refactor: improve monthly_summary calculations

app/apps/monthly_overview/views.py

@@ -1,8 +1,5 @@
-from decimal import Decimal
-
 from django.contrib.auth.decorators import login_required
 from django.db.models import (
-    Sum,
     Q,
 )
 from django.shortcuts import render, redirect
@@ -10,9 +7,13 @@ from django.utils import timezone
 from django.views.decorators.http import require_http_methods
 
 from apps.common.decorators.htmx import only_htmx
-from apps.common.functions.dates import remaining_days_in_month
+from apps.common.utils.dicts import remove_falsey_entries
+from apps.monthly_overview.utils.daily_spending_allowance import (
+    calculate_daily_allowance_currency,
+)
 from apps.transactions.filters import TransactionsFilter
 from apps.transactions.models import Transaction
+from apps.transactions.utils.calculations import calculate_currency_totals
 from apps.transactions.utils.default_ordering import default_order
 
 
@@ -91,163 +92,27 @@ def transactions_list(request, month: int, year: int):
 @login_required
 @require_http_methods(["GET"])
 def monthly_summary(request, month: int, year: int):
-    # Helper function to calculate sums for different transaction types
-    def calculate_sum(transaction_type, is_paid):
-        return (
-            base_queryset.filter(type=transaction_type, is_paid=is_paid)
-            .values(
-                "account__currency__name",
-                "account__currency__suffix",
-                "account__currency__prefix",
-                "account__currency__decimal_places",
-            )
-            .annotate(total=Sum("amount"))
-            .order_by("account__currency__name")
-        )
-
-    # Helper function to format currency sums
-    def format_currency_sum(queryset):
-        return [
-            {
-                "currency": item["account__currency__name"],
-                "suffix": item["account__currency__suffix"],
-                "prefix": item["account__currency__prefix"],
-                "decimal_places": item["account__currency__decimal_places"],
-                "amount": item["total"],
-            }
-            for item in queryset
-        ]
-
-    # Calculate totals
-    def calculate_total(income, expenses):
-        totals = {}
-
-        # Process income
-        for item in income:
-            currency = item["account__currency__name"]
-            totals[currency] = totals.get(currency, Decimal("0")) + item["total"]
-
-        # Subtract expenses
-        for item in expenses:
-            currency = item["account__currency__name"]
-            totals[currency] = totals.get(currency, Decimal("0")) - item["total"]
-
-        return [
-            {
-                "currency": currency,
-                "suffix": next(
-                    (
-                        item["account__currency__suffix"]
-                        for item in list(income) + list(expenses)
-                        if item["account__currency__name"] == currency
-                    ),
-                    "",
-                ),
-                "prefix": next(
-                    (
-                        item["account__currency__prefix"]
-                        for item in list(income) + list(expenses)
-                        if item["account__currency__name"] == currency
-                    ),
-                    "",
-                ),
-                "decimal_places": next(
-                    (
-                        item["account__currency__decimal_places"]
-                        for item in list(income) + list(expenses)
-                        if item["account__currency__name"] == currency
-                    ),
-                    2,
-                ),
-                "amount": amount,
-            }
-            for currency, amount in totals.items()
-        ]
-
-    # Calculate total final
-    def sum_totals(total1, total2):
-        totals = {}
-        for item in total1 + total2:
-            currency = item["currency"]
-            totals[currency] = totals.get(currency, Decimal("0")) + item["amount"]
-        return [
-            {
-                "currency": currency,
-                "suffix": next(
-                    item["suffix"]
-                    for item in total1 + total2
-                    if item["currency"] == currency
-                ),
-                "prefix": next(
-                    item["prefix"]
-                    for item in total1 + total2
-                    if item["currency"] == currency
-                ),
-                "decimal_places": next(
-                    item["decimal_places"]
-                    for item in total1 + total2
-                    if item["currency"] == currency
-                ),
-                "amount": amount,
-            }
-            for currency, amount in totals.items()
-        ]
-
     # Base queryset with all required filters
     base_queryset = Transaction.objects.filter(
         reference_date__year=year, reference_date__month=month, account__is_asset=False
     ).exclude(Q(category__mute=True) & ~Q(category=None))
 
-    # Calculate sums for different transaction types
-    paid_income = calculate_sum(Transaction.Type.INCOME, True)
-    projected_income = calculate_sum(Transaction.Type.INCOME, False)
-    paid_expenses = calculate_sum(Transaction.Type.EXPENSE, True)
-    projected_expenses = calculate_sum(Transaction.Type.EXPENSE, False)
+    data = calculate_currency_totals(base_queryset, ignore_empty=True)
 
-    total_current = calculate_total(paid_income, paid_expenses)
-    total_projected = calculate_total(projected_income, projected_expenses)
-
-    total_final = sum_totals(total_current, total_projected)
-
-    # Calculate daily spending allowance
-    remaining_days = remaining_days_in_month(
-        month=month, year=year, current_date=timezone.localdate(timezone.now())
-    )
-    if (
-        timezone.localdate(timezone.now()).month == month
-        and timezone.localdate(timezone.now()).year == year
-    ):
-        daily_spending_allowance = [
-            {
-                "currency": item["currency"],
-                "suffix": item["suffix"],
-                "prefix": item["prefix"],
-                "decimal_places": item["decimal_places"],
-                "amount": (
-                    amount
-                    if (amount := item["amount"] / remaining_days) > 0
-                    else Decimal("0")
-                ),
-            }
-            for item in total_final
-        ]
-    else:
-        daily_spending_allowance = []
-
-    # Construct the response dictionary
-    data = {
-        "paid_income": format_currency_sum(paid_income),
-        "projected_income": format_currency_sum(projected_income),
-        "paid_expenses": format_currency_sum(paid_expenses),
-        "projected_expenses": format_currency_sum(projected_expenses),
-        "total_current": total_current,
-        "total_projected": total_projected,
-        "total_final": total_final,
-        "daily_spending_allowance": daily_spending_allowance,
+    context = {
+        "income_current": remove_falsey_entries(data, "income_current"),
+        "income_projected": remove_falsey_entries(data, "income_projected"),
+        "expense_current": remove_falsey_entries(data, "expense_current"),
+        "total_current": remove_falsey_entries(data, "total_current"),
+        "total_final": remove_falsey_entries(data, "total_final"),
+        "total_projected": remove_falsey_entries(data, "total_projected"),
+        "daily_spending_allowance": calculate_daily_allowance_currency(
+            currency_totals=data, month=month, year=year
+        ),
     }
 
     return render(
         request,
         "monthly_overview/fragments/monthly_summary.html",
-        context={"totals": data},
+        context=context,
     )