1. Ларин Сергей Сергеевич 612.

src/part1/constants.py

@@ -1,38 +1,23 @@
-"""Bit layout and default epoch for the Twitter Snowflake ID generator.
-
-A Snowflake identifier is a 63-bit positive integer packed as follows, from
-the most significant bit downwards:
-
-    1 bit   unused sign bit, always zero
-    41 bits milliseconds elapsed since a custom epoch
-    10 bits node identifier
-    12 bits per-millisecond sequence counter
-
-The shift and mask constants should be derived from the bit widths so that
-changing a width keeps everything else consistent.
-"""
-
 from typing import Final
 
 
-# TODO: замените заглушки (0) на корректные значения, см. TASK.md.
-# Все константы, зависящие от ёмкостей *_BITS, должны вычисляться из них.
+def bits_value_max(n: int) -> int:
+    return 2**n - 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] = 1219190400
 
 # 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] = bits_value_max(TIMESTAMP_BITS)
+NODE_ID_MAX: Final[int] = bits_value_max(NODE_ID_BITS)
+SEQUENCE_ID_MAX: Final[int] = bits_value_max(SEQUENCE_ID_BITS)
 
-# Здесь можно добавить собственные вспомогательные константы
-# (например, сдвиги полей при сборке идентификатора).
+TIMESTAMP_MOVE: Final[int] = NODE_ID_BITS + SEQUENCE_ID_BITS

src/part1/snowflake.py

@@ -13,102 +13,69 @@
 :func:`decode_node_id` and :func:`decode_sequence_id`.
 """
 
-import time  # noqa: F401
+import time
 
-from .constants import (  # noqa: F401
-    EPOCH_MS_DEFAULT,
-    NODE_ID_DEFAULT,
-    NODE_ID_MAX,
-    SEQUENCE_ID_MAX,
-    TIMESTAMP_MS_MAX,
-)
+from .constants import *
 
 
 def read_current_millis(epoch_ms: int) -> int:
-    """Read the number of milliseconds elapsed since the custom epoch.
+    call_time = (
+        time.time_ns() // 1_000_000  # наносекунды в милисекунды(time.time() - float)
+    )
+    return call_time - epoch_ms
+    # """Read the number of milliseconds elapsed since the custom epoch.
 
-    Args:
-        epoch_ms: The custom epoch expressed as Unix milliseconds.
+    # 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
+    # Returns:
+    #     The count of whole milliseconds between ``epoch_ms`` and now. May be
+    #     negative if ``epoch_ms`` lies in the future.
+    # """
 
 
 def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int:
-    """Read the timestamp field out of a Snowflake identifier.
+    return (snowflake_id >> TIMESTAMP_MOVE) + epoch_ms
 
-    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).
+    # """Read the timestamp field out of a Snowflake identifier.
 
-    Returns:
-        The absolute Unix time in milliseconds at which the identifier was
-        generated.
-    """
-    # TODO: реализуйте функцию
-    return 0
+    # 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.
+    # """
 
 
 def decode_node_id(snowflake_id: int) -> int:
-    """Read the node identifier field out of a Snowflake identifier.
+    return (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_BITS
 
-    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
+def decode_sequence_id(snowflake_id: int) -> int:
+    return snowflake_id & SEQUENCE_ID_MAX
 
 
-def decode_sequence_id(snowflake_id: int) -> int:
-    """Read the sequence counter field out of a Snowflake identifier.
+def generate_snowflake_id(
+    sequence_id: int, node_id: int = NODE_ID_DEFAULT, epoch_ms: int = EPOCH_MS_DEFAULT
+) -> int | None:
+    time_call_gen = read_current_millis(epoch_ms)
 
-    Args:
-        snowflake_id: An identifier produced by :func:`generate_snowflake_id`.
+    if node_id < 0 or node_id > NODE_ID_MAX:
+        print("node_id must be in [0,", NODE_ID_MAX, "]")
+        return None
 
-    Returns:
-        The per-millisecond sequence counter packed into ``snowflake_id``, in
-        the range ``[0, SEQUENCE_ID_MAX]``.
-    """
-    # TODO: реализуйте функцию
-    return 0
+    if sequence_id < 0 or sequence_id > SEQUENCE_ID_MAX:
+        print("sequence_id must be in [0,", SEQUENCE_ID_MAX, "]")
+        return None
 
+    if time_call_gen > TIMESTAMP_MS_MAX:
+        print("overflows time stamp")
+        return None
 
-def generate_snowflake_id(
-    sequence_id: int,
-    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
+    snowflake_id = (
+        (time_call_gen << TIMESTAMP_MOVE) | (node_id << sequence_id) | sequence_id
+    )
+    return snowflake_id

