import os

from fam_core.config_loader import _resolve_env_vars


def test_resolves_string_env_var(monkeypatch):
    monkeypatch.setenv("FAM_CORE_TEST_VAR", "hello")
    assert _resolve_env_vars("${FAM_CORE_TEST_VAR}") == "hello"


def test_unset_env_var_left_as_literal():
    assert _resolve_env_vars("${SOME_TOTALLY_UNSET_VAR_XYZ}") == "${SOME_TOTALLY_UNSET_VAR_XYZ}"


def test_resolves_nested_dict(monkeypatch):
    monkeypatch.setenv("FAM_CORE_TEST_VAR", "secret")
    data = {"a": {"b": "${FAM_CORE_TEST_VAR}"}, "c": ["${FAM_CORE_TEST_VAR}", "plain"]}
    out = _resolve_env_vars(data)
    assert out == {"a": {"b": "secret"}, "c": ["secret", "plain"]}


def test_non_string_values_passed_through():
    assert _resolve_env_vars(42) == 42
    assert _resolve_env_vars(True) is True
    assert _resolve_env_vars(None) is None