from pathlib import Path

import pytest

from engine.character import ClothingPiece, Character
from engine.defs import DefRegistry
from resources.logic.combat import defender_armor, perform_attack

DEFS_DIR = Path(__file__).resolve().parent.parent / "resources" / "defs"


@pytest.fixture()
def registry():
    return DefRegistry.load(DEFS_DIR)


def make_human(registry, **kwargs) -> Character:
    return Character(species_id="human", default_body_parts=registry.new_default_body_parts("human"), **kwargs)


class FixedRng:
    def __init__(self, roll: int, choice_value=None):
        self._roll = roll
        self._choice_value = choice_value

    def randint(self, _lo, _hi):
        return self._roll

    def choice(self, seq):
        return self._choice_value if self._choice_value is not None else seq[0]


def test_defender_armor_sums_worn_clothing(registry):
    defender = make_human(registry, clothing=[ClothingPiece("torso", "leather_jacket")])
    assert defender_armor(defender, registry) == pytest.approx(3.0)  # leather_jacket's armor_reduction


def test_unarmored_defender_has_zero_armor(registry):
    defender = make_human(registry)
    assert defender_armor(defender, registry) == 0.0


def test_armor_reduces_damage_taken(registry):
    attacker = make_human(registry)
    attacker.bio["athletics"] = 10

    unarmored = make_human(registry)
    armored = make_human(registry, clothing=[ClothingPiece("torso", "leather_jacket")])

    unarmored_result = perform_attack(attacker, unarmored, registry, rng=FixedRng(roll=15, choice_value="torso"))
    armored_result = perform_attack(attacker, armored, registry, rng=FixedRng(roll=15, choice_value="torso"))

    assert armored_result.armor_reduction == pytest.approx(3.0)
    assert armored_result.damage == pytest.approx(max(0.0, unarmored_result.damage - 3.0))


def test_heavy_armor_can_absorb_a_hit_entirely(registry):
    attacker = make_human(registry)
    defender = make_human(registry, clothing=[ClothingPiece("torso", "leather_jacket")])

    # a roll that only barely clears the DC: margin (1) is smaller than armor_reduction (3)
    result = perform_attack(attacker, defender, registry, rng=FixedRng(roll=11, choice_value="torso"))
    assert result.hit is True  # the check itself succeeded...
    assert result.damage == 0.0  # ...but armor soaked up all of it
    assert defender.get_body_part("torso").integrity == pytest.approx(100.0)