import logging
import os
import threading

from pythonjsonlogger.json import JsonFormatter

_VALID_LEVELS = {"DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"}
_FORMAT = "%(asctime)s %(name)s %(levelname)s %(message)s"
_NOISY_LOGGERS = ("urllib3", "httpx", "httpcore", "asyncio", "multipart")
_UVICORN_LOGGERS = ("uvicorn", "uvicorn.error", "uvicorn.access")

_lock = threading.Lock()
_configured = False


def _resolve_level() -> tuple[str, bool]:
	"""Return (level_name, was_valid). Falls back to INFO if invalid."""
	raw = os.getenv("LOG_LEVEL", "INFO").upper()
	return (raw, True) if raw in _VALID_LEVELS else ("INFO", False)


# Kept for backwards compatibility with `from simple_logger_handler import LOG_LEVEL`
LOG_LEVEL, _ = _resolve_level()


def _build_formatter() -> logging.Formatter:
	if os.getenv("LOG_FORMAT", "json").lower() == "text":
		return logging.Formatter(_FORMAT)  # readable output for local development
	return JsonFormatter(_FORMAT)


def configure_logging(*, force: bool = False) -> None:
	"""Configure the root logger once. Safe to call repeatedly and from threads.

	Environment variables:
		LOG_LEVEL   DEBUG | INFO | WARNING | ERROR | CRITICAL  (default INFO)
		LOG_FORMAT  json | text                                (default json)
	"""
	global _configured
	with _lock:
		if _configured and not force:
			return

		level, valid = _resolve_level()
		root = logging.getLogger()

		# Remove only handlers we added earlier, so we never clobber
		# handlers installed by pytest, Sentry, etc.
		for h in list(root.handlers):
			if getattr(h, "_shared_handler", False):
				root.removeHandler(h)

		handler = logging.StreamHandler()
		handler.setFormatter(_build_formatter())
		handler._shared_handler = True  # marker for idempotency
		root.addHandler(handler)
		root.setLevel(level)

		for name in _NOISY_LOGGERS:
			logging.getLogger(name).setLevel(max(logging.WARNING, root.level))

		_configured = True

		if not valid:
			root.warning("Invalid LOG_LEVEL %r, falling back to INFO",
						os.getenv("LOG_LEVEL"))


def adopt_uvicorn_loggers() -> None:
	"""Route uvicorn's logs through the root handler (same format as everything else).

	Uvicorn installs its own handlers at startup, so call this from your app's
	lifespan, which runs after uvicorn has configured itself.
	"""
	for name in _UVICORN_LOGGERS:
		lg = logging.getLogger(name)
		lg.handlers.clear()
		lg.setLevel(logging.NOTSET)  # inherit from root
		lg.propagate = True


def setup_logger(name: str) -> logging.Logger:
	"""Return a named logger, ensuring logging is configured."""
	configure_logging()
	return logging.getLogger(name)