fix(combat): channel energy targets living vs undead

README.md

@@ -381,11 +381,15 @@ Règles modélisées :
   toute transparence (noms décoratifs / de race) — aucun n'est silencieusement ignoré
   (`tests/test_feats.py`).
 - Capacités de classe émises par `default_policy`, chacune conditionnée à une ressource
-  `> 0` dépensée dans la méthode d'exécution : `channel_energy` (oni, allié < 50 % ou
+  `> 0` dépensée dans la méthode d'exécution : `channel_energy` (oni, énergie positive :
-  ennemis groupés à 30 ft), sortilège `evil_eye` (nairda), deed `up_close_and_deadly`
+  si un allié est < 50 % de ses PV → soigne tous les êtres vivants à 30 ft ; sinon, si au
+  moins 2 morts-vivants ennemis sont groupés à 30 ft → les blesse en 2d6 ; le camp de la
+  cible n'est pas pris en compte — seul `creature_type` compte, `selective_channeling` non
+  modélisé), sortilège `evil_eye` (nairda), deed `up_close_and_deadly`
   (tammara, action bonus +1d6 à ≤ 30 ft), `inspire_courage` + `spell_combat` (misty)
   — couvertes par `tests/test_class_abilities.py`.
-- Le Liche (`data/monsters/lich.json`) : aura de terreur (30 ft, Volonté DD 22 ou
+- Le Liche (`data/monsters/lich.json`) : `creature_type: "undead"` (sensible à l'énergie
+  positive canalisée), aura de terreur (30 ft, Volonté DD 22 ou
   `shaken` 1 round, au début de son tour) et contact paralysant (au toucher,
   `paralysé` 1d4+1 rounds), RD 15/magie+contondant ; son JSON porte un dictionnaire
   `spell_slots` sans clés dupliquées.

data/monsters/lich.json

@@ -2,6 +2,7 @@
   "name": "Lich",
   "level": 11,
   "size": "Medium",
+  "creature_type": "undead",
   "abilities": {
     "str_score": 12,
     "dex_score": 14,

src/pf1e_simulator/combat.py

@@ -295,6 +295,7 @@ class Action:
     hex_name: str | None = None  # "evil_eye", "slumber", "cackle"
     deed_name: str | None = None  # "up_close_and_deadly", "quick_clear"
     class_ability: str | None = None  # "deed"|"spell_combat"|"inspire_courage"|"hex"|"channel"
+    channel_mode: Literal["heal", "harm"] | None = None  # channel energy polarity for this use
 
 
 @dataclass(frozen=True)
@@ -1156,7 +1157,9 @@ class CombatEngine:
         """Dispatch a class-ability action by kind, reading its carrier field."""
         kind = action.kind
         if kind == "channel_energy":
-            self._execute_channel_energy(state, target)
+            self._execute_channel_energy(
+                state, target, action.channel_mode or "heal"
+            )
         elif kind == "hex":
             self._execute_hex(state, target, action.hex_name)
         elif kind == "deed":
@@ -1393,9 +1396,18 @@ class CombatEngine:
             )
 
     def _execute_channel_energy(
-        self, state: CombatantState, target: CombatantState | None
+        self,
+        state: CombatantState,
+        target: CombatantState | None,
+        channel_mode: Literal["heal", "harm"],
     ) -> None:
-        """Execute channel energy (burst 30ft, 2d6 heal/damage, spends channel energy)."""
+        """Execute channel energy (positive energy, burst 30ft, 2d6).
+
+        Heal mode heals all living creatures in the burst; harm mode damages
+        all undead creatures in the burst — the target's side does not matter
+        (PF1e Channel Energy: positive energy heals living creatures and
+        damages undead creatures within 30 feet).
+        """
         if not state.spend_resource("channel_energy", 1):
             self._log(
                 f"round {self._current_round} {state.combatant.id}: "
@@ -1407,8 +1419,7 @@ class CombatEngine:
 
         # Channel energy affects all creatures within 30ft (6 cells)
         radius_cells = 30 // _SQUARE_FT  # 6 cells
-        center = state.pos
+        affected = self._creatures_in_range(state.pos, radius_cells)
-        affected = self._creatures_in_range(center, radius_cells)
 
         if not affected:
             self._log(
@@ -1417,22 +1428,21 @@ class CombatEngine:
             )
             return
 
-        # Determine if healing or harming based on target relationship
+        wanted_type = "living" if channel_mode == "heal" else "undead"
-        is_harm = target.side != state.side
+        hit = [s for s in affected if s.combatant.creature_type == wanted_type]
 
