"""
Demeter Server — Logging Configuration

Sets up structured logging with optional Loki integration.
Falls back to console-only logging if Loki is unreachable.
"""

from __future__ import annotations

import logging
import sys
from typing import Optional


def setup_logging(loki_url: Optional[str] = None, debug: bool = False) -> None:
    """
    Configure logging for the Demeter server.

    Args:
        loki_url: Loki push endpoint (e.g., "http://localhost:3100/loki/api/v1/push").
                  If None, logs go to console only.
        debug: Enable DEBUG level logging.
    """
    level = logging.DEBUG if debug else logging.INFO

    # Root logger
    root = logging.getLogger()
    root.setLevel(level)

    # Console handler
    console = logging.StreamHandler(sys.stdout)
    console.setLevel(level)
    fmt = logging.Formatter(
        "[%(asctime)s] %(levelname)-8s %(name)s — %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )
    console.setFormatter(fmt)
    root.addHandler(console)

    # Loki handler (optional)
    if loki_url:
        try:
            import logging_loki

            loki_handler = logging_loki.LokiHandler(
                url=loki_url,
                tags={"app": "demeter-server"},
                version="1",
            )
            loki_handler.setLevel(level)
            root.addHandler(loki_handler)
            logging.getLogger(__name__).info("Loki logging enabled at %s", loki_url)
        except ImportError:
            logging.getLogger(__name__).warning(
                "python-logging-loki not installed, Loki logging disabled"
            )
        except Exception as e:
            logging.getLogger(__name__).warning(
                "Failed to connect to Loki at %s: %s", loki_url, e
            )

    # Quiet noisy libraries
    logging.getLogger("aiocoap").setLevel(logging.WARNING)
    logging.getLogger("uvicorn.access").setLevel(logging.WARNING)