diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..22c27cee 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,20 @@ # Все константы, зависящие от ёмкостей *_BITS, должны вычисляться из них. # Twitter's original Snowflake epoch: 2010-11-04 01:42:54.657 UTC. -EPOCH_MS_DEFAULT: Final[int] = 0 +EPOCH_MS_DEFAULT: Final[int] = 1288834974657 # Node identifier used when the caller does not supply one. -NODE_ID_DEFAULT: Final[int] = 0 +NODE_ID_DEFAULT: Final[int] = 1 # Width of each field, in bits. -TIMESTAMP_BITS: Final[int] = 0 -NODE_ID_BITS: Final[int] = 0 -SEQUENCE_ID_BITS: Final[int] = 0 +TIMESTAMP_BITS: Final[int] = 41 +NODE_ID_BITS: Final[int] = 10 +SEQUENCE_ID_BITS: Final[int] = 12 # Largest value each field can hold. -TIMESTAMP_MS_MAX: Final[int] = 0 -NODE_ID_MAX: Final[int] = 0 -SEQUENCE_ID_MAX: Final[int] = 0 +TIMESTAMP_MS_MAX: Final[int] = 2**41 - 1 +NODE_ID_MAX: Final[int] = 2**10 - 1 +SEQUENCE_ID_MAX: Final[int] = 2**12 - 1 # Здесь можно добавить собственные вспомогательные константы # (например, сдвиги полей при сборке идентификатора). diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..8c015a63 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,12 +13,17 @@ :func:`decode_node_id` and :func:`decode_sequence_id`. """ -import time # noqa: F401 +import time -from .constants import ( # noqa: F401 +from .constants import ( + # Epoch EPOCH_MS_DEFAULT, + # Node ID + NODE_ID_BITS, NODE_ID_DEFAULT, NODE_ID_MAX, + # Sequence ID + SEQUENCE_ID_BITS, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, ) @@ -35,7 +40,8 @@ def read_current_millis(epoch_ms: int) -> int: negative if ``epoch_ms`` lies in the future. """ # TODO: реализуйте функцию - return 0 + a = (time.time_ns() // 1000000) - epoch_ms + return a def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -51,7 +57,8 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> generated. """ # TODO: реализуйте функцию - return 0 + epoch_time = snowflake_id >> (SEQUENCE_ID_BITS + NODE_ID_BITS) + return epoch_time + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -65,7 +72,8 @@ def decode_node_id(snowflake_id: int) -> int: ``[0, NODE_ID_MAX]``. """ # TODO: реализуйте функцию - return 0 + node_num = (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_MAX + return node_num def decode_sequence_id(snowflake_id: int) -> int: @@ -79,7 +87,8 @@ def decode_sequence_id(snowflake_id: int) -> int: the range ``[0, SEQUENCE_ID_MAX]``. """ # TODO: реализуйте функцию - return 0 + seq_id = snowflake_id & SEQUENCE_ID_MAX + return seq_id def generate_snowflake_id( @@ -111,4 +120,19 @@ def generate_snowflake_id( 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 + elif not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + a = (time.time_ns() // 1000000) - epoch_ms + if a > TIMESTAMP_MS_MAX: + print("overflows") + return None + else: + return ( + (a << (NODE_ID_BITS + SEQUENCE_ID_BITS)) + | (node_id << SEQUENCE_ID_BITS) + | sequence_id + ) diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..0fac6e6b 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, @@ -24,7 +24,17 @@ # TODO: задайте позиции полей внутри кортежа CartLine LINE_PRODUCT_ID_INDEX: Final = 0 -LINE_QUANTITY_INDEX: Final = 0 +LINE_QUANTITY_INDEX: Final = 1 + + +def find_cart_line( + cart: list[CartLine], + product_id: int, +) -> CartLine | None: + for cart_line in cart: + if cart_line[LINE_PRODUCT_ID_INDEX] == product_id: + return cart_line + return None def add_to_cart( @@ -54,7 +64,33 @@ def add_to_cart( 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 + stock = product[QUANTITY_INDEX] + if stock < quantity: + print( + f"not enough stock for product {product_id}: {stock} available, {quantity} requested" + ) + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], stock - quantity), + ) + cart_line = find_cart_line(cart, product_id) + + if cart_line is not None: + new_cart_line = (product_id, quantity + cart_line[LINE_QUANTITY_INDEX]) + for i in range(len(cart)): + if cart[i][LINE_PRODUCT_ID_INDEX] == product_id: + cart[i] = new_cart_line + return new_cart_line + else: + new_cart_line = (product_id, quantity) + cart.append(new_cart_line) + return new_cart_line def remove_from_cart( @@ -86,4 +122,33 @@ def remove_from_cart( line for the product or holds too few units. """ # TODO: реализуйте функцию - return (0, 0) + cart_line = find_cart_line(cart, product_id) + + if cart_line is None: + print(f"product {product_id} is not in the cart") + return None + stock_in_cart = cart_line[LINE_QUANTITY_INDEX] + if stock_in_cart < quantity: + print( + f"cart holds only {stock_in_cart} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + product = read_product(storage, product_id) + if product is None: + return None + stock_in_product = product[QUANTITY_INDEX] + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], stock_in_product + quantity), + ) + + new_cart_line = (product_id, stock_in_cart - quantity) + index_cart_line = cart.index(cart_line) + + if (stock_in_cart - quantity) != 0: + cart[index_cart_line] = new_cart_line + else: + cart.pop(index_cart_line) + + return new_cart_line diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..38544578 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: @@ -35,7 +35,9 @@ def generate_product_id(storage: list[Product]) -> int: 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( @@ -57,7 +59,16 @@ def create_product( name is printed. """ # TODO: реализуйте функцию - return 0 + + name, price, quan = fields + n_id = generate_product_id(storage) + + if any(product[NAME_INDEX] == name for product in storage): + print(f"product name '{name}' is already taken") + return None + + storage.append((n_id, name, normalize_price(price), quan)) + return n_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -73,7 +84,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: 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( @@ -100,7 +115,14 @@ def update_product( left unchanged and a message is printed). """ # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + name, price, qual = fields + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + update = (product_id, name, normalize_price(price), qual) + storage[i] = update + return update + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -117,4 +139,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None: a message is printed). """ # TODO: реализуйте функцию - return 0 + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + storage.remove(product) + return product_id + print(f"no product with id {product_id}") + return None diff --git a/src/part2/storage.py b/src/part2/storage.py index b63d5fc7..35821c5f 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -26,9 +26,9 @@ # TODO: задайте позиции полей внутри кортежа Product PRODUCT_ID_INDEX: Final = 0 -NAME_INDEX: Final = 0 -PRICE_INDEX: Final = 0 -QUANTITY_INDEX: Final = 0 +NAME_INDEX: Final = 1 +PRICE_INDEX: Final = 2 +QUANTITY_INDEX: Final = 3 # TODO: задайте идентификатор первого товара в пустом хранилище -PRODUCT_ID_MIN: Final[int] = 0 +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part2/utils.py b/src/part2/utils.py index 11bd7a76..2b6aa266 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 +26,4 @@ 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..2472e2ef 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -1,32 +1,26 @@ """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 +:data:`~src.part2.storage.Product` tuples -- as its first argument and works on it in place. The failure path never raises: the operation prints an explanatory message to stdout and returns ``None``. The identifier of a new product is derived from the store itself (:func:`generate_product_id`): one past the greatest identifier in use, or -:data:`~src.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. +:data:`~src.part2.storage.PRODUCT_ID_MIN` when the store is empty. +Product names are kept unique -- :func:`create_product` refuses a name that +is already taken. """ from decimal import Decimal -from .storage import ( # noqa: F401 +from .storage import ( NAME_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, Product, ) -from .utils import normalize_price, normalize_product_name # noqa: F401 +from .utils import normalize_price, normalize_product_name def generate_product_id(storage: list[Product]) -> int: @@ -37,11 +31,13 @@ def generate_product_id(storage: list[Product]) -> int: Returns: One past the greatest identifier currently held in ``storage``, or - :data:`~src.part3.storage.PRODUCT_ID_MIN` when ``storage`` is + :data:`~src.part2.storage.PRODUCT_ID_MIN` when ``storage`` is empty. """ - # TODO: реализуйте функцию (используйте своё решение части 2) - return 0 + # TODO: реализуйте функцию + if not storage: + return PRODUCT_ID_MIN + return max(product[PRODUCT_ID_INDEX] for product in storage) + 1 def create_product( @@ -53,19 +49,31 @@ def create_product( 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. + ``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. + The identifier generated for the new product, or ``None`` when a + product with the same name already exists. In the ``None`` case + ``storage`` is left unchanged and a message naming the clashing + name is printed. """ # TODO: реализуйте функцию - return 0 + + name1, price, quan = fields + name = normalize_product_name(name1) + + if 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}' is already taken") + return None + + n_id = generate_product_id(storage) + storage.append((n_id, name, normalize_price(price), quan)) + return n_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -80,8 +88,12 @@ 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 (используйте своё решение части 2) - return (0, "", Decimal(0), 0) + # TODO: реализуйте функцию + 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( @@ -104,14 +116,37 @@ def update_product( 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. + ``None`` when no product