         # 2d6 damage/healing
         dmg = 1 + self._rng.roll_die(11)  # 2d6
 
-        for affected_state in affected:
+        for affected_state in hit:
-            is_ally = affected_state.side == state.side
+            if channel_mode == "heal":
-            if is_ally and not is_harm:
                 self._channel_heal(state, affected_state, dmg)
-            elif not is_ally and is_harm:
+            else:
                 self._channel_damage(state, affected_state, dmg)
 
         self._log(
             f"round {self._current_round} {state.combatant.id}: "
-            f"channel energy ({'harm' if is_harm else 'heal'}) {dmg} -> {len(affected)} targets"
+            f"channel energy ({channel_mode}) {dmg} -> {len(hit)} targets"
         )
 
     def _channel_heal(
@@ -2524,8 +2534,15 @@ def default_policy(engine: CombatEngine, state: CombatantState) -> tuple[Action,
         return (Action(kind="withdraw", target_id=target.combatant.id),)
 
     # Channel energy (oni): standard action that heal/harms in a 30ft burst.
-    if _emit_channel_energy(engine, state):
+    channel_mode = _emit_channel_energy(engine, state)
-        return (Action(kind="channel_energy", target_id=target.combatant.id),)
+    if channel_mode is not None:
+        return (
+            Action(
+                kind="channel_energy",
+                target_id=target.combatant.id,
+                channel_mode=channel_mode,
+            ),
+        )
 
     # Hex (nairda): standard action when the target is within close range.
     if _emit_hex(engine, state, target):
@@ -2558,21 +2575,24 @@ _GROUPED_ENEMY_COUNT = 2
 _HEX_RANGE_FT = 25
 
 
-def _emit_channel_energy(engine: CombatEngine, state: CombatantState) -> bool:
+def _emit_channel_energy(
-    """True when oni should channel energy: resource available and a trigger is met."""
+    engine: CombatEngine, state: CombatantState
+) -> Literal["heal", "harm"] | None:
+    """Channel mode when oni should channel (heal living / harm undead)."""
     if state.resources_left.get("channel_energy", 0) <= 0:
-        return False
+        return None
     if _find_ally_needing_heal(engine, state) is not None:
-        return True
+        return "heal"
     radius_cells = 30 // _SQUARE_FT
-    grouped_enemies = [
+    grouped_undead_enemies = [
         s
         for s in engine.states
         if s.side != state.side
         and s.active
+        and s.combatant.creature_type == "undead"
         and engine.grid.distance(state.pos, s.pos) <= radius_cells
     ]
-    return len(grouped_enemies) >= _GROUPED_ENEMY_COUNT
+    return "harm" if len(grouped_undead_enemies) >= _GROUPED_ENEMY_COUNT else None
 
 
 def _emit_hex(

src/pf1e_simulator/models.py

@@ -267,6 +267,7 @@ class Combatant(_FrozenModel):
     name: str
     level: int = Field(ge=1)
     size: str = "Medium"
+    creature_type: Literal["living", "undead", "construct"] = "living"
     abilities: AbilityScores
     hp_max: int = Field(ge=1)
     ac: ACProfile

tests/test_class_abilities.py

@@ -7,6 +7,8 @@ tammara (deeds), misty (spell_combat + inspire_courage). Each class has an
 
 from __future__ import annotations
 
+from typing import Literal
+
 from pf1e_simulator.combat import Action, CombatantState, CombatEngine, default_policy
 from pf1e_simulator.dice import parse_dice
 from pf1e_simulator.grid import Grid
@@ -29,6 +31,7 @@ def _combatant(
     resources: dict[str, int] | None = None,
     spells: list[str] | None = None,
     hp_max: int = 20,
+    creature_type: Literal["living", "undead", "construct"] = "living",
 ) -> Combatant:
     attack = AttackSpec(
         id=f"{cid}-w",
@@ -55,6 +58,7 @@ def _combatant(
         attacks=[attack],
         resources=resources or {},
         spells=spells or [],
+        creature_type=creature_type,
     )
 
 
@@ -134,6 +138,69 @@ def test_oni_channel_energy_spends_resource() -> None:
     assert me.resources_left["channel_energy"] == 5
 
