"""Tests for the backend profile skeleton (D2)."""

import pytest

from portfolio_optimiser.backends import (
    AzureFoundryBackend,
    ChatBackend,
    LocalBackend,
    Profile,
    get_backend,
)


def test_get_backend_by_string() -> None:
    assert isinstance(get_backend("azure"), AzureFoundryBackend)
    assert isinstance(get_backend("local"), LocalBackend)


def test_get_backend_by_enum() -> None:
    assert get_backend(Profile.AZURE).profile is Profile.AZURE
    assert get_backend(Profile.LOCAL).profile is Profile.LOCAL


def test_backends_satisfy_seam() -> None:
    # Structural conformance to the ChatBackend Protocol (the D2 seam).
    assert isinstance(get_backend("azure"), ChatBackend)
    assert isinstance(get_backend("local"), ChatBackend)


def test_unknown_profile_fails_fast() -> None:
    with pytest.raises(ValueError):
        get_backend("on-prem")


@pytest.mark.parametrize("profile", ["azure", "local"])
def test_create_chat_client_is_skeleton(profile: str) -> None:
    # Fase 0: the seam is defined but not wired — must fail loudly, not silently.
    with pytest.raises(NotImplementedError):
        get_backend(profile).create_chat_client(model="dummy-model")