"""Logging to stderr (stdout is the protocol channel in stdio mode)."""

from __future__ import annotations

import json
import logging
import sys
from datetime import UTC, datetime


class JsonFormatter(logging.Formatter):
    """One JSON object per line, for log aggregation."""

    def format(self, record: logging.LogRecord) -> str:
        entry = {
            "time": datetime.fromtimestamp(record.created, tz=UTC).isoformat(timespec="milliseconds"),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }
        if record.exc_info:
            entry["exception"] = self.formatException(record.exc_info)
        return json.dumps(entry, ensure_ascii=False)


def setup_logging(level: str = "INFO", fmt: str = "text") -> None:
    handler = logging.StreamHandler(sys.stderr)
    if fmt == "json":
        handler.setFormatter(JsonFormatter())
    else:
        handler.setFormatter(logging.Formatter("%(asctime)s %(levelname)-7s %(name)s: %(message)s"))
    logging.basicConfig(level=level.upper(), handlers=[handler], force=True)
    # The SDK logs every request at INFO; keep it quieter unless debugging.
    if level.upper() != "DEBUG":
        for noisy in ("mcp.server.lowlevel.server", "mcp.server.streamable_http", "mcp.server.streamable_http_manager"):
            logging.getLogger(noisy).setLevel(logging.WARNING)