pf1e-simulator/tests/test_retrieve_weapon.py

"""Tests for the ``retrieve_weapon`` action (recovering a stolen weapon).

L7 of the ``llm-policy-contract`` plan: ``Action`` gains a
``retrieve_weapon`` kind and a ``weapon_id`` field so a policy can restore a
weapon rendered unusable in ``state.weapon_stolen``. The weapon is removed
from ``state.weapon_stolen`` and becomes usable again via ``usable_attacks()``.
(The steal maneuver no longer fills this set: APG Steal forbids taking wielded
weapons.)

No default policy emits ``retrieve_weapon``; it is only accepted by
``_execute`` (usage via custom policy / LLM).
"""

from __future__ import annotations

from pf1e_simulator.combat import Action, CombatantState, CombatEngine
from pf1e_simulator.grid import Grid
from pf1e_simulator.map import MapSpec, TerrainType
from pf1e_simulator.models import (
    AbilityScores,
    ACProfile,
    AttackSpec,
    Combatant,
    DamageComponent,
    Saves,
)
from pf1e_simulator.rng import ScriptedRng, SeededRng


def make_combatant(cid: str, *, attack_bonus: int = 2) -> Combatant:
    attack = AttackSpec(
        id=f"{cid}-w",
        name="sword",
        kind="melee",
        attack_bonus=attack_bonus,
        damage=[DamageComponent(formula="1d4", types=["slashing"])],
    )
    return Combatant(
        id=cid,
        name=cid,
        level=1,
        size="Medium",
        abilities=AbilityScores(
            str_score=10, dex_score=10, con_score=10,
            int_score=10, wis_score=10, cha_score=10,
        ),
        hp_max=6,
        ac=ACProfile(total=13, touch=13, flat_footed=13),
        bab=attack_bonus,
        initiative_mod=0,
        speed_land_ft=30,
        saves=Saves(fort=0, ref=0, will=0),
        attacks=[attack],
    )


def make_state(combatant: Combatant, side: str, pos: tuple[int, int]) -> CombatantState:
    return CombatantState(combatant=combatant, side=side, pos=pos, hp=combatant.hp_max)


def make_grid() -> Grid:
    legend = {".": TerrainType(type="floor", move_cost=1)}
    spec = MapSpec(name="test", terrain=tuple(["." * 8] * 8), legend=legend)
    return Grid.from_spec(spec)


def make_engine(queue: list[int], states: list[CombatantState]) -> CombatEngine:
    return CombatEngine(ScriptedRng(queue), make_grid(), states)


def _weapon_ids(state: CombatantState) -> list[str]:
    return [w.id for w in state.usable_attacks()]


# --- Test 1: retrieve restores a stolen weapon -------------------------------

def test_retrieve_restores_stolen_weapon() -> None:
    a_spec = make_combatant("a", attack_bonus=2)
    b_spec = make_combatant("b")
    a = make_state(a_spec, "players", (1, 1))
    b = make_state(b_spec, "monsters", (1, 2))
    # The steal maneuver no longer takes wielded weapons (APG Steal), so the
    # stolen state is set directly — retrieve_weapon is the mechanism under
    # test here.
    b.weapon_stolen.add("b-w")
    engine = make_engine([], [a, b])
    assert "b-w" not in _weapon_ids(b)
    engine._execute(b, Action(kind="retrieve_weapon", weapon_id="b-w"))
    assert not b.weapon_stolen
    assert "b-w" in _weapon_ids(b)


# --- Test 2: weapon_id=None -> nothing to retrieve, state unchanged ----------

def test_retrieve_none_logs_nothing_to_retrieve() -> None:
    a_spec = make_combatant("a", attack_bonus=2)
    b_spec = make_combatant("b")
    a = make_state(a_spec, "players", (1, 1))
    b = make_state(b_spec, "monsters", (1, 2))
    b.weapon_stolen.add("b-w")
    engine = make_engine([], [a, b])
    engine._execute(b, Action(kind="retrieve_weapon"))
    assert "nothing to retrieve" in engine._transcript[-1]
    assert b.weapon_stolen == {"b-w"}


# --- Test 3: unknown id (never stolen) -> log, state unchanged ---------------

def test_retrieve_unknown_id_logs_nothing_to_retrieve() -> None:
    a_spec = make_combatant("a", attack_bonus=2)
    b_spec = make_combatant("b")
    a = make_state(a_spec, "players", (1, 1))
    b = make_state(b_spec, "monsters", (1, 2))
    b.weapon_stolen.add("b-w")
    engine = make_engine([], [a, b])
    engine._execute(b, Action(kind="retrieve_weapon", weapon_id="ghost"))
    assert "nothing to retrieve" in engine._transcript[-1]
    assert b.weapon_stolen == {"b-w"}


# --- Test 4: steal leaves wielded weapons; retrieve restores a stolen id -----

def test_steal_then_retrieve_restores_weapon() -> None:
    # APG Steal: a wielded weapon cannot be taken — the maneuver provokes,
    # succeeds, and steals nothing; the owner keeps swinging. A weapon that IS
    # stolen (model state set directly) is restored by retrieve_weapon.
    a_spec = make_combatant("a", attack_bonus=2)
    b_spec = make_combatant("b")
    a = make_state(a_spec, "players", (1, 1))
    b = make_state(b_spec, "monsters", (1, 2))
    engine = make_engine([1, 12], [a, b])
    engine._execute(a, Action(kind="maneuver", target_id="b", maneuver="steal"))
    assert not b.weapon_stolen
    assert engine.weapon_for(b, a) is not None
    b.weapon_stolen.add("b-w")
    engine._execute(b, Action(kind="retrieve_weapon", weapon_id="b-w"))
    assert not b.weapon_stolen
    assert engine.weapon_for(b, a) is not None
    assert "retrieve b-w (restored)" in engine._transcript[-1]


# --- Test 5: determinism -----------------------------------------------------

def _run_with_retrieve() -> tuple[str, ...]:
    a_spec = make_combatant("a", attack_bonus=5)
    b_spec = make_combatant("b")
    a = make_state(a_spec, "players", (1, 1))
    b = make_state(b_spec, "monsters", (1, 2))
    b.weapon_stolen.add("b-w")

    def policy(engine: CombatEngine, state: CombatantState) -> tuple[Action, ...]:
        if state.combatant.id == "b":
            return (Action(kind="retrieve_weapon", weapon_id="b-w"),)
        return (Action(kind="wait"),)

    engine = CombatEngine(SeededRng(42), make_grid(), [a, b], policy=policy)
    return engine.run().transcript


def test_determinism_same_seed_same_transcript() -> None:
    assert _run_with_retrieve() == _run_with_retrieve()