carries that identifier (``storage`` is + left unchanged and a message is printed). """ # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + name1, price, qual = fields + name = normalize_product_name(name1) + + if name == "": + print("product name must not be blank") + return None + + index = None + for i, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + index = i + break + + if index is None: + print(f"no product with id {product_id}") + return None + + if any( + product[NAME_INDEX] == name and product[PRODUCT_ID_INDEX] != product_id + for product in storage + ): + print(f"product name '{name}' is already taken") + return None + + updated = (product_id, name, normalize_price(price), qual) + storage[index] = updated + return updated def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -127,5 +162,10 @@ 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 (используйте своё решение части 2) - return 0 + # TODO: реализуйте функцию + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + storage.remove(product) + return product_id + print(f"no product with id {product_id}") + return None diff --git a/src/part3/run_admin.py b/src/part3/run_admin.py index c5feeb0b..626a678c 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -29,22 +29,33 @@ 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: @@ -55,6 +66,7 @@ def show_help() -> None: note on how multi-word names are parsed. """ # TODO: реализуйте функцию + print(HELP_TEXT) def print_result(result: object) -> None: @@ -66,6 +78,8 @@ def print_result(result: object) -> None: printed in that case. """ # TODO: реализуйте функцию + if result is not None: + print(result) def run_command(storage: list[Product], line: str) -> bool: @@ -89,7 +103,49 @@ def run_command(storage: list[Product], line: str) -> bool: ``update`` does not parse as a decimal number. """ # TODO: реализуйте функцию - return False + + if line == "exit": + return False + if line == "help": + show_help() + return True + if line == "show": + print(get_storage_str_representation(storage)) + return True + + words = line.split() + + if len(words) >= 4 and words[0] == "create": + name = " ".join(words[1:-2]) + price = Decimal(words[-2]) + quantity = int(words[-1]) + result: object = create_product(storage, (name, price, quantity)) + print_result(result) + return True + + if len(words) == 2 and words[0] == "read": + product_id = int(words[1]) + result = read_product(storage, product_id) + print_result(result) + return True + + if len(words) >= 5 and words[0] == "update": + product_id = int(words[1]) + name = " ".join(words[2:-2]) + price = Decimal(words[-2]) + quantity = int(words[-1]) + result = update_product(storage, product_id, (name, price, quantity)) + print_result(result) + return True + + if len(words) == 2 and words[0] == "delete": + product_id = int(words[1]) + result = delete_product(storage, product_id) + print_result(result) + return True + + print(f"{line!s} is not a command") + return True def main() -> None: diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..36e9af7f 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -27,9 +27,9 @@ # 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..f2fbf0a3 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 @@ -28,14 +28,14 @@ # 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 +48,8 @@ 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) + # TODO: реализуйте функцию + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -67,7 +67,7 @@ def normalize_product_name(name: str) -> str: whitespace. """ # TODO: реализуйте функцию - return "" + return " ".join(name.split()).lower() # TODO: при необходимости добавьте свои вспомогательные функции @@ -92,4 +92,46 @@ def get_storage_str_representation(storage: list[Product]) -> str: the header labels. """ # TODO: реализуйте функцию - return "" + ids = [] + names = [] + prices = [] + quantitys = [] + + for product in storage: + ids.append(str(product[0])) + names.append(product[1]) + prices.append(str(product[2])) + quantitys.append(str(product[3])) + + w_id = max(len(TABLE_HEADERS[0]), max((len(x) for x in ids), default=0)) + w_name = max(len(TABLE_HEADERS[1]), max((len(x) for x in names), default=0)) + w_pr = max(len(TABLE_HEADERS[2]), max((len(x) for x in prices), default=0)) + w_qty = max(len(TABLE_HEADERS[3]), max((len(x) for x in quantitys), default=0)) + + change_str_main = ( + f"| {TABLE_HEADERS[0].ljust(w_id)} " + f"| {TABLE_HEADERS[1].ljust(w_name)} " + f"| {TABLE_HEADERS[2].ljust(w_pr)} " + f"| {TABLE_HEADERS[3].ljust(w_qty)} |" + ) + + change_str_dif = ( + f"|{'-' * (w_id + 2)}" + f"|{'-' * (w_name + 2)}" + f"|{'-' * (w_pr + 2)}" + f"|{'-' * (w_qty + 2)}|" + ) + + rows = [] + for i in range(len(storage)): + row = ( + f"| {ids[i].ljust(w_id)} " + f"| {names[i].ljust(w_name)} " + f"| {prices[i].ljust(w_pr)} " + f"| {quantitys[i].ljust(w_qty)} |" + ) + rows.append(row) + + res = "\n".join([change_str_main, change_str_dif, *rows]) + + return res