FFT-111 Add actualisation to import actuals

config/flags.py

@@ -0,0 +1 @@
+ACTUALISATION = "actualisation"

conftest.py

@@ -0,0 +1,17 @@
+import pytest
+from django.contrib.auth import get_user_model
+
+
+@pytest.fixture
+def test_user(db):
+    test_user_email = "test@test.com"
+    test_password = "test_password"
+
+    test_user, _ = get_user_model().objects.get_or_create(
+        username="test_user",
+        email=test_user_email,
+    )
+    test_user.set_password(test_password)
+    test_user.save()
+
+    return test_user

core/constants.py

@@ -1,4 +1,4 @@
-from .types import Months
+from .types import FinancialPeriods, Months
 
 
 MONTHS: Months = (
@@ -15,3 +15,4 @@
     "feb",
     "mar",
 )
+PERIODS: FinancialPeriods = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)

core/types.py

@@ -1,6 +1,21 @@
 from typing import Literal, TypedDict
 
 
+FinancialPeriods = tuple[
+    Literal[1],
+    Literal[2],
+    Literal[3],
+    Literal[4],
+    Literal[5],
+    Literal[6],
+    Literal[7],
+    Literal[8],
+    Literal[9],
+    Literal[10],
+    Literal[11],
+    Literal[12],
+]
+
 Month = Literal[
     "apr",
     "may",

forecast/import_actuals.py

@@ -1,8 +1,12 @@
 import datetime
 import logging
 
+import waffle
 from django.db import connection
+from django.db.models import F
 
+from config import flags
+from core.constants import PERIODS
 from core.import_csv import get_fk, get_fk_from_field
 from core.models import FinancialYear
 from forecast.models import (
@@ -292,8 +296,16 @@ def upload_trial_balance_report(file_upload, month_number, financial_year):
     if check_financial_code.error_found:
         final_status = FileUpload.PROCESSEDWITHERROR
     else:
+        uploaded_actuals = ActualUploadMonthlyFigure.objects.filter(
+            financial_year=financial_year, financial_period=period_obj
+        )
+
         # Now copy the newly uploaded actuals to the correct table
         if year_obj.current:
+            if waffle.switch_is_active(flags.ACTUALISATION):
+                for uploaded_actual in uploaded_actuals:
+                    actualisation(period=period_obj, actual=uploaded_actual)
+
             copy_current_year_actuals_to_monthly_figure(period_obj, financial_year)
             FinancialPeriod.objects.filter(
                 financial_period_code__lte=period_obj.financial_period_code
@@ -307,11 +319,42 @@ def upload_trial_balance_report(file_upload, month_number, financial_year):
         if check_financial_code.warning_found:
             final_status = FileUpload.PROCESSEDWITHWARNING
 
-        ActualUploadMonthlyFigure.objects.filter(
-            financial_year=financial_year, financial_period=period_obj
-        ).delete()
+        uploaded_actuals.delete()
 
     set_file_upload_feedback(
         file_upload, f"Processed {rows_to_process} rows.", final_status
     )
     return True
+
+
+def actualisation(period: FinancialPeriod, actual: ActualUploadMonthlyFigure) -> None:
+    # get the current forecast that is being turned into an actual
+    forecast = ForecastMonthlyFigure.objects.filter(
+        financial_code_id=actual.financial_code_id,
+        financial_year_id=actual.financial_year_id,
+        financial_period_id=actual.financial_period_id,
+        archived_status__isnull=True,
+    ).first()
+
+    # work out how many period we have left in the financial year
+    periods_left = len(PERIODS) - period.financial_period_code
+    # handle a missing forecast object and assume a forecast amount of 0
+    forecast_amount = forecast.amount if forecast else 0
+    # work out the difference the actual will leave us with
+    difference = forecast_amount - actual.amount
+
+    if periods_left:
+        # floor divide the difference by how many periods are left in the financial year
+        # TODO: How should monetary values be treated with regards to rounding?
+        difference //= periods_left
+
+    # adjust the remaining forecast periods by the difference
+    for i in range(periods_left):
+        ForecastMonthlyFigure.objects.update_or_create(
+            financial_code_id=actual.financial_code_id,
+            financial_year_id=actual.financial_year_id,
+            financial_period_id=period.pk + i + 1,
+            archived_status=None,
+            defaults={"amount": F("amount") + difference},
+            create_defaults={"amount": difference},
+        )

forecast/models.py

@@ -287,9 +287,12 @@ def get_max_period(self):
 
 
 class FinancialPeriod(BaseModel):
-    """Financial periods: correspond
-    to month, but there are 3 extra
-    periods at the end"""
+    """Financial periods: correspond to month, but there are 3 extra periods at the end.
+
+    There are 15 objects in total.
+
+    The objects are managed in migrations and therefore always available in tests.
+    """
 
     financial_period_code = models.IntegerField(primary_key=True)  # April = 1
     period_long_name = models.CharField(max_length=20)
@@ -1027,8 +1030,9 @@ class MonthlyFigureAbstract(BaseModel):
     """It contains the forecast and the actuals.
     The current month defines what is Actual and what is Forecast"""
 
-    amount = models.BigIntegerField(default=0)  # stored in pence
     id = models.AutoField(primary_key=True)
+
+    amount = models.BigIntegerField(default=0)  # stored in pence
     financial_year = models.ForeignKey(
         FinancialYear,
         on_delete=models.PROTECT,

forecast/services.py

@@ -1,4 +1,4 @@
-from core.constants import MONTHS
+from core.constants import PERIODS
 from core.models import FinancialYear
 from forecast.models import FinancialCode, FinancialPeriod, ForecastMonthlyFigure
 
@@ -40,7 +40,7 @@ def update_period(self, *, period: int | FinancialPeriod, amount: int):
         figure.save()
 
     def update(self, forecast: list[int]):
-        assert len(forecast) == len(MONTHS)
+        assert len(forecast) == len(PERIODS)
 
-        for i, _ in enumerate(MONTHS):
-            self.update_period(period=i + 1, amount=forecast[i])
+        for period in PERIODS:
+            self.update_period(period=period, amount=forecast[period - 1])