pf1e-simulator/tests/test_multi_projectile.py

"""Multi-projectile spells (Package S2b).

PF1e (SRD spells/magic-missile.md): Magic Missile fires "one missile, plus one
additional missile per two caster levels beyond 1st [...] maximum of five
missiles", each 1d4+1 force, auto-hit (no attack roll).
(SRD spells/scorching-ray.md): Scorching Ray fires "one ray, plus one
additional ray for every four levels beyond 3rd (to a maximum of three rays at
11th level)", each a ranged touch attack for 4d6 fire.

Each projectile rolls its own damage and (for a ray) its own attack; if the
target drops mid-sequence the remaining projectiles are lost (the engine's
existing multi-attack convention).
"""

from __future__ import annotations

from pathlib import Path

import pytest

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,
    Saves,
)
from pf1e_simulator.rng import ScriptedRng
from pf1e_simulator.spells import DamageEffect, load_spell, load_spell_registry

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


def _caster(cid: str = "caster", *, level: int = 1) -> 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=18, 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={0: 99, 1: 99, 2: 99, 3: 99, 4: 99, 5: 99, 6: 99},
    )


def _target(cid: str = "target", *, hp_max: int = 200, touch_ac: int = 10) -> 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=touch_ac, touch=touch_ac, flat_footed=touch_ac),
        bab=1,
        initiative_mod=0,
        speed_land_ft=30,
        saves=Saves(fort=2, ref=2, will=2),
        attacks=[attack],
    )


def _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)
    t = CombatantState(combatant=target, side="monsters", pos=target_pos, hp=target.hp_max)
    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


def _projectile_count(spell_file: str, level: int) -> int:
    spell = load_spell(_SPELLS_DIR / spell_file)
    effect = spell.effects[0]
    assert isinstance(effect, DamageEffect)
    assert effect.projectiles is not None
    return effect.projectiles.count_for(level)


class TestMagicMissileProjectileCount:
    """Given: Magic Missile's projectile scaling (base 1, +1 per 2 levels
    beyond 1st, max 5)
    When: the count is resolved for caster levels 1 / 4 / 9 / 20
    Then: it is 1 / 2 / 5 / 5 missiles (SRD spells/magic-missile.md)."""

    def test_count_at_level_1(self) -> None:
        assert _projectile_count("magic_missile.json", 1) == 1

    def test_count_at_level_4(self) -> None:
        assert _projectile_count("magic_missile.json", 4) == 2

    def test_count_at_level_9(self) -> None:
        assert _projectile_count("magic_missile.json", 9) == 5

    def test_count_caps_at_five(self) -> None:
        assert _projectile_count("magic_missile.json", 20) == 5


class TestScorchingRayProjectileCount:
    """Given: Scorching Ray's projectile scaling (base 1, +1 per 4 levels
    beyond 3rd, max 3)
    When: the count is resolved for caster levels 1 / 7 / 11 / 20
    Then: it is 1 / 2 / 3 / 3 rays (SRD spells/scorching-ray.md)."""

    def test_count_at_level_1(self) -> None:
        assert _projectile_count("scorching_ray.json", 1) == 1

    def test_count_at_level_7(self) -> None:
        assert _projectile_count("scorching_ray.json", 7) == 2

    def test_count_at_level_11(self) -> None:
        assert _projectile_count("scorching_ray.json", 11) == 3

    def test_count_caps_at_three(self) -> None:
        assert _projectile_count("scorching_ray.json", 20) == 3


class TestMagicMissileFiresAllMissiles:
    """Given: a level-5 caster (3 missiles) and a high-hp target
    When: Magic Missile is cast (auto-hit, no attack roll)
    Then: all three missiles land, each rolling its own 1d4+1."""

