fix(combat): channel energy targets living vs undead

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(center, radius_cells)
+        affected = self._creatures_in_range(state.pos, radius_cells)
 
         if not affected:
             self._log(
@@ -1417,22 +1428,21 @@ class CombatEngine:
             )
             return
 
-        # Determine if healing or harming based on target relationship
-        is_harm = target.side != state.side
+        wanted_type = "living" if channel_mode == "heal" else "undead"
+        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:
-            is_ally = affected_state.side == state.side
-            if is_ally and not is_harm:
+        for affected_state in hit:
+            if channel_mode == "heal":
                 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):
-        return (Action(kind="channel_energy", target_id=target.combatant.id),)
+    channel_mode = _emit_channel_energy(engine, state)
+    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:
-    """True when oni should channel energy: resource available and a trigger is met."""
+def _emit_channel_energy(
+    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(