130 lines
4.7 KiB
Python
130 lines
4.7 KiB
Python
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"""Cartesian-product scenario generator.
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Default counts:
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4 jurisdictions × 3 strategies × 5 leave-UK years × 2 glides = 120
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Jurisdictions modelled by default: uk, nomad, cyprus, bulgaria.
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Malaysia and Thailand are essentially equivalent in our tax engine
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(both 0% on foreign income); pick one and document. Cyprus is
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included because GeSY is non-trivial; Bulgaria for its 10% flat tax.
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UK-stay scenarios duplicate across leave_uk_year (since you don't
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leave) — kept in the product so the dashboard can present a uniform
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heatmap; the simulator effectively ignores leave_year for UK.
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"""
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from __future__ import annotations
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from dataclasses import dataclass, field
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from decimal import Decimal
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from typing import Any
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from fire_planner.glide_path import GLIDE_PATHS
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from fire_planner.simulator import RegimeFn, constant_regime, jurisdiction_schedule
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from fire_planner.strategies.base import WithdrawalStrategy
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from fire_planner.strategies.guyton_klinger import GuytonKlingerStrategy
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from fire_planner.strategies.trinity import TrinityStrategy
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from fire_planner.strategies.vpw import VpwStrategy, VpwWithFloorStrategy
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from fire_planner.tax.base import TaxRegime
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from fire_planner.tax.bulgaria import BulgariaTaxRegime
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from fire_planner.tax.cyprus import CyprusTaxRegime
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from fire_planner.tax.malaysia import MalaysiaTaxRegime
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from fire_planner.tax.nomad import NomadTaxRegime
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from fire_planner.tax.thailand import ThailandTaxRegime
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from fire_planner.tax.uae import UaeTaxRegime
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from fire_planner.tax.uk import UkTaxRegime
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DEFAULT_JURISDICTIONS = ("uk", "nomad", "cyprus", "bulgaria")
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DEFAULT_STRATEGIES = ("trinity", "guyton_klinger", "vpw")
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DEFAULT_LEAVE_YEARS = (1, 2, 3, 4, 5)
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DEFAULT_GLIDES = ("rising", "static_60_40")
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@dataclass(frozen=True)
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class ScenarioSpec:
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"""One scenario in the Cartesian product."""
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jurisdiction: str
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strategy: str
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leave_uk_year: int
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glide_path: str
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spending_gbp: Decimal
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nw_seed_gbp: Decimal
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horizon_years: int = 60
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savings_per_year_gbp: Decimal = Decimal("0")
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config: dict[str, Any] = field(default_factory=dict)
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@property
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def external_id(self) -> str:
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return (f"{self.jurisdiction}-{self.strategy}-leave-y{self.leave_uk_year}-"
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f"glide-{self.glide_path}")
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def build_strategy(name: str, floor: float | None = None) -> WithdrawalStrategy:
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if name == "trinity":
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return TrinityStrategy()
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if name == "guyton_klinger":
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return GuytonKlingerStrategy()
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if name == "vpw":
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return VpwStrategy()
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if name == "vpw_floor":
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if floor is None:
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raise ValueError("vpw_floor strategy requires a `floor` value (real GBP)")
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return VpwWithFloorStrategy(floor=floor)
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raise KeyError(f"Unknown strategy: {name!r}")
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_JURISDICTION_CONSTRUCTORS: dict[str, type[TaxRegime]] = {
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"uk": UkTaxRegime,
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"nomad": NomadTaxRegime,
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"malaysia": MalaysiaTaxRegime,
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"thailand": ThailandTaxRegime,
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"cyprus": CyprusTaxRegime,
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"bulgaria": BulgariaTaxRegime,
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"uae": UaeTaxRegime,
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}
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def build_regime_schedule(jurisdiction: str, leave_uk_year: int) -> RegimeFn:
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"""For UK-stay, returns a constant UK regime ignoring leave_year.
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For other jurisdictions, UK pre-departure and the target after."""
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if jurisdiction == "uk":
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return constant_regime(UkTaxRegime())
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cls = _JURISDICTION_CONSTRUCTORS.get(jurisdiction)
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if cls is None:
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raise KeyError(f"Unknown jurisdiction: {jurisdiction!r}")
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return jurisdiction_schedule(
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pre_departure=UkTaxRegime(),
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post_departure=cls(),
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leave_year=leave_uk_year,
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)
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def cartesian_scenarios(
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spending_gbp: Decimal,
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nw_seed_gbp: Decimal,
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savings_per_year_gbp: Decimal = Decimal("0"),
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horizon_years: int = 60,
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jurisdictions: tuple[str, ...] = DEFAULT_JURISDICTIONS,
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strategies: tuple[str, ...] = DEFAULT_STRATEGIES,
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leave_years: tuple[int, ...] = DEFAULT_LEAVE_YEARS,
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glides: tuple[str, ...] = DEFAULT_GLIDES,
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) -> list[ScenarioSpec]:
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out: list[ScenarioSpec] = []
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for jur in jurisdictions:
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for strat in strategies:
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for leave_y in leave_years:
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for glide in glides:
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if glide not in GLIDE_PATHS:
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raise KeyError(f"Unknown glide path: {glide!r}")
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out.append(
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ScenarioSpec(
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jurisdiction=jur,
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strategy=strat,
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leave_uk_year=leave_y,
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glide_path=glide,
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spending_gbp=spending_gbp,
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nw_seed_gbp=nw_seed_gbp,
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horizon_years=horizon_years,
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savings_per_year_gbp=savings_per_year_gbp,
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))
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return out
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