADERS, *(tuple(map(str, product)) for product in storage)] + widths = tuple( + max(len(row[index]) for row in rows) for index in range(len(TABLE_HEADERS)) + ) + + def format_row(row: tuple[str, ...]) -> str: + return ( + "|" + + "|".join( + f" {value:<{width}} " for value, width in zip(row, widths, strict=True) + ) + + "|" + ) + + separator = "|" + "|".join("-" * (width + 2) for width in widths) + "|" + return "\n".join( + (format_row(TABLE_HEADERS), separator, *(format_row(row) for row in rows[1:])) + ) diff --git a/src/part4/cart.py b/src/part4/cart.py index aed9bb72..b1c15d4d 100644 --- a/src/part4/cart.py +++ b/src/part4/cart.py @@ -9,10 +9,8 @@ an explanatory message to stdout and returns ``None``. """ -from .storage import Product - - -# TODO: при необходимости добавьте свои вспомогательные функции +from .crud import read_product, update_product +from .storage import QUANTITY_KEY, Product def add_to_cart( @@ -46,8 +44,21 @@ def add_to_cart( ``None`` when the product is unknown or the store cannot cover the request. """ - # TODO: реализуйте функцию - return 0 + product = read_product(storage, product_id) + if product is None: + return None + available = product[QUANTITY_KEY] + if available < quantity: + print( + f"not enough stock for product {product_id}: {available} available, " + f"{quantity} requested" + ) + return None + update_product( + storage, product_names, 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 +94,27 @@ 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 + held = cart.get(product_id) + if held is None: + print(f"product {product_id} is not in the cart") + return None + if held < quantity: + print( + f"cart holds only {held} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + product = read_product(storage, product_id) + if product is None: + return None + update_product( + storage, + product_names, + product_id, + {QUANTITY_KEY: product[QUANTITY_KEY] + quantity}, + ) + remaining = held - quantity + if remaining: + cart[product_id] = remaining + else: + del cart[product_id] + return remaining diff --git a/src/part4/crud.py b/src/part4/crud.py index 471eff00..82514634 100644 --- a/src/part4/crud.py +++ b/src/part4/crud.py @@ -23,16 +23,16 @@ than a scan over ``storage.values()``. """ -import uuid # noqa: F401 +import uuid from typing import Any -from .storage import ( # noqa: F401 +from .storage import ( NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product, ) -from .utils import normalize_price, normalize_product_name # noqa: F401 +from .utils import normalize_price, normalize_product_name def generate_product_id() -> str: @@ -41,8 +41,7 @@ def generate_product_id() -> str: Returns: A freshly generated UUID, stringified. """ - # TODO: реализуйте функцию - return "" + return str(uuid.uuid4()) def create_product( @@ -73,8 +72,21 @@ def create_product( and ``product_names`` are left unchanged and an explanatory message is printed. """ - # TODO: реализуйте функцию - return "" + 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!r} 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 +100,10 @@ def read_product(storage: dict[str, Product], product_id: str) -> Product | None The matching product record, or ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию - return {} + product = storage.get(product_id) + if product is None: + print(f"no product with id {product_id}") + return product def update_product( @@ -129,8 +143,28 @@ def update_product( and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию - return {} + product = storage.get(product_id) + if product is None: + print(f"no product with id {product_id}") + return None + + old_name = product[NAME_KEY] + if NAME_KEY in fields: + fields[NAME_KEY] = normalize_product_name(fields[NAME_KEY]) + if not fields[NAME_KEY]: + print("product name must not be blank") + return None + if fields[NAME_KEY] != old_name and fields[NAME_KEY] in product_names: + print(f"product name {fields[NAME_KEY]!r} is already taken") + return None + if PRICE_KEY in fields: + fields[PRICE_KEY] = normalize_price(fields[PRICE_KEY]) + + product.update(fields) + if NAME_KEY in fields and fields[NAME_KEY] != old_name: + product_names.remove(old_name) + product_names.add(fields[NAME_KEY]) + return product def delete_product( @@ -153,5 +187,9 @@ def delete_product( product carried that identifier (``storage`` and ``product_names`` are left unchanged and a message is printed). """ - # TODO: реализуйте функцию - return "" + product = storage.pop(product_id, None) + if product is None: + print(f"no product with id {product_id}") + return None + product_names.remove(product[NAME_KEY]) + return product_id diff --git a/src/part4/run_admin.py b/src/part4/run_admin.py index 2247b29b..157fffe7 100644 --- a/src/part4/run_admin.py +++ b/src/part4/run_admin.py @@ -28,22 +28,32 @@ is left untouched and the loop keeps running; only ``exit`` stops it. """ -from decimal import Decimal, InvalidOperation # noqa: F401 +from decimal import Decimal, InvalidOperation from typing import Final -from .crud import ( # noqa: F401 +from .crud import ( create_product, delete_product, read_product, update_product, ) -from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product # noqa: F401 -from .utils import get_storage_str_representation # noqa: F401 +from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product +from .utils import get_storage_str_representation -# TODO: задайте приглашение и текст справки (используйте своё решение части 3) -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = """Available commands: + help show this message + exit leave the console + show print the whole store as a table + create add a product, print its new id + read print the product with that id + update overwrite that product's fields + delete remove the product with that id + +For create and update the price and quantity are the last two words of the +line; everything before them is the product name, so it may contain spaces +(for example "Gibson SG Junior") and needs no quoting.""" def show_help() -> None: @@ -53,7 +63,7 @@ def show_help() -> None: is: a heading, one line per command with a short description, and a note on how multi-word names are parsed. """ - # TODO: реализуйте функцию (используйте своё решение части 3) + print(HELP_TEXT) def print_result(result: object) -> None: @@ -64,7 +74,8 @@ 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 +102,35 @@ 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 + words = line.split() + match words: + case ["help"]: + show_help() + case ["exit"]: + return False + case ["show"]: + print(get_storage_str_representation(storage)) + case ["create", *name, price, quantity] if name: + fields = { + NAME_KEY: " ".join(name), + PRICE_KEY: Decimal(price), + QUANTITY_KEY: int(quantity), + } + print_result(create_product(storage, product_names, fields)) + case ["read", product_id]: + print_result(read_product(storage, product_id)) + case ["update", product_id, *name, price, quantity] if name: + fields = { + NAME_KEY: " ".join(name), + PRICE_KEY: Decimal(price), + QUANTITY_KEY: int(quantity), + } + print_result(update_product(storage, product_names, product_id, fields)) + case ["delete", product_id]: + print_result(delete_product(storage, product_names, product_id)) + case _: + print(f"{line!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..edbbed94 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(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: @@ -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: @@ -71,11 +67,7 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return "" - - -# TODO: при необходимости добавьте свои вспомогательные функции + return " ".join(name.split()).lower() def get_storage_str_representation(storage: dict[str, Product]) -> str: @@ -96,5 +88,32 @@ def get_storage_str_representation(storage: dict[str, Product]) -> str: ``storage`` is empty only the header and separator rows are returned, sized to the header labels. """ - # TODO: реализуйте функцию (используйте своё