feat(combat): resolve all natural melee weapons in full_attack

src/pf1e_simulator/combat.py

@@ -2295,13 +2295,13 @@ class CombatEngine:
             return
         if target is None:
             return
+        if kind == "attack":
             weapon = self.weapon_for(state, target)
             if weapon is None:
                 return
-        if kind == "attack":
             self._single_attack(state, target, weapon)
         elif kind == "full_attack":
-            self._full_attack(state, target, weapon)
+            self._full_attack(state, target)
     def _execute_charge(self, state: CombatantState, target: CombatantState | None) -> None:
         if target is None or not target.active:
             return
@@ -2819,8 +2819,30 @@ class CombatEngine:
         self._resolve_swing(attacker, target, weapon, label=weapon.name)
 
     def _full_attack(
+        self, attacker: CombatantState, target: CombatantState
+    ) -> None:
+        melee_weapons = [
+            w
+            for w in attacker.usable_attacks()
+            if w.kind == "melee" and self._melee_weapon_usable(attacker, target, w)
+        ]
+        if not melee_weapons:
+            # No melee weapon reaches: fall back to weapon_for (ranged/touch),
+            # preserving the pre-L3 single-weapon behavior.
+            weapon = self.weapon_for(attacker, target)
+            if weapon is None:
+                return
+            self._full_attack_weapon(attacker, target, weapon)
+            return
+        for weapon in melee_weapons:
+            if not attacker.active or not target.active:
+                return
+            self._full_attack_weapon(attacker, target, weapon)
+
+    def _full_attack_weapon(
         self, attacker: CombatantState, target: CombatantState, weapon: AttackSpec
     ) -> None:
+        """Resolve one weapon's full-attack swings (count swings or BAB iteratives)."""
         if weapon.count > 1:
             self._attack(attacker, target, weapon)
             return
@@ -2831,6 +2853,8 @@ class CombatEngine:
         for i in range(n):
             if not attacker.active:
                 return
+            if not target.active:
+                return
             if self._check_provoked_aoo(attacker, weapon):
                 return
             label = weapon.name if n == 1 else f"{weapon.name} #{i + 1}"
@@ -2840,6 +2864,20 @@ class CombatEngine:
             ):
                 return
 
+    def _melee_weapon_usable(
+        self, attacker: CombatantState, target: CombatantState, weapon: AttackSpec
+    ) -> bool:
+        """True if ``weapon`` (a melee weapon) can reach ``target`` with clear LoE."""
+        if not has_line_of_effect_cells(
+            self._grid, attacker.occupied_cells(), target.occupied_cells()
+        ):
+            return False
+        dist_ft = self.creature_distance(attacker, target) * _SQUARE_FT
+        effective_reach_ft = _effective_reach_ft(attacker, weapon)
+        if weapon.reach_ft > _SQUARE_FT:
+            return _SQUARE_FT < dist_ft <= effective_reach_ft
+        return dist_ft <= effective_reach_ft
+
     def _step5(self, state: CombatantState, target: CombatantState) -> None:
         if state.moved_this_turn:
             return

