from pathlib import Path

import pytest

from engine.defs import DefRegistry
from engine.map_loader import MapLoader
from engine.world_creation import AVAILABLE_WORLD_TEMPLATES, WorldCreationMenu, WorldTemplate, build_world_from_template

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


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


@pytest.fixture()
def map_loader():
    return MapLoader(DEFS_DIR / "maps")


# --- WorldCreationMenu -----------------------------------------------------------------------


def test_menu_starts_with_the_available_templates():
    menu = WorldCreationMenu()
    assert [t.id for t in menu.templates] == [t.id for t in AVAILABLE_WORLD_TEMPLATES]
    assert menu.selected_index is None


def test_currently_only_one_template_is_available():
    # campaign/survival/creative (procedurally generated) modes are planned follow-ups, not yet
    # implemented - this pins down the "just the test map for now" scope explicitly
    assert [t.id for t in AVAILABLE_WORLD_TEMPLATES] == ["test_map"]


def test_select_sets_selected_index():
    menu = WorldCreationMenu()
    menu.select(0)
    assert menu.selected_index == 0


def test_select_out_of_range_is_ignored():
    menu = WorldCreationMenu()
    menu.select(99)
    assert menu.selected_index is None


def test_selected_template_reads_back_the_right_one():
    menu = WorldCreationMenu()
    menu.select(0)
    assert menu.selected_template() is AVAILABLE_WORLD_TEMPLATES[0]


def test_selected_template_none_before_any_selection():
    menu = WorldCreationMenu()
    assert menu.selected_template() is None


# --- build_world_from_template ------------------------------------------------------------------


def test_build_world_from_template_loads_the_map_and_its_embeddings(registry, map_loader):
    template = AVAILABLE_WORLD_TEMPLATES[0]
    world = build_world_from_template(template, registry, map_loader)
    assert "harbor_world" in world.maps
    assert "ship_test" in world.maps  # embedded child map also gets added
    assert world.entities == {}  # world creation alone spawns no one


def test_build_world_from_template_raises_for_a_generator_only_template(registry, map_loader):
    generator_template = WorldTemplate(id="campaign", name="Campaign", map_file=None)
    with pytest.raises(NotImplementedError):
        build_world_from_template(generator_template, registry, map_loader)