решение части 3) - return "" + rows = [ + TABLE_HEADERS, + *( + ( + product_id, + product[NAME_KEY], + str(product[PRICE_KEY]), + str(product[QUANTITY_KEY]), + ) + for product_id, product in storage.items() + ), + ] + widths = tuple( + max(len(row[index]) for row in rows) for index in range(len(TABLE_HEADERS)) + ) + + def format_row(row: tuple[str, ...]) -> str: + return ( + "|" + + "|".join( + f" {value:<{width}} " for value, width in zip(row, widths, strict=True) + ) + + "|" + ) + + separator = "|" + "|".join("-" * (width + 2) for width in widths) + "|" + return "\n".join( + (format_row(TABLE_HEADERS), separator, *(format_row(row) for row in rows[1:])) + ) diff --git a/src/part5/cart.py b/src/part5/cart.py index a2363b3a..de4613cd 100644 --- a/src/part5/cart.py +++ b/src/part5/cart.py @@ -9,10 +9,8 @@ an explanatory message to stdout and returns ``None``. """ -from .storage import Product - - -# TODO: при необходимости добавьте свои вспомогательные функции +from .crud import read_product, update_product +from .storage import QUANTITY_KEY, Product def add_to_cart( @@ -47,8 +45,21 @@ def add_to_cart( ``None`` when the product is unknown or the store cannot cover the request. """ - # TODO: реализуйте функцию (используйте своё решение части 4) - return 0 + product = read_product(storage, product_id) + if product is None: + return None + available = product[QUANTITY_KEY] + if available < quantity: + print( + f"not enough stock for product {product_id}: {available} available, " + f"{quantity} requested" + ) + return None + update_product( + storage, product_names, product_id, {QUANTITY_KEY: available - quantity} + ) + cart[product_id] = cart.get(product_id, 0) + quantity + return cart[product_id] def remove_from_cart( @@ -62,7 +73,8 @@ def remove_from_cart( 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. Otherwise the cart loses + 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. @@ -84,5 +96,27 @@ 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 (используйте своё решение части 4) - return 0 + held = cart.get(product_id) + if held is None: + print(f"product {product_id} is not in the cart") + return None + if held < quantity: + print( + f"cart holds only {held} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + product = read_product(storage, product_id) + if product is None: + return None + update_product( + storage, + product_names, + product_id, + {QUANTITY_KEY: product[QUANTITY_KEY] + quantity}, + ) + remaining = held - quantity + if remaining: + cart[product_id] = remaining + else: + del cart[product_id] + return remaining diff --git a/src/part5/constants.py b/src/part5/constants.py index 984671bb..6a2b9dff 100644 --- a/src/part5/constants.py +++ b/src/part5/constants.py @@ -15,23 +15,22 @@ from typing import Final -# TODO: замените заглушки (0) на корректные значения (используйте своё решение -# части 1). - # 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 +# Field shifts used when packing and unpacking an identifier. +NODE_ID_SHIFT: Final[int] = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT: Final[int] = SEQUENCE_ID_BITS + NODE_ID_BITS diff --git a/src/part5/crud.py b/src/part5/crud.py index 243b0528..89b5df2b 100644 --- a/src/part5/crud.py +++ b/src/part5/crud.py @@ -27,7 +27,7 @@ than a scan over ``storage.values()``. The four store operations (everything except :func:`generate_snowflake_id`) -should be decorated with :func:`~src.part5.decorators.collect_stats`, which +are decorated with :func:`~src.part5.decorators.collect_stats`, which counts their successful calls and their failed ones (those returning ``None``) in the module-level :data:`STATS_REGISTRY`, filed under :data:`CREATE_KEY`, :data:`READ_KEY`, :data:`UPDATE_KEY` and @@ -38,20 +38,30 @@ from collections.abc import Callable from typing import Any, Final -from .decorators import Registry -from .storage import Product +from .decorators import Registry, collect_stats +from .snowflake import get_snowflake_id_generator +from .storage import ( + NAME_KEY, + PRICE_KEY, + QUANTITY_KEY, + Product, +) +from .utils import normalize_price, normalize_product_name +# Counters of the store operations, shared by every store of the process. STATS_REGISTRY: Final[Registry] = {} -# TODO: задайте ключи операций в реестре, см. TASK.md -CREATE_KEY: Final[str] = "" -READ_KEY: Final[str] = "" -UPDATE_KEY: Final[str] = "" -DELETE_KEY: Final[str] = "" +# Registry keys of the four operations; they match the console command names. +CREATE_KEY: Final[str] = "create" +READ_KEY: Final[str] = "read" +UPDATE_KEY: Final[str] = "update" +DELETE_KEY: Final[str] = "delete" -# TODO: при необходимости заведите здесь общий генератор Snowflake-идентификаторов -# для generate_snowflake_id (см. TASK.md) +# The Snowflake generator shared by every call of generate_snowflake_id. +# Created once at import time; None if the default settings turned out +# invalid (in which case the reason was already printed at import). +_snowflake_id_generator: Callable[[], int | None] | None = get_snowflake_id_generator() def generate_snowflake_id() -> int | None: @@ -65,11 +75,12 @@ def generate_snowflake_id() -> int | None: :func:`~src.part5.snowflake.get_snowflake_id_generator` for the cases. """ - # TODO: реализуйте функцию - return 0 + if _snowflake_id_generator is None: + return None + return _snowflake_id_generator() -# TODO: оберните операцию декоратором collect_stats +@collect_stats(CREATE_KEY, STATS_REGISTRY) def create_product( storage: dict[int, Product], product_names: set[str], @@ -104,11 +115,26 @@ def create_product( ``product_names`` are left unchanged and an explanatory message is printed (for the last case, by ``generate_id`` itself). """ - # TODO: реализуйте функцию - return 0 - - -# TODO: оберните операцию декоратором collect_stats + 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!r} is already taken") + return None + product_id = generate_id() + if product_id is None: + return None + 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 + + +@collect_stats(READ_KEY, STATS_REGISTRY) def read_product(storage: dict[int, Product], product_id: int) -> Product | None: """Return the product stored under ``product_id``. @@ -120,11 +146,13 @@ def read_product(storage: dict[int, Product], product_id: int) -> Product | None The matching product record, or ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию (используйте своё решение части 4) - return {} + product = storage.get(product_id) + if product is None: + print(f"no product with id {product_id}") + return product -# TODO: оберните операцию декоратором collect_stats +@collect_stats(UPDATE_KEY, STATS_REGISTRY) def update_product( storage: dict[int, Product], product_names: set[str], @@ -162,11 +190,31 @@ def update_product( and an explanatory message is printed. Renaming a product to its own current name is allowed. """ - # TODO: реализуйте функцию (используйте своё решение части 4) - return {} - - -# TODO: оберните операцию декоратором collect_stats + product = storage.get(product_id) + if product is None: + print(f"no product with id {product_id}") + return None + + old_name = product[NAME_KEY] + if NAME_KEY in fields: + fields[NAME_KEY] = normalize_product_name(fields[NAME_KEY]) + if not fields[NAME_KEY]: + print("product name must not be blank") + return None + if fields[NAME_KEY] != old_name and fields[NAME_KEY] in product_names: + print(f"product name {fields[NAME_KEY]!r} is already taken") + return None + if PRICE_KEY in fields: + fields[PRICE_KEY] = normalize_price(fields[PRICE_KEY]) + + product.update(fields) + if NAME_KEY in fields and fields[NAME_KEY] != old_name: + product_names.remove(old_name) + product_names.add(fields[NAME_KEY]) + return product + + +@collect_stats(DELETE_KEY, STATS_REGISTRY) def delete_product( storage: dict[int, Product], product_names: set[str], @@ -187,5 +235,9 @@ def delete_product( product carried that identifier (``storage`` and ``product_names`` are left unchanged and a message is printed). """ - # TODO: реализуйте функцию (используйте