tests/test_multi_natural_weapons.py

@@ -0,0 +1,205 @@
+"""Tests for L3 of the ``llm-policy-contract`` plan: multiple natural weapons
+in a single full_attack.
+
+Previously ``_full_attack`` only struck with the single weapon returned by
+``weapon_for`` (the first usable one). A combatant with several natural
+weapons (e.g. "bite" + "2x Talons") only struck with the first in a
+full_attack. This module locks in the new behaviour: ``_full_attack`` iterates
+over every melee weapon in ``usable_attacks()``, resolves each one's swings,
+and excludes ranged/touch weapons from the loop.
+"""
+
+from __future__ import annotations
+
+from typing import Literal
+
+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 _attack(
+    cid: str, name: str, *, kind: Literal["melee", "ranged", "touch"] = "melee",
+    count: int = 1, attack_bonus: int = 2,
+) -> AttackSpec:
+    return AttackSpec(
+        id=f"{cid}-{name.replace(' ', '-')}",
+        name=name,
+        kind=kind,
+        attack_bonus=attack_bonus,
+        damage=[DamageComponent(formula="1d4", types=["slashing"])],
+        count=count,
+    )
+
+
+def make_combatant(
+    cid: str, attacks: list[AttackSpec], *, bab: int = 1, hp_max: int = 20,
+) -> Combatant:
+    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=hp_max,
+        ac=ACProfile(total=13, touch=13, flat_footed=13),
+        bab=bab,
+        initiative_mod=0,
+        speed_land_ft=30,
+        saves=Saves(fort=0, ref=0, will=0),
+        attacks=attacks,
+    )
+
+
+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 _full_attack_transcript(
+    attacker: CombatantState, target: CombatantState, queue: list[int],
+) -> list[str]:
+    engine = make_engine(queue, [attacker, target])
+    engine._execute(attacker, Action(kind="full_attack", target_id=target.combatant.id))
+    return list(engine._transcript)
+
+
+def _labels(transcript: list[str]) -> list[str]:
+    """Extract the swing labels (e.g. "bite", "claw #1") from swing log lines."""
+    return [
+        line.split(": ", 1)[1].split(" vs ", 1)[0]
+        for line in transcript
+        if " vs " in line and " d20=" in line
+    ]
+
+
+# --- Test 1: multiple melee weapons all resolve in one full_attack ----------
+
+def test_full_attack_resolves_all_melee_weapons() -> None:
+    a_spec = make_combatant(
+        "a",
+        [
+            _attack("a", "bite", count=1),
+            _attack("a", "claw", count=2),
+        ],
+        bab=1,
+        hp_max=20,
+    )
+    b_spec = make_combatant("b", [_attack("b", "sword")], hp_max=20)
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    # bite (1 swing) + claw (2 swings): each swing = attack roll + damage roll.
+    transcript = _full_attack_transcript(a, b, [15, 2, 15, 2, 15, 2])
+    labels = _labels(transcript)
+    assert labels == ["bite", "claw #1", "claw #2"]
+
+
+# --- Test 2: ranged weapons are excluded from the full_attack loop ----------
+
+def test_full_attack_excludes_ranged_weapon() -> None:
+    a_spec = make_combatant(
+        "a",
+        [
+            _attack("a", "sword", count=1),
+            _attack("a", "short bow", kind="ranged", attack_bonus=4),
+        ],
+        bab=1,
+        hp_max=20,
+    )
+    b_spec = make_combatant("b", [_attack("b", "sword")], hp_max=20)
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    transcript = _full_attack_transcript(a, b, [15, 2])
+    labels = _labels(transcript)
+    assert labels == ["sword"]
+    assert not any("short bow" in line for line in transcript)
+
+
+# --- Test 3: mono-weapon full_attack keeps its labels and swing count -------
+
+def test_full_attack_mono_weapon_labels_and_count() -> None:
+    # BAB 6 -> n = 2 iteratives, labels "sword #1" / "sword #2".
+    a_spec = make_combatant("a", [_attack("a", "sword", count=1)], bab=6, hp_max=20)
+    b_spec = make_combatant("b", [_attack("b", "sword")], hp_max=20)
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    transcript = _full_attack_transcript(a, b, [15, 2, 15, 2])
+    assert _labels(transcript) == ["sword #1", "sword #2"]
+
+    # BAB 1 -> n = 1, single label "sword" (no "#1").
+    a_spec = make_combatant("a", [_attack("a", "sword", count=1)], bab=1, hp_max=20)
+    a = make_state(a_spec, "players", (1, 1))
+    transcript = _full_attack_transcript(a, b, [15, 2])
+    assert _labels(transcript) == ["sword"]
+
+
+# --- Test 4: remaining swings/weapons are lost when the target drops --------
+
+def test_full_attack_stops_when_target_drops() -> None:
+    a_spec = make_combatant(
+        "a",
+        [
+            _attack("a", "bite", count=1),
+            _attack("a", "claw", count=2),
+        ],
+        bab=1,
+        hp_max=20,
+    )
+    b_spec = make_combatant("b", [_attack("b", "sword")], hp_max=1)
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    # bite hits for 2 -> target (1 hp) drops; claw swings are lost.
+    transcript = _full_attack_transcript(a, b, [15, 2])
+    labels = _labels(transcript)
+    assert labels == ["bite"]
+    assert not any("claw" in line for line in transcript)
+
+
+# --- Test 5: determinism ----------------------------------------------------
+
+def _run_full_attack() -> tuple[str, ...]:
+    a_spec = make_combatant(
+        "a",
+        [
+            _attack("a", "bite", count=1),
+            _attack("a", "claw", count=2),
+        ],
+        bab=1,
+        hp_max=20,
+    )
+    b_spec = make_combatant("b", [_attack("b", "sword")], hp_max=20)
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+
+    def policy(engine: CombatEngine, state: CombatantState) -> tuple[Action, ...]:
+        if state.combatant.id == "a":
+            return (Action(kind="full_attack", target_id="b"),)
+        return (Action(kind="wait"),)
+
+    engine = CombatEngine(SeededRng(42), make_grid(), [a, b], policy=policy)
+    return engine.run().transcript
+
+
+def test_full_attack_determinism_same_seed_same_transcript() -> None:
+    assert _run_full_attack() == _run_full_attack()