 
+def test_oni_channel_harm_does_not_damage_living_enemy() -> None:
+    """Regression: positive energy must not damage living creatures (reported bug:
+    oni harmed a Giant Belostomatid — living vermin). Harm mode only hits undead."""
+    oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
+    vermin = _combatant("belostomatid", hp_max=30)
+    engine, me, enemy = _engine(oni, [vermin], rng_queue=[11])
+
+    action = Action(
+        kind="channel_energy", target_id=vermin.id, channel_mode="harm"
+    )
+    engine._execute(me, action)
+
+    assert me.hp == 30  # living caster unaffected by harm mode
+    assert enemy[0].hp == 30  # living vermin unaffected by harm mode
+
+
+def test_oni_channel_harm_damages_undead() -> None:
+    """Harm mode damages undead creatures in the burst regardless of side."""
+    oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
+    lich = _combatant("lich", hp_max=100, creature_type="undead")
+    engine, me, enemy = _engine(oni, [lich], rng_queue=[11])
+
+    action = Action(kind="channel_energy", target_id=lich.id, channel_mode="harm")
+    engine._execute(me, action)
+
+    assert enemy[0].hp == 100 - (1 + 11)  # 2d6 = 1 + roll_die(11)
+
+
+def test_oni_channel_heal_heals_living_enemies_in_range() -> None:
+    """Heal mode heals all living creatures in the burst — including enemies
+    (Selective Channeling, which would exclude them, is not modeled)."""
+    oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
+    goblin = _combatant("goblin", hp_max=6)
+    engine, me, enemy = _engine(oni, [goblin], rng_queue=[5])
+    enemy[0].hp = 2
+
+    action = Action(
+        kind="channel_energy", target_id=me.combatant.id, channel_mode="heal"
+    )
+    engine._execute(me, action)
+
+    assert enemy[0].hp == min(2 + (1 + 5), 6)  # healed, capped at hp_max
+
+
+def test_oni_emits_channel_harm_only_for_grouped_undead() -> None:
+    """Channel harm is emitted only when at least 2 undead enemies are grouped at 30ft
+    — living enemies are never harmed by positive energy."""
+    oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
+    lich1 = _combatant("lich1", hp_max=100, creature_type="undead")
+
+    engine, me, _ = _engine(oni, [lich1])
+    assert not any(a.kind == "channel_energy" for a in default_policy(engine, me))
+
+    lich2 = _combatant("lich2", hp_max=100, creature_type="undead")
+    engine, me, _ = _engine(oni, [lich1, lich2])
+    actions = default_policy(engine, me)
+
+    assert any(
+        a.kind == "channel_energy" and a.channel_mode == "harm"
+        for a in actions
+    )
+
+
 # --- nairda: hex ---
 
 

tests/test_determinism.py

@@ -35,9 +35,9 @@ def _make_grid() -> Grid:
 
 
 def _make_channel_policy(_engine: CombatEngine, state: CombatantState) -> tuple[Action, ...]:
-    """Emit a channel_energy on an alpha, otherwise the default policy."""
+    """Emit a channel_energy (heal mode) on an alpha, otherwise the default policy."""
     if state.combatant.id == "oni-a":
-        return (Action(kind="channel_energy", target_id="oni-b"),)
+        return (Action(kind="channel_energy", target_id="oni-b", channel_mode="heal"),)
     return default_policy(_engine, state)
 
 

tests/test_runner_spells.py

@@ -37,15 +37,19 @@ def test_monte_carlo_caster_pc_casts_spell() -> None:
     """oni (cleric) casts against data/spells/ once it drops below 50% HP.
 
     oni's known spells overlap the registry's heal spells (Cure Light/Moderate
-    Wounds); with enough damage taken it heals via cast_spell. The Monte Carlo
+    Wounds); with enough damage taken it heals via cast_spell. Channel energy is
+    stripped from the resource pool: it now heals living creatures in the burst,
+    so below 50% HP oni self-heals by channeling and never reaches the spell
+    branch — this test stays a pure spell-wiring check. The Monte Carlo
     loop mirrors run_encounter: build fresh states and one CombatEngine per run
     with the registry from SPELLS_DIR.
     """
+    oni = load_combatant(ONI).model_copy(update={"resources": {}})
     spec = EncounterSpec(
         map=load_map(MAP),
         round_cap=100,
         sides=(
-            Side(name="players", combatants=(load_combatant(ONI),), zone="A"),
+            Side(name="players", combatants=(oni,), zone="A"),
             Side(name="monsters", combatants=(load_combatant(GOBLIN),) * 4, zone="B"),
         ),
     )