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)