import logging
import os
import sys

_LOGGER_NAMESPACE = "o11y_mcp_server"


def configure_logging() -> None:
    level_name = (os.getenv("MCP_SERVER_LOG_LEVEL") or "INFO").upper()
    level = getattr(logging, level_name, logging.INFO)
    formatter = logging.Formatter("%(asctime)s %(levelname)s %(name)s %(message)s")
    root = logging.getLogger(_LOGGER_NAMESPACE)
    if not root.handlers:
        handler = logging.StreamHandler(sys.stderr)
        handler.setFormatter(formatter)
        root.addHandler(handler)
    log_file = os.getenv("MCP_SERVER_LOG_FILE")
    if log_file and not any(isinstance(h, logging.FileHandler) for h in root.handlers):
        file_handler = logging.FileHandler(log_file)
        file_handler.setFormatter(formatter)
        root.addHandler(file_handler)
    root.setLevel(level)


def get_logger(name: str) -> logging.Logger:
    configure_logging()
    return logging.getLogger(f"{_LOGGER_NAMESPACE}.{name}")