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https://github.com/eitchtee/WYGIWYH.git
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Herculino Trotta
81e572c8ab
Per-currency monthly net changes from active, tracked accounts, plus the exchange rate for currencies with an exchange currency.
91 lines
2.9 KiB
Python
91 lines
2.9 KiB
Python
from decimal import Decimal
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from django.db.models import Case, DecimalField, F, Sum, Value, When
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from django.db.models.functions import TruncMonth
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from django.utils import timezone
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from apps.accounts.models import Account
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from apps.currencies.models import Currency
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from apps.currencies.utils.convert import convert
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from apps.transactions.models import Transaction
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def get_simulator_baseline(user):
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"""
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Build the projected baseline the simulator applies hypothetical entries on.
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For each currency, returns the projected net change (every transaction,
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paid or not) of each month that has transactions, keyed by "YYYY-MM", so
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the balance at the start of any month can be derived by summing every
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month before it. Archived and untracked accounts are ignored.
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Currencies with an exchange currency also carry the rate used to show
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their converted amounts.
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"""
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accounts = Account.objects.filter(is_archived=False).exclude(
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id__in=user.untracked_accounts.values_list("id", flat=True)
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)
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currencies = (
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Currency.objects.filter(
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id__in=accounts.values_list("currency", flat=True), is_archived=False
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)
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.select_related("exchange_currency")
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.order_by("name")
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)
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monthly = {}
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for row in (
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Transaction.objects.filter(account__in=accounts)
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.annotate(month=TruncMonth("reference_date"))
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.values("account__currency", "month")
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.annotate(
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total=Sum(
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Case(
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When(type=Transaction.Type.INCOME, then=F("amount")),
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When(type=Transaction.Type.EXPENSE, then=-F("amount")),
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default=Value(0),
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output_field=DecimalField(),
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)
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)
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)
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.order_by()
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):
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monthly.setdefault(row["account__currency"], {})[
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row["month"].strftime("%Y-%m")
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] = float(row["total"] or 0)
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return {
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"current_month": timezone.localdate(timezone.now()).strftime("%Y-%m"),
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"currencies": [
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{
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"id": currency.id,
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"name": currency.name,
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"code": currency.code,
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"prefix": currency.prefix,
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"suffix": currency.suffix,
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"decimal_places": currency.decimal_places,
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"monthly": monthly.get(currency.id, {}),
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"exchange": _get_exchange(currency),
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}
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for currency in currencies
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],
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}
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def _get_exchange(currency):
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if not currency.exchange_currency:
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return None
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rate, prefix, suffix, decimal_places = convert(
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Decimal("1"), currency, currency.exchange_currency
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)
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if rate is None:
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return None
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return {
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"rate": float(rate),
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"prefix": prefix,
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"suffix": suffix,
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"decimal_places": decimal_places,
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}
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