Ankush Menat
3 years ago
committed by
Ankush Menat
2 changed files with 145 additions and 78 deletions
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from typing import Callable, List, NewType, Optional, Tuple |
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from frappe.utils import flt |
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FifoBin = NewType("FifoBin", List[float]) |
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# Indexes of values inside FIFO bin 2-tuple |
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QTY = 0 |
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RATE = 1 |
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class FifoValuation: |
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"""Valuation method where a queue of all the incoming stock is maintained. |
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New stock is added at end of the queue. |
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Qty consumption happens on First In First Out basis. |
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Queue is implemented using "bins" of [qty, rate]. |
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ref: https://en.wikipedia.org/wiki/FIFO_and_LIFO_accounting |
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""" |
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def __init__(self, state: Optional[List[FifoBin]]): |
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self.queue: List[FifoBin] = state if state is not None else [] |
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def get_state(self) -> List[FifoBin]: |
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"""Get current state of queue.""" |
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return self.queue |
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def get_total_stock_and_value(self) -> Tuple[float, float]: |
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total_qty = 0.0 |
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total_value = 0.0 |
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for qty, rate in self.queue: |
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total_qty += flt(qty) |
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total_value += flt(qty) * flt(rate) |
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return _round_off_if_near_zero(total_qty), _round_off_if_near_zero(total_value) |
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def add_stock(self, qty: float, rate: float) -> List[FifoBin]: |
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"""Update fifo queue with new stock and return queue. |
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args: |
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qty: new quantity to add |
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rate: incoming rate of new quantity""" |
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if not len(self.queue): |
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self.queue.append([0, 0]) |
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# last row has the same rate, merge new bin. |
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if self.queue[-1][RATE] == rate: |
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self.queue[-1][QTY] += qty |
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else: |
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# Item has a positive balance qty, add new entry |
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if self.queue[-1][QTY] > 0: |
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self.queue.append([qty, rate]) |
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else: # negative balance qty |
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qty = self.queue[-1][QTY] + qty |
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if qty > 0: # new balance qty is positive |
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self.queue[-1] = [qty, rate] |
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else: # new balance qty is still negative, maintain same rate |
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self.queue[-1][QTY] = qty |
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return self.get_state() |
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def remove_stock( |
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self, qty: float, rate: float, rate_generator: Callable[[], float] |
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) -> List[FifoBin]: |
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"""Remove stock from the queue and return queue. |
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args: |
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qty: quantity to remove |
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rate: outgoing rate |
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rate_generator: function to be called if queue is not found and rate is required. |
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""" |
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while qty: |
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if not len(self.queue): |
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# rely on rate generator. |
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self.queue.append([0, rate_generator()]) |
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index = None |
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if rate > 0: |
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# Find the entry where rate matched with outgoing rate |
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for idx, fifo_bin in enumerate(self.queue): |
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if fifo_bin[RATE] == rate: |
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index = idx |
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break |
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# If no entry found with outgoing rate, collapse stack |
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if index is None: # nosemgrep |
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new_stock_value = sum(d[QTY] * d[RATE] for d in self.queue) - qty * rate |
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new_stock_qty = sum(d[QTY] for d in self.queue) - qty |
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self.queue = [[new_stock_qty, new_stock_value / new_stock_qty if new_stock_qty > 0 else rate]] |
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break |
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else: |
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index = 0 |
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# select first bin or the bin with same rate |
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fifo_bin = self.queue[index] |
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if qty >= fifo_bin[QTY]: |
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# consume current bin |
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qty = _round_off_if_near_zero(qty - fifo_bin[QTY]) |
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self.queue.pop(index) |
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if not self.queue and qty: |
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# stock finished, qty still remains to be withdrawn |
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# negative stock, keep in as a negative bin |
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self.queue.append([-qty, rate or fifo_bin[RATE]]) |
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break |
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else: |
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# qty found in current bin consume it and exit |
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fifo_bin[QTY] = fifo_bin[QTY] - qty |
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qty = 0 |
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return self.get_state() |
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def _round_off_if_near_zero(number: float, precision: int = 6) -> float: |
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"""Rounds off the number to zero only if number is close to zero for decimal |
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specified in precision. Precision defaults to 6. |
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""" |
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if flt(number) < (1.0 / (10 ** precision)): |
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return 0 |
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return flt(number) |
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