"""Goal contract (parity row 2): absolute target, hard/soft, fail-fast §10.

Hard goal reached -> a STRUCTURED stop signal (typed event, never silent);
soft goal reached -> a flag without stopping. The percent-goal baseline is
D-E-gated: attempting to construct one is an explicit ``NotImplementedError``
refusal, never silent semantics.
"""

from __future__ import annotations

import math

import pytest
from pydantic import ValidationError

from portfolio_optimiser_claude.goals import GoalContract, GoalReached


class TestFailFastConstruction:
    """§10: a malformed goal never constructs."""

    @pytest.mark.parametrize("target", [0.0, -100000.0, math.inf, math.nan])
    def test_non_positive_or_non_finite_target_is_refused(self, target: float) -> None:
        with pytest.raises(ValidationError):
            GoalContract(target_nok=target, mode="hard")

    def test_unknown_mode_is_refused(self) -> None:
        with pytest.raises(ValidationError):
            GoalContract(target_nok=100000.0, mode="maybe")  # type: ignore[arg-type]

    def test_percent_goal_is_an_explicit_gated_refusal(self) -> None:
        # D-E-gated: the field is reserved, the semantics are NOT implemented —
        # construction refuses loudly instead of guessing a baseline.
        with pytest.raises(NotImplementedError, match="D-E"):
            GoalContract(target_nok=100000.0, mode="hard", target_percent=10.0)


class TestHardGoal:
    """Hard goal reached -> typed stop event carrying target + observed."""

    def test_reaching_the_target_raises_a_structured_stop(self) -> None:
        contract = GoalContract(target_nok=100000.0, mode="hard")
        with pytest.raises(GoalReached) as excinfo:
            contract.check(125000.0)
        assert excinfo.value.target_nok == 100000.0
        assert excinfo.value.observed_nok == 125000.0

    def test_exactly_at_the_target_counts_as_reached(self) -> None:
        with pytest.raises(GoalReached):
            GoalContract(target_nok=100000.0, mode="hard").check(100000.0)

    def test_under_the_target_returns_false_without_raising(self) -> None:
        assert GoalContract(target_nok=100000.0, mode="hard").check(99999.0) is False


class TestSoftGoal:
    """Soft goal reached -> a flag, never a stop."""

    def test_reaching_the_target_flags_without_stopping(self) -> None:
        assert GoalContract(target_nok=100000.0, mode="soft").check(125000.0) is True

    def test_under_the_target_returns_false(self) -> None:
        assert GoalContract(target_nok=100000.0, mode="soft").check(50000.0) is False