"""Structured logging: console + per-run JSONL file under logs/."""

from __future__ import annotations

import json
import logging
import sys
import time
from pathlib import Path


class JsonlHandler(logging.Handler):
    def __init__(self, path: Path):
        super().__init__()
        path.parent.mkdir(parents=True, exist_ok=True)
        self._f = open(path, "a")

    def emit(self, record: logging.LogRecord) -> None:
        entry = {
            "ts": time.strftime("%Y-%m-%dT%H:%M:%S%z"),
            "level": record.levelname,
            "name": record.name,
            "msg": record.getMessage(),
        }
        if hasattr(record, "extra_fields"):
            entry.update(record.extra_fields)
        self._f.write(json.dumps(entry) + "\n")
        self._f.flush()


def get_logger(name: str, logfile: Path | None = None) -> logging.Logger:
    logger = logging.getLogger(name)
    if logger.handlers:
        return logger
    logger.setLevel(logging.INFO)
    sh = logging.StreamHandler(sys.stderr)
    sh.setFormatter(logging.Formatter("%(asctime)s %(levelname)s %(name)s: %(message)s"))
    logger.addHandler(sh)
    if logfile is not None:
        logger.addHandler(JsonlHandler(logfile))
    return logger