from pathlib import Path

import pytest
from PIL import Image

from engine.defs import DefRegistry
from engine.placeholder_textures import TEXTURE_SIZE
from scripts.export_blank_textures import export_blank_textures

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


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


def test_writes_a_correctly_sized_blank_file_for_a_known_item(registry, tmp_path):
    export_blank_textures(registry, tmp_path)
    staff_def = registry.item_defs["staff_oak"]
    path = tmp_path / staff_def.texture
    assert path.exists()
    with Image.open(path) as img:
        assert img.size == (TEXTURE_SIZE, TEXTURE_SIZE)
        assert img.mode == "RGBA"


def test_written_image_is_mostly_transparent(registry, tmp_path):
    export_blank_textures(registry, tmp_path)
    staff_def = registry.item_defs["staff_oak"]
    with Image.open(tmp_path / staff_def.texture) as img:
        alphas = img.tobytes()[3::4]  # every 4th byte of an RGBA buffer is alpha
        # a small label is drawn, but the vast majority of a 32x32 canvas stays untouched
        assert alphas.count(0) > len(alphas) * 0.5


def test_covers_items_and_body_parts_too(registry, tmp_path):
    export_blank_textures(registry, tmp_path)
    item_def = next(d for d in registry.item_defs.values() if d.texture)
    part_def = next(d for d in registry.body_part_defs.values() if d.texture)
    assert (tmp_path / item_def.texture).exists()
    assert (tmp_path / part_def.texture).exists()


def test_reports_written_and_skipped_counts(registry, tmp_path):
    written_first, skipped_first = export_blank_textures(registry, tmp_path)
    assert written_first > 0
    assert skipped_first == 0

    written_second, skipped_second = export_blank_textures(registry, tmp_path)
    assert written_second == 0
    assert skipped_second == written_first


def test_does_not_overwrite_a_file_an_artist_already_replaced(registry, tmp_path):
    export_blank_textures(registry, tmp_path)
    staff_def = registry.item_defs["staff_oak"]
    path = tmp_path / staff_def.texture
    path.write_bytes(b"real-art-not-a-real-png")

    export_blank_textures(registry, tmp_path)
    assert path.read_bytes() == b"real-art-not-a-real-png"