"""File watcher for Python source files."""

from __future__ import annotations

import asyncio

import logging

from collections.abc import Callable

from watchfiles import PythonFilter, awatch

logger = logging.getLogger(__name__)

async def watch_python_files(

on_change: Callable[[list[str]], None],

stop_event: asyncio.Event,

) -> None:

"""Watch for Python file changes in the current directory.

Uses watchfiles which already ignores .venv, __pycache__, node_modules, .git.

PythonFilter restricts to .py / .pyx files only.

"""

try:

async for changes in awatch(

".", watch_filter=PythonFilter(), stop_event=stop_event

):

changed_files = [str(path) for _, path in changes]

logger.debug("Detected file changes: %s", changed_files)

on_change(changed_files)

except Exception:

if not stop_event.is_set():

logger.exception("File watcher error")