import logging
from logging.handlers import RotatingFileHandler
from pathlib import Path


def configure_logging(log_file: Path) -> None:
    """Configure console and file logging once for local service runs."""
    log_file.parent.mkdir(parents=True, exist_ok=True)
    root_logger = logging.getLogger()
    root_logger.setLevel(logging.INFO)

    if not _has_handler("signalscout-console"):
        # Console logs are for the terminal window that runs `make run`.
        console_handler = logging.StreamHandler()
        console_handler.name = "signalscout-console"
        console_handler.setFormatter(_formatter())
        root_logger.addHandler(console_handler)

    if not _has_handler("signalscout-file"):
        # File logs persist agent failures after the terminal scrollback is gone.
        file_handler = RotatingFileHandler(
            log_file,
            maxBytes=2_000_000,
            backupCount=3,
            encoding="utf-8",
        )
        file_handler.name = "signalscout-file"
        file_handler.setFormatter(_formatter())
        root_logger.addHandler(file_handler)


def _formatter() -> logging.Formatter:
    # Include module name so source, API, and runner failures are easy to separate.
    return logging.Formatter("%(asctime)s %(levelname)s [%(name)s] %(message)s")


def _has_handler(name: str) -> bool:
    # Uvicorn imports the app during startup, so handlers must be idempotent.
    return any(handler.name == name for handler in logging.getLogger().handlers)