"""
Structured logging helper for Netdata.

Netdata does not expose a generic "push a log line" API reachable with
just a room token from outside an Agent (see credentials.py). Until a
real push mechanism (StatsD or an OpenTelemetry log receiver) is
confirmed enabled on the agent, the supported path is the standard one:
emit structured JSON lines to stdout, which Netdata's log collectors
(systemd-journal / generic log source) are built to tail and parse.
"""
import logging
import sys

from pythonjsonlogger import jsonlogger

from .credentials import netdata

_LOGGER_NAME = "netdata"


def get_netdata_logger() -> logging.Logger:
    logger = logging.getLogger(_LOGGER_NAME)

    if not logger.handlers:
        handler = logging.StreamHandler(stream=sys.stdout)
        handler.setFormatter(
            jsonlogger.JsonFormatter("%(asctime)s %(levelname)s %(name)s %(message)s")
        )
        logger.addHandler(handler)
        logger.setLevel(logging.INFO)
        logger.propagate = False

    return logger


def log_event(message, level="info", **fields):
    """Log a structured event intended to be picked up by Netdata.

    Extra keyword arguments are attached as structured fields on the JSON
    log line, e.g. log_event("hello world", source="netdata_logging.hello").
    """
    logger = get_netdata_logger()
    log_fn = getattr(logger, level.lower(), logger.info)
    log_fn(message, extra={"netdata_agent_host": netdata.agent_host, **fields})