import time
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler
from pathlib import Path


class FileChangeHandler(FileSystemEventHandler):
    def __init__(self, callback=None):
        self.callback = callback

    def on_modified(self, event):
        if not event.is_directory:
            if self.callback:
                self.callback(event.src_path)
            print(f"[Watcher] Datei geändert: {event.src_path}")


def start_watcher(path: Path, callback=None):
    """Startet den File-Watcher in einem Hintergrundthread."""
    event_handler = FileChangeHandler(callback=callback)
    observer = Observer()
    observer.schedule(event_handler, str(path), recursive=True)
    observer.start()

    return observer