import pytest

from engine.entity import Entity, EntityPosition
from engine.map import Map
from engine.tile import Tile, TileLayerDef, TileLayerInstance
from engine.world import World


class FakeRegistry:
    def get_tile_layer_def(self, layer, def_id):
        if layer == "room" and def_id == "stairs_up":
            return TileLayerDef(id="stairs_up", layer="room", walkable=True, staircase_direction="up")
        if layer == "room" and def_id == "stairs_down":
            return TileLayerDef(id="stairs_down", layer="room", walkable=True, staircase_direction="down")
        if layer == "room" and def_id == "wood_wall":
            return TileLayerDef(id="wood_wall", layer="room", walkable=False)
        return None


def make_two_story_map():
    tower = Map("tower", 3, 3, 2)
    for x in range(3):
        for y in range(3):
            for z in range(2):
                tower.set_tile(x, y, z, Tile(flooring=TileLayerInstance("wood_deck")))
    tower.get_tile(1, 1, 0).room = TileLayerInstance("stairs_up")
    tower.get_tile(1, 1, 1).room = TileLayerInstance("stairs_down")

    world = World(registry=FakeRegistry())
    world.add_map(tower)
    return world, tower


def test_tile_staircase_direction_reads_room_layer():
    tower = make_two_story_map()[1]
    registry = FakeRegistry()
    assert tower.get_tile(1, 1, 0).staircase_direction(registry) == "up"
    assert tower.get_tile(1, 1, 1).staircase_direction(registry) == "down"
    assert tower.get_tile(0, 0, 0).staircase_direction(registry) is None


def test_walking_onto_stairs_up_carries_entity_to_next_floor():
    world, _tower = make_two_story_map()
    player = Entity(position=EntityPosition("tower", 0, 1, 0))
    assert world.try_move(player, 1, 0, 0) is True
    assert (player.position.x, player.position.y, player.position.z) == (1, 1, 1)


def test_walking_onto_stairs_down_carries_entity_to_floor_below():
    world, _tower = make_two_story_map()
    player = Entity(position=EntityPosition("tower", 0, 1, 1))
    assert world.try_move(player, 1, 0, 0) is True
    assert (player.position.x, player.position.y, player.position.z) == (1, 1, 0)


def test_landing_on_staircase_does_not_cascade_further():
    # standing on the stairs_down tile at z=1 doesn't repeatedly bounce back down on each call
    world, _tower = make_two_story_map()
    player = Entity(position=EntityPosition("tower", 1, 1, 1))
    # a no-op self-check: player is already there; simulate a step off and back via two moves
    assert world.try_move(player, 1, 0, 0) is True  # off the stairs, to (2,1,1)
    assert player.position.z == 1
    assert world.try_move(player, -1, 0, 0) is True  # back onto stairs_down at (1,1,1)
    assert player.position.z == 0  # single hop down, landed on ground floor


def test_staircase_at_top_floor_edge_does_not_crash_or_move_out_of_bounds():
    tower = Map("tower", 3, 3, 1)  # only one floor - "up" has nowhere to go
    for x in range(3):
        for y in range(3):
            tower.set_tile(x, y, 0, Tile(flooring=TileLayerInstance("wood_deck")))
    tower.get_tile(1, 1, 0).room = TileLayerInstance("stairs_up")
    world = World(registry=FakeRegistry())
    world.add_map(tower)

    player = Entity(position=EntityPosition("tower", 0, 1, 0))
    assert world.try_move(player, 1, 0, 0) is True
    assert (player.position.x, player.position.y, player.position.z) == (1, 1, 0)  # stayed put, no crash


def test_staircase_blocked_if_target_floor_tile_unwalkable():
    world, tower = make_two_story_map()
    tower.get_tile(1, 1, 1).room = TileLayerInstance("wood_wall")  # block the landing spot above
    player = Entity(position=EntityPosition("tower", 0, 1, 0))
    assert world.try_move(player, 1, 0, 0) is True  # the horizontal step itself still succeeds
    assert (player.position.x, player.position.y, player.position.z) == (1, 1, 0)  # but no ascent


def test_continuous_move_onto_staircase_also_transitions_floor():
    world, _tower = make_two_story_map()
    player = Entity(position=EntityPosition("tower", 0.3, 1.4, 0))
    assert world.try_move_continuous(player, 1, 0, 0, distance=0.8) is True
    assert player.position.z == 1
    assert player.position.x == pytest.approx(1.1)
    assert player.position.y == pytest.approx(1.4)