"""Settings.from_env. Contract: semif-serve.contract.md § Configuration, INV-6."""
import json

import pytest

from semif_serve.config import DEFAULT_REVISION, Settings

TOKEN = "t" * 40


def test_defaults_from_a_minimal_env():
    s = Settings.from_env({"SEMIF_API_TOKEN": TOKEN})
    assert (s.api_token, s.revision, s.device, s.max_tokens, s.max_decisions) == (TOKEN, DEFAULT_REVISION, "cuda", 4096, 64)
    assert s.vram_cap_gib is None and s.calibration == {}


@pytest.mark.parametrize("env", [{}, {"SEMIF_API_TOKEN": "short"}, {"SEMIF_API_TOKEN": "x" * 31}])
def test_a_missing_or_short_token_is_refused_at_startup(env):
    with pytest.raises(ValueError, match="SEMIF_API_TOKEN"):
        Settings.from_env(env)


def test_numbers_and_calibration_file_are_parsed(tmp_path):
    cal = tmp_path / "cal.json"
    cal.write_text(json.dumps({"triage": 2.5}))
    s = Settings.from_env({"SEMIF_API_TOKEN": TOKEN, "SEMIF_VRAM_CAP_GIB": "12", "SEMIF_MAX_DECISIONS": "8",
                           "SEMIF_CALIBRATION": str(cal)})
    assert (s.vram_cap_gib, s.max_decisions, s.calibration) == (12.0, 8, {"triage": 2.5})


@pytest.mark.parametrize("table", [{"w": 0}, {"w": -1.0}, {"w": "2"}, {"w": float("inf")}, ["w", 2.0]])
def test_a_calibration_table_needs_positive_finite_numbers(tmp_path, table):
    cal = tmp_path / "cal.json"
    cal.write_text(json.dumps(table))
    with pytest.raises(ValueError, match="SEMIF_CALIBRATION"):
        Settings.from_env({"SEMIF_API_TOKEN": TOKEN, "SEMIF_CALIBRATION": str(cal)})