"""env_loader: load the nearest .env without clobbering real env vars."""
import os

from proteus.env_loader import find_dotenv, load_dotenv


def test_loads_keys_without_overriding_existing(tmp_path, monkeypatch):
    (tmp_path / ".env").write_text(
        "# provider keys\n"
        "OLLAMA_API_KEY=from_dotenv\n"
        'OPENAI_API_KEY="quoted_value"\n'
        "export ANTHROPIC_API_KEY=exported_style  # inline note\n"
        "ALREADY_SET=should_not_win\n"
    )
    # Isolate os.environ to a throwaway dict so load_dotenv (which mutates the
    # global environment) can't leak provider keys into later tests.
    monkeypatch.setattr(os, "environ", {"ALREADY_SET": "real_env"})

    loaded = load_dotenv(start=tmp_path)
    assert loaded == str(tmp_path / ".env")
    assert os.environ["OLLAMA_API_KEY"] == "from_dotenv"
    assert os.environ["OPENAI_API_KEY"] == "quoted_value"          # quotes stripped
    assert os.environ["ANTHROPIC_API_KEY"] == "exported_style"     # export + inline comment handled
    assert os.environ["ALREADY_SET"] == "real_env"                 # not overridden


def test_finds_dotenv_walking_up(tmp_path):
    (tmp_path / ".env").write_text("K=v\n")
    deep = tmp_path / "a" / "b" / "c"
    deep.mkdir(parents=True)
    assert find_dotenv(start=deep) == tmp_path / ".env"            # walks up to the root .env


def test_returns_none_when_absent(tmp_path):
    assert load_dotenv(start=tmp_path) is None