package filewatcher

import (
	"context"
	"path"

	"github.com/fsnotify/fsnotify"
	"github.com/sirupsen/logrus"
)

// Watch creates file system monitoring for the given file and runs the callback on changes.
func Watch(ctx context.Context, filepath string, callback func(watcher *fsnotify.Watcher)) {
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		logrus.Fatalf("could not create file watcher: %v", err)
	}

	defer func(watcher *fsnotify.Watcher) {
		_ = watcher.Close()

		logrus.Infof("stopped watching for %s changes", filepath)
	}(watcher)

	go callback(watcher)

	err = watcher.Add(path.Dir(filepath))
	if err != nil {
		logrus.Fatalf("could not watch %s: %v", filepath, err)
	}

	logrus.Infof("watching for changes on %s", filepath)

	<-ctx.Done()
	logrus.Infof("ending background tasks for %s", filepath)
}