pf1e-simulator/tests/test_hex_aoe_dr.py

"""Tests for hex DC, AoE save DC, and spell damage DR bypass (Task 5)."""

from __future__ import annotations

from pathlib import Path

from pf1e_simulator.combat import CombatantState, CombatEngine
from pf1e_simulator.dice import parse_dice
from pf1e_simulator.grid import Grid
from pf1e_simulator.map import MapSpec, TerrainType
from pf1e_simulator.models import (
    AbilityScores,
    ACProfile,
    AttackSpec,
    Combatant,
    DamageComponent,
    DamageReduction,
    Saves,
)
from pf1e_simulator.rng import ScriptedRng
from pf1e_simulator.spells import load_spell_registry

_SPELLS_DIR = Path(__file__).resolve().parent.parent / "data" / "spells"


def _make_caster(cid: str = "caster", *, level: int = 5, int_score: int = 18) -> Combatant:
    attack = AttackSpec(
        id=f"{cid}-w",
        name="dagger",
        kind="melee",
        attack_bonus=2,
        damage=[DamageComponent(formula=parse_dice("1d4"), types=["piercing"])],
    )
    return Combatant(
        id=cid,
        name=cid,
        level=level,
        size="Medium",
        abilities=AbilityScores(
            str_score=10, dex_score=14, con_score=12,
            int_score=int_score, wis_score=12, cha_score=10,
        ),
        hp_max=20,
        ac=ACProfile(total=12, touch=12, flat_footed=10),
        bab=2,
        initiative_mod=2,
        speed_land_ft=30,
        saves=Saves(fort=3, ref=4, will=4),
        attacks=[attack],
        casting_ability="int",
        spell_slots={1: 4, 2: 3, 3: 2},
        resources={"hexes": 3, "channel_energy": 6},
    )


def _make_target(cid: str = "target", *, hp_max: int = 30) -> Combatant:
    attack = AttackSpec(
        id=f"{cid}-w",
        name="club",
        kind="melee",
        attack_bonus=3,
        damage=[DamageComponent(formula=parse_dice("1d6"), types=["bludgeoning"])],
    )
    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=10, touch=10, flat_footed=10),
        bab=1,
        initiative_mod=0,
        speed_land_ft=30,
        saves=Saves(fort=2, ref=2, will=2),
        attacks=[attack],
    )


def _make_engine(
    caster: Combatant,
    target: Combatant,
    queue: list[int],
    *,
    caster_pos: tuple[int, int] = (0, 0),
    target_pos: tuple[int, int] = (3, 0),
) -> tuple[CombatEngine, CombatantState, CombatantState]:
    c = CombatantState(
        combatant=caster, side="players", pos=caster_pos, hp=caster.hp_max,
        resources_left=dict(caster.resources),
    )
    t = CombatantState(
        combatant=target, side="monsters", pos=target_pos, hp=target.hp_max,
        resources_left=dict(target.resources),
    )
    legend = {".": TerrainType(type="floor", move_cost=1)}
    spec = MapSpec(name="test", terrain=tuple(["." * 12] * 12), legend=legend)
    grid = Grid.from_spec(spec)
    reg = load_spell_registry(_SPELLS_DIR)
    engine = CombatEngine(ScriptedRng(queue), grid, [c, t], spell_registry=reg)
    return engine, c, t


class TestHexDcUsesInt:
    """Given: a witch with level 4, INT 21 (mod +5)
    When: evil_eye hex is cast (Will save)
    Then: DC = 10 + 4//2 + (21-10)//2 = 17.

    Behavioral test: target has Will +2. d20=13 -> total 15.
    DC 17: 15 < 17 -> fail -> shaken applied.
    DC 12 (wrong, uses CHA): 15 >= 12 -> success -> no effect.
    """

    def test_hex_dc_uses_int_not_cha(self) -> None:
        caster = _make_caster(level=4, int_score=21)
        target = _make_target(hp_max=100)
        engine, c, t = _make_engine(caster, target, [13])
        engine._execute_hex(c, t, "evil_eye")
        assert any("shaken" in line for line in engine._transcript)


class TestAoEDcEqualsCasterSpellDc:
    """Given: a caster with INT 18 (mod +4) casting Fireball (level 3)
    When: the AoE targets a secondary creature (caster self in area)
    Then: the area save DC equals the caster's spell DC (17), not hardcoded 15.

    Behavioral test: secondary target (caster) has ref +4.
    d20=12 -> total 12+4=16. DC 17 -> 16<17 -> fail (full damage).
    If DC 15 (old bug): 16>=15 -> success (half damage).
    """

    def test_area_save_uses_caster_dc(self) -> None:
        caster = _make_caster(level=5, int_score=18)
        target = _make_target(hp_max=200)
        queue = [1, 12, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
        engine, c, t = _make_engine(caster, target, queue)
        hp_before_caster = c.hp
        hp_before_target = t.hp
        engine._cast_spell(c, t, "Fireball")
        assert t.hp == hp_before_target - 18
        assert c.hp == hp_before_caster - 18


class TestSpellDamageBypassesDr:
    """Given: a target with DR 5/- (bypassed by nothing)
    When: a spell deals fire damage
    Then: DR does NOT reduce spell damage (PF1e: spells/energy bypass DR)."""

    def test_dr_does_not_reduce_spell_damage(self) -> None:
        caster = _make_caster(level=5, int_score=18)
        target = _make_target(hp_max=200)
        target_with_dr = target.model_copy(update={
            "dr": DamageReduction(amount=5, bypass=frozenset()),
        })
        queue = [2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
        engine, c, t = _make_engine(caster, target_with_dr, queue)
        hp_before = t.hp
        engine._cast_spell(c, t, "Fireball")
        assert t.hp == hp_before - 18