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,
    GENERATED_WORLD_SIZE,
    WorldCreationMenu,
    build_world_from_template,
    find_spawn_position,
)

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_available_templates_are_test_map_and_generated():
    assert [t.id for t in AVAILABLE_WORLD_TEMPLATES] == ["test_map", "generated"]


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_generates_a_procedural_map_for_the_generated_template(registry, map_loader):
    generated_template = next(t for t in AVAILABLE_WORLD_TEMPLATES if t.id == "generated")
    world = build_world_from_template(generated_template, registry, map_loader, seed=42)
    assert "generated" in world.maps
    generated_map = world.maps["generated"]
    assert (generated_map.width, generated_map.height) == (GENERATED_WORLD_SIZE, GENERATED_WORLD_SIZE)
    assert world.entities == {}


def test_build_world_from_template_generation_is_deterministic_for_the_same_seed(registry, map_loader):
    generated_template = next(t for t in AVAILABLE_WORLD_TEMPLATES if t.id == "generated")
    world_a = build_world_from_template(generated_template, registry, map_loader, seed=7)
    world_b = build_world_from_template(generated_template, registry, map_loader, seed=7)
    map_a, map_b = world_a.maps["generated"], world_b.maps["generated"]
    for y in range(map_a.height):
        for x in range(map_a.width):
            assert map_a.get_tile(x, y, 0).layer_id("flooring") == map_b.get_tile(x, y, 0).layer_id("flooring")


# --- find_spawn_position -------------------------------------------------------------------------


def test_find_spawn_position_lands_on_a_walkable_dry_tile(registry, map_loader):
    template = AVAILABLE_WORLD_TEMPLATES[0]
    world = build_world_from_template(template, registry, map_loader)
    position = find_spawn_position(world.maps["harbor_world"], registry)
    assert position is not None
    tile = world.maps["harbor_world"].get_tile(position.x, position.y, position.z)
    assert tile.is_walkable(registry) is True
    assert tile.roof is None
    assert tile.layer_id("flooring") != "water"


def test_find_spawn_position_works_on_a_generated_map(registry, map_loader):
    generated_template = next(t for t in AVAILABLE_WORLD_TEMPLATES if t.id == "generated")
    world = build_world_from_template(generated_template, registry, map_loader, seed=42)
    position = find_spawn_position(world.maps["generated"], registry)
    assert position is not None
    assert position.map_id == "generated"