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 +24,7 @@
 
 # TODO: задайте позиции полей внутри кортежа CartLine
 LINE_PRODUCT_ID_INDEX: Final = 0
-LINE_QUANTITY_INDEX: Final = 0
+LINE_QUANTITY_INDEX: Final = 1
 
 
 def add_to_cart(
@@ -53,9 +53,30 @@ 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)
-
+    prod = read_product(storage, product_id)
+    if prod is None:
+        return None
+
+    if prod[QUANTITY_INDEX] < quantity:
+        print(f"not enough stock for product {product_id}")
+        return None
+
+    new_stock_qty = prod[QUANTITY_INDEX] - quantity
+    update_product(
+        storage,
+        product_id,
+        (prod[NAME_INDEX], prod[PRICE_INDEX], new_stock_qty),
+    )
+
+    for i, line in enumerate(cart):
+        if line[LINE_PRODUCT_ID_INDEX] == product_id:
+            new_cart_qty = line[LINE_QUANTITY_INDEX] + quantity
+            cart[i] = (product_id, new_cart_qty)
+            return (product_id, new_cart_qty)
+
+    new_line = (product_id, quantity)
+    cart.append(new_line)
+    return new_line
 
 def remove_from_cart(
     storage: list[Product],
@@ -85,5 +106,36 @@ 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)
+    found_index = -1
+    for i, line in enumerate(cart):
+        if line[LINE_PRODUCT_ID_INDEX] == product_id:
+            found_index = i
+            break
+
+    if found_index == -1:
+        print(f"product {product_id} is not in the cart")
+        return None
+
+    line = cart[found_index]
+    if line[LINE_QUANTITY_INDEX] < quantity:
+        print(f"not enough quantity in cart for product {product_id}")
+        return None
+
+    new_cart_qty = line[LINE_QUANTITY_INDEX] - quantity
+    if new_cart_qty == 0:
+        cart.pop(found_index)
+        res_line = (product_id, 0)
+    else:
+        cart[found_index] = (product_id, new_cart_qty)
+        res_line = (product_id, new_cart_qty)
+
+    product = read_product(storage, product_id)
+    if product is not None:
+        new_stock_qty = product[QUANTITY_INDEX] + quantity
+        update_product(
+            storage,
+            product_id,
+            (product[NAME_INDEX], product[PRICE_INDEX], new_stock_qty),
+        )
+
+    return res_line

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:
@@ -34,9 +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
-
+    if len(storage) == 0:
+        return PRODUCT_ID_MIN
+
+    max_id = max(product[PRODUCT_ID_INDEX] for product in storage)
+    return max_id + 1
 
 def create_product(
     storage: list[Product], fields: tuple[str, Decimal, int]
@@ -56,9 +58,17 @@ 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[0], fields[1], fields[2]
+    for product in storage:
+        if product[NAME_INDEX] == name:
+            print(f"product name '{name}' is already taken")
+            return None
+
+    new_id = generate_product_id(storage)
+    normalized_price = normalize_price(price)
+
+    new_product: Product = (new_id, name, normalized_price, quantity)
+    storage.append(new_product)
 
 def read_product(storage: list[Product], product_id: int) -> Product | None:
     """Return the product stored under ``product_id``.
@@ -72,9 +82,12 @@ def read_product(storage: list[Product], product_id: int) -> Product | None:
         ``None`` when no product carries that identifier (a message is
         printed in that case).
     """
-    # TODO: реализуйте функцию
-    return (0, "", Decimal(0), 0)
+    for product in storage:
+        if product[PRODUCT_ID_INDEX] == product_id:
+            return product
 
+    print(f"product with id {product_id} not found")
+    return None
 
 def update_product(
     storage: list[Product],
@@ -99,9 +112,18 @@ 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)
 
+    name, price, quantity = fields[0], fields[1], fields[2]
+
+    for i, product in enumerate(storage):
+        if product[PRODUCT_ID_INDEX] == product_id:
+            norm_price = normalize_price(price)
+            upd_product: Product = (product_id, name, norm_price, quantity)
+            storage[i] = upd_product
+            return upd_product
+
+    print(f"product with id {product_id} not found")
+    return None
 
 def delete_product(storage: list[Product], product_id: int) -> int | None:
     """Remove the product stored under ``product_id`` from ``storage``.
@@ -116,5 +138,10 @@ def delete_product(storage: list[Product], product_id: int) -> int | None:
         product carried that identifier (``storage`` is left unchanged and
         a message is printed).
     """
-    # TODO: реализуйте функцию
-    return 0
+    for i, product in enumerate(storage):
+        if product[PRODUCT_ID_INDEX] == product_id:
+            storage.pop(i)
+            return product_id
+
+    print(f"product with id {product_id} not found")
+    return None