refactor: valuation class to allow extending
diff --git a/erpnext/stock/valuation.py b/erpnext/stock/valuation.py
index 45c5083..f056439 100644
--- a/erpnext/stock/valuation.py
+++ b/erpnext/stock/valuation.py
@@ -1,15 +1,54 @@
+from abc import ABC, abstractmethod, abstractproperty
from typing import Callable, List, NewType, Optional, Tuple
from frappe.utils import flt
-FifoBin = NewType("FifoBin", List[float])
+StockBin = NewType("FifoBin", List[float])
# Indexes of values inside FIFO bin 2-tuple
QTY = 0
RATE = 1
-class FIFOValuation:
+class BinWiseValuation(ABC):
+
+ @abstractmethod
+ def add_stock(self, qty: float, rate: float) -> None:
+ pass
+
+ @abstractmethod
+ def remove_stock(
+ self, qty: float, outgoing_rate: float = 0.0, rate_generator: Callable[[], float] = None
+ ) -> List[StockBin]:
+ pass
+
+ @abstractproperty
+ def state(self) -> List[StockBin]:
+ pass
+
+ def get_total_stock_and_value(self) -> Tuple[float, float]:
+ total_qty = 0.0
+ total_value = 0.0
+
+ for qty, rate in self.state:
+ total_qty += flt(qty)
+ total_value += flt(qty) * flt(rate)
+
+ return _round_off_if_near_zero(total_qty), _round_off_if_near_zero(total_value)
+
+ def __repr__(self):
+ return str(self.state)
+
+ def __iter__(self):
+ return iter(self.state)
+
+ def __eq__(self, other):
+ if isinstance(other, list):
+ return self.state == other
+ return type(self) == type(other) and self.state == other.state
+
+
+class FIFOValuation(BinWiseValuation):
"""Valuation method where a queue of all the incoming stock is maintained.
New stock is added at end of the queue.
@@ -24,34 +63,14 @@
# ref: https://docs.python.org/3/reference/datamodel.html#slots
__slots__ = ["queue",]
- def __init__(self, state: Optional[List[FifoBin]]):
- self.queue: List[FifoBin] = state if state is not None else []
+ def __init__(self, state: Optional[List[StockBin]]):
+ self.queue: List[StockBin] = state if state is not None else []
- def __repr__(self):
- return str(self.queue)
-
- def __iter__(self):
- return iter(self.queue)
-
- def __eq__(self, other):
- if isinstance(other, list):
- return self.queue == other
- return self.queue == other.queue
-
- def get_state(self) -> List[FifoBin]:
+ @property
+ def state(self) -> List[StockBin]:
"""Get current state of queue."""
return self.queue
- def get_total_stock_and_value(self) -> Tuple[float, float]:
- total_qty = 0.0
- total_value = 0.0
-
- for qty, rate in self.queue:
- total_qty += flt(qty)
- total_value += flt(qty) * flt(rate)
-
- return _round_off_if_near_zero(total_qty), _round_off_if_near_zero(total_value)
-
def add_stock(self, qty: float, rate: float) -> None:
"""Update fifo queue with new stock.
@@ -78,7 +97,7 @@
def remove_stock(
self, qty: float, outgoing_rate: float = 0.0, rate_generator: Callable[[], float] = None
- ) -> List[FifoBin]:
+ ) -> List[StockBin]:
"""Remove stock from the queue and return popped bins.
args:
@@ -136,6 +155,51 @@
return consumed_bins
+class LIFOValuation(BinWiseValuation):
+ """Valuation method where a *stack* of all the incoming stock is maintained.
+
+ New stock is added at top of the stack.
+ Qty consumption happens on Last In First Out basis.
+
+ Stack is implemented using "bins" of [qty, rate].
+
+ ref: https://en.wikipedia.org/wiki/FIFO_and_LIFO_accounting
+ """
+
+ # specifying the attributes to save resources
+ # ref: https://docs.python.org/3/reference/datamodel.html#slots
+ __slots__ = ["queue",]
+
+ def __init__(self, state: Optional[List[StockBin]]):
+ self.stack: List[StockBin] = state if state is not None else []
+
+ @property
+ def state(self) -> List[StockBin]:
+ """Get current state of stack."""
+ return self.stack
+
+ def add_stock(self, qty: float, rate: float) -> None:
+ """Update lifo stack with new stock.
+
+ args:
+ qty: new quantity to add
+ rate: incoming rate of new quantity"""
+ pass
+
+
+ def remove_stock(
+ self, qty: float, outgoing_rate: float = 0.0, rate_generator: Callable[[], float] = None
+ ) -> List[StockBin]:
+ """Remove stock from the stack and return popped bins.
+
+ args:
+ qty: quantity to remove
+ rate: outgoing rate
+ rate_generator: function to be called if stack is not found and rate is required.
+ """
+ pass
+
+
def _round_off_if_near_zero(number: float, precision: int = 7) -> float:
"""Rounds off the number to zero only if number is close to zero for decimal
specified in precision. Precision defaults to 7.