"""Cartesian scenario builder + strategy/regime factory."""
from decimal import Decimal

import pytest

from fire_planner.scenarios import (
    DEFAULT_GLIDES,
    DEFAULT_JURISDICTIONS,
    DEFAULT_LEAVE_YEARS,
    DEFAULT_STRATEGIES,
    ScenarioSpec,
    build_regime_schedule,
    build_strategy,
    cartesian_scenarios,
)
from fire_planner.strategies.guyton_klinger import GuytonKlingerStrategy
from fire_planner.strategies.trinity import TrinityStrategy
from fire_planner.strategies.vpw import VpwStrategy, VpwWithFloorStrategy
from fire_planner.tax.bulgaria import BulgariaTaxRegime
from fire_planner.tax.cyprus import CyprusTaxRegime
from fire_planner.tax.uae import UaeTaxRegime
from fire_planner.tax.uk import UkTaxRegime


def test_default_cartesian_count_is_120() -> None:
    specs = cartesian_scenarios(spending_gbp=Decimal("100000"), nw_seed_gbp=Decimal("1000000"))
    expected = (len(DEFAULT_JURISDICTIONS) * len(DEFAULT_STRATEGIES) * len(DEFAULT_LEAVE_YEARS) *
                len(DEFAULT_GLIDES))
    assert expected == 120
    assert len(specs) == 120


def test_external_id_format() -> None:
    spec = ScenarioSpec(
        jurisdiction="cyprus",
        strategy="vpw",
        leave_uk_year=3,
        glide_path="rising",
        spending_gbp=Decimal("100000"),
        nw_seed_gbp=Decimal("1000000"),
    )
    assert spec.external_id == "cyprus-vpw-leave-y3-glide-rising"


def test_cartesian_unique_external_ids() -> None:
    specs = cartesian_scenarios(spending_gbp=Decimal("100000"), nw_seed_gbp=Decimal("1000000"))
    ids = [s.external_id for s in specs]
    assert len(ids) == len(set(ids))


def test_build_strategy_dispatch() -> None:
    assert isinstance(build_strategy("trinity"), TrinityStrategy)
    assert isinstance(build_strategy("guyton_klinger"), GuytonKlingerStrategy)
    assert isinstance(build_strategy("vpw"), VpwStrategy)


def test_build_strategy_vpw_floor_requires_floor() -> None:
    s = build_strategy("vpw_floor", floor=40_000.0)
    assert isinstance(s, VpwWithFloorStrategy)
    assert s.floor == 40_000.0


def test_build_strategy_vpw_floor_missing_floor_raises() -> None:
    with pytest.raises(ValueError):
        build_strategy("vpw_floor")


def test_build_strategy_unknown_raises() -> None:
    with pytest.raises(KeyError):
        build_strategy("walmart")


def test_build_regime_schedule_uae() -> None:
    fn = build_regime_schedule("uae", leave_uk_year=2)
    assert isinstance(fn(0), UkTaxRegime)
    assert isinstance(fn(1), UkTaxRegime)
    assert isinstance(fn(2), UaeTaxRegime)
    assert isinstance(fn(50), UaeTaxRegime)


def test_build_regime_schedule_uk_constant() -> None:
    fn = build_regime_schedule("uk", leave_uk_year=3)
    # All years should resolve to UK
    assert isinstance(fn(0), UkTaxRegime)
    assert isinstance(fn(50), UkTaxRegime)


def test_build_regime_schedule_cyprus_switches_at_leave_year() -> None:
    fn = build_regime_schedule("cyprus", leave_uk_year=3)
    assert isinstance(fn(0), UkTaxRegime)
    assert isinstance(fn(2), UkTaxRegime)
    assert isinstance(fn(3), CyprusTaxRegime)
    assert isinstance(fn(50), CyprusTaxRegime)


def test_build_regime_schedule_bulgaria() -> None:
    fn = build_regime_schedule("bulgaria", leave_uk_year=1)
    assert isinstance(fn(0), UkTaxRegime)
    assert isinstance(fn(1), BulgariaTaxRegime)


def test_build_regime_schedule_unknown_raises() -> None:
    with pytest.raises(KeyError):
        build_regime_schedule("madeupistan", leave_uk_year=3)


def test_cartesian_unknown_glide_raises() -> None:
    with pytest.raises(KeyError):
        cartesian_scenarios(
            spending_gbp=Decimal("100000"),
            nw_seed_gbp=Decimal("1000000"),
            glides=("staircase", ),
        )