"""Structured JSON logging.

Every log record is a single JSON line. Anything related to a job carries the
job_id so the whole conversion can be reconstructed from the log.
"""

import json
import logging
import sys
from contextvars import ContextVar

current_job_id: ContextVar[str | None] = ContextVar("current_job_id", default=None)

_RESERVED = {
    "args", "asctime", "created", "exc_info", "exc_text", "filename", "funcName",
    "levelname", "levelno", "lineno", "module", "msecs", "message", "msg", "name",
    "pathname", "process", "processName", "relativeCreated", "stack_info",
    "thread", "threadName", "taskName",
}


class JsonFormatter(logging.Formatter):
    def format(self, record: logging.LogRecord) -> str:
        payload: dict[str, object] = {
            "ts": self.formatTime(record, "%Y-%m-%dT%H:%M:%S%z"),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }

        job_id = getattr(record, "job_id", None) or current_job_id.get()
        if job_id:
            payload["job_id"] = job_id

        for key, value in record.__dict__.items():
            if key not in _RESERVED and not key.startswith("_") and key != "job_id":
                payload[key] = value

        if record.exc_info:
            payload["exception"] = self.formatException(record.exc_info)

        return json.dumps(payload, ensure_ascii=False, default=str)


def setup_logging(level: str) -> None:
    handler = logging.StreamHandler(sys.stdout)
    handler.setFormatter(JsonFormatter())

    root = logging.getLogger()
    root.handlers.clear()
    root.addHandler(handler)
    root.setLevel(getattr(logging, level, logging.INFO))

    # uvicorn keeps its own handlers, route them through ours as well
    for name in ("uvicorn", "uvicorn.access", "uvicorn.error"):
        logger = logging.getLogger(name)
        logger.handlers.clear()
        logger.propagate = True