feat(rules): SplashSpec data model - data-driven splash marker on thrown weapons, Alchemist's Fire splash 1 fire on oni/tammara (SRD Throw Splash Weapon, Alchemist's fire)

data/pcs/oni.json

@@ -72,7 +72,11 @@
    "crit_mult": 2,
    "reach_ft": 5,
    "count": 1,
-   "range_increment_ft": 10
+   "range_increment_ft": 10,
+   "splash": {
+    "damage": 1,
+    "type": "fire"
+   }
   },
   {
    "name": "Attaques naturelles (Shifter Claws / formes fées)",

data/pcs/tammara.json

@@ -111,7 +111,11 @@
       "crit_mult": 2,
       "reach_ft": 5,
       "count": 1,
-      "range_increment_ft": 10
+      "range_increment_ft": 10,
+      "splash": {
+        "damage": 1,
+        "type": "fire"
+      }
     },
     {
       "name": "Unarmed Strike",

src/pf1e_simulator/models.py

@@ -7,9 +7,9 @@ never sees raw JSON.
 
 from __future__ import annotations
 
-from typing import Literal
+from typing import Literal, Self
 
-from pydantic import BaseModel, ConfigDict, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator
 
 from pf1e_simulator.abilities import AbilitySpec  # noqa: TC001
 from pf1e_simulator.dice import DiceExpr, DiceParseError, parse_dice
@@ -232,6 +232,24 @@ class DamageComponent(_FrozenModel):
         return value
 
 
+class SplashSpec(_FrozenModel):
+    """Splash payload of a thrown splash weapon (SRD "Throw Splash Weapon").
+
+    ``damage`` is the FLAT splash damage every creature within 5 feet of the
+    point of impact takes on a direct hit — no attack roll, no saving throw
+    (SRD "Alchemist's fire": "Every creature within 5 feet of the point where
+    the flask hits takes 1 point of fire damage from the splash"). ``type`` is
+    the energy type ("fire", "acid", ...): splash is energy damage, so the
+    component-based energy resistance/immunity path applies and damage
+    reduction does not; the flat amount is never multiplied on a critical hit.
+    On a miss the weapon scatters (1d8 direction, one range increment) and
+    deals only this splash at where it landed.
+    """
+
+    damage: int = Field(ge=0)
+    type: str = Field(min_length=1)
+
+
 _HAFTED_WEAPON_TOKENS: tuple[str, ...] = (
     "axe", "spear", "hammer", "mace", "flail", "staff", "pick", "javelin",
 )
@@ -291,6 +309,23 @@ class AttackSpec(_FrozenModel):
     hardness: int | None = Field(default=None, ge=0)
     hit_points: int | None = Field(default=None, ge=1)
     enhancement: int = Field(default=0, ge=0, le=20)
+    # SRD "Throw Splash Weapon": a thrown splash weapon (alchemist's fire,
+    # acid, holy water) is a ranged attack with a splash payload; it must be
+    # thrown (ranged kind or ranged touch with a range increment), so the
+    # validator below rejects splash on melee or increment-less attacks.
+    splash: SplashSpec | None = None
+
+    @model_validator(mode="after")
+    def _splash_needs_thrown_range(self) -> Self:
+        if self.splash is not None and (
+            self.kind == "melee" or self.range_increment_ft is None
+        ):
+            msg = (
+                f"attack {self.id!r}: splash requires a thrown weapon "
+                "(kind ranged/touch with range_increment_ft)"
+            )
+            raise ValueError(msg)
+        return self
 
     def object_stats(self) -> tuple[int, int]:
         """Hardness and hit points of the weapon as an OBJECT (Medium item).