    def test_three_missiles_sum(self) -> None:
        caster = _caster(level=5)
        target = _target(hp_max=200)
        engine, c, t = _engine(caster, target, [4, 5, 6])
        hp_before = t.hp
        engine._cast_spell(c, t, "Magic Missile")
        # (4+1) + (5+1) + (6+1) = 18
        assert t.hp == hp_before - 18

    def test_no_attack_roll_consumed(self) -> None:
        """Given: auto-hit — no ranged touch attack roll is made
        When: exactly three d4 rolls are scripted
        Then: the cast consumes them all for damage (no touch-attack line)."""
        caster = _caster(level=5)
        target = _target(hp_max=200)
        engine, c, t = _engine(caster, target, [3, 3, 3])
        engine._cast_spell(c, t, "Magic Missile")
        assert not any("touch attack" in line for line in engine._transcript)
        assert t.hp == 200 - 3 * (3 + 1)


class TestScorchingRayPerProjectileAttack:
    """Given: a caster firing several rays at a target
    When: Scorching Ray is cast
    Then: each ray rolls its OWN ranged touch attack, and only the rays that
    hit deal their 4d6."""

    def test_each_ray_rolls_its_own_attack(self) -> None:
        caster = _caster(level=11)  # 3 rays
        target = _target(hp_max=500, touch_ac=10)
        # 3 rays, each: d20 attack (15 -> hits AC 10 with bab2+dex2=+4)
        # then 4d6 damage (four scripted d6s of 3 each)
        queue = [15, 3, 3, 3, 3, 15, 3, 3, 3, 3, 15, 3, 3, 3, 3]
        engine, c, t = _engine(caster, target, queue)
        hp_before = t.hp
        engine._cast_spell(c, t, "Scorching Ray")
        attack_lines = [ln for ln in engine._transcript if "ranged touch attack" in ln]
        assert len(attack_lines) == 3
        # 3 rays x 4d6 (each 3) = 3 x 12 = 36
        assert t.hp == hp_before - 36

    def test_missed_ray_deals_no_damage(self) -> None:
        """Given: the first ray's attack roll is a natural 1 (auto-miss)
        When: the second ray hits
        Then: only the hit ray deals damage."""
        caster = _caster(level=7)  # 2 rays
        target = _target(hp_max=500, touch_ac=10)
        # ray 1: d20=1 (auto miss); ray 2: d20=15 hit + 4d6 of 3
        queue = [1, 15, 3, 3, 3, 3]
        engine, c, t = _engine(caster, target, queue)
        hp_before = t.hp
        engine._cast_spell(c, t, "Scorching Ray")
        # only the second ray lands: 4d6 (3+3+3+3) = 12
        assert t.hp == hp_before - 12


class TestProjectilesLostWhenTargetDrops:
    """Given: a level-5 caster (3 missiles) and a target that dies on the
    second missile
    When: Magic Missile is cast
    Then: the third missile is lost (target dropped mid-sequence)."""

    def test_remaining_missiles_lost(self) -> None:
        caster = _caster(level=5)
        # each missile rolls 4+1 = 5; hp 6 -> 1 -> -4 after two, third lost
        target = _target(hp_max=6)
        engine, c, t = _engine(caster, target, [4, 4, 4])
        engine._cast_spell(c, t, "Magic Missile")
        assert t.hp == 6 - 10


class TestProjectileLoaderValidation:
    """Given: a projectiles spec in a spell JSON
    When: parsed
    Then: the scaling fields are carried; a max below base is a data error."""

    def test_parses_projectile_spec(self, tmp_path: Path) -> None:
        spell_file = tmp_path / "volley.json"
        spell_file.write_text(
            '{"name": "Volley", "level": 2, "school": "evocation",'
            ' "range": "close", "save": "none", "requires_ranged_touch": true,'
            ' "effects": [{"type": "damage", "formula": "4d6", "types": ["fire"],'
            ' "projectiles": {"base": 1, "per_levels": 4, "at_level": 3, "max": 3}}]}'
        )
        spell = load_spell(spell_file)
        effect = spell.effects[0]
        assert isinstance(effect, DamageEffect)
        assert effect.projectiles is not None
        assert effect.projectiles.count_for(11) == 3

    def test_rejects_max_below_base(self, tmp_path: Path) -> None:
        spell_file = tmp_path / "bad.json"
        spell_file.write_text(
            '{"name": "Bad", "level": 1, "school": "evocation",'
            ' "range": "close", "save": "none",'
            ' "effects": [{"type": "damage", "formula": "1d4", "types": ["force"],'
            ' "projectiles": {"base": 2, "per_levels": 2, "at_level": 1, "max": 1}}]}'
        )
        with pytest.raises(ValueError, match="projectiles max must be >= base"):
            load_spell(spell_file)