import json
import logging
from datetime import UTC, datetime

try:
    # For module mode: `uvicorn app.main:app`
    from app.settings import settings
except ModuleNotFoundError:
    # For script mode: `python app/main.py` or VS Code "Run Python File"
    from settings import settings


_CONFIGURED = False


class JsonFormatter(logging.Formatter):
    def format(self, record: logging.LogRecord) -> str:
        payload: dict[str, object] = {
            "timestamp": datetime.now(UTC).isoformat(),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }

        for key in (
            "event",
            "request_id",
            "method",
            "path",
            "status_code",
            "duration_ms",
            "client_ip",
            "user_id",
            "conversation_id",
            "message_id",
            "seq",
            "client_msg_id",
            "idempotent",
            "count",
            "has_more",
            "cursor_seq",
            "limit",
            "reason",
            "sql_ms",
            "statement",
            "username",
        ):
            if hasattr(record, key):
                payload[key] = getattr(record, key)

        if record.exc_info:
            payload["exception"] = self.formatException(record.exc_info)
        return json.dumps(payload, ensure_ascii=False)


def configure_logging() -> None:
    global _CONFIGURED
    if _CONFIGURED:
        return

    log_level_name = settings.log_level.upper().strip()
    log_level = getattr(logging, log_level_name, logging.INFO)

    handler = logging.StreamHandler()
    if settings.log_json:
        handler.setFormatter(JsonFormatter())
    else:
        handler.setFormatter(
            logging.Formatter(
                fmt="%(asctime)s | %(levelname)s | %(name)s | %(message)s",
            )
        )

    root_logger = logging.getLogger()
    root_logger.handlers.clear()
    root_logger.setLevel(log_level)
    root_logger.addHandler(handler)

    # Keep uvicorn logs consistent with app logs.
    for logger_name in ("uvicorn", "uvicorn.error", "uvicorn.access"):
        uvicorn_logger = logging.getLogger(logger_name)
        uvicorn_logger.handlers.clear()
        uvicorn_logger.propagate = True
    logging.getLogger("httpx").setLevel(logging.WARNING)

    _CONFIGURED = True