diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..fec8d028 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,25 @@ # 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). + +# Shift amounts +SEQUENCE_ID_SHIFT = 0 +NODE_ID_SHIFT = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT = SEQUENCE_ID_BITS + NODE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..979a38a0 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,14 +13,16 @@ :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 +36,7 @@ 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 + return int(time.time() * 1000) - 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 + stored_ms = (snowflake_id >> TIMESTAMP_SHIFT) & TIMESTAMP_MS_MAX + return stored_ms + 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 >> 0) & SEQUENCE_ID_MAX def generate_snowflake_id( @@ -110,5 +109,25 @@ 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 + + elapsed_ms = read_current_millis(epoch_ms) + if elapsed_ms > TIMESTAMP_MS_MAX: + print( + f"timestamp overflows: elapsed {elapsed_ms} ms exceeds \n\ + TIMESTAMP_MS_MAX ({TIMESTAMP_MS_MAX})" + ) + return None + + snowflake_id = ( + (elapsed_ms << TIMESTAMP_SHIFT) + | (node_id << NODE_ID_SHIFT) + | (sequence_id << 0) + ) + return snowflake_id diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..f915a397 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: + for line in cart: + if line[LINE_PRODUCT_ID_INDEX] == product_id: + return line + return 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 not product: + return None + if product[QUANTITY_INDEX] < quantity: + print( + f"not enough stock for product {product_id}: {product[QUANTITY_INDEX]} available, {quantity} requested" + ) + return None + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] - quantity), + ) + + line = find_cart_line(cart, product_id) + if line: + cart.remove(line) + updated_line = (product_id, line[LINE_QUANTITY_INDEX] + quantity) + cart.append(updated_line) + return updated_line + else: + new_line = (product_id, quantity) + cart.append(new_line) + return new_line def remove_from_cart( @@ -85,5 +113,32 @@ 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 not line: + print(f"product {product_id} is not in the cart") + return None + + if line[LINE_QUANTITY_INDEX] < quantity: + print( + f"cart holds only {line[LINE_QUANTITY_INDEX]} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + + product = read_product(storage, product_id) + if not product: + print("read_product") + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] + quantity), + ) + + cart.remove(line) + if line[LINE_QUANTITY_INDEX] - quantity == 0: + return (product_id, 0) + + updated_line = (product_id, line[LINE_QUANTITY_INDEX] - quantity) + cart.append(updated_line) + return updated_line diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..181f2c63 100644 --- a/src/part2/crud.py +++ b/src/part2/crud.py @@ -14,13 +14,15 @@ from decimal import Decimal -from .storage import ( # noqa: F401 +from .storage import ( NAME_INDEX, + PRICE_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, + QUANTITY_INDEX, Product, ) -from .utils import normalize_price # noqa: F401 +from .utils import normalize_price def generate_product_id(storage: list[Product]) -> int: @@ -34,8 +36,9 @@ 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 +59,17 @@ 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) + price = normalize_price(price) + storage.append((product_id, name, price, quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -72,8 +84,16 @@ 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[PRODUCT_ID_INDEX], + product[NAME_INDEX], + product[PRICE_INDEX], + product[QUANTITY_INDEX], + ) + print(f"no product with id {product_id}") + return None def update_product( @@ -99,8 +119,18 @@ 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) + for ind, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + updated_product = ( + product_id, + fields[0], + normalize_price(fields[1]), + fields[2], + ) + storage[ind] = updated_product + return storage[ind] + print(f"no product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -116,5 +146,9 @@ 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 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..74ca50e5 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -24,11 +24,11 @@ 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..ba133eb1 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, ROUND_HALF_UP) diff --git a/src/part3/crud.py b/src/part3/crud.py index 68811d7e..9abe5eb6 100644 --- a/src/part3/crud.py +++ b/src/part3/crud.py @@ -20,13 +20,15 @@ from decimal import Decimal -from .storage import ( # noqa: F401 +from .storage import ( NAME_INDEX, + PRICE_INDEX, PRODUCT_ID_INDEX, PRODUCT_ID_MIN, + QUANTITY_INDEX, 