wlfb
020f41e9f2
Implementiert Task 5 mit TDD-Ansatz: projection.py mit Projection-Klasse und project()-Funktion für Cashflow-Simulation; scenario.py mit PlainRecurring, PlainPlanned, PlainModifier Dataclasses und build_cashflows() für Szenarien-Zahlungsströme mit Modifier-Support (remove, percent, absolute). Alle 15 Tests grün. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
83 lines
2.6 KiB
Python
83 lines
2.6 KiB
Python
from dataclasses import dataclass
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from datetime import date
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from decimal import ROUND_HALF_UP, Decimal
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from app.engine.loans import Installment
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from app.engine.recurrence import occurrences
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CENT = Decimal("0.01")
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@dataclass(frozen=True)
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class PlainRecurring:
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id: int
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name: str
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amount: Decimal
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rhythm: str
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due_day: int
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start_date: date | None
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end_date: date | None
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category_id: int | None
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@dataclass(frozen=True)
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class PlainPlanned:
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name: str
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amount: Decimal
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due: date
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category_id: int | None
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@dataclass(frozen=True)
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class PlainModifier:
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target_type: str
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target_id: int
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kind: str
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value: Decimal
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def _modified(amount: Decimal, category_id: int | None, recurring_id: int | None,
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modifiers: list[PlainModifier]) -> Decimal | None:
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for m in modifiers:
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hit = ((m.target_type == "category" and category_id == m.target_id)
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or (m.target_type == "recurring" and recurring_id == m.target_id))
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if not hit:
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continue
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if m.kind == "remove":
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return None
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if m.kind == "percent":
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amount = (amount * (Decimal(100) - m.value) / Decimal(100)).quantize(CENT, ROUND_HALF_UP)
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elif m.kind == "absolute":
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if amount < 0:
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amount = min(Decimal("0"), amount + m.value)
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else:
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amount = max(Decimal("0"), amount - m.value)
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return amount
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def build_cashflows(recurring: list[PlainRecurring], planned: list[PlainPlanned],
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loan_schedules: list[list[Installment]],
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loan_payouts: list[tuple[date, Decimal]],
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modifiers: list[PlainModifier],
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window_start: date, window_end: date) -> list[tuple[date, Decimal]]:
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flows: list[tuple[date, Decimal]] = []
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for r in recurring:
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amount = _modified(r.amount, r.category_id, r.id, modifiers)
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if amount is None:
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continue
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for d in occurrences(r.rhythm, r.due_day, window_start, window_end,
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r.start_date, r.end_date):
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flows.append((d, amount))
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for p in planned:
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amount = _modified(p.amount, p.category_id, None, modifiers)
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if amount is not None and window_start <= p.due <= window_end:
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flows.append((p.due, amount))
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for d, payout in loan_payouts:
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if window_start <= d <= window_end:
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flows.append((d, payout))
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for sched in loan_schedules:
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for inst in sched:
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if window_start <= inst.due <= window_end:
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flows.append((inst.due, inst.payment))
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return sorted(flows)
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