"""Test registry module."""

from collections.abc import Callable, Generator
import threading
from typing import Any

import pytest

from asusrouter.registry import ARCallableRegistry as ARCallReg


@pytest.fixture(autouse=True)
def clear_registry() -> Generator[None, None, None]:
    """Ensure tests start with a clean registry state."""

    ARCallReg.clear()
    yield
    ARCallReg.clear()


def test_register_and_get_callable_by_instance_and_class() -> None:
    """Test registering and retrieving callables by instance and class."""

    class Base:
        pass

    class Child(Base):
        pass

    def base_get(s: Any) -> str:
        return "base"

    # register using kwargs API
    ARCallReg.register(Base, get_state=base_get)

    # lookup by instance
    fn = ARCallReg.get_callable(Child(), "get_state")
    assert fn is base_get
    assert fn is not None
    assert fn(Child()) == "base"

    # lookup by class
    fn2 = ARCallReg.get_callable(Child, "get_state")
    assert fn2 is base_get


def test_get_all_for_merges_mro_correctly() -> None:
    """Test that get_all_for merges MRO correctly."""

    class A:
        pass

    class B(A):
        pass

    def a_get(s: Any) -> str:
        return "a"

    def b_get(s: Any) -> str:
        return "b"

    def a_set(s: Any, v: Any) -> tuple[str, Any]:
        return ("a-set", v)

    ARCallReg.register(A, get_state=a_get, set_state=a_set)
    ARCallReg.register(B, get_state=b_get)

    merged = ARCallReg.get_all_for(B())
    # B overrides get_state, but inherits set_state from A
    assert merged["get_state"] is b_get
    assert merged["set_state"] is a_set


def test_unregister_and_clear() -> None:
    """Test unregistering and clearing the registry."""

    class S:
        pass

    def fn(s: Any) -> str:
        return "ok"

    ARCallReg.register(S, get_state=fn)
    assert ARCallReg.get_callable(S(), "get_state") is fn

    ARCallReg.unregister(S)
    assert ARCallReg.get_callable(S(), "get_state") is None

    # re-register and then clear everything
    ARCallReg.register(S, get_state=fn)
    ARCallReg.clear()
    assert ARCallReg.get_callable(S(), "get_state") is None


def test_get_callable_returns_none_when_missing() -> None:
    """Test that get_callable returns None when no callable is found."""

    class X:
        pass

    assert ARCallReg.get_callable(X(), "nope") is None
    assert ARCallReg.get_all_for(X()) == {}


def test_concurrent_registers_are_thread_safe() -> None:
    """Test that concurrent registrations are thread-safe."""

    class Root:
        pass

    def make_fn(i: int) -> Callable[[Any], int]:
        """Create a function that returns the given integer."""

        def f(s: Any) -> int:
            """Return the given integer."""

            return i

        return f

    def worker(i: int) -> None:
        """Register a function in the ARCallableRegistry."""

        ARCallReg.register(Root, **{f"fn{i}": make_fn(i)})

    threads = [threading.Thread(target=worker, args=(i,)) for i in range(8)]
    for t in threads:
        t.start()
    for t in threads:
        t.join()

    all_map = ARCallReg.get_all_for(Root())
    # expect all registered names to be present
    for i in range(8):
        key = f"fn{i}"
        assert key in all_map
        assert callable(all_map[key])