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 +42,9 @@ 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 + if not storage: + return PRODUCT_ID_MIN + return max(product[PRODUCT_ID_INDEX] for product in storage) + 1 def create_product( @@ -64,8 +67,22 @@ 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 + raw_name, price, quantity = fields + name = normalize_product_name(raw_name) + + if not name: + print("product name must not be blank") + return None + + 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) + price = normalize_price(price) + storage.append((product_id, name, price, quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -80,8 +97,16 @@ 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[PRODUCT_ID_INDEX], + product[NAME_INDEX], + product[PRICE_INDEX], + product[QUANTITY_INDEX], + ) + print(f"no product with id {product_id}") + return None def update_product( @@ -110,8 +135,28 @@ 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) + raw_name, price, quantity = fields + name = normalize_product_name(raw_name) + price = normalize_price(price) + + target_index: int | None = None + for index, product in enumerate(storage): + if product[PRODUCT_ID_INDEX] == product_id: + target_index = index + break + + if target_index is None: + print(f"no product with id {product_id}") + return None + + for product in storage: + if product[NAME_INDEX] == name and product[PRODUCT_ID_INDEX] != product_id: + print(f"product name '{name}' is already taken") + return None + + updated = (product_id, name, price, quantity) + storage[target_index] = updated + return updated def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -127,5 +172,9 @@ 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 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..85fa1641 100644 --- a/src/part3/run_admin.py +++ b/src/part3/run_admin.py @@ -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 +99,60 @@ 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() + + if not words: + print(f"'{line}' is not a command") + return True + + command = words[0] + + match command: + case "help" if len(words) == 1: + show_help() + return True + + case "exit" if len(words) == 1: + return False + + case "show" if len(words) == 1: + print(get_storage_str_representation(storage)) + return True + + case "create" if len(words) >= 4: + name = " ".join(words[1:-2]) + price = Decimal(words[-2]) + quantity = int(words[-1]) + result: int | Product | None = create_product( + storage, (name, price, quantity) + ) + print_result(result) + return True + + case "read" if len(words) == 2: + product_id = int(words[1]) + result = read_product(storage, product_id) + print_result(result) + return True + + case "update" if len(words) >= 5: + 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 + + case "delete" if len(words) == 2: + product_id = int(words[1]) + result = delete_product(storage, product_id) + print_result(result) + return True + + case _: + print(f"'{line}' is not a command") + return True def main() -> None: diff --git a/src/part3/storage.py b/src/part3/storage.py index c5e34be5..319eab75 100644 --- a/src/part3/storage.py +++ b/src/part3/storage.py @@ -24,12 +24,11 @@ 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..9764c47f 100644 --- a/src/part3/utils.py +++ b/src/part3/utils.py @@ -18,24 +18,17 @@ 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 re import sub 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: @@ -48,8 +41,7 @@ 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, ROUND_HALF_UP) def normalize_product_name(name: str) -> str: @@ -66,11 +58,16 @@ def normalize_product_name(name: str) -> str: The result is an empty string when ``name`` holds nothing but whitespace. """ - # TODO: реализуйте функцию - return "" + return sub(r"\s+", " ", name.strip()).lower() -# TODO: при необходимости добавьте свои вспомогательные функции +def format_row(values: list[str] | tuple[str, ...], widths: list[int]) -> str: + cells = [values[i].ljust(widths[i]) for i in range(len(widths))] + return "| " + " | ".join(cells) + " |" + + +def separator(widths: list[int]) -> str: + return "|" + "|".join(["-" * (w + 2) for w in widths]) + "|" def get_storage_str_representation(storage: list[Product]) -> str: @@ -91,5 +88,24 @@ 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: list[list[str]] = [] + for product in storage: + rows.append( + [ + str(product[PRODUCT_ID_INDEX]), + str(product[NAME_INDEX]), + str(product[PRICE_INDEX]), + str(product[QUANTITY_INDEX]), + ] + ) + + widths = [len(h) for h in TABLE_HEADERS] + for row in rows: + for i, value in enumerate(row): + widths[i] = max(widths[i], len(value)) + + lines = [format_row(TABLE_HEADERS, widths), separator(widths)] + for row in rows: + lines.append(format_row(row, widths)) + + return "\n".join(lines)