своё решение части 4) - return 0 + product = storage.pop(product_id, None) + if product is None: + print(f"no product with id {product_id}") + return None + product_names.remove(product[NAME_KEY]) + return product_id diff --git a/src/part5/decorators.py b/src/part5/decorators.py index 21a9f237..82bc6ea8 100644 --- a/src/part5/decorators.py +++ b/src/part5/decorators.py @@ -14,15 +14,19 @@ """ from collections.abc import Callable +from functools import wraps from typing import Final -# TODO: задайте имена двух счётчиков, см. TASK.md -SUCCESS_KEY: Final[str] = "" -FAILS_KEY: Final[str] = "" +# Names of the two counters kept in a Stats record. +SUCCESS_KEY: Final[str] = "success" +FAILS_KEY: Final[str] = "fails" +# Counters of one function: how many calls succeeded and how many failed. type Stats = dict[str, int] + +# Counters of every registered function, keyed by the registration key. type Registry = dict[str, Stats] @@ -53,5 +57,23 @@ def collect_stats[**P, R]( ``None``. The decorated function has the same signature, name and docstring as the original (see :func:`functools.wraps`). """ - # TODO: реализуйте декоратор - return lambda function: function + + def decorator(function: Callable[P, R | None]) -> Callable[P, R | None]: + if key in registry: + print(f"stats key {key!r} is already registered") + return function + + registry[key] = {SUCCESS_KEY: 0, FAILS_KEY: 0} + + @wraps(function) + def wrapper(*args: P.args, **kwargs: P.kwargs) -> R | None: + result = function(*args, **kwargs) + if result is None: + registry[key][FAILS_KEY] += 1 + else: + registry[key][SUCCESS_KEY] += 1 + return result + + return wrapper + + return decorator diff --git a/src/part5/run_admin.py b/src/part5/run_admin.py index d2e83947..734d98e3 100644 --- a/src/part5/run_admin.py +++ b/src/part5/run_admin.py @@ -36,16 +36,35 @@ is left untouched and the loop keeps running; only ``exit`` stops it. """ -from decimal import InvalidOperation +from decimal import Decimal, InvalidOperation from typing import Final -from .storage import Product - - -# TODO: задайте приглашение и текст справки (используйте своё решение части 4, -# не забудьте добавить команду stats, см. TASK.md) -PROMPT: Final[str] = "" -HELP_TEXT: Final[str] = "" +from .crud import ( + STATS_REGISTRY, + create_product, + delete_product, + generate_snowflake_id, + read_product, + update_product, +) +from .storage import NAME_KEY, PRICE_KEY, QUANTITY_KEY, Product +from .utils import get_stats_str_representation, get_storage_str_representation + + +PROMPT: Final[str] = "admin> " +HELP_TEXT: Final[str] = """Available commands: + help show this message + exit leave the console + show print the whole store as a table + create add a product, print its new id + read print the product with that id + update overwrite that product's fields + delete remove the product with that id + stats print call statistics of the CRUD commands + +For create and update the price and quantity are the last two words of the +line; everything before them is the product name, so it may contain spaces +(for example "Gibson SG Junior") and needs no quoting.""" def show_help() -> None: @@ -55,7 +74,7 @@ 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 4) + print(HELP_TEXT) def print_result(result: object) -> None: @@ -66,7 +85,8 @@ 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 4) + if result is not None: + print(result) def run_command( @@ -93,8 +113,41 @@ 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 + words = line.split() + match words: + case ["help"]: + show_help() + case ["exit"]: + return False + case ["show"]: + print(get_storage_str_representation(storage)) + case ["create", *name, price, quantity] if name: + fields = { + NAME_KEY: " ".join(name), + PRICE_KEY: Decimal(price), + QUANTITY_KEY: int(quantity), + } + print_result( + create_product(storage, product_names, fields, generate_snowflake_id) + ) + case ["read", product_id]: + print_result(read_product(storage, int(product_id))) + case ["update", product_id, *name, price, quantity] if name: + fields = { + NAME_KEY: " ".join(name), + PRICE_KEY: Decimal(price), + QUANTITY_KEY: int(quantity), + } + print_result( + update_product(storage, product_names, int(product_id), fields) + ) + case ["delete", product_id]: + print_result(delete_product(storage, product_names, int(product_id))) + case ["stats"]: + print(get_stats_str_representation(STATS_REGISTRY)) + case _: + print(f"{line!r} is not a command") + return True def main() -> None: diff --git a/src/part5/snowflake.py b/src/part5/snowflake.py index 64e28468..78e62ce0 100644 --- a/src/part5/snowflake.py +++ b/src/part5/snowflake.py @@ -14,9 +14,18 @@ :func:`decode_node_id` and :func:`decode_sequence_id`. """ +import time from collections.abc import Callable -from .constants import EPOCH_MS_DEFAULT, NODE_ID_DEFAULT +from .constants import ( + EPOCH_MS_DEFAULT, + NODE_ID_DEFAULT, + NODE_ID_MAX, + NODE_ID_SHIFT, + SEQUENCE_ID_MAX, + TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, +) def read_current_millis(epoch_ms: int) -> int: @@ -29,8 +38,7 @@ def read_current_millis(epoch_ms: int) -> int: The count of whole milliseconds between ``epoch_ms`` and now. Negative if ``epoch_ms`` lies in the future. """ - # TODO: реализуйте функцию (используйте своё решение части 1) - return 0 + return int(time.time() * 1000) - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -45,8 +53,7 @@ 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 (используйте своё решение части 1) - return 0 + return (snowflake_id >> TIMESTAMP_SHIFT) + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -60,8 +67,7 @@ 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 (используйте своё решение части 1) - return 0 + return (snowflake_id >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: @@ -75,8 +81,7 @@ 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 (используйте своё решение части 1) - return 0 + return snowflake_id & SEQUENCE_ID_MAX def get_snowflake_id_generator( @@ -108,5 +113,34 @@ def get_snowflake_id_generator( to stdout, if ``node_id`` is outside ``[0, NODE_ID_MAX]`` or ``epoch_ms`` lies in the future. """ - # TODO: реализуйте функцию - return lambda: 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 read_current_millis(epoch_ms) < 0: + print(f"epoch_ms must not be in the future, got {epoch_ms}") + return None + + last_ms: int | None = None + sequence_id = 0 + + def generate_snowflake_id() -> int | None: + nonlocal last_ms, sequence_id + + ms = read_current_millis(epoch_ms) + if ms == last_ms and sequence_id > SEQUENCE_ID_MAX: + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + if ms > TIMESTAMP_MS_MAX: + print(f"timestamp {ms} ms overflows {TIMESTAMP_MS_MAX} ms") + return None + if ms != last_ms: + last_ms = ms + sequence_id = 0 + + snowflake_id = ( + (ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id + ) + sequence_id += 1 + return snowflake_id + + return generate_snowflake_id diff --git a/src/part5/storage.py b/src/part5/storage.py index fa8ef3bb..b59f0a19 100644 --- a/src/part5/storage.py +++ b/src/part5/storage.py @@ -38,7 +38,7 @@ type Product = dict[str, Any] -# TODO: задайте имена полей записи (используйте своё решение части 4) -NAME_KEY: Final = "" -PRICE_KEY: Final = "" -QUANTITY_KEY: Final = "" +# Name of each field inside a Product record. +NAME_KEY: Final = "name" +PRICE_KEY: Final = "price" +QUANTITY_KEY: Final = "quantity" diff --git a/src/part5/utils.py b/src/part5/utils.py index b2ad4dc4..3620e374 100644 --- a/src/part5/utils.py +++ b/src/part5/utils.py @@ -21,23 +21,39 @@ look, with the success rate of every command as a percentage. """ -from decimal import Decimal +from decimal import ROUND_HALF_UP, Decimal from typing import Final -from .decorators import Registry -from .storage import Product +from .decorators import FAILS_KEY, SUCCESS_KEY, Registry +from .storage import ( + NAME_KEY, + PRICE_KEY, + QUANTITY_KEY, + Product, +) -# TODO: задайте число знаков после запятой и шаг квантования (используйте своё -# решение части 4) -PRICE_PRECISION: Final[int] = 0 -PRICE_STEP: Final = Decimal(0) +# Number of fractional digits every stored price is rounded to. +# Quantisation step derived from PRICE_PRECISION, e.g. Decimal("0.01"). +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). +TABLE_HEADERS: Final[tuple[str, ...]] = ("ID", "name", "price", "quantity") -# TODO: задайте заголовки столбцов таблицы (используйте своё решение части 4) -TABLE_HEADERS: Final[tuple[str, ...]] = () -# TODO: задайте заголовки столбцов таблицы статистики, см. TASK.md -STATS_TABLE_HEADERS: Final[tuple[str, ...]] = () +# Column headers of the table produced by get_stats_str_representation, +# left to right; measured per call the same way as TABLE_HEADERS. +STATS_TABLE_HEADERS: Final[tuple[str, ...]] = ( + "command name", + "success", + "fails", + "success rate", +) + +# Step the success rate percentage is rounded to, e.g. Decimal("0.01"). +_STATS_RATE_STEP: Final = Decimal(1).scaleb(-2) def normalize_price(price: Decimal) -> Decimal: @@ -50,8 +66,7 @@ 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 4) - return Decimal(0) + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -68,11 +83,44 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию (используйте своё решение части 4) - return "" + return " ".join(name.split()).lower() + +def _render_table(headers: tuple[str, ...], rows: tuple[tuple[str, ...], ...]) -> str: + """Lay out a header row, a dashed separator and ``rows`` as a table. -# TODO: при необходимости добавьте свои вспомогательные функции + Every column is made exactly as wide as the longest value it carries + in this call, its header counted, and each cell is padded with one + space on both sides. + + Args: + headers: The labels of the columns, left to right. + rows: One tuple of cell values per data row; each as wide as + ``headers``. + + Returns: + The rendered multi-line string without a trailing newline. When + ``rows`` is empty only the header and separator lines remain, + sized to the header labels. + """ + table = (headers, *rows) + widths = tuple( + max(len(row[index]) for row in table) for index in range(len(headers)) + ) + + def format_row(row: tuple[str, ...]) -> str: + return ( + "|" + + "|".join( + f" {value:<{width}} " for value, width in zip(row, widths, strict=True) + ) + + "|" + ) + + separator = "|" + "|".join("-" * (width + 2) for width in widths) + "|" + return "\n".join( + (format_row(headers), separator, *(format_row(row) for row in rows)) + ) def get_storage_str_representation(storage: dict[int, Product]) -> str: @@ -93,8 +141,35 @@ def get_storage_str_representation(storage: dict[int, 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 4) - return "" + rows = tuple( + ( + str(product_id), + product[NAME_KEY], + str(product[PRICE_KEY]), + str(product[QUANTITY_KEY]), + ) + for product_id, product in storage.items() + ) + return _render_table(TABLE_HEADERS, rows) + + +def _format_success_rate(success: int, fails: int) -> str: + """Format the share of successful calls as a percentage. + + Args: + success: The number of successful calls. + fails: The number of failed calls. + + Returns: + ``success`` out of all calls as a percentage with exactly two + fractional digits and a ``%`` sign, halves rounded up. A function + that was never called yields ``0.00%`` rather than an error. + """ + total = success + fails + if not total: + return "0.00%" + rate = Decimal(success * 100) / Decimal(total) + return f"{rate.quantize(_STATS_RATE_STEP, rounding=ROUND_HALF_UP)}%" def get_stats_str_representation(registry: Registry) -> str: @@ -116,5 +191,13 @@ def get_stats_str_representation(registry: Registry) -> str: empty only the header and separator rows are returned, sized to the header labels. """ - # TODO: реализуйте функцию - return "" + rows = tuple( + ( + key, + str(stats[SUCCESS_KEY]), + str(stats[FAILS_KEY]), + _format_success_rate(stats[SUCCESS_KEY], stats[FAILS_KEY]), + ) + for key, stats in registry.items() + ) + return _render_table(STATS_TABLE_HEADERS, rows)