from __future__ import annotations

import io
import json
import logging

from quartermaster.logging_config import LOG_CONFIG


def _build_formatter():
    """Instantiate the JSON formatter from LOG_CONFIG for direct testing."""
    from pydoc import locate

    cfg = dict(LOG_CONFIG["formatters"]["json"])
    factory_path = cfg.pop("()")
    factory = locate(factory_path)
    assert factory is not None, f"formatter factory not importable: {factory_path}"
    return factory(**cfg)


def test_log_config_emits_json_with_required_fields():
    formatter = _build_formatter()
    stream = io.StringIO()
    handler = logging.StreamHandler(stream)
    handler.setFormatter(formatter)

    logger = logging.getLogger("tests.logging_smoke")
    logger.handlers = [handler]
    logger.propagate = False
    logger.setLevel(logging.INFO)

    logger.info("smoke message", extra={"event": "smoke"})

    line = stream.getvalue().strip()
    assert line, "formatter produced no output"
    payload = json.loads(line)

    assert payload["event"] == "smoke"
    assert payload["level"] == "INFO"
    assert payload["logger"] == "tests.logging_smoke"
    assert payload["message"] == "smoke message"
    assert